| Message ID | 20221123201552.7865-3-casey@schaufler-ca.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Paul Moore |
| Headers | show |
| Series | LSM: Three basic syscalls | expand |
On 23/11/2022 21:15, Casey Schaufler wrote: > Add an integer member "attrs_used" to the struct lsm_id which > identifies the API related data associated with each security > module. The initial set of features maps to information that > has traditionaly been available in /proc/self/attr. They are > documented in a new userspace-api file. > > Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> > --- > Documentation/userspace-api/index.rst | 1 + > Documentation/userspace-api/lsm.rst | 55 +++++++++++++++++++++++++++ > include/linux/lsm_hooks.h | 2 + > include/uapi/linux/lsm.h | 12 ++++++ > security/apparmor/lsm.c | 1 + > security/selinux/hooks.c | 2 + > security/smack/smack_lsm.c | 1 + > 7 files changed, 74 insertions(+) > create mode 100644 Documentation/userspace-api/lsm.rst > > diff --git a/Documentation/userspace-api/index.rst b/Documentation/userspace-api/index.rst > index c78da9ce0ec4..6feff0fcd88f 100644 > --- a/Documentation/userspace-api/index.rst > +++ b/Documentation/userspace-api/index.rst > @@ -30,6 +30,7 @@ place where this information is gathered. > sysfs-platform_profile > vduse > futex2 > + lsm > > .. only:: subproject and html > > diff --git a/Documentation/userspace-api/lsm.rst b/Documentation/userspace-api/lsm.rst > new file mode 100644 > index 000000000000..6ddf5506110b > --- /dev/null > +++ b/Documentation/userspace-api/lsm.rst > @@ -0,0 +1,55 @@ > +.. SPDX-License-Identifier: GPL-2.0 > +.. Copyright (C) 2022 Casey Schaufler <casey@schaufler-ca.com> > +.. Copyright (C) 2022 Intel Corporation > + > +===================================== > +Linux Security Modules > +===================================== > + > +:Author: Casey Schaufler > +:Date: November 2022 > + > +Linux security modules (LSM) provide a mechanism to implement > +additional access controls to the Linux security policies. > + > +The various security modules may support any of these attributes: > + > +``LSM_ATTR_CURRENT`` is the current, active security context of the > +process. > +The proc filesystem provides this value in ``/proc/self/attr/current``. > +This is supported by the SELinux, Smack and AppArmor security modules. > +Smack also provides this value in ``/proc/self/attr/smack/current``. > +AppArmor also provides this value in ``/proc/self/attr/apparmor/current``. > + > +``LSM_ATTR_EXEC`` is the security context of the process at the time the > +current image was executed. > +The proc filesystem provides this value in ``/proc/self/attr/exec``. > +This is supported by the SELinux and AppArmor security modules. > +AppArmor also provides this value in ``/proc/self/attr/apparmor/exec``. > + > +``LSM_ATTR_FSCREATE`` is the security context of the process used when > +creating file system objects. > +The proc filesystem provides this value in ``/proc/self/attr/fscreate``. > +This is supported by the SELinux security module. > + > +``LSM_ATTR_KEYCREATE`` is the security context of the process used when > +creating key objects. > +The proc filesystem provides this value in ``/proc/self/attr/keycreate``. > +This is supported by the SELinux security module. > + > +``LSM_ATTR_PREV`` is the security context of the process at the time the > +current security context was set. > +The proc filesystem provides this value in ``/proc/self/attr/prev``. > +This is supported by the SELinux and AppArmor security modules. > +AppArmor also provides this value in ``/proc/self/attr/apparmor/prev``. > + > +``LSM_ATTR_SOCKCREATE`` is the security context of the process used when > +creating socket objects. > +The proc filesystem provides this value in ``/proc/self/attr/sockcreate``. > +This is supported by the SELinux security module. > + > +Additional documentation > +======================== > + > +* Documentation/security/lsm.rst > +* Documentation/security/lsm-development.rst > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h > index d306db1044d1..7e88acc37a29 100644 > --- a/include/linux/lsm_hooks.h > +++ b/include/linux/lsm_hooks.h > @@ -1606,12 +1606,14 @@ struct security_hook_heads { > * struct lsm_id - identify a Linux Security Module. > * @lsm: Name of the LSM. Must be approved by the LSM maintainers. > * @id: LSM ID number from uapi/linux/lsm.h > + * @attrs_used: Which attributes this LSM supports. > * > * Contains the information that identifies the LSM. > */ > struct lsm_id { > const u8 *lsm; > u32 id; > + u64 attrs_used; I'd prefer this field to be part of the previous patch. This doesn't change much but it is to highlight that the struct lsm_id size should not change unless properly handled by userspace. > }; > > /* > diff --git a/include/uapi/linux/lsm.h b/include/uapi/linux/lsm.h > index 47791c330cbf..8e9124bf622c 100644 > --- a/include/uapi/linux/lsm.h > +++ b/include/uapi/linux/lsm.h > @@ -29,4 +29,16 @@ > #define LSM_ID_BPF 110 > #define LSM_ID_LANDLOCK 111 > > +/* > + * LSM_ATTR_XXX values identify the /proc/.../attr entry that the > + * context represents. Not all security modules provide all of these > + * values. Some security modules provide none of them. > + */ > +#define LSM_ATTR_CURRENT 0x0001 > +#define LSM_ATTR_EXEC 0x0002 > +#define LSM_ATTR_FSCREATE 0x0004 > +#define LSM_ATTR_KEYCREATE 0x0008 > +#define LSM_ATTR_PREV 0x0010 > +#define LSM_ATTR_SOCKCREATE 0x0020 > + > #endif /* _UAPI_LINUX_LSM_H */ > diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c > index b859b1af6c75..3a6bf4f95d84 100644 > --- a/security/apparmor/lsm.c > +++ b/security/apparmor/lsm.c > @@ -1206,6 +1206,7 @@ struct lsm_blob_sizes apparmor_blob_sizes __lsm_ro_after_init = { > static struct lsm_id apparmor_lsmid __lsm_ro_after_init = { > .lsm = "apparmor", > .id = LSM_ID_APPARMOR, > + .attrs_used = LSM_ATTR_CURRENT | LSM_ATTR_PREV | LSM_ATTR_EXEC, > }; > > static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = { > diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c > index 5fcce36267bd..e831d9c38c54 100644 > --- a/security/selinux/hooks.c > +++ b/security/selinux/hooks.c > @@ -7018,6 +7018,8 @@ static int selinux_uring_cmd(struct io_uring_cmd *ioucmd) > static struct lsm_id selinux_lsmid __lsm_ro_after_init = { > .lsm = "selinux", > .id = LSM_ID_SELINUX, > + .attrs_used = LSM_ATTR_CURRENT | LSM_ATTR_EXEC | LSM_ATTR_FSCREATE | > + LSM_ATTR_KEYCREATE | LSM_ATTR_PREV | LSM_ATTR_SOCKCREATE, > }; > > /* > diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c > index c7ba80e20b8d..c2a05217bde4 100644 > --- a/security/smack/smack_lsm.c > +++ b/security/smack/smack_lsm.c > @@ -4791,6 +4791,7 @@ struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = { > static struct lsm_id smack_lsmid __lsm_ro_after_init = { > .lsm = "smack", > .id = LSM_ID_SMACK, > + .attrs_used = LSM_ATTR_CURRENT, > }; > > static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
On 11/25/2022 8:41 AM, Mickaël Salaün wrote: > > On 23/11/2022 21:15, Casey Schaufler wrote: >> Add an integer member "attrs_used" to the struct lsm_id which >> identifies the API related data associated with each security >> module. The initial set of features maps to information that >> has traditionaly been available in /proc/self/attr. They are >> documented in a new userspace-api file. >> >> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> >> --- >> Documentation/userspace-api/index.rst | 1 + >> Documentation/userspace-api/lsm.rst | 55 +++++++++++++++++++++++++++ >> include/linux/lsm_hooks.h | 2 + >> include/uapi/linux/lsm.h | 12 ++++++ >> security/apparmor/lsm.c | 1 + >> security/selinux/hooks.c | 2 + >> security/smack/smack_lsm.c | 1 + >> 7 files changed, 74 insertions(+) >> create mode 100644 Documentation/userspace-api/lsm.rst >> >> diff --git a/Documentation/userspace-api/index.rst >> b/Documentation/userspace-api/index.rst >> index c78da9ce0ec4..6feff0fcd88f 100644 >> --- a/Documentation/userspace-api/index.rst >> +++ b/Documentation/userspace-api/index.rst >> @@ -30,6 +30,7 @@ place where this information is gathered. >> sysfs-platform_profile >> vduse >> futex2 >> + lsm >> .. only:: subproject and html >> diff --git a/Documentation/userspace-api/lsm.rst >> b/Documentation/userspace-api/lsm.rst >> new file mode 100644 >> index 000000000000..6ddf5506110b >> --- /dev/null >> +++ b/Documentation/userspace-api/lsm.rst >> @@ -0,0 +1,55 @@ >> +.. SPDX-License-Identifier: GPL-2.0 >> +.. Copyright (C) 2022 Casey Schaufler <casey@schaufler-ca.com> >> +.. Copyright (C) 2022 Intel Corporation >> + >> +===================================== >> +Linux Security Modules >> +===================================== >> + >> +:Author: Casey Schaufler >> +:Date: November 2022 >> + >> +Linux security modules (LSM) provide a mechanism to implement >> +additional access controls to the Linux security policies. >> + >> +The various security modules may support any of these attributes: >> + >> +``LSM_ATTR_CURRENT`` is the current, active security context of the >> +process. >> +The proc filesystem provides this value in ``/proc/self/attr/current``. >> +This is supported by the SELinux, Smack and AppArmor security modules. >> +Smack also provides this value in ``/proc/self/attr/smack/current``. >> +AppArmor also provides this value in >> ``/proc/self/attr/apparmor/current``. >> + >> +``LSM_ATTR_EXEC`` is the security context of the process at the time >> the >> +current image was executed. >> +The proc filesystem provides this value in ``/proc/self/attr/exec``. >> +This is supported by the SELinux and AppArmor security modules. >> +AppArmor also provides this value in ``/proc/self/attr/apparmor/exec``. >> + >> +``LSM_ATTR_FSCREATE`` is the security context of the process used when >> +creating file system objects. >> +The proc filesystem provides this value in >> ``/proc/self/attr/fscreate``. >> +This is supported by the SELinux security module. >> + >> +``LSM_ATTR_KEYCREATE`` is the security context of the process used when >> +creating key objects. >> +The proc filesystem provides this value in >> ``/proc/self/attr/keycreate``. >> +This is supported by the SELinux security module. >> + >> +``LSM_ATTR_PREV`` is the security context of the process at the time >> the >> +current security context was set. >> +The proc filesystem provides this value in ``/proc/self/attr/prev``. >> +This is supported by the SELinux and AppArmor security modules. >> +AppArmor also provides this value in ``/proc/self/attr/apparmor/prev``. >> + >> +``LSM_ATTR_SOCKCREATE`` is the security context of the process used >> when >> +creating socket objects. >> +The proc filesystem provides this value in >> ``/proc/self/attr/sockcreate``. >> +This is supported by the SELinux security module. >> + >> +Additional documentation >> +======================== >> + >> +* Documentation/security/lsm.rst >> +* Documentation/security/lsm-development.rst >> diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h >> index d306db1044d1..7e88acc37a29 100644 >> --- a/include/linux/lsm_hooks.h >> +++ b/include/linux/lsm_hooks.h >> @@ -1606,12 +1606,14 @@ struct security_hook_heads { >> * struct lsm_id - identify a Linux Security Module. >> * @lsm: Name of the LSM. Must be approved by the LSM maintainers. >> * @id: LSM ID number from uapi/linux/lsm.h >> + * @attrs_used: Which attributes this LSM supports. >> * >> * Contains the information that identifies the LSM. >> */ >> struct lsm_id { >> const u8 *lsm; >> u32 id; >> + u64 attrs_used; > > I'd prefer this field to be part of the previous patch. This doesn't > change much but it is to highlight that the struct lsm_id size should > not change unless properly handled by userspace. Sigh. Given my druthers there would be a lot fewer, but somewhat larger, patches in this set. I will happily make this change, but fear reprisal from those who want a bizzilion tiny patches. (You know who you are) Also note that this is not an externally visible structure, and that the lsm_ctx structure that is user visible hasn't been introduced yet. > > >> }; >> /* >> diff --git a/include/uapi/linux/lsm.h b/include/uapi/linux/lsm.h >> index 47791c330cbf..8e9124bf622c 100644 >> --- a/include/uapi/linux/lsm.h >> +++ b/include/uapi/linux/lsm.h >> @@ -29,4 +29,16 @@ >> #define LSM_ID_BPF 110 >> #define LSM_ID_LANDLOCK 111 >> +/* >> + * LSM_ATTR_XXX values identify the /proc/.../attr entry that the >> + * context represents. Not all security modules provide all of these >> + * values. Some security modules provide none of them. >> + */ >> +#define LSM_ATTR_CURRENT 0x0001 >> +#define LSM_ATTR_EXEC 0x0002 >> +#define LSM_ATTR_FSCREATE 0x0004 >> +#define LSM_ATTR_KEYCREATE 0x0008 >> +#define LSM_ATTR_PREV 0x0010 >> +#define LSM_ATTR_SOCKCREATE 0x0020 >> + >> #endif /* _UAPI_LINUX_LSM_H */ >> diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c >> index b859b1af6c75..3a6bf4f95d84 100644 >> --- a/security/apparmor/lsm.c >> +++ b/security/apparmor/lsm.c >> @@ -1206,6 +1206,7 @@ struct lsm_blob_sizes apparmor_blob_sizes >> __lsm_ro_after_init = { >> static struct lsm_id apparmor_lsmid __lsm_ro_after_init = { >> .lsm = "apparmor", >> .id = LSM_ID_APPARMOR, >> + .attrs_used = LSM_ATTR_CURRENT | LSM_ATTR_PREV | LSM_ATTR_EXEC, >> }; >> static struct security_hook_list apparmor_hooks[] >> __lsm_ro_after_init = { >> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c >> index 5fcce36267bd..e831d9c38c54 100644 >> --- a/security/selinux/hooks.c >> +++ b/security/selinux/hooks.c >> @@ -7018,6 +7018,8 @@ static int selinux_uring_cmd(struct >> io_uring_cmd *ioucmd) >> static struct lsm_id selinux_lsmid __lsm_ro_after_init = { >> .lsm = "selinux", >> .id = LSM_ID_SELINUX, >> + .attrs_used = LSM_ATTR_CURRENT | LSM_ATTR_EXEC | >> LSM_ATTR_FSCREATE | >> + LSM_ATTR_KEYCREATE | LSM_ATTR_PREV | LSM_ATTR_SOCKCREATE, >> }; >> /* >> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c >> index c7ba80e20b8d..c2a05217bde4 100644 >> --- a/security/smack/smack_lsm.c >> +++ b/security/smack/smack_lsm.c >> @@ -4791,6 +4791,7 @@ struct lsm_blob_sizes smack_blob_sizes >> __lsm_ro_after_init = { >> static struct lsm_id smack_lsmid __lsm_ro_after_init = { >> .lsm = "smack", >> .id = LSM_ID_SMACK, >> + .attrs_used = LSM_ATTR_CURRENT, >> }; >> static struct security_hook_list smack_hooks[] >> __lsm_ro_after_init = {
diff --git a/Documentation/userspace-api/index.rst b/Documentation/userspace-api/index.rst index c78da9ce0ec4..6feff0fcd88f 100644 --- a/Documentation/userspace-api/index.rst +++ b/Documentation/userspace-api/index.rst @@ -30,6 +30,7 @@ place where this information is gathered. sysfs-platform_profile vduse futex2 + lsm .. only:: subproject and html diff --git a/Documentation/userspace-api/lsm.rst b/Documentation/userspace-api/lsm.rst new file mode 100644 index 000000000000..6ddf5506110b --- /dev/null +++ b/Documentation/userspace-api/lsm.rst @@ -0,0 +1,55 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. Copyright (C) 2022 Casey Schaufler <casey@schaufler-ca.com> +.. Copyright (C) 2022 Intel Corporation + +===================================== +Linux Security Modules +===================================== + +:Author: Casey Schaufler +:Date: November 2022 + +Linux security modules (LSM) provide a mechanism to implement +additional access controls to the Linux security policies. + +The various security modules may support any of these attributes: + +``LSM_ATTR_CURRENT`` is the current, active security context of the +process. +The proc filesystem provides this value in ``/proc/self/attr/current``. +This is supported by the SELinux, Smack and AppArmor security modules. +Smack also provides this value in ``/proc/self/attr/smack/current``. +AppArmor also provides this value in ``/proc/self/attr/apparmor/current``. + +``LSM_ATTR_EXEC`` is the security context of the process at the time the +current image was executed. +The proc filesystem provides this value in ``/proc/self/attr/exec``. +This is supported by the SELinux and AppArmor security modules. +AppArmor also provides this value in ``/proc/self/attr/apparmor/exec``. + +``LSM_ATTR_FSCREATE`` is the security context of the process used when +creating file system objects. +The proc filesystem provides this value in ``/proc/self/attr/fscreate``. +This is supported by the SELinux security module. + +``LSM_ATTR_KEYCREATE`` is the security context of the process used when +creating key objects. +The proc filesystem provides this value in ``/proc/self/attr/keycreate``. +This is supported by the SELinux security module. + +``LSM_ATTR_PREV`` is the security context of the process at the time the +current security context was set. +The proc filesystem provides this value in ``/proc/self/attr/prev``. +This is supported by the SELinux and AppArmor security modules. +AppArmor also provides this value in ``/proc/self/attr/apparmor/prev``. + +``LSM_ATTR_SOCKCREATE`` is the security context of the process used when +creating socket objects. +The proc filesystem provides this value in ``/proc/self/attr/sockcreate``. +This is supported by the SELinux security module. + +Additional documentation +======================== + +* Documentation/security/lsm.rst +* Documentation/security/lsm-development.rst diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index d306db1044d1..7e88acc37a29 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -1606,12 +1606,14 @@ struct security_hook_heads { * struct lsm_id - identify a Linux Security Module. * @lsm: Name of the LSM. Must be approved by the LSM maintainers. * @id: LSM ID number from uapi/linux/lsm.h + * @attrs_used: Which attributes this LSM supports. * * Contains the information that identifies the LSM. */ struct lsm_id { const u8 *lsm; u32 id; + u64 attrs_used; }; /* diff --git a/include/uapi/linux/lsm.h b/include/uapi/linux/lsm.h index 47791c330cbf..8e9124bf622c 100644 --- a/include/uapi/linux/lsm.h +++ b/include/uapi/linux/lsm.h @@ -29,4 +29,16 @@ #define LSM_ID_BPF 110 #define LSM_ID_LANDLOCK 111 +/* + * LSM_ATTR_XXX values identify the /proc/.../attr entry that the + * context represents. Not all security modules provide all of these + * values. Some security modules provide none of them. + */ +#define LSM_ATTR_CURRENT 0x0001 +#define LSM_ATTR_EXEC 0x0002 +#define LSM_ATTR_FSCREATE 0x0004 +#define LSM_ATTR_KEYCREATE 0x0008 +#define LSM_ATTR_PREV 0x0010 +#define LSM_ATTR_SOCKCREATE 0x0020 + #endif /* _UAPI_LINUX_LSM_H */ diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c index b859b1af6c75..3a6bf4f95d84 100644 --- a/security/apparmor/lsm.c +++ b/security/apparmor/lsm.c @@ -1206,6 +1206,7 @@ struct lsm_blob_sizes apparmor_blob_sizes __lsm_ro_after_init = { static struct lsm_id apparmor_lsmid __lsm_ro_after_init = { .lsm = "apparmor", .id = LSM_ID_APPARMOR, + .attrs_used = LSM_ATTR_CURRENT | LSM_ATTR_PREV | LSM_ATTR_EXEC, }; static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = { diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 5fcce36267bd..e831d9c38c54 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -7018,6 +7018,8 @@ static int selinux_uring_cmd(struct io_uring_cmd *ioucmd) static struct lsm_id selinux_lsmid __lsm_ro_after_init = { .lsm = "selinux", .id = LSM_ID_SELINUX, + .attrs_used = LSM_ATTR_CURRENT | LSM_ATTR_EXEC | LSM_ATTR_FSCREATE | + LSM_ATTR_KEYCREATE | LSM_ATTR_PREV | LSM_ATTR_SOCKCREATE, }; /* diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index c7ba80e20b8d..c2a05217bde4 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -4791,6 +4791,7 @@ struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = { static struct lsm_id smack_lsmid __lsm_ro_after_init = { .lsm = "smack", .id = LSM_ID_SMACK, + .attrs_used = LSM_ATTR_CURRENT, }; static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
Add an integer member "attrs_used" to the struct lsm_id which identifies the API related data associated with each security module. The initial set of features maps to information that has traditionaly been available in /proc/self/attr. They are documented in a new userspace-api file. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> --- Documentation/userspace-api/index.rst | 1 + Documentation/userspace-api/lsm.rst | 55 +++++++++++++++++++++++++++ include/linux/lsm_hooks.h | 2 + include/uapi/linux/lsm.h | 12 ++++++ security/apparmor/lsm.c | 1 + security/selinux/hooks.c | 2 + security/smack/smack_lsm.c | 1 + 7 files changed, 74 insertions(+) create mode 100644 Documentation/userspace-api/lsm.rst