| Message ID | 20230515161339.631577-9-konstantin.meskhidze@huawei.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | Network support for Landlock | expand |
On 15/05/2023 18:13, Konstantin Meskhidze wrote: > This commit adds network rules support in the ruleset management > helpers and the landlock_create_ruleset syscall. > Refactor user space API to support network actions. Add new network > access flags, network rule and network attributes. Increment Landlock > ABI version. Expand access_masks_t to u32 to be sure network access > rights can be stored. Implement socket_bind() and socket_connect() > LSM hooks, which enables to restrict TCP socket binding and connection > to specific ports. > > Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net> > Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com> > --- > > Changes since v10: > * Removes "packed" attribute. > * Applies Mickaёl's patch with some refactoring. > * Deletes get_port() and check_addrlen() helpers. > * Refactors check_socket_access() by squashing get_port() and > check_addrlen() helpers into it. > * Fixes commit message. > > Changes since v9: > * Changes UAPI port field to __u64. > * Moves shared code into check_socket_access(). > * Adds get_raw_handled_net_accesses() and > get_current_net_domain() helpers. > * Minor fixes. > > Changes since v8: > * Squashes commits. > * Refactors commit message. > * Changes UAPI port field to __be16. > * Changes logic of bind/connect hooks with AF_UNSPEC families. > * Adds address length checking. > * Minor fixes. > > Changes since v7: > * Squashes commits. > * Increments ABI version to 4. > * Refactors commit message. > * Minor fixes. > > Changes since v6: > * Renames landlock_set_net_access_mask() to landlock_add_net_access_mask() > because it OR values. > * Makes landlock_add_net_access_mask() more resilient incorrect values. > * Refactors landlock_get_net_access_mask(). > * Renames LANDLOCK_MASK_SHIFT_NET to LANDLOCK_SHIFT_ACCESS_NET and use > LANDLOCK_NUM_ACCESS_FS as value. > * Updates access_masks_t to u32 to support network access actions. > * Refactors landlock internal functions to support network actions with > landlock_key/key_type/id types. > > Changes since v5: > * Gets rid of partial revert from landlock_add_rule > syscall. > * Formats code with clang-format-14. > > Changes since v4: > * Refactors landlock_create_ruleset() - splits ruleset and > masks checks. > * Refactors landlock_create_ruleset() and landlock mask > setters/getters to support two rule types. > * Refactors landlock_add_rule syscall add_rule_path_beneath > function by factoring out get_ruleset_from_fd() and > landlock_put_ruleset(). > > Changes since v3: > * Splits commit. > * Adds network rule support for internal landlock functions. > * Adds set_mask and get_mask for network. > * Adds rb_root root_net_port. > > --- > include/uapi/linux/landlock.h | 48 +++++ > security/landlock/Kconfig | 1 + > security/landlock/Makefile | 2 + > security/landlock/limits.h | 6 +- > security/landlock/net.c | 174 +++++++++++++++++++ > security/landlock/net.h | 26 +++ > security/landlock/ruleset.c | 52 +++++- > security/landlock/ruleset.h | 63 +++++-- > security/landlock/setup.c | 2 + > security/landlock/syscalls.c | 72 +++++++- > tools/testing/selftests/landlock/base_test.c | 2 +- > 11 files changed, 425 insertions(+), 23 deletions(-) > create mode 100644 security/landlock/net.c > create mode 100644 security/landlock/net.h > [...] > diff --git a/security/landlock/net.c b/security/landlock/net.c > new file mode 100644 > index 000000000000..f8d2be53ac0d > --- /dev/null > +++ b/security/landlock/net.c > @@ -0,0 +1,174 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Landlock LSM - Network management and hooks > + * > + * Copyright © 2022 Huawei Tech. Co., Ltd. > + * Copyright © 2022 Microsoft Corporation You can replace these dates with "2022-2023", and same for all your other "2022" I guess.
Complementary review: On 15/05/2023 18:13, Konstantin Meskhidze wrote: > This commit adds network rules support in the ruleset management > helpers and the landlock_create_ruleset syscall. > Refactor user space API to support network actions. Add new network > access flags, network rule and network attributes. Increment Landlock > ABI version. Expand access_masks_t to u32 to be sure network access > rights can be stored. Implement socket_bind() and socket_connect() > LSM hooks, which enables to restrict TCP socket binding and connection > to specific ports. > > Co-developed-by: Mickaël Salaün <mic@digikod.net> > Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com> > --- > > Changes since v10: > * Removes "packed" attribute. > * Applies Mickaёl's patch with some refactoring. > * Deletes get_port() and check_addrlen() helpers. > * Refactors check_socket_access() by squashing get_port() and > check_addrlen() helpers into it. > * Fixes commit message. > > Changes since v9: > * Changes UAPI port field to __u64. > * Moves shared code into check_socket_access(). > * Adds get_raw_handled_net_accesses() and > get_current_net_domain() helpers. > * Minor fixes. > > Changes since v8: > * Squashes commits. > * Refactors commit message. > * Changes UAPI port field to __be16. > * Changes logic of bind/connect hooks with AF_UNSPEC families. > * Adds address length checking. > * Minor fixes. > > Changes since v7: > * Squashes commits. > * Increments ABI version to 4. > * Refactors commit message. > * Minor fixes. > > Changes since v6: > * Renames landlock_set_net_access_mask() to landlock_add_net_access_mask() > because it OR values. > * Makes landlock_add_net_access_mask() more resilient incorrect values. > * Refactors landlock_get_net_access_mask(). > * Renames LANDLOCK_MASK_SHIFT_NET to LANDLOCK_SHIFT_ACCESS_NET and use > LANDLOCK_NUM_ACCESS_FS as value. > * Updates access_masks_t to u32 to support network access actions. > * Refactors landlock internal functions to support network actions with > landlock_key/key_type/id types. > > Changes since v5: > * Gets rid of partial revert from landlock_add_rule > syscall. > * Formats code with clang-format-14. > > Changes since v4: > * Refactors landlock_create_ruleset() - splits ruleset and > masks checks. > * Refactors landlock_create_ruleset() and landlock mask > setters/getters to support two rule types. > * Refactors landlock_add_rule syscall add_rule_path_beneath > function by factoring out get_ruleset_from_fd() and > landlock_put_ruleset(). > > Changes since v3: > * Splits commit. > * Adds network rule support for internal landlock functions. > * Adds set_mask and get_mask for network. > * Adds rb_root root_net_port. > > --- > include/uapi/linux/landlock.h | 48 +++++ > security/landlock/Kconfig | 1 + > security/landlock/Makefile | 2 + > security/landlock/limits.h | 6 +- > security/landlock/net.c | 174 +++++++++++++++++++ > security/landlock/net.h | 26 +++ > security/landlock/ruleset.c | 52 +++++- > security/landlock/ruleset.h | 63 +++++-- > security/landlock/setup.c | 2 + > security/landlock/syscalls.c | 72 +++++++- > tools/testing/selftests/landlock/base_test.c | 2 +- > 11 files changed, 425 insertions(+), 23 deletions(-) > create mode 100644 security/landlock/net.c > create mode 100644 security/landlock/net.h > > diff --git a/include/uapi/linux/landlock.h b/include/uapi/linux/landlock.h > index 81d09ef9aa50..93794759dad4 100644 > --- a/include/uapi/linux/landlock.h > +++ b/include/uapi/linux/landlock.h > @@ -31,6 +31,13 @@ struct landlock_ruleset_attr { > * this access right. > */ > __u64 handled_access_fs; > + Please remove this empty line. > + /** > + * @handled_access_net: Bitmask of actions (cf. `Network flags`_) > + * that is handled by this ruleset and should then be forbidden if no > + * rule explicitly allow them. > + */ > + __u64 handled_access_net; > }; > > /* > @@ -54,6 +61,11 @@ enum landlock_rule_type { > * landlock_path_beneath_attr . > */ > LANDLOCK_RULE_PATH_BENEATH = 1, > + /** > + * @LANDLOCK_RULE_NET_SERVICE: Type of a &struct > + * landlock_net_service_attr . > + */ > + LANDLOCK_RULE_NET_SERVICE = 2, > }; > > /** > @@ -79,6 +91,23 @@ struct landlock_path_beneath_attr { > */ > } __attribute__((packed)); > > +/** > + * struct landlock_net_service_attr - TCP subnet definition s/TCP subnet definition/Network service definition/ > + * > + * Argument of sys_landlock_add_rule(). > + */ > +struct landlock_net_service_attr { > + /** > + * @allowed_access: Bitmask of allowed access network for services > + * (cf. `Network flags`_). > + */ > + __u64 allowed_access; > + /** > + * @port: Network port. > + */ > + __u64 port; > +}; > + > /** > * DOC: fs_access > * > @@ -189,4 +218,23 @@ struct landlock_path_beneath_attr { > #define LANDLOCK_ACCESS_FS_TRUNCATE (1ULL << 14) > /* clang-format on */ > > +/** > + * DOC: net_access > + * > + * Network flags > + * ~~~~~~~~~~~~~~~~ > + * > + * These flags enable to restrict a sandboxed process to a set of network > + * actions. > + * > + * TCP sockets with allowed actions: > + * > + * - %LANDLOCK_ACCESS_NET_BIND_TCP: Bind a TCP socket to a local port. > + * - %LANDLOCK_ACCESS_NET_CONNECT_TCP: Connect an active TCP socket to > + * a remote port. > + */ > +/* clang-format off */ > +#define LANDLOCK_ACCESS_NET_BIND_TCP (1ULL << 0) > +#define LANDLOCK_ACCESS_NET_CONNECT_TCP (1ULL << 1) > +/* clang-format on */ > #endif /* _UAPI_LINUX_LANDLOCK_H */ > diff --git a/security/landlock/Kconfig b/security/landlock/Kconfig > index 8e33c4e8ffb8..10c099097533 100644 > --- a/security/landlock/Kconfig > +++ b/security/landlock/Kconfig > @@ -3,6 +3,7 @@ > config SECURITY_LANDLOCK > bool "Landlock support" > depends on SECURITY && !ARCH_EPHEMERAL_INODES > + select SECURITY_NETWORK > select SECURITY_PATH > help > Landlock is a sandboxing mechanism that enables processes to restrict > diff --git a/security/landlock/Makefile b/security/landlock/Makefile > index 7bbd2f413b3e..53d3c92ae22e 100644 > --- a/security/landlock/Makefile > +++ b/security/landlock/Makefile > @@ -2,3 +2,5 @@ obj-$(CONFIG_SECURITY_LANDLOCK) := landlock.o > > landlock-y := setup.o syscalls.o object.o ruleset.o \ > cred.o ptrace.o fs.o > + > +landlock-$(CONFIG_INET) += net.o > \ No newline at end of file > diff --git a/security/landlock/limits.h b/security/landlock/limits.h > index bafb3b8dc677..8a1a6463c64e 100644 > --- a/security/landlock/limits.h > +++ b/security/landlock/limits.h > @@ -23,6 +23,10 @@ > #define LANDLOCK_NUM_ACCESS_FS __const_hweight64(LANDLOCK_MASK_ACCESS_FS) > #define LANDLOCK_SHIFT_ACCESS_FS 0 > > -/* clang-format on */ > +#define LANDLOCK_LAST_ACCESS_NET LANDLOCK_ACCESS_NET_CONNECT_TCP > +#define LANDLOCK_MASK_ACCESS_NET ((LANDLOCK_LAST_ACCESS_NET << 1) - 1) > +#define LANDLOCK_NUM_ACCESS_NET __const_hweight64(LANDLOCK_MASK_ACCESS_NET) > +#define LANDLOCK_SHIFT_ACCESS_NET LANDLOCK_NUM_ACCESS_FS > > +/* clang-format on */ Please the empty line to make this patch clean. > #endif /* _SECURITY_LANDLOCK_LIMITS_H */ > diff --git a/security/landlock/net.c b/security/landlock/net.c > new file mode 100644 > index 000000000000..f8d2be53ac0d > --- /dev/null > +++ b/security/landlock/net.c > @@ -0,0 +1,174 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Landlock LSM - Network management and hooks > + * > + * Copyright © 2022 Huawei Tech. Co., Ltd. > + * Copyright © 2022 Microsoft Corporation > + */ > + > +#include <linux/in.h> > +#include <linux/net.h> > +#include <linux/socket.h> > +#include <net/ipv6.h> > + > +#include "common.h" > +#include "cred.h" > +#include "limits.h" > +#include "net.h" > +#include "ruleset.h" > + > +int landlock_append_net_rule(struct landlock_ruleset *const ruleset, > + const u16 port, access_mask_t access_rights) > +{ > + int err; > + const struct landlock_id id = { > + .key.data = (__force uintptr_t)htons(port), > + .type = LANDLOCK_KEY_NET_PORT, > + }; > + > + BUILD_BUG_ON(sizeof(port) > sizeof(id.key.data)); > + > + /* Transforms relative access rights to absolute ones. */ > + access_rights |= LANDLOCK_MASK_ACCESS_NET & > + ~landlock_get_net_access_mask(ruleset, 0); > + > + mutex_lock(&ruleset->lock); > + err = landlock_insert_rule(ruleset, id, access_rights); > + mutex_unlock(&ruleset->lock); > + > + return err; > +} > + > +static access_mask_t > +get_raw_handled_net_accesses(const struct landlock_ruleset *const domain) > +{ > + access_mask_t access_dom = 0; > + size_t layer_level; > + > + for (layer_level = 0; layer_level < domain->num_layers; layer_level++) > + access_dom |= landlock_get_net_access_mask(domain, layer_level); > + return access_dom; > +} > + > +static const struct landlock_ruleset *get_current_net_domain(void) > +{ > + const struct landlock_ruleset *const dom = > + landlock_get_current_domain(); > + > + if (!dom || !get_raw_handled_net_accesses(dom)) > + return NULL; > + > + return dom; > +} > + > +static int check_socket_access(struct socket *const sock, > + struct sockaddr *const address, > + const int addrlen, > + const access_mask_t access_request) > +{ > + __be16 port; > + layer_mask_t layer_masks[LANDLOCK_NUM_ACCESS_NET] = {}; > + const struct landlock_rule *rule; > + access_mask_t handled_access; > + struct landlock_id id = { > + .type = LANDLOCK_KEY_NET_PORT, > + }; > + const struct landlock_ruleset *const domain = get_current_net_domain(); > + > + if (WARN_ON_ONCE(!domain)) The WARN_ON_ONCE() needs to be removed for processes not sandboxed. This should be printed when running the tests. > + return 0; > + if (WARN_ON_ONCE(domain->num_layers < 1)) > + return -EACCES; > + > + /* Checks if it's a TCP socket. */ > + if (sock->type != SOCK_STREAM) > + return 0; > + > + /* Checks for minimal header length. */ > + if (addrlen < offsetofend(struct sockaddr, sa_family)) You can use "typeof(*address)" instead of struct sockaddr, this makes it easier to review. > + return -EINVAL; > + [...]
On 15/05/2023 18:13, Konstantin Meskhidze wrote: > This commit adds network rules support in the ruleset management > helpers and the landlock_create_ruleset syscall. > Refactor user space API to support network actions. Add new network > access flags, network rule and network attributes. Increment Landlock > ABI version. Expand access_masks_t to u32 to be sure network access > rights can be stored. Implement socket_bind() and socket_connect() > LSM hooks, which enables to restrict TCP socket binding and connection > to specific ports. > > Co-developed-by: Mickaël Salaün <mic@digikod.net> > Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com> > --- > > Changes since v10: > * Removes "packed" attribute. > * Applies Mickaёl's patch with some refactoring. > * Deletes get_port() and check_addrlen() helpers. > * Refactors check_socket_access() by squashing get_port() and > check_addrlen() helpers into it. > * Fixes commit message. > > Changes since v9: > * Changes UAPI port field to __u64. > * Moves shared code into check_socket_access(). > * Adds get_raw_handled_net_accesses() and > get_current_net_domain() helpers. > * Minor fixes. > > Changes since v8: > * Squashes commits. > * Refactors commit message. > * Changes UAPI port field to __be16. > * Changes logic of bind/connect hooks with AF_UNSPEC families. > * Adds address length checking. > * Minor fixes. > > Changes since v7: > * Squashes commits. > * Increments ABI version to 4. > * Refactors commit message. > * Minor fixes. > > Changes since v6: > * Renames landlock_set_net_access_mask() to landlock_add_net_access_mask() > because it OR values. > * Makes landlock_add_net_access_mask() more resilient incorrect values. > * Refactors landlock_get_net_access_mask(). > * Renames LANDLOCK_MASK_SHIFT_NET to LANDLOCK_SHIFT_ACCESS_NET and use > LANDLOCK_NUM_ACCESS_FS as value. > * Updates access_masks_t to u32 to support network access actions. > * Refactors landlock internal functions to support network actions with > landlock_key/key_type/id types. > > Changes since v5: > * Gets rid of partial revert from landlock_add_rule > syscall. > * Formats code with clang-format-14. > > Changes since v4: > * Refactors landlock_create_ruleset() - splits ruleset and > masks checks. > * Refactors landlock_create_ruleset() and landlock mask > setters/getters to support two rule types. > * Refactors landlock_add_rule syscall add_rule_path_beneath > function by factoring out get_ruleset_from_fd() and > landlock_put_ruleset(). > > Changes since v3: > * Splits commit. > * Adds network rule support for internal landlock functions. > * Adds set_mask and get_mask for network. > * Adds rb_root root_net_port. > > --- > include/uapi/linux/landlock.h | 48 +++++ > security/landlock/Kconfig | 1 + > security/landlock/Makefile | 2 + > security/landlock/limits.h | 6 +- > security/landlock/net.c | 174 +++++++++++++++++++ > security/landlock/net.h | 26 +++ > security/landlock/ruleset.c | 52 +++++- > security/landlock/ruleset.h | 63 +++++-- > security/landlock/setup.c | 2 + > security/landlock/syscalls.c | 72 +++++++- > tools/testing/selftests/landlock/base_test.c | 2 +- > 11 files changed, 425 insertions(+), 23 deletions(-) > create mode 100644 security/landlock/net.c > create mode 100644 security/landlock/net.h > > diff --git a/include/uapi/linux/landlock.h b/include/uapi/linux/landlock.h > index 81d09ef9aa50..93794759dad4 100644 > --- a/include/uapi/linux/landlock.h > +++ b/include/uapi/linux/landlock.h > @@ -31,6 +31,13 @@ struct landlock_ruleset_attr { > * this access right. > */ > __u64 handled_access_fs; > + > + /** > + * @handled_access_net: Bitmask of actions (cf. `Network flags`_) > + * that is handled by this ruleset and should then be forbidden if no > + * rule explicitly allow them. > + */ > + __u64 handled_access_net; > }; > > /* > @@ -54,6 +61,11 @@ enum landlock_rule_type { > * landlock_path_beneath_attr . > */ > LANDLOCK_RULE_PATH_BENEATH = 1, > + /** > + * @LANDLOCK_RULE_NET_SERVICE: Type of a &struct > + * landlock_net_service_attr . > + */ > + LANDLOCK_RULE_NET_SERVICE = 2, > }; > > /** > @@ -79,6 +91,23 @@ struct landlock_path_beneath_attr { > */ > } __attribute__((packed)); > > +/** > + * struct landlock_net_service_attr - TCP subnet definition > + * > + * Argument of sys_landlock_add_rule(). > + */ > +struct landlock_net_service_attr { > + /** > + * @allowed_access: Bitmask of allowed access network for services > + * (cf. `Network flags`_). > + */ > + __u64 allowed_access; > + /** > + * @port: Network port. > + */ > + __u64 port; > +}; The "net service" name reflects the semantic but it doesn't fit well with the data type. It works with TCP, UDP and other protocols such as VSOCK, but not unix sockets. I think it makes more sense to rename LANDLOCK_RULE_NET_SERVICE to LANDLOCK_RULE_NET_PORT and landlock_net_service_attr to landlock_net_port_attr. Please be careful with the documentation, non-kernel code, and comments as well. In the future, we could add a landlock_net_path_attr to identify a unix abstract path, which would also be a network service, but it would not accept the TCP access rights. The access right names (LANDLOCK_ACCESS_NET_{BIND,CONNECT}_TCP) are still good. I'm still improving tests, so you might wait a bit before renaming the related files.
On Tue, May 16, 2023 at 12:13:35AM +0800, Konstantin Meskhidze wrote: > +static int add_rule_net_service(struct landlock_ruleset *ruleset, > + const void __user *const rule_attr) > +{ > +#if IS_ENABLED(CONFIG_INET) > + struct landlock_net_service_attr net_service_attr; > + int res; > + access_mask_t mask; > + > + /* Copies raw user space buffer, only one type for now. */ Nit, which I came across by accident: I believe the remark "only one type for now" referred to the fact that path_beneath_attr was the only rule type up until now - but that is not true any more. Please adapt the wording also in add_rule_path_beneath, where the same comment exists. –Günther
On 27/06/2023 18:14, Mickaël Salaün wrote: > > On 15/05/2023 18:13, Konstantin Meskhidze wrote: >> This commit adds network rules support in the ruleset management >> helpers and the landlock_create_ruleset syscall. >> Refactor user space API to support network actions. Add new network >> access flags, network rule and network attributes. Increment Landlock >> ABI version. Expand access_masks_t to u32 to be sure network access >> rights can be stored. Implement socket_bind() and socket_connect() >> LSM hooks, which enables to restrict TCP socket binding and connection >> to specific ports. It is important to explain the decision rationales. Please explain new types, something like this: The new landlock_net_port_attr structure has two fields. The allowed_access field contains the LANDLOCK_ACCESS_NET_* rights. The port field contains the port value according to the the allowed protocol. This field can take up to a 64-bit value [1] but the maximum value depends on the related protocol (e.g. 16-bit for TCP). [1] https://lore.kernel.org/r/278ab07f-7583-a4e0-3d37-1bacd091531d@digikod.net
6/26/2023 9:41 PM, Mickaël Salaün пишет: > > On 15/05/2023 18:13, Konstantin Meskhidze wrote: >> This commit adds network rules support in the ruleset management >> helpers and the landlock_create_ruleset syscall. >> Refactor user space API to support network actions. Add new network >> access flags, network rule and network attributes. Increment Landlock >> ABI version. Expand access_masks_t to u32 to be sure network access >> rights can be stored. Implement socket_bind() and socket_connect() >> LSM hooks, which enables to restrict TCP socket binding and connection >> to specific ports. >> >> Co-developed-by: Mickaël Salaün <mic@digikod.net> > > Signed-off-by: Mickaël Salaün <mic@digikod.net> > > >> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com> >> --- >> >> Changes since v10: >> * Removes "packed" attribute. >> * Applies Mickaёl's patch with some refactoring. >> * Deletes get_port() and check_addrlen() helpers. >> * Refactors check_socket_access() by squashing get_port() and >> check_addrlen() helpers into it. >> * Fixes commit message. >> >> Changes since v9: >> * Changes UAPI port field to __u64. >> * Moves shared code into check_socket_access(). >> * Adds get_raw_handled_net_accesses() and >> get_current_net_domain() helpers. >> * Minor fixes. >> >> Changes since v8: >> * Squashes commits. >> * Refactors commit message. >> * Changes UAPI port field to __be16. >> * Changes logic of bind/connect hooks with AF_UNSPEC families. >> * Adds address length checking. >> * Minor fixes. >> >> Changes since v7: >> * Squashes commits. >> * Increments ABI version to 4. >> * Refactors commit message. >> * Minor fixes. >> >> Changes since v6: >> * Renames landlock_set_net_access_mask() to landlock_add_net_access_mask() >> because it OR values. >> * Makes landlock_add_net_access_mask() more resilient incorrect values. >> * Refactors landlock_get_net_access_mask(). >> * Renames LANDLOCK_MASK_SHIFT_NET to LANDLOCK_SHIFT_ACCESS_NET and use >> LANDLOCK_NUM_ACCESS_FS as value. >> * Updates access_masks_t to u32 to support network access actions. >> * Refactors landlock internal functions to support network actions with >> landlock_key/key_type/id types. >> >> Changes since v5: >> * Gets rid of partial revert from landlock_add_rule >> syscall. >> * Formats code with clang-format-14. >> >> Changes since v4: >> * Refactors landlock_create_ruleset() - splits ruleset and >> masks checks. >> * Refactors landlock_create_ruleset() and landlock mask >> setters/getters to support two rule types. >> * Refactors landlock_add_rule syscall add_rule_path_beneath >> function by factoring out get_ruleset_from_fd() and >> landlock_put_ruleset(). >> >> Changes since v3: >> * Splits commit. >> * Adds network rule support for internal landlock functions. >> * Adds set_mask and get_mask for network. >> * Adds rb_root root_net_port. >> >> --- >> include/uapi/linux/landlock.h | 48 +++++ >> security/landlock/Kconfig | 1 + >> security/landlock/Makefile | 2 + >> security/landlock/limits.h | 6 +- >> security/landlock/net.c | 174 +++++++++++++++++++ >> security/landlock/net.h | 26 +++ >> security/landlock/ruleset.c | 52 +++++- >> security/landlock/ruleset.h | 63 +++++-- >> security/landlock/setup.c | 2 + >> security/landlock/syscalls.c | 72 +++++++- >> tools/testing/selftests/landlock/base_test.c | 2 +- >> 11 files changed, 425 insertions(+), 23 deletions(-) >> create mode 100644 security/landlock/net.c >> create mode 100644 security/landlock/net.h >> > > [...] > >> diff --git a/security/landlock/net.c b/security/landlock/net.c >> new file mode 100644 >> index 000000000000..f8d2be53ac0d >> --- /dev/null >> +++ b/security/landlock/net.c >> @@ -0,0 +1,174 @@ >> +// SPDX-License-Identifier: GPL-2.0-only >> +/* >> + * Landlock LSM - Network management and hooks >> + * >> + * Copyright © 2022 Huawei Tech. Co., Ltd. >> + * Copyright © 2022 Microsoft Corporation > > You can replace these dates with "2022-2023", and same for all your > other "2022" I guess. Ok. Thanks. I will change the dates. > .
6/26/2023 9:57 PM, Mickaël Salaün пишет: > Complementary review: > > On 15/05/2023 18:13, Konstantin Meskhidze wrote: >> This commit adds network rules support in the ruleset management >> helpers and the landlock_create_ruleset syscall. >> Refactor user space API to support network actions. Add new network >> access flags, network rule and network attributes. Increment Landlock >> ABI version. Expand access_masks_t to u32 to be sure network access >> rights can be stored. Implement socket_bind() and socket_connect() >> LSM hooks, which enables to restrict TCP socket binding and connection >> to specific ports. >> >> Co-developed-by: Mickaël Salaün <mic@digikod.net> >> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com> >> --- >> >> Changes since v10: >> * Removes "packed" attribute. >> * Applies Mickaёl's patch with some refactoring. >> * Deletes get_port() and check_addrlen() helpers. >> * Refactors check_socket_access() by squashing get_port() and >> check_addrlen() helpers into it. >> * Fixes commit message. >> >> Changes since v9: >> * Changes UAPI port field to __u64. >> * Moves shared code into check_socket_access(). >> * Adds get_raw_handled_net_accesses() and >> get_current_net_domain() helpers. >> * Minor fixes. >> >> Changes since v8: >> * Squashes commits. >> * Refactors commit message. >> * Changes UAPI port field to __be16. >> * Changes logic of bind/connect hooks with AF_UNSPEC families. >> * Adds address length checking. >> * Minor fixes. >> >> Changes since v7: >> * Squashes commits. >> * Increments ABI version to 4. >> * Refactors commit message. >> * Minor fixes. >> >> Changes since v6: >> * Renames landlock_set_net_access_mask() to landlock_add_net_access_mask() >> because it OR values. >> * Makes landlock_add_net_access_mask() more resilient incorrect values. >> * Refactors landlock_get_net_access_mask(). >> * Renames LANDLOCK_MASK_SHIFT_NET to LANDLOCK_SHIFT_ACCESS_NET and use >> LANDLOCK_NUM_ACCESS_FS as value. >> * Updates access_masks_t to u32 to support network access actions. >> * Refactors landlock internal functions to support network actions with >> landlock_key/key_type/id types. >> >> Changes since v5: >> * Gets rid of partial revert from landlock_add_rule >> syscall. >> * Formats code with clang-format-14. >> >> Changes since v4: >> * Refactors landlock_create_ruleset() - splits ruleset and >> masks checks. >> * Refactors landlock_create_ruleset() and landlock mask >> setters/getters to support two rule types. >> * Refactors landlock_add_rule syscall add_rule_path_beneath >> function by factoring out get_ruleset_from_fd() and >> landlock_put_ruleset(). >> >> Changes since v3: >> * Splits commit. >> * Adds network rule support for internal landlock functions. >> * Adds set_mask and get_mask for network. >> * Adds rb_root root_net_port. >> >> --- >> include/uapi/linux/landlock.h | 48 +++++ >> security/landlock/Kconfig | 1 + >> security/landlock/Makefile | 2 + >> security/landlock/limits.h | 6 +- >> security/landlock/net.c | 174 +++++++++++++++++++ >> security/landlock/net.h | 26 +++ >> security/landlock/ruleset.c | 52 +++++- >> security/landlock/ruleset.h | 63 +++++-- >> security/landlock/setup.c | 2 + >> security/landlock/syscalls.c | 72 +++++++- >> tools/testing/selftests/landlock/base_test.c | 2 +- >> 11 files changed, 425 insertions(+), 23 deletions(-) >> create mode 100644 security/landlock/net.c >> create mode 100644 security/landlock/net.h >> >> diff --git a/include/uapi/linux/landlock.h b/include/uapi/linux/landlock.h >> index 81d09ef9aa50..93794759dad4 100644 >> --- a/include/uapi/linux/landlock.h >> +++ b/include/uapi/linux/landlock.h >> @@ -31,6 +31,13 @@ struct landlock_ruleset_attr { >> * this access right. >> */ >> __u64 handled_access_fs; >> + > > Please remove this empty line. Ok. Thanks. > > >> + /** >> + * @handled_access_net: Bitmask of actions (cf. `Network flags`_) >> + * that is handled by this ruleset and should then be forbidden if no >> + * rule explicitly allow them. >> + */ >> + __u64 handled_access_net; >> }; >> >> /* >> @@ -54,6 +61,11 @@ enum landlock_rule_type { >> * landlock_path_beneath_attr . >> */ >> LANDLOCK_RULE_PATH_BENEATH = 1, >> + /** >> + * @LANDLOCK_RULE_NET_SERVICE: Type of a &struct >> + * landlock_net_service_attr . >> + */ >> + LANDLOCK_RULE_NET_SERVICE = 2, >> }; >> >> /** >> @@ -79,6 +91,23 @@ struct landlock_path_beneath_attr { >> */ >> } __attribute__((packed)); >> >> +/** >> + * struct landlock_net_service_attr - TCP subnet definition > > s/TCP subnet definition/Network service definition/ > Ok. Thanks. > >> + * >> + * Argument of sys_landlock_add_rule(). >> + */ >> +struct landlock_net_service_attr { >> + /** >> + * @allowed_access: Bitmask of allowed access network for services >> + * (cf. `Network flags`_). >> + */ >> + __u64 allowed_access; >> + /** >> + * @port: Network port. >> + */ >> + __u64 port; >> +}; >> + >> /** >> * DOC: fs_access >> * >> @@ -189,4 +218,23 @@ struct landlock_path_beneath_attr { >> #define LANDLOCK_ACCESS_FS_TRUNCATE (1ULL << 14) >> /* clang-format on */ >> >> +/** >> + * DOC: net_access >> + * >> + * Network flags >> + * ~~~~~~~~~~~~~~~~ >> + * >> + * These flags enable to restrict a sandboxed process to a set of network >> + * actions. >> + * >> + * TCP sockets with allowed actions: >> + * >> + * - %LANDLOCK_ACCESS_NET_BIND_TCP: Bind a TCP socket to a local port. >> + * - %LANDLOCK_ACCESS_NET_CONNECT_TCP: Connect an active TCP socket to >> + * a remote port. >> + */ >> +/* clang-format off */ >> +#define LANDLOCK_ACCESS_NET_BIND_TCP (1ULL << 0) >> +#define LANDLOCK_ACCESS_NET_CONNECT_TCP (1ULL << 1) >> +/* clang-format on */ >> #endif /* _UAPI_LINUX_LANDLOCK_H */ >> diff --git a/security/landlock/Kconfig b/security/landlock/Kconfig >> index 8e33c4e8ffb8..10c099097533 100644 >> --- a/security/landlock/Kconfig >> +++ b/security/landlock/Kconfig >> @@ -3,6 +3,7 @@ >> config SECURITY_LANDLOCK >> bool "Landlock support" >> depends on SECURITY && !ARCH_EPHEMERAL_INODES >> + select SECURITY_NETWORK >> select SECURITY_PATH >> help >> Landlock is a sandboxing mechanism that enables processes to restrict >> diff --git a/security/landlock/Makefile b/security/landlock/Makefile >> index 7bbd2f413b3e..53d3c92ae22e 100644 >> --- a/security/landlock/Makefile >> +++ b/security/landlock/Makefile >> @@ -2,3 +2,5 @@ obj-$(CONFIG_SECURITY_LANDLOCK) := landlock.o >> >> landlock-y := setup.o syscalls.o object.o ruleset.o \ >> cred.o ptrace.o fs.o >> + >> +landlock-$(CONFIG_INET) += net.o >> \ No newline at end of file >> diff --git a/security/landlock/limits.h b/security/landlock/limits.h >> index bafb3b8dc677..8a1a6463c64e 100644 >> --- a/security/landlock/limits.h >> +++ b/security/landlock/limits.h >> @@ -23,6 +23,10 @@ >> #define LANDLOCK_NUM_ACCESS_FS __const_hweight64(LANDLOCK_MASK_ACCESS_FS) >> #define LANDLOCK_SHIFT_ACCESS_FS 0 >> >> -/* clang-format on */ >> +#define LANDLOCK_LAST_ACCESS_NET LANDLOCK_ACCESS_NET_CONNECT_TCP >> +#define LANDLOCK_MASK_ACCESS_NET ((LANDLOCK_LAST_ACCESS_NET << 1) - 1) >> +#define LANDLOCK_NUM_ACCESS_NET __const_hweight64(LANDLOCK_MASK_ACCESS_NET) >> +#define LANDLOCK_SHIFT_ACCESS_NET LANDLOCK_NUM_ACCESS_FS >> >> +/* clang-format on */ > > Please the empty line to make this patch clean. Ok. I will. > > >> #endif /* _SECURITY_LANDLOCK_LIMITS_H */ >> diff --git a/security/landlock/net.c b/security/landlock/net.c >> new file mode 100644 >> index 000000000000..f8d2be53ac0d >> --- /dev/null >> +++ b/security/landlock/net.c >> @@ -0,0 +1,174 @@ >> +// SPDX-License-Identifier: GPL-2.0-only >> +/* >> + * Landlock LSM - Network management and hooks >> + * >> + * Copyright © 2022 Huawei Tech. Co., Ltd. >> + * Copyright © 2022 Microsoft Corporation >> + */ >> + >> +#include <linux/in.h> >> +#include <linux/net.h> >> +#include <linux/socket.h> >> +#include <net/ipv6.h> >> + >> +#include "common.h" >> +#include "cred.h" >> +#include "limits.h" >> +#include "net.h" >> +#include "ruleset.h" >> + >> +int landlock_append_net_rule(struct landlock_ruleset *const ruleset, >> + const u16 port, access_mask_t access_rights) >> +{ >> + int err; >> + const struct landlock_id id = { >> + .key.data = (__force uintptr_t)htons(port), >> + .type = LANDLOCK_KEY_NET_PORT, >> + }; >> + >> + BUILD_BUG_ON(sizeof(port) > sizeof(id.key.data)); >> + >> + /* Transforms relative access rights to absolute ones. */ >> + access_rights |= LANDLOCK_MASK_ACCESS_NET & >> + ~landlock_get_net_access_mask(ruleset, 0); >> + >> + mutex_lock(&ruleset->lock); >> + err = landlock_insert_rule(ruleset, id, access_rights); >> + mutex_unlock(&ruleset->lock); >> + >> + return err; >> +} >> + >> +static access_mask_t >> +get_raw_handled_net_accesses(const struct landlock_ruleset *const domain) >> +{ >> + access_mask_t access_dom = 0; >> + size_t layer_level; >> + >> + for (layer_level = 0; layer_level < domain->num_layers; layer_level++) >> + access_dom |= landlock_get_net_access_mask(domain, layer_level); >> + return access_dom; >> +} >> + >> +static const struct landlock_ruleset *get_current_net_domain(void) >> +{ >> + const struct landlock_ruleset *const dom = >> + landlock_get_current_domain(); >> + >> + if (!dom || !get_raw_handled_net_accesses(dom)) >> + return NULL; >> + >> + return dom; >> +} >> + >> +static int check_socket_access(struct socket *const sock, >> + struct sockaddr *const address, >> + const int addrlen, >> + const access_mask_t access_request) >> +{ >> + __be16 port; >> + layer_mask_t layer_masks[LANDLOCK_NUM_ACCESS_NET] = {}; >> + const struct landlock_rule *rule; >> + access_mask_t handled_access; >> + struct landlock_id id = { >> + .type = LANDLOCK_KEY_NET_PORT, >> + }; >> + const struct landlock_ruleset *const domain = get_current_net_domain(); >> + >> + if (WARN_ON_ONCE(!domain)) > > The WARN_ON_ONCE() needs to be removed for processes not sandboxed. This > should be printed when running the tests. > Probably during the boot stage it prints once since no process is landlocked at this stage. So we need to leave it like this: if (!domain) return 0; ???? > > >> + return 0; >> + if (WARN_ON_ONCE(domain->num_layers < 1)) >> + return -EACCES; >> + >> + /* Checks if it's a TCP socket. */ >> + if (sock->type != SOCK_STREAM) >> + return 0; >> + >> + /* Checks for minimal header length. */ >> + if (addrlen < offsetofend(struct sockaddr, sa_family)) > > You can use "typeof(*address)" instead of struct sockaddr, this makes it > easier to review. > Do mean to change offsetofend() by typeof(*address)?? > >> + return -EINVAL; >> + > > [...] > .
6/27/2023 7:14 PM, Mickaël Salaün пишет: > > On 15/05/2023 18:13, Konstantin Meskhidze wrote: >> This commit adds network rules support in the ruleset management >> helpers and the landlock_create_ruleset syscall. >> Refactor user space API to support network actions. Add new network >> access flags, network rule and network attributes. Increment Landlock >> ABI version. Expand access_masks_t to u32 to be sure network access >> rights can be stored. Implement socket_bind() and socket_connect() >> LSM hooks, which enables to restrict TCP socket binding and connection >> to specific ports. >> >> Co-developed-by: Mickaël Salaün <mic@digikod.net> >> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com> >> --- >> >> Changes since v10: >> * Removes "packed" attribute. >> * Applies Mickaёl's patch with some refactoring. >> * Deletes get_port() and check_addrlen() helpers. >> * Refactors check_socket_access() by squashing get_port() and >> check_addrlen() helpers into it. >> * Fixes commit message. >> >> Changes since v9: >> * Changes UAPI port field to __u64. >> * Moves shared code into check_socket_access(). >> * Adds get_raw_handled_net_accesses() and >> get_current_net_domain() helpers. >> * Minor fixes. >> >> Changes since v8: >> * Squashes commits. >> * Refactors commit message. >> * Changes UAPI port field to __be16. >> * Changes logic of bind/connect hooks with AF_UNSPEC families. >> * Adds address length checking. >> * Minor fixes. >> >> Changes since v7: >> * Squashes commits. >> * Increments ABI version to 4. >> * Refactors commit message. >> * Minor fixes. >> >> Changes since v6: >> * Renames landlock_set_net_access_mask() to landlock_add_net_access_mask() >> because it OR values. >> * Makes landlock_add_net_access_mask() more resilient incorrect values. >> * Refactors landlock_get_net_access_mask(). >> * Renames LANDLOCK_MASK_SHIFT_NET to LANDLOCK_SHIFT_ACCESS_NET and use >> LANDLOCK_NUM_ACCESS_FS as value. >> * Updates access_masks_t to u32 to support network access actions. >> * Refactors landlock internal functions to support network actions with >> landlock_key/key_type/id types. >> >> Changes since v5: >> * Gets rid of partial revert from landlock_add_rule >> syscall. >> * Formats code with clang-format-14. >> >> Changes since v4: >> * Refactors landlock_create_ruleset() - splits ruleset and >> masks checks. >> * Refactors landlock_create_ruleset() and landlock mask >> setters/getters to support two rule types. >> * Refactors landlock_add_rule syscall add_rule_path_beneath >> function by factoring out get_ruleset_from_fd() and >> landlock_put_ruleset(). >> >> Changes since v3: >> * Splits commit. >> * Adds network rule support for internal landlock functions. >> * Adds set_mask and get_mask for network. >> * Adds rb_root root_net_port. >> >> --- >> include/uapi/linux/landlock.h | 48 +++++ >> security/landlock/Kconfig | 1 + >> security/landlock/Makefile | 2 + >> security/landlock/limits.h | 6 +- >> security/landlock/net.c | 174 +++++++++++++++++++ >> security/landlock/net.h | 26 +++ >> security/landlock/ruleset.c | 52 +++++- >> security/landlock/ruleset.h | 63 +++++-- >> security/landlock/setup.c | 2 + >> security/landlock/syscalls.c | 72 +++++++- >> tools/testing/selftests/landlock/base_test.c | 2 +- >> 11 files changed, 425 insertions(+), 23 deletions(-) >> create mode 100644 security/landlock/net.c >> create mode 100644 security/landlock/net.h >> >> diff --git a/include/uapi/linux/landlock.h b/include/uapi/linux/landlock.h >> index 81d09ef9aa50..93794759dad4 100644 >> --- a/include/uapi/linux/landlock.h >> +++ b/include/uapi/linux/landlock.h >> @@ -31,6 +31,13 @@ struct landlock_ruleset_attr { >> * this access right. >> */ >> __u64 handled_access_fs; >> + >> + /** >> + * @handled_access_net: Bitmask of actions (cf. `Network flags`_) >> + * that is handled by this ruleset and should then be forbidden if no >> + * rule explicitly allow them. >> + */ >> + __u64 handled_access_net; >> }; >> >> /* >> @@ -54,6 +61,11 @@ enum landlock_rule_type { >> * landlock_path_beneath_attr . >> */ >> LANDLOCK_RULE_PATH_BENEATH = 1, >> + /** >> + * @LANDLOCK_RULE_NET_SERVICE: Type of a &struct >> + * landlock_net_service_attr . >> + */ >> + LANDLOCK_RULE_NET_SERVICE = 2, >> }; >> >> /** >> @@ -79,6 +91,23 @@ struct landlock_path_beneath_attr { >> */ >> } __attribute__((packed)); >> >> +/** >> + * struct landlock_net_service_attr - TCP subnet definition >> + * >> + * Argument of sys_landlock_add_rule(). >> + */ >> +struct landlock_net_service_attr { >> + /** >> + * @allowed_access: Bitmask of allowed access network for services >> + * (cf. `Network flags`_). >> + */ >> + __u64 allowed_access; >> + /** >> + * @port: Network port. >> + */ >> + __u64 port; >> +}; > > The "net service" name reflects the semantic but it doesn't fit well > with the data type. It works with TCP, UDP and other protocols such as > VSOCK, but not unix sockets. I think it makes more sense to rename > LANDLOCK_RULE_NET_SERVICE to LANDLOCK_RULE_NET_PORT and > landlock_net_service_attr to landlock_net_port_attr. Please be careful > with the documentation, non-kernel code, and comments as well. > > In the future, we could add a landlock_net_path_attr to identify a unix > abstract path, which would also be a network service, but it would not > accept the TCP access rights. > > The access right names (LANDLOCK_ACCESS_NET_{BIND,CONNECT}_TCP) are > still good. > Ok. "net service" will be renamed. Thanks. > > I'm still improving tests, so you might wait a bit before renaming the > related files. > .
6/29/2023 5:04 PM, Mickaël Salaün пишет: > > On 27/06/2023 18:14, Mickaël Salaün wrote: >> >> On 15/05/2023 18:13, Konstantin Meskhidze wrote: >>> This commit adds network rules support in the ruleset management >>> helpers and the landlock_create_ruleset syscall. >>> Refactor user space API to support network actions. Add new network >>> access flags, network rule and network attributes. Increment Landlock >>> ABI version. Expand access_masks_t to u32 to be sure network access >>> rights can be stored. Implement socket_bind() and socket_connect() >>> LSM hooks, which enables to restrict TCP socket binding and connection >>> to specific ports. > > It is important to explain the decision rationales. Please explain new > types, something like this: > > The new landlock_net_port_attr structure has two fields. The > allowed_access field contains the LANDLOCK_ACCESS_NET_* rights. The port > field contains the port value according to the the allowed protocol. > This field can take up to a 64-bit value [1] but the maximum value > depends on the related protocol (e.g. 16-bit for TCP). > Ok. Thanks. > [1] > https://lore.kernel.org/r/278ab07f-7583-a4e0-3d37-1bacd091531d@digikod.net > .
6/27/2023 10:48 PM, Günther Noack пишет: > On Tue, May 16, 2023 at 12:13:35AM +0800, Konstantin Meskhidze wrote: >> +static int add_rule_net_service(struct landlock_ruleset *ruleset, >> + const void __user *const rule_attr) >> +{ >> +#if IS_ENABLED(CONFIG_INET) >> + struct landlock_net_service_attr net_service_attr; >> + int res; >> + access_mask_t mask; >> + >> + /* Copies raw user space buffer, only one type for now. */ > > Nit, which I came across by accident: I believe the remark "only one > type for now" referred to the fact that path_beneath_attr was the only > rule type up until now - but that is not true any more. Please adapt > the wording also in add_rule_path_beneath, where the same comment > exists. > Thanks. I will fix it. > –Günther > .
On 03/07/2023 12:36, Konstantin Meskhidze (A) wrote: > > > 6/26/2023 9:57 PM, Mickaël Salaün пишет: >> Complementary review: >> >> On 15/05/2023 18:13, Konstantin Meskhidze wrote: >>> This commit adds network rules support in the ruleset management >>> helpers and the landlock_create_ruleset syscall. >>> Refactor user space API to support network actions. Add new network >>> access flags, network rule and network attributes. Increment Landlock >>> ABI version. Expand access_masks_t to u32 to be sure network access >>> rights can be stored. Implement socket_bind() and socket_connect() >>> LSM hooks, which enables to restrict TCP socket binding and connection >>> to specific ports. >>> >>> Co-developed-by: Mickaël Salaün <mic@digikod.net> >>> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com> >>> --- >>> >>> Changes since v10: >>> * Removes "packed" attribute. >>> * Applies Mickaёl's patch with some refactoring. >>> * Deletes get_port() and check_addrlen() helpers. >>> * Refactors check_socket_access() by squashing get_port() and >>> check_addrlen() helpers into it. >>> * Fixes commit message. >>> >>> Changes since v9: >>> * Changes UAPI port field to __u64. >>> * Moves shared code into check_socket_access(). >>> * Adds get_raw_handled_net_accesses() and >>> get_current_net_domain() helpers. >>> * Minor fixes. >>> >>> Changes since v8: >>> * Squashes commits. >>> * Refactors commit message. >>> * Changes UAPI port field to __be16. >>> * Changes logic of bind/connect hooks with AF_UNSPEC families. >>> * Adds address length checking. >>> * Minor fixes. >>> >>> Changes since v7: >>> * Squashes commits. >>> * Increments ABI version to 4. >>> * Refactors commit message. >>> * Minor fixes. >>> >>> Changes since v6: >>> * Renames landlock_set_net_access_mask() to landlock_add_net_access_mask() >>> because it OR values. >>> * Makes landlock_add_net_access_mask() more resilient incorrect values. >>> * Refactors landlock_get_net_access_mask(). >>> * Renames LANDLOCK_MASK_SHIFT_NET to LANDLOCK_SHIFT_ACCESS_NET and use >>> LANDLOCK_NUM_ACCESS_FS as value. >>> * Updates access_masks_t to u32 to support network access actions. >>> * Refactors landlock internal functions to support network actions with >>> landlock_key/key_type/id types. >>> >>> Changes since v5: >>> * Gets rid of partial revert from landlock_add_rule >>> syscall. >>> * Formats code with clang-format-14. >>> >>> Changes since v4: >>> * Refactors landlock_create_ruleset() - splits ruleset and >>> masks checks. >>> * Refactors landlock_create_ruleset() and landlock mask >>> setters/getters to support two rule types. >>> * Refactors landlock_add_rule syscall add_rule_path_beneath >>> function by factoring out get_ruleset_from_fd() and >>> landlock_put_ruleset(). >>> >>> Changes since v3: >>> * Splits commit. >>> * Adds network rule support for internal landlock functions. >>> * Adds set_mask and get_mask for network. >>> * Adds rb_root root_net_port. >>> >>> --- >>> include/uapi/linux/landlock.h | 48 +++++ >>> security/landlock/Kconfig | 1 + >>> security/landlock/Makefile | 2 + >>> security/landlock/limits.h | 6 +- >>> security/landlock/net.c | 174 +++++++++++++++++++ >>> security/landlock/net.h | 26 +++ >>> security/landlock/ruleset.c | 52 +++++- >>> security/landlock/ruleset.h | 63 +++++-- >>> security/landlock/setup.c | 2 + >>> security/landlock/syscalls.c | 72 +++++++- >>> tools/testing/selftests/landlock/base_test.c | 2 +- >>> 11 files changed, 425 insertions(+), 23 deletions(-) >>> create mode 100644 security/landlock/net.c >>> create mode 100644 security/landlock/net.h >>> >>> diff --git a/include/uapi/linux/landlock.h b/include/uapi/linux/landlock.h >>> index 81d09ef9aa50..93794759dad4 100644 >>> --- a/include/uapi/linux/landlock.h >>> +++ b/include/uapi/linux/landlock.h >>> @@ -31,6 +31,13 @@ struct landlock_ruleset_attr { >>> * this access right. >>> */ >>> __u64 handled_access_fs; >>> + >> >> Please remove this empty line. > > Ok. Thanks. >> >> >>> + /** >>> + * @handled_access_net: Bitmask of actions (cf. `Network flags`_) >>> + * that is handled by this ruleset and should then be forbidden if no >>> + * rule explicitly allow them. >>> + */ >>> + __u64 handled_access_net; >>> }; >>> >>> /* >>> @@ -54,6 +61,11 @@ enum landlock_rule_type { >>> * landlock_path_beneath_attr . >>> */ >>> LANDLOCK_RULE_PATH_BENEATH = 1, >>> + /** >>> + * @LANDLOCK_RULE_NET_SERVICE: Type of a &struct >>> + * landlock_net_service_attr . >>> + */ >>> + LANDLOCK_RULE_NET_SERVICE = 2, >>> }; >>> >>> /** >>> @@ -79,6 +91,23 @@ struct landlock_path_beneath_attr { >>> */ >>> } __attribute__((packed)); >>> >>> +/** >>> + * struct landlock_net_service_attr - TCP subnet definition >> >> s/TCP subnet definition/Network service definition/ >> > Ok. Thanks. >> >>> + * >>> + * Argument of sys_landlock_add_rule(). >>> + */ >>> +struct landlock_net_service_attr { >>> + /** >>> + * @allowed_access: Bitmask of allowed access network for services >>> + * (cf. `Network flags`_). >>> + */ >>> + __u64 allowed_access; >>> + /** >>> + * @port: Network port. >>> + */ >>> + __u64 port; >>> +}; >>> + >>> /** >>> * DOC: fs_access >>> * >>> @@ -189,4 +218,23 @@ struct landlock_path_beneath_attr { >>> #define LANDLOCK_ACCESS_FS_TRUNCATE (1ULL << 14) >>> /* clang-format on */ >>> >>> +/** >>> + * DOC: net_access >>> + * >>> + * Network flags >>> + * ~~~~~~~~~~~~~~~~ >>> + * >>> + * These flags enable to restrict a sandboxed process to a set of network >>> + * actions. >>> + * >>> + * TCP sockets with allowed actions: >>> + * >>> + * - %LANDLOCK_ACCESS_NET_BIND_TCP: Bind a TCP socket to a local port. >>> + * - %LANDLOCK_ACCESS_NET_CONNECT_TCP: Connect an active TCP socket to >>> + * a remote port. >>> + */ >>> +/* clang-format off */ >>> +#define LANDLOCK_ACCESS_NET_BIND_TCP (1ULL << 0) >>> +#define LANDLOCK_ACCESS_NET_CONNECT_TCP (1ULL << 1) >>> +/* clang-format on */ >>> #endif /* _UAPI_LINUX_LANDLOCK_H */ >>> diff --git a/security/landlock/Kconfig b/security/landlock/Kconfig >>> index 8e33c4e8ffb8..10c099097533 100644 >>> --- a/security/landlock/Kconfig >>> +++ b/security/landlock/Kconfig >>> @@ -3,6 +3,7 @@ >>> config SECURITY_LANDLOCK >>> bool "Landlock support" >>> depends on SECURITY && !ARCH_EPHEMERAL_INODES >>> + select SECURITY_NETWORK >>> select SECURITY_PATH >>> help >>> Landlock is a sandboxing mechanism that enables processes to restrict >>> diff --git a/security/landlock/Makefile b/security/landlock/Makefile >>> index 7bbd2f413b3e..53d3c92ae22e 100644 >>> --- a/security/landlock/Makefile >>> +++ b/security/landlock/Makefile >>> @@ -2,3 +2,5 @@ obj-$(CONFIG_SECURITY_LANDLOCK) := landlock.o >>> >>> landlock-y := setup.o syscalls.o object.o ruleset.o \ >>> cred.o ptrace.o fs.o >>> + >>> +landlock-$(CONFIG_INET) += net.o >>> \ No newline at end of file >>> diff --git a/security/landlock/limits.h b/security/landlock/limits.h >>> index bafb3b8dc677..8a1a6463c64e 100644 >>> --- a/security/landlock/limits.h >>> +++ b/security/landlock/limits.h >>> @@ -23,6 +23,10 @@ >>> #define LANDLOCK_NUM_ACCESS_FS __const_hweight64(LANDLOCK_MASK_ACCESS_FS) >>> #define LANDLOCK_SHIFT_ACCESS_FS 0 >>> >>> -/* clang-format on */ >>> +#define LANDLOCK_LAST_ACCESS_NET LANDLOCK_ACCESS_NET_CONNECT_TCP >>> +#define LANDLOCK_MASK_ACCESS_NET ((LANDLOCK_LAST_ACCESS_NET << 1) - 1) >>> +#define LANDLOCK_NUM_ACCESS_NET __const_hweight64(LANDLOCK_MASK_ACCESS_NET) >>> +#define LANDLOCK_SHIFT_ACCESS_NET LANDLOCK_NUM_ACCESS_FS >>> >>> +/* clang-format on */ >> >> Please the empty line to make this patch clean. > > Ok. I will. >> >> >>> #endif /* _SECURITY_LANDLOCK_LIMITS_H */ >>> diff --git a/security/landlock/net.c b/security/landlock/net.c >>> new file mode 100644 >>> index 000000000000..f8d2be53ac0d >>> --- /dev/null >>> +++ b/security/landlock/net.c >>> @@ -0,0 +1,174 @@ >>> +// SPDX-License-Identifier: GPL-2.0-only >>> +/* >>> + * Landlock LSM - Network management and hooks >>> + * >>> + * Copyright © 2022 Huawei Tech. Co., Ltd. >>> + * Copyright © 2022 Microsoft Corporation >>> + */ >>> + >>> +#include <linux/in.h> >>> +#include <linux/net.h> >>> +#include <linux/socket.h> >>> +#include <net/ipv6.h> >>> + >>> +#include "common.h" >>> +#include "cred.h" >>> +#include "limits.h" >>> +#include "net.h" >>> +#include "ruleset.h" >>> + >>> +int landlock_append_net_rule(struct landlock_ruleset *const ruleset, >>> + const u16 port, access_mask_t access_rights) >>> +{ >>> + int err; >>> + const struct landlock_id id = { >>> + .key.data = (__force uintptr_t)htons(port), >>> + .type = LANDLOCK_KEY_NET_PORT, >>> + }; >>> + >>> + BUILD_BUG_ON(sizeof(port) > sizeof(id.key.data)); >>> + >>> + /* Transforms relative access rights to absolute ones. */ >>> + access_rights |= LANDLOCK_MASK_ACCESS_NET & >>> + ~landlock_get_net_access_mask(ruleset, 0); >>> + >>> + mutex_lock(&ruleset->lock); >>> + err = landlock_insert_rule(ruleset, id, access_rights); >>> + mutex_unlock(&ruleset->lock); >>> + >>> + return err; >>> +} >>> + >>> +static access_mask_t >>> +get_raw_handled_net_accesses(const struct landlock_ruleset *const domain) >>> +{ >>> + access_mask_t access_dom = 0; >>> + size_t layer_level; >>> + >>> + for (layer_level = 0; layer_level < domain->num_layers; layer_level++) >>> + access_dom |= landlock_get_net_access_mask(domain, layer_level); >>> + return access_dom; >>> +} >>> + >>> +static const struct landlock_ruleset *get_current_net_domain(void) >>> +{ >>> + const struct landlock_ruleset *const dom = >>> + landlock_get_current_domain(); >>> + >>> + if (!dom || !get_raw_handled_net_accesses(dom)) >>> + return NULL; >>> + >>> + return dom; >>> +} >>> + >>> +static int check_socket_access(struct socket *const sock, >>> + struct sockaddr *const address, >>> + const int addrlen, >>> + const access_mask_t access_request) >>> +{ >>> + __be16 port; >>> + layer_mask_t layer_masks[LANDLOCK_NUM_ACCESS_NET] = {}; >>> + const struct landlock_rule *rule; >>> + access_mask_t handled_access; >>> + struct landlock_id id = { >>> + .type = LANDLOCK_KEY_NET_PORT, >>> + }; >>> + const struct landlock_ruleset *const domain = get_current_net_domain(); >>> + >>> + if (WARN_ON_ONCE(!domain)) >> >> The WARN_ON_ONCE() needs to be removed for processes not sandboxed. This >> should be printed when running the tests. >> > Probably during the boot stage it prints once since no process is > landlocked at this stage. > So we need to leave it like this: > if (!domain) > return 0; Yes > ???? >> >> >>> + return 0; >>> + if (WARN_ON_ONCE(domain->num_layers < 1)) >>> + return -EACCES; >>> + >>> + /* Checks if it's a TCP socket. */ >>> + if (sock->type != SOCK_STREAM) >>> + return 0; >>> + >>> + /* Checks for minimal header length. */ >>> + if (addrlen < offsetofend(struct sockaddr, sa_family)) >> >> You can use "typeof(*address)" instead of struct sockaddr, this makes it >> easier to review. >> > Do mean to change offsetofend() by typeof(*address)?? No: if (addrlen < offsetofend(typeof(*address), sa_family)) >> >>> + return -EINVAL; >>> + >> >> [...] >> .
7/3/2023 8:06 PM, Mickaël Salaün пишет: > > On 03/07/2023 12:36, Konstantin Meskhidze (A) wrote: >> >> >> 6/26/2023 9:57 PM, Mickaël Salaün пишет: >>> Complementary review: >>> >>> On 15/05/2023 18:13, Konstantin Meskhidze wrote: >>>> This commit adds network rules support in the ruleset management >>>> helpers and the landlock_create_ruleset syscall. >>>> Refactor user space API to support network actions. Add new network >>>> access flags, network rule and network attributes. Increment Landlock >>>> ABI version. Expand access_masks_t to u32 to be sure network access >>>> rights can be stored. Implement socket_bind() and socket_connect() >>>> LSM hooks, which enables to restrict TCP socket binding and connection >>>> to specific ports. >>>> >>>> Co-developed-by: Mickaël Salaün <mic@digikod.net> >>>> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com> >>>> --- >>>> >>>> Changes since v10: >>>> * Removes "packed" attribute. >>>> * Applies Mickaёl's patch with some refactoring. >>>> * Deletes get_port() and check_addrlen() helpers. >>>> * Refactors check_socket_access() by squashing get_port() and >>>> check_addrlen() helpers into it. >>>> * Fixes commit message. >>>> >>>> Changes since v9: >>>> * Changes UAPI port field to __u64. >>>> * Moves shared code into check_socket_access(). >>>> * Adds get_raw_handled_net_accesses() and >>>> get_current_net_domain() helpers. >>>> * Minor fixes. >>>> >>>> Changes since v8: >>>> * Squashes commits. >>>> * Refactors commit message. >>>> * Changes UAPI port field to __be16. >>>> * Changes logic of bind/connect hooks with AF_UNSPEC families. >>>> * Adds address length checking. >>>> * Minor fixes. >>>> >>>> Changes since v7: >>>> * Squashes commits. >>>> * Increments ABI version to 4. >>>> * Refactors commit message. >>>> * Minor fixes. >>>> >>>> Changes since v6: >>>> * Renames landlock_set_net_access_mask() to landlock_add_net_access_mask() >>>> because it OR values. >>>> * Makes landlock_add_net_access_mask() more resilient incorrect values. >>>> * Refactors landlock_get_net_access_mask(). >>>> * Renames LANDLOCK_MASK_SHIFT_NET to LANDLOCK_SHIFT_ACCESS_NET and use >>>> LANDLOCK_NUM_ACCESS_FS as value. >>>> * Updates access_masks_t to u32 to support network access actions. >>>> * Refactors landlock internal functions to support network actions with >>>> landlock_key/key_type/id types. >>>> >>>> Changes since v5: >>>> * Gets rid of partial revert from landlock_add_rule >>>> syscall. >>>> * Formats code with clang-format-14. >>>> >>>> Changes since v4: >>>> * Refactors landlock_create_ruleset() - splits ruleset and >>>> masks checks. >>>> * Refactors landlock_create_ruleset() and landlock mask >>>> setters/getters to support two rule types. >>>> * Refactors landlock_add_rule syscall add_rule_path_beneath >>>> function by factoring out get_ruleset_from_fd() and >>>> landlock_put_ruleset(). >>>> >>>> Changes since v3: >>>> * Splits commit. >>>> * Adds network rule support for internal landlock functions. >>>> * Adds set_mask and get_mask for network. >>>> * Adds rb_root root_net_port. >>>> >>>> --- >>>> include/uapi/linux/landlock.h | 48 +++++ >>>> security/landlock/Kconfig | 1 + >>>> security/landlock/Makefile | 2 + >>>> security/landlock/limits.h | 6 +- >>>> security/landlock/net.c | 174 +++++++++++++++++++ >>>> security/landlock/net.h | 26 +++ >>>> security/landlock/ruleset.c | 52 +++++- >>>> security/landlock/ruleset.h | 63 +++++-- >>>> security/landlock/setup.c | 2 + >>>> security/landlock/syscalls.c | 72 +++++++- >>>> tools/testing/selftests/landlock/base_test.c | 2 +- >>>> 11 files changed, 425 insertions(+), 23 deletions(-) >>>> create mode 100644 security/landlock/net.c >>>> create mode 100644 security/landlock/net.h >>>> >>>> diff --git a/include/uapi/linux/landlock.h b/include/uapi/linux/landlock.h >>>> index 81d09ef9aa50..93794759dad4 100644 >>>> --- a/include/uapi/linux/landlock.h >>>> +++ b/include/uapi/linux/landlock.h >>>> @@ -31,6 +31,13 @@ struct landlock_ruleset_attr { >>>> * this access right. >>>> */ >>>> __u64 handled_access_fs; >>>> + >>> >>> Please remove this empty line. >> >> Ok. Thanks. >>> >>> >>>> + /** >>>> + * @handled_access_net: Bitmask of actions (cf. `Network flags`_) >>>> + * that is handled by this ruleset and should then be forbidden if no >>>> + * rule explicitly allow them. >>>> + */ >>>> + __u64 handled_access_net; >>>> }; >>>> >>>> /* >>>> @@ -54,6 +61,11 @@ enum landlock_rule_type { >>>> * landlock_path_beneath_attr . >>>> */ >>>> LANDLOCK_RULE_PATH_BENEATH = 1, >>>> + /** >>>> + * @LANDLOCK_RULE_NET_SERVICE: Type of a &struct >>>> + * landlock_net_service_attr . >>>> + */ >>>> + LANDLOCK_RULE_NET_SERVICE = 2, >>>> }; >>>> >>>> /** >>>> @@ -79,6 +91,23 @@ struct landlock_path_beneath_attr { >>>> */ >>>> } __attribute__((packed)); >>>> >>>> +/** >>>> + * struct landlock_net_service_attr - TCP subnet definition >>> >>> s/TCP subnet definition/Network service definition/ >>> >> Ok. Thanks. >>> >>>> + * >>>> + * Argument of sys_landlock_add_rule(). >>>> + */ >>>> +struct landlock_net_service_attr { >>>> + /** >>>> + * @allowed_access: Bitmask of allowed access network for services >>>> + * (cf. `Network flags`_). >>>> + */ >>>> + __u64 allowed_access; >>>> + /** >>>> + * @port: Network port. >>>> + */ >>>> + __u64 port; >>>> +}; >>>> + >>>> /** >>>> * DOC: fs_access >>>> * >>>> @@ -189,4 +218,23 @@ struct landlock_path_beneath_attr { >>>> #define LANDLOCK_ACCESS_FS_TRUNCATE (1ULL << 14) >>>> /* clang-format on */ >>>> >>>> +/** >>>> + * DOC: net_access >>>> + * >>>> + * Network flags >>>> + * ~~~~~~~~~~~~~~~~ >>>> + * >>>> + * These flags enable to restrict a sandboxed process to a set of network >>>> + * actions. >>>> + * >>>> + * TCP sockets with allowed actions: >>>> + * >>>> + * - %LANDLOCK_ACCESS_NET_BIND_TCP: Bind a TCP socket to a local port. >>>> + * - %LANDLOCK_ACCESS_NET_CONNECT_TCP: Connect an active TCP socket to >>>> + * a remote port. >>>> + */ >>>> +/* clang-format off */ >>>> +#define LANDLOCK_ACCESS_NET_BIND_TCP (1ULL << 0) >>>> +#define LANDLOCK_ACCESS_NET_CONNECT_TCP (1ULL << 1) >>>> +/* clang-format on */ >>>> #endif /* _UAPI_LINUX_LANDLOCK_H */ >>>> diff --git a/security/landlock/Kconfig b/security/landlock/Kconfig >>>> index 8e33c4e8ffb8..10c099097533 100644 >>>> --- a/security/landlock/Kconfig >>>> +++ b/security/landlock/Kconfig >>>> @@ -3,6 +3,7 @@ >>>> config SECURITY_LANDLOCK >>>> bool "Landlock support" >>>> depends on SECURITY && !ARCH_EPHEMERAL_INODES >>>> + select SECURITY_NETWORK >>>> select SECURITY_PATH >>>> help >>>> Landlock is a sandboxing mechanism that enables processes to restrict >>>> diff --git a/security/landlock/Makefile b/security/landlock/Makefile >>>> index 7bbd2f413b3e..53d3c92ae22e 100644 >>>> --- a/security/landlock/Makefile >>>> +++ b/security/landlock/Makefile >>>> @@ -2,3 +2,5 @@ obj-$(CONFIG_SECURITY_LANDLOCK) := landlock.o >>>> >>>> landlock-y := setup.o syscalls.o object.o ruleset.o \ >>>> cred.o ptrace.o fs.o >>>> + >>>> +landlock-$(CONFIG_INET) += net.o >>>> \ No newline at end of file >>>> diff --git a/security/landlock/limits.h b/security/landlock/limits.h >>>> index bafb3b8dc677..8a1a6463c64e 100644 >>>> --- a/security/landlock/limits.h >>>> +++ b/security/landlock/limits.h >>>> @@ -23,6 +23,10 @@ >>>> #define LANDLOCK_NUM_ACCESS_FS __const_hweight64(LANDLOCK_MASK_ACCESS_FS) >>>> #define LANDLOCK_SHIFT_ACCESS_FS 0 >>>> >>>> -/* clang-format on */ >>>> +#define LANDLOCK_LAST_ACCESS_NET LANDLOCK_ACCESS_NET_CONNECT_TCP >>>> +#define LANDLOCK_MASK_ACCESS_NET ((LANDLOCK_LAST_ACCESS_NET << 1) - 1) >>>> +#define LANDLOCK_NUM_ACCESS_NET __const_hweight64(LANDLOCK_MASK_ACCESS_NET) >>>> +#define LANDLOCK_SHIFT_ACCESS_NET LANDLOCK_NUM_ACCESS_FS >>>> >>>> +/* clang-format on */ >>> >>> Please the empty line to make this patch clean. >> >> Ok. I will. >>> >>> >>>> #endif /* _SECURITY_LANDLOCK_LIMITS_H */ >>>> diff --git a/security/landlock/net.c b/security/landlock/net.c >>>> new file mode 100644 >>>> index 000000000000..f8d2be53ac0d >>>> --- /dev/null >>>> +++ b/security/landlock/net.c >>>> @@ -0,0 +1,174 @@ >>>> +// SPDX-License-Identifier: GPL-2.0-only >>>> +/* >>>> + * Landlock LSM - Network management and hooks >>>> + * >>>> + * Copyright © 2022 Huawei Tech. Co., Ltd. >>>> + * Copyright © 2022 Microsoft Corporation >>>> + */ >>>> + >>>> +#include <linux/in.h> >>>> +#include <linux/net.h> >>>> +#include <linux/socket.h> >>>> +#include <net/ipv6.h> >>>> + >>>> +#include "common.h" >>>> +#include "cred.h" >>>> +#include "limits.h" >>>> +#include "net.h" >>>> +#include "ruleset.h" >>>> + >>>> +int landlock_append_net_rule(struct landlock_ruleset *const ruleset, >>>> + const u16 port, access_mask_t access_rights) >>>> +{ >>>> + int err; >>>> + const struct landlock_id id = { >>>> + .key.data = (__force uintptr_t)htons(port), >>>> + .type = LANDLOCK_KEY_NET_PORT, >>>> + }; >>>> + >>>> + BUILD_BUG_ON(sizeof(port) > sizeof(id.key.data)); >>>> + >>>> + /* Transforms relative access rights to absolute ones. */ >>>> + access_rights |= LANDLOCK_MASK_ACCESS_NET & >>>> + ~landlock_get_net_access_mask(ruleset, 0); >>>> + >>>> + mutex_lock(&ruleset->lock); >>>> + err = landlock_insert_rule(ruleset, id, access_rights); >>>> + mutex_unlock(&ruleset->lock); >>>> + >>>> + return err; >>>> +} >>>> + >>>> +static access_mask_t >>>> +get_raw_handled_net_accesses(const struct landlock_ruleset *const domain) >>>> +{ >>>> + access_mask_t access_dom = 0; >>>> + size_t layer_level; >>>> + >>>> + for (layer_level = 0; layer_level < domain->num_layers; layer_level++) >>>> + access_dom |= landlock_get_net_access_mask(domain, layer_level); >>>> + return access_dom; >>>> +} >>>> + >>>> +static const struct landlock_ruleset *get_current_net_domain(void) >>>> +{ >>>> + const struct landlock_ruleset *const dom = >>>> + landlock_get_current_domain(); >>>> + >>>> + if (!dom || !get_raw_handled_net_accesses(dom)) >>>> + return NULL; >>>> + >>>> + return dom; >>>> +} >>>> + >>>> +static int check_socket_access(struct socket *const sock, >>>> + struct sockaddr *const address, >>>> + const int addrlen, >>>> + const access_mask_t access_request) >>>> +{ >>>> + __be16 port; >>>> + layer_mask_t layer_masks[LANDLOCK_NUM_ACCESS_NET] = {}; >>>> + const struct landlock_rule *rule; >>>> + access_mask_t handled_access; >>>> + struct landlock_id id = { >>>> + .type = LANDLOCK_KEY_NET_PORT, >>>> + }; >>>> + const struct landlock_ruleset *const domain = get_current_net_domain(); >>>> + >>>> + if (WARN_ON_ONCE(!domain)) >>> >>> The WARN_ON_ONCE() needs to be removed for processes not sandboxed. This >>> should be printed when running the tests. >>> >> Probably during the boot stage it prints once since no process is >> landlocked at this stage. >> So we need to leave it like this: >> if (!domain) >> return 0; > > Yes > > >> ???? >>> >>> >>>> + return 0; >>>> + if (WARN_ON_ONCE(domain->num_layers < 1)) >>>> + return -EACCES; >>>> + >>>> + /* Checks if it's a TCP socket. */ >>>> + if (sock->type != SOCK_STREAM) >>>> + return 0; >>>> + >>>> + /* Checks for minimal header length. */ >>>> + if (addrlen < offsetofend(struct sockaddr, sa_family)) >>> >>> You can use "typeof(*address)" instead of struct sockaddr, this makes it >>> easier to review. >>> >> Do mean to change offsetofend() by typeof(*address)?? > > No: if (addrlen < offsetofend(typeof(*address), sa_family)) > Got it. Thanks. >>> >>>> + return -EINVAL; >>>> + >>> >>> [...] >>> . > .
On Tue, May 16, 2023 at 12:13:35AM +0800, Konstantin Meskhidze wrote: > This commit adds network rules support in the ruleset management > helpers and the landlock_create_ruleset syscall. > Refactor user space API to support network actions. Add new network > access flags, network rule and network attributes. Increment Landlock > ABI version. Expand access_masks_t to u32 to be sure network access > rights can be stored. Implement socket_bind() and socket_connect() > LSM hooks, which enables to restrict TCP socket binding and connection > to specific ports. > > Co-developed-by: Mickaël Salaün <mic@digikod.net> > Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com> > --- [...] > diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c > index 8a54e87dbb17..5cb0a1bc6ec0 100644 > --- a/security/landlock/syscalls.c > +++ b/security/landlock/syscalls.c [...] > +static int add_rule_net_service(struct landlock_ruleset *ruleset, > + const void __user *const rule_attr) > +{ > +#if IS_ENABLED(CONFIG_INET) We should define two add_rule_net_service() functions according to IS_ENABLED(CONFIG_INET) instead of changing the body of the only function. The second function would only return -EAFNOSUPPORT. This cosmetic change would make the code cleaner. > + struct landlock_net_service_attr net_service_attr; > + int res; > + access_mask_t mask; > + > + /* Copies raw user space buffer, only one type for now. */ > + res = copy_from_user(&net_service_attr, rule_attr, > + sizeof(net_service_attr)); > + if (res) > + return -EFAULT; > + > + /* > + * Informs about useless rule: empty allowed_access (i.e. deny rules) > + * are ignored by network actions. > + */ > + if (!net_service_attr.allowed_access) > + return -ENOMSG; > + > + /* > + * Checks that allowed_access matches the @ruleset constraints > + * (ruleset->access_masks[0] is automatically upgraded to 64-bits). > + */ > + mask = landlock_get_net_access_mask(ruleset, 0); > + if ((net_service_attr.allowed_access | mask) != mask) > + return -EINVAL; > + > + /* Denies inserting a rule with port 0 or higher than 65535. */ > + if ((net_service_attr.port == 0) || (net_service_attr.port > U16_MAX)) > + return -EINVAL; > + > + /* Imports the new rule. */ > + return landlock_append_net_rule(ruleset, net_service_attr.port, > + net_service_attr.allowed_access); > +#else /* IS_ENABLED(CONFIG_INET) */ > + return -EAFNOSUPPORT; > +#endif /* IS_ENABLED(CONFIG_INET) */ > +}
8/3/2023 5:12 PM, Mickaël Salaün пишет: > On Tue, May 16, 2023 at 12:13:35AM +0800, Konstantin Meskhidze wrote: >> This commit adds network rules support in the ruleset management >> helpers and the landlock_create_ruleset syscall. >> Refactor user space API to support network actions. Add new network >> access flags, network rule and network attributes. Increment Landlock >> ABI version. Expand access_masks_t to u32 to be sure network access >> rights can be stored. Implement socket_bind() and socket_connect() >> LSM hooks, which enables to restrict TCP socket binding and connection >> to specific ports. >> >> Co-developed-by: Mickaël Salaün <mic@digikod.net> >> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com> >> --- > > [...] > >> diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c >> index 8a54e87dbb17..5cb0a1bc6ec0 100644 >> --- a/security/landlock/syscalls.c >> +++ b/security/landlock/syscalls.c > > [...] > >> +static int add_rule_net_service(struct landlock_ruleset *ruleset, >> + const void __user *const rule_attr) >> +{ >> +#if IS_ENABLED(CONFIG_INET) > > We should define two add_rule_net_service() functions according to > IS_ENABLED(CONFIG_INET) instead of changing the body of the only > function. The second function would only return -EAFNOSUPPORT. This > cosmetic change would make the code cleaner. Ok. Got it. > > >> + struct landlock_net_service_attr net_service_attr; >> + int res; >> + access_mask_t mask; >> + >> + /* Copies raw user space buffer, only one type for now. */ >> + res = copy_from_user(&net_service_attr, rule_attr, >> + sizeof(net_service_attr)); >> + if (res) >> + return -EFAULT; >> + >> + /* >> + * Informs about useless rule: empty allowed_access (i.e. deny rules) >> + * are ignored by network actions. >> + */ >> + if (!net_service_attr.allowed_access) >> + return -ENOMSG; >> + >> + /* >> + * Checks that allowed_access matches the @ruleset constraints >> + * (ruleset->access_masks[0] is automatically upgraded to 64-bits). >> + */ >> + mask = landlock_get_net_access_mask(ruleset, 0); >> + if ((net_service_attr.allowed_access | mask) != mask) >> + return -EINVAL; >> + >> + /* Denies inserting a rule with port 0 or higher than 65535. */ >> + if ((net_service_attr.port == 0) || (net_service_attr.port > U16_MAX)) >> + return -EINVAL; >> + >> + /* Imports the new rule. */ >> + return landlock_append_net_rule(ruleset, net_service_attr.port, >> + net_service_attr.allowed_access); >> +#else /* IS_ENABLED(CONFIG_INET) */ >> + return -EAFNOSUPPORT; >> +#endif /* IS_ENABLED(CONFIG_INET) */ >> +} > .
diff --git a/include/uapi/linux/landlock.h b/include/uapi/linux/landlock.h index 81d09ef9aa50..93794759dad4 100644 --- a/include/uapi/linux/landlock.h +++ b/include/uapi/linux/landlock.h @@ -31,6 +31,13 @@ struct landlock_ruleset_attr { * this access right. */ __u64 handled_access_fs; + + /** + * @handled_access_net: Bitmask of actions (cf. `Network flags`_) + * that is handled by this ruleset and should then be forbidden if no + * rule explicitly allow them. + */ + __u64 handled_access_net; }; /* @@ -54,6 +61,11 @@ enum landlock_rule_type { * landlock_path_beneath_attr . */ LANDLOCK_RULE_PATH_BENEATH = 1, + /** + * @LANDLOCK_RULE_NET_SERVICE: Type of a &struct + * landlock_net_service_attr . + */ + LANDLOCK_RULE_NET_SERVICE = 2, }; /** @@ -79,6 +91,23 @@ struct landlock_path_beneath_attr { */ } __attribute__((packed)); +/** + * struct landlock_net_service_attr - TCP subnet definition + * + * Argument of sys_landlock_add_rule(). + */ +struct landlock_net_service_attr { + /** + * @allowed_access: Bitmask of allowed access network for services + * (cf. `Network flags`_). + */ + __u64 allowed_access; + /** + * @port: Network port. + */ + __u64 port; +}; + /** * DOC: fs_access * @@ -189,4 +218,23 @@ struct landlock_path_beneath_attr { #define LANDLOCK_ACCESS_FS_TRUNCATE (1ULL << 14) /* clang-format on */ +/** + * DOC: net_access + * + * Network flags + * ~~~~~~~~~~~~~~~~ + * + * These flags enable to restrict a sandboxed process to a set of network + * actions. + * + * TCP sockets with allowed actions: + * + * - %LANDLOCK_ACCESS_NET_BIND_TCP: Bind a TCP socket to a local port. + * - %LANDLOCK_ACCESS_NET_CONNECT_TCP: Connect an active TCP socket to + * a remote port. + */ +/* clang-format off */ +#define LANDLOCK_ACCESS_NET_BIND_TCP (1ULL << 0) +#define LANDLOCK_ACCESS_NET_CONNECT_TCP (1ULL << 1) +/* clang-format on */ #endif /* _UAPI_LINUX_LANDLOCK_H */ diff --git a/security/landlock/Kconfig b/security/landlock/Kconfig index 8e33c4e8ffb8..10c099097533 100644 --- a/security/landlock/Kconfig +++ b/security/landlock/Kconfig @@ -3,6 +3,7 @@ config SECURITY_LANDLOCK bool "Landlock support" depends on SECURITY && !ARCH_EPHEMERAL_INODES + select SECURITY_NETWORK select SECURITY_PATH help Landlock is a sandboxing mechanism that enables processes to restrict diff --git a/security/landlock/Makefile b/security/landlock/Makefile index 7bbd2f413b3e..53d3c92ae22e 100644 --- a/security/landlock/Makefile +++ b/security/landlock/Makefile @@ -2,3 +2,5 @@ obj-$(CONFIG_SECURITY_LANDLOCK) := landlock.o landlock-y := setup.o syscalls.o object.o ruleset.o \ cred.o ptrace.o fs.o + +landlock-$(CONFIG_INET) += net.o \ No newline at end of file diff --git a/security/landlock/limits.h b/security/landlock/limits.h index bafb3b8dc677..8a1a6463c64e 100644 --- a/security/landlock/limits.h +++ b/security/landlock/limits.h @@ -23,6 +23,10 @@ #define LANDLOCK_NUM_ACCESS_FS __const_hweight64(LANDLOCK_MASK_ACCESS_FS) #define LANDLOCK_SHIFT_ACCESS_FS 0 -/* clang-format on */ +#define LANDLOCK_LAST_ACCESS_NET LANDLOCK_ACCESS_NET_CONNECT_TCP +#define LANDLOCK_MASK_ACCESS_NET ((LANDLOCK_LAST_ACCESS_NET << 1) - 1) +#define LANDLOCK_NUM_ACCESS_NET __const_hweight64(LANDLOCK_MASK_ACCESS_NET) +#define LANDLOCK_SHIFT_ACCESS_NET LANDLOCK_NUM_ACCESS_FS +/* clang-format on */ #endif /* _SECURITY_LANDLOCK_LIMITS_H */ diff --git a/security/landlock/net.c b/security/landlock/net.c new file mode 100644 index 000000000000..f8d2be53ac0d --- /dev/null +++ b/security/landlock/net.c @@ -0,0 +1,174 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Landlock LSM - Network management and hooks + * + * Copyright © 2022 Huawei Tech. Co., Ltd. + * Copyright © 2022 Microsoft Corporation + */ + +#include <linux/in.h> +#include <linux/net.h> +#include <linux/socket.h> +#include <net/ipv6.h> + +#include "common.h" +#include "cred.h" +#include "limits.h" +#include "net.h" +#include "ruleset.h" + +int landlock_append_net_rule(struct landlock_ruleset *const ruleset, + const u16 port, access_mask_t access_rights) +{ + int err; + const struct landlock_id id = { + .key.data = (__force uintptr_t)htons(port), + .type = LANDLOCK_KEY_NET_PORT, + }; + + BUILD_BUG_ON(sizeof(port) > sizeof(id.key.data)); + + /* Transforms relative access rights to absolute ones. */ + access_rights |= LANDLOCK_MASK_ACCESS_NET & + ~landlock_get_net_access_mask(ruleset, 0); + + mutex_lock(&ruleset->lock); + err = landlock_insert_rule(ruleset, id, access_rights); + mutex_unlock(&ruleset->lock); + + return err; +} + +static access_mask_t +get_raw_handled_net_accesses(const struct landlock_ruleset *const domain) +{ + access_mask_t access_dom = 0; + size_t layer_level; + + for (layer_level = 0; layer_level < domain->num_layers; layer_level++) + access_dom |= landlock_get_net_access_mask(domain, layer_level); + return access_dom; +} + +static const struct landlock_ruleset *get_current_net_domain(void) +{ + const struct landlock_ruleset *const dom = + landlock_get_current_domain(); + + if (!dom || !get_raw_handled_net_accesses(dom)) + return NULL; + + return dom; +} + +static int check_socket_access(struct socket *const sock, + struct sockaddr *const address, + const int addrlen, + const access_mask_t access_request) +{ + __be16 port; + layer_mask_t layer_masks[LANDLOCK_NUM_ACCESS_NET] = {}; + const struct landlock_rule *rule; + access_mask_t handled_access; + struct landlock_id id = { + .type = LANDLOCK_KEY_NET_PORT, + }; + const struct landlock_ruleset *const domain = get_current_net_domain(); + + if (WARN_ON_ONCE(!domain)) + return 0; + if (WARN_ON_ONCE(domain->num_layers < 1)) + return -EACCES; + + /* Checks if it's a TCP socket. */ + if (sock->type != SOCK_STREAM) + return 0; + + /* Checks for minimal header length. */ + if (addrlen < offsetofend(struct sockaddr, sa_family)) + return -EINVAL; + + switch (address->sa_family) { + case AF_UNSPEC: + case AF_INET: + if (addrlen < sizeof(struct sockaddr_in)) + return -EINVAL; + port = ((struct sockaddr_in *)address)->sin_port; + break; +#if IS_ENABLED(CONFIG_IPV6) + case AF_INET6: + if (addrlen < SIN6_LEN_RFC2133) + return -EINVAL; + port = ((struct sockaddr_in6 *)address)->sin6_port; + break; +#endif + default: + return 0; + } + + /* Specific AF_UNSPEC handling. */ + if (address->sa_family == AF_UNSPEC) { + /* + * Connecting to an address with AF_UNSPEC dissolves the TCP + * association, which have the same effect as closing the + * connection while retaining the socket object (i.e., the file + * descriptor). As for dropping privileges, closing + * connections is always allowed. + */ + if (access_request == LANDLOCK_ACCESS_NET_CONNECT_TCP) + return 0; + + /* + * For compatibility reason, accept AF_UNSPEC for bind + * accesses (mapped to AF_INET) only if the address is + * INADDR_ANY (cf. __inet_bind). Checking the address is + * required to not wrongfully return -EACCES instead of + * -EAFNOSUPPORT. + */ + if (access_request == LANDLOCK_ACCESS_NET_BIND_TCP) { + const struct sockaddr_in *const sockaddr = + (struct sockaddr_in *)address; + + if (sockaddr->sin_addr.s_addr != htonl(INADDR_ANY)) + return -EAFNOSUPPORT; + } + } + + id.key.data = (__force uintptr_t)port; + BUILD_BUG_ON(sizeof(port) > sizeof(id.key.data)); + + rule = landlock_find_rule(domain, id); + handled_access = landlock_init_layer_masks( + domain, access_request, &layer_masks, LANDLOCK_KEY_NET_PORT); + if (landlock_unmask_layers(rule, handled_access, &layer_masks, + ARRAY_SIZE(layer_masks))) + return 0; + + return -EACCES; +} + +static int hook_socket_bind(struct socket *const sock, + struct sockaddr *const address, const int addrlen) +{ + return check_socket_access(sock, address, addrlen, + LANDLOCK_ACCESS_NET_BIND_TCP); +} + +static int hook_socket_connect(struct socket *const sock, + struct sockaddr *const address, + const int addrlen) +{ + return check_socket_access(sock, address, addrlen, + LANDLOCK_ACCESS_NET_CONNECT_TCP); +} + +static struct security_hook_list landlock_hooks[] __lsm_ro_after_init = { + LSM_HOOK_INIT(socket_bind, hook_socket_bind), + LSM_HOOK_INIT(socket_connect, hook_socket_connect), +}; + +__init void landlock_add_net_hooks(void) +{ + security_add_hooks(landlock_hooks, ARRAY_SIZE(landlock_hooks), + LANDLOCK_NAME); +} diff --git a/security/landlock/net.h b/security/landlock/net.h new file mode 100644 index 000000000000..0da1d9dff5ab --- /dev/null +++ b/security/landlock/net.h @@ -0,0 +1,26 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Landlock LSM - Network management and hooks + * + * Copyright © 2022 Huawei Tech. Co., Ltd. + */ + +#ifndef _SECURITY_LANDLOCK_NET_H +#define _SECURITY_LANDLOCK_NET_H + +#include "common.h" +#include "ruleset.h" +#include "setup.h" + +#if IS_ENABLED(CONFIG_INET) +__init void landlock_add_net_hooks(void); + +int landlock_append_net_rule(struct landlock_ruleset *const ruleset, + const u16 port, access_mask_t access_rights); +#else /* IS_ENABLED(CONFIG_INET) */ +static inline void landlock_add_net_hooks(void) +{ +} +#endif /* IS_ENABLED(CONFIG_INET) */ + +#endif /* _SECURITY_LANDLOCK_NET_H */ diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c index b07ad57ee40a..fa1f45587830 100644 --- a/security/landlock/ruleset.c +++ b/security/landlock/ruleset.c @@ -36,6 +36,9 @@ static struct landlock_ruleset *create_ruleset(const u32 num_layers) refcount_set(&new_ruleset->usage, 1); mutex_init(&new_ruleset->lock); new_ruleset->root_inode = RB_ROOT; +#if IS_ENABLED(CONFIG_INET) + new_ruleset->root_net_port = RB_ROOT; +#endif /* IS_ENABLED(CONFIG_INET) */ new_ruleset->num_layers = num_layers; /* * hierarchy = NULL @@ -46,16 +49,21 @@ static struct landlock_ruleset *create_ruleset(const u32 num_layers) } struct landlock_ruleset * -landlock_create_ruleset(const access_mask_t fs_access_mask) +landlock_create_ruleset(const access_mask_t fs_access_mask, + const access_mask_t net_access_mask) { struct landlock_ruleset *new_ruleset; /* Informs about useless ruleset. */ - if (!fs_access_mask) + if (!fs_access_mask && !net_access_mask) return ERR_PTR(-ENOMSG); new_ruleset = create_ruleset(1); - if (!IS_ERR(new_ruleset)) + if (IS_ERR(new_ruleset)) + return new_ruleset; + if (fs_access_mask) landlock_add_fs_access_mask(new_ruleset, fs_access_mask, 0); + if (net_access_mask) + landlock_add_net_access_mask(new_ruleset, net_access_mask, 0); return new_ruleset; } @@ -73,6 +81,10 @@ static bool is_object_pointer(const enum landlock_key_type key_type) switch (key_type) { case LANDLOCK_KEY_INODE: return true; +#if IS_ENABLED(CONFIG_INET) + case LANDLOCK_KEY_NET_PORT: + return false; +#endif /* IS_ENABLED(CONFIG_INET) */ } WARN_ON_ONCE(1); return false; @@ -126,6 +138,11 @@ static struct rb_root *get_root(struct landlock_ruleset *const ruleset, case LANDLOCK_KEY_INODE: root = &ruleset->root_inode; break; +#if IS_ENABLED(CONFIG_INET) + case LANDLOCK_KEY_NET_PORT: + root = &ruleset->root_net_port; + break; +#endif /* IS_ENABLED(CONFIG_INET) */ } if (WARN_ON_ONCE(!root)) return ERR_PTR(-EINVAL); @@ -154,7 +171,8 @@ static void build_check_ruleset(void) BUILD_BUG_ON(ruleset.num_rules < LANDLOCK_MAX_NUM_RULES); BUILD_BUG_ON(ruleset.num_layers < LANDLOCK_MAX_NUM_LAYERS); BUILD_BUG_ON(access_masks < - (LANDLOCK_MASK_ACCESS_FS << LANDLOCK_SHIFT_ACCESS_FS)); + ((LANDLOCK_MASK_ACCESS_FS << LANDLOCK_SHIFT_ACCESS_FS) | + (LANDLOCK_MASK_ACCESS_NET << LANDLOCK_SHIFT_ACCESS_NET))); } /** @@ -373,6 +391,12 @@ static int merge_ruleset(struct landlock_ruleset *const dst, if (err) goto out_unlock; +#if IS_ENABLED(CONFIG_INET) + /* Merges the @src network port tree. */ + err = merge_tree(dst, src, LANDLOCK_KEY_NET_PORT); + if (err) + goto out_unlock; +#endif /* IS_ENABLED(CONFIG_INET) */ out_unlock: mutex_unlock(&src->lock); mutex_unlock(&dst->lock); @@ -429,6 +453,12 @@ static int inherit_ruleset(struct landlock_ruleset *const parent, if (err) goto out_unlock; +#if IS_ENABLED(CONFIG_INET) + /* Copies the @parent network port tree. */ + err = inherit_tree(parent, child, LANDLOCK_KEY_NET_PORT); + if (err) + goto out_unlock; +#endif /* IS_ENABLED(CONFIG_INET) */ if (WARN_ON_ONCE(child->num_layers <= parent->num_layers)) { err = -EINVAL; goto out_unlock; @@ -461,6 +491,11 @@ static void free_ruleset(struct landlock_ruleset *const ruleset) rbtree_postorder_for_each_entry_safe(freeme, next, &ruleset->root_inode, node) free_rule(freeme, LANDLOCK_KEY_INODE); +#if IS_ENABLED(CONFIG_INET) + rbtree_postorder_for_each_entry_safe(freeme, next, + &ruleset->root_net_port, node) + free_rule(freeme, LANDLOCK_KEY_NET_PORT); +#endif /* IS_ENABLED(CONFIG_INET) */ put_hierarchy(ruleset->hierarchy); kfree(ruleset); } @@ -641,7 +676,8 @@ get_access_mask_t(const struct landlock_ruleset *const ruleset, * * @domain: The domain that defines the current restrictions. * @access_request: The requested access rights to check. - * @layer_masks: The layer masks to populate. + * @layer_masks: It must contain LANDLOCK_NUM_ACCESS_FS or LANDLOCK_NUM_ACCESS_NET + * elements according to @key_type. * @key_type: The key type to switch between access masks of different types. * * Returns: An access mask where each access right bit is set which is handled @@ -662,6 +698,12 @@ landlock_init_layer_masks(const struct landlock_ruleset *const domain, get_access_mask = landlock_get_fs_access_mask; num_access = LANDLOCK_NUM_ACCESS_FS; break; +#if IS_ENABLED(CONFIG_INET) + case LANDLOCK_KEY_NET_PORT: + get_access_mask = landlock_get_net_access_mask; + num_access = LANDLOCK_NUM_ACCESS_NET; + break; +#endif /* IS_ENABLED(CONFIG_INET) */ default: WARN_ON_ONCE(1); return 0; diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h index 2251e6048ccf..dcf7fbac8367 100644 --- a/security/landlock/ruleset.h +++ b/security/landlock/ruleset.h @@ -33,13 +33,16 @@ typedef u16 access_mask_t; /* Makes sure all filesystem access rights can be stored. */ static_assert(BITS_PER_TYPE(access_mask_t) >= LANDLOCK_NUM_ACCESS_FS); +/* Makes sure all network access rights can be stored. */ +static_assert(BITS_PER_TYPE(access_mask_t) >= LANDLOCK_NUM_ACCESS_NET); /* Makes sure for_each_set_bit() and for_each_clear_bit() calls are OK. */ static_assert(sizeof(unsigned long) >= sizeof(access_mask_t)); /* Ruleset access masks. */ -typedef u16 access_masks_t; +typedef u32 access_masks_t; /* Makes sure all ruleset access rights can be stored. */ -static_assert(BITS_PER_TYPE(access_masks_t) >= LANDLOCK_NUM_ACCESS_FS); +static_assert(BITS_PER_TYPE(access_masks_t) >= + LANDLOCK_NUM_ACCESS_FS + LANDLOCK_NUM_ACCESS_NET); typedef u16 layer_mask_t; /* Makes sure all layers can be checked. */ @@ -84,6 +87,13 @@ enum landlock_key_type { * keys. */ LANDLOCK_KEY_INODE = 1, +#if IS_ENABLED(CONFIG_INET) + /** + * @LANDLOCK_KEY_NET_PORT: Type of &landlock_ruleset.root_net_port's + * node keys. + */ + LANDLOCK_KEY_NET_PORT = 2, +#endif /* IS_ENABLED(CONFIG_INET) */ }; /** @@ -158,6 +168,15 @@ struct landlock_ruleset { * reaches zero. */ struct rb_root root_inode; +#if IS_ENABLED(CONFIG_INET) + /** + * @root_net_port: Root of a red-black tree containing &struct + * landlock_rule nodes with network port. Once a ruleset is tied to a + * process (i.e. as a domain), this tree is immutable until @usage + * reaches zero. + */ + struct rb_root root_net_port; +#endif /* IS_ENABLED(CONFIG_INET) */ /** * @hierarchy: Enables hierarchy identification even when a parent * domain vanishes. This is needed for the ptrace protection. @@ -196,13 +215,13 @@ struct landlock_ruleset { */ u32 num_layers; /** - * @access_masks: Contains the subset of filesystem - * actions that are restricted by a ruleset. A domain - * saves all layers of merged rulesets in a stack - * (FAM), starting from the first layer to the last - * one. These layers are used when merging rulesets, - * for user space backward compatibility (i.e. - * future-proof), and to properly handle merged + * @access_masks: Contains the subset of filesystem and + * network actions that are restricted by a ruleset. + * A domain saves all layers of merged rulesets in a + * stack (FAM), starting from the first layer to the + * last one. These layers are used when merging + * rulesets, for user space backward compatibility + * (i.e. future-proof), and to properly handle merged * rulesets without overlapping access rights. These * layers are set once and never changed for the * lifetime of the ruleset. @@ -213,7 +232,8 @@ struct landlock_ruleset { }; struct landlock_ruleset * -landlock_create_ruleset(const access_mask_t access_mask); +landlock_create_ruleset(const access_mask_t access_mask_fs, + const access_mask_t access_mask_net); void landlock_put_ruleset(struct landlock_ruleset *const ruleset); void landlock_put_ruleset_deferred(struct landlock_ruleset *const ruleset); @@ -249,6 +269,19 @@ landlock_add_fs_access_mask(struct landlock_ruleset *const ruleset, (fs_mask << LANDLOCK_SHIFT_ACCESS_FS); } +static inline void +landlock_add_net_access_mask(struct landlock_ruleset *const ruleset, + const access_mask_t net_access_mask, + const u16 layer_level) +{ + access_mask_t net_mask = net_access_mask & LANDLOCK_MASK_ACCESS_NET; + + /* Should already be checked in sys_landlock_create_ruleset(). */ + WARN_ON_ONCE(net_access_mask != net_mask); + ruleset->access_masks[layer_level] |= + (net_mask << LANDLOCK_SHIFT_ACCESS_NET); +} + static inline access_mask_t landlock_get_raw_fs_access_mask(const struct landlock_ruleset *const ruleset, const u16 layer_level) @@ -266,6 +299,16 @@ landlock_get_fs_access_mask(const struct landlock_ruleset *const ruleset, return landlock_get_raw_fs_access_mask(ruleset, layer_level) | LANDLOCK_ACCESS_FS_INITIALLY_DENIED; } + +static inline access_mask_t +landlock_get_net_access_mask(const struct landlock_ruleset *const ruleset, + const u16 layer_level) +{ + return (ruleset->access_masks[layer_level] >> + LANDLOCK_SHIFT_ACCESS_NET) & + LANDLOCK_MASK_ACCESS_NET; +} + bool landlock_unmask_layers(const struct landlock_rule *const rule, const access_mask_t access_request, layer_mask_t (*const layer_masks)[], diff --git a/security/landlock/setup.c b/security/landlock/setup.c index 3f196d2ce4f9..7e4a598177b8 100644 --- a/security/landlock/setup.c +++ b/security/landlock/setup.c @@ -14,6 +14,7 @@ #include "fs.h" #include "ptrace.h" #include "setup.h" +#include "net.h" bool landlock_initialized __lsm_ro_after_init = false; @@ -29,6 +30,7 @@ static int __init landlock_init(void) landlock_add_cred_hooks(); landlock_add_ptrace_hooks(); landlock_add_fs_hooks(); + landlock_add_net_hooks(); landlock_initialized = true; pr_info("Up and running.\n"); return 0; diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c index 8a54e87dbb17..5cb0a1bc6ec0 100644 --- a/security/landlock/syscalls.c +++ b/security/landlock/syscalls.c @@ -29,6 +29,7 @@ #include "cred.h" #include "fs.h" #include "limits.h" +#include "net.h" #include "ruleset.h" #include "setup.h" @@ -74,7 +75,8 @@ static void build_check_abi(void) { struct landlock_ruleset_attr ruleset_attr; struct landlock_path_beneath_attr path_beneath_attr; - size_t ruleset_size, path_beneath_size; + struct landlock_net_service_attr net_service_attr; + size_t ruleset_size, path_beneath_size, net_service_size; /* * For each user space ABI structures, first checks that there is no @@ -82,13 +84,19 @@ static void build_check_abi(void) * struct size. */ ruleset_size = sizeof(ruleset_attr.handled_access_fs); + ruleset_size += sizeof(ruleset_attr.handled_access_net); BUILD_BUG_ON(sizeof(ruleset_attr) != ruleset_size); - BUILD_BUG_ON(sizeof(ruleset_attr) != 8); + BUILD_BUG_ON(sizeof(ruleset_attr) != 16); path_beneath_size = sizeof(path_beneath_attr.allowed_access); path_beneath_size += sizeof(path_beneath_attr.parent_fd); BUILD_BUG_ON(sizeof(path_beneath_attr) != path_beneath_size); BUILD_BUG_ON(sizeof(path_beneath_attr) != 12); + + net_service_size = sizeof(net_service_attr.allowed_access); + net_service_size += sizeof(net_service_attr.port); + BUILD_BUG_ON(sizeof(net_service_attr) != net_service_size); + BUILD_BUG_ON(sizeof(net_service_attr) != 16); } /* Ruleset handling */ @@ -129,7 +137,7 @@ static const struct file_operations ruleset_fops = { .write = fop_dummy_write, }; -#define LANDLOCK_ABI_VERSION 3 +#define LANDLOCK_ABI_VERSION 4 /** * sys_landlock_create_ruleset - Create a new ruleset @@ -188,8 +196,14 @@ SYSCALL_DEFINE3(landlock_create_ruleset, LANDLOCK_MASK_ACCESS_FS) return -EINVAL; + /* Checks network content (and 32-bits cast). */ + if ((ruleset_attr.handled_access_net | LANDLOCK_MASK_ACCESS_NET) != + LANDLOCK_MASK_ACCESS_NET) + return -EINVAL; + /* Checks arguments and transforms to kernel struct. */ - ruleset = landlock_create_ruleset(ruleset_attr.handled_access_fs); + ruleset = landlock_create_ruleset(ruleset_attr.handled_access_fs, + ruleset_attr.handled_access_net); if (IS_ERR(ruleset)) return PTR_ERR(ruleset); @@ -315,13 +329,54 @@ static int add_rule_path_beneath(struct landlock_ruleset *const ruleset, return err; } +static int add_rule_net_service(struct landlock_ruleset *ruleset, + const void __user *const rule_attr) +{ +#if IS_ENABLED(CONFIG_INET) + struct landlock_net_service_attr net_service_attr; + int res; + access_mask_t mask; + + /* Copies raw user space buffer, only one type for now. */ + res = copy_from_user(&net_service_attr, rule_attr, + sizeof(net_service_attr)); + if (res) + return -EFAULT; + + /* + * Informs about useless rule: empty allowed_access (i.e. deny rules) + * are ignored by network actions. + */ + if (!net_service_attr.allowed_access) + return -ENOMSG; + + /* + * Checks that allowed_access matches the @ruleset constraints + * (ruleset->access_masks[0] is automatically upgraded to 64-bits). + */ + mask = landlock_get_net_access_mask(ruleset, 0); + if ((net_service_attr.allowed_access | mask) != mask) + return -EINVAL; + + /* Denies inserting a rule with port 0 or higher than 65535. */ + if ((net_service_attr.port == 0) || (net_service_attr.port > U16_MAX)) + return -EINVAL; + + /* Imports the new rule. */ + return landlock_append_net_rule(ruleset, net_service_attr.port, + net_service_attr.allowed_access); +#else /* IS_ENABLED(CONFIG_INET) */ + return -EAFNOSUPPORT; +#endif /* IS_ENABLED(CONFIG_INET) */ +} + /** * sys_landlock_add_rule - Add a new rule to a ruleset * * @ruleset_fd: File descriptor tied to the ruleset that should be extended * with the new rule. - * @rule_type: Identify the structure type pointed to by @rule_attr (only - * %LANDLOCK_RULE_PATH_BENEATH for now). + * @rule_type: Identify the structure type pointed to by @rule_attr: + * %LANDLOCK_RULE_PATH_BENEATH or %LANDLOCK_RULE_NET_SERVICE. * @rule_attr: Pointer to a rule (only of type &struct * landlock_path_beneath_attr for now). * @flags: Must be 0. @@ -332,6 +387,8 @@ static int add_rule_path_beneath(struct landlock_ruleset *const ruleset, * Possible returned errors are: * * - %EOPNOTSUPP: Landlock is supported by the kernel but disabled at boot time; + * - %EAFNOSUPPORT: @rule_type is LANDLOCK_RULE_NET_SERVICE but TCP/IP is not + * supported by the running kernel; * - %EINVAL: @flags is not 0, or inconsistent access in the rule (i.e. * &landlock_path_beneath_attr.allowed_access is not a subset of the * ruleset handled accesses); @@ -366,6 +423,9 @@ SYSCALL_DEFINE4(landlock_add_rule, const int, ruleset_fd, case LANDLOCK_RULE_PATH_BENEATH: err = add_rule_path_beneath(ruleset, rule_attr); break; + case LANDLOCK_RULE_NET_SERVICE: + err = add_rule_net_service(ruleset, rule_attr); + break; default: err = -EINVAL; break; diff --git a/tools/testing/selftests/landlock/base_test.c b/tools/testing/selftests/landlock/base_test.c index 792c3f0a59b4..646f778dfb1e 100644 --- a/tools/testing/selftests/landlock/base_test.c +++ b/tools/testing/selftests/landlock/base_test.c @@ -75,7 +75,7 @@ TEST(abi_version) const struct landlock_ruleset_attr ruleset_attr = { .handled_access_fs = LANDLOCK_ACCESS_FS_READ_FILE, }; - ASSERT_EQ(3, landlock_create_ruleset(NULL, 0, + ASSERT_EQ(4, landlock_create_ruleset(NULL, 0, LANDLOCK_CREATE_RULESET_VERSION)); ASSERT_EQ(-1, landlock_create_ruleset(&ruleset_attr, 0,
This commit adds network rules support in the ruleset management helpers and the landlock_create_ruleset syscall. Refactor user space API to support network actions. Add new network access flags, network rule and network attributes. Increment Landlock ABI version. Expand access_masks_t to u32 to be sure network access rights can be stored. Implement socket_bind() and socket_connect() LSM hooks, which enables to restrict TCP socket binding and connection to specific ports. Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com> --- Changes since v10: * Removes "packed" attribute. * Applies Mickaёl's patch with some refactoring. * Deletes get_port() and check_addrlen() helpers. * Refactors check_socket_access() by squashing get_port() and check_addrlen() helpers into it. * Fixes commit message. Changes since v9: * Changes UAPI port field to __u64. * Moves shared code into check_socket_access(). * Adds get_raw_handled_net_accesses() and get_current_net_domain() helpers. * Minor fixes. Changes since v8: * Squashes commits. * Refactors commit message. * Changes UAPI port field to __be16. * Changes logic of bind/connect hooks with AF_UNSPEC families. * Adds address length checking. * Minor fixes. Changes since v7: * Squashes commits. * Increments ABI version to 4. * Refactors commit message. * Minor fixes. Changes since v6: * Renames landlock_set_net_access_mask() to landlock_add_net_access_mask() because it OR values. * Makes landlock_add_net_access_mask() more resilient incorrect values. * Refactors landlock_get_net_access_mask(). * Renames LANDLOCK_MASK_SHIFT_NET to LANDLOCK_SHIFT_ACCESS_NET and use LANDLOCK_NUM_ACCESS_FS as value. * Updates access_masks_t to u32 to support network access actions. * Refactors landlock internal functions to support network actions with landlock_key/key_type/id types. Changes since v5: * Gets rid of partial revert from landlock_add_rule syscall. * Formats code with clang-format-14. Changes since v4: * Refactors landlock_create_ruleset() - splits ruleset and masks checks. * Refactors landlock_create_ruleset() and landlock mask setters/getters to support two rule types. * Refactors landlock_add_rule syscall add_rule_path_beneath function by factoring out get_ruleset_from_fd() and landlock_put_ruleset(). Changes since v3: * Splits commit. * Adds network rule support for internal landlock functions. * Adds set_mask and get_mask for network. * Adds rb_root root_net_port. --- include/uapi/linux/landlock.h | 48 +++++ security/landlock/Kconfig | 1 + security/landlock/Makefile | 2 + security/landlock/limits.h | 6 +- security/landlock/net.c | 174 +++++++++++++++++++ security/landlock/net.h | 26 +++ security/landlock/ruleset.c | 52 +++++- security/landlock/ruleset.h | 63 +++++-- security/landlock/setup.c | 2 + security/landlock/syscalls.c | 72 +++++++- tools/testing/selftests/landlock/base_test.c | 2 +- 11 files changed, 425 insertions(+), 23 deletions(-) create mode 100644 security/landlock/net.c create mode 100644 security/landlock/net.h -- 2.25.1