| Message ID | 20201116232536.1752908-1-kpsingh@chromium.org (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | [bpf-next,v2,1/2] bpf: Add bpf_lsm_set_bprm_opts helper | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Link |
| netdev/fixes_present | success | Link |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Clearly marked for bpf-next |
| netdev/subject_prefix | success | Link |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | fail | Errors and warnings before: 15751 this patch: 15752 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | warning | CHECK: Blank lines aren't necessary after an open brace '{' |
| netdev/build_allmodconfig_warn | fail | Errors and warnings before: 15663 this patch: 15664 |
| netdev/header_inline | success | Link |
| netdev/stable | success | Stable not CCed |
On Mon, Nov 16, 2020 at 11:25:35PM +0000, KP Singh wrote: > From: KP Singh <kpsingh@google.com> > > The helper allows modification of certain bits on the linux_binprm > struct starting with the secureexec bit which can be updated using the > BPF_LSM_F_BPRM_SECUREEXEC flag. > > secureexec can be set by the LSM for privilege gaining executions to set > the AT_SECURE auxv for glibc. When set, the dynamic linker disables the > use of certain environment variables (like LD_PRELOAD). > > Signed-off-by: KP Singh <kpsingh@google.com> > --- > include/uapi/linux/bpf.h | 14 ++++++++++++++ > kernel/bpf/bpf_lsm.c | 27 +++++++++++++++++++++++++++ > scripts/bpf_helpers_doc.py | 2 ++ > tools/include/uapi/linux/bpf.h | 14 ++++++++++++++ > 4 files changed, 57 insertions(+) > > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h > index 162999b12790..7f1b6ba8246c 100644 > --- a/include/uapi/linux/bpf.h > +++ b/include/uapi/linux/bpf.h > @@ -3787,6 +3787,14 @@ union bpf_attr { > * *ARG_PTR_TO_BTF_ID* of type *task_struct*. > * Return > * Pointer to the current task. > + * > + * long bpf_lsm_set_bprm_opts(struct linux_binprm *bprm, u64 flags) > + * > + * Description > + * Sets certain options on the *bprm*: > + * > + * **BPF_LSM_F_BPRM_SECUREEXEC** Set the secureexec bit > + * which sets the **AT_SECURE** auxv for glibc. The return value needs to be documented also. > */ > #define __BPF_FUNC_MAPPER(FN) \ > FN(unspec), \ > @@ -3948,6 +3956,7 @@ union bpf_attr { > FN(task_storage_get), \ > FN(task_storage_delete), \ > FN(get_current_task_btf), \ > + FN(lsm_set_bprm_opts), \ > /* */ > > /* integer value in 'imm' field of BPF_CALL instruction selects which helper > @@ -4119,6 +4128,11 @@ enum bpf_lwt_encap_mode { > BPF_LWT_ENCAP_IP, > }; > > +/* Flags for LSM helpers */ > +enum { > + BPF_LSM_F_BPRM_SECUREEXEC = (1ULL << 0), > +}; > + > #define __bpf_md_ptr(type, name) \ > union { \ > type name; \ > diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c > index 553107f4706a..31f85474a0ef 100644 > --- a/kernel/bpf/bpf_lsm.c > +++ b/kernel/bpf/bpf_lsm.c > @@ -7,6 +7,7 @@ > #include <linux/filter.h> > #include <linux/bpf.h> > #include <linux/btf.h> > +#include <linux/binfmts.h> > #include <linux/lsm_hooks.h> > #include <linux/bpf_lsm.h> > #include <linux/kallsyms.h> > @@ -51,6 +52,30 @@ int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog, > return 0; > } > > +/* Mask for all the currently supported BPRM option flags */ > +#define BPF_LSM_F_BRPM_OPTS_MASK 0x1ULL If there is a need to have v3, it will be better to use BPF_LSM_F_BPRM_SECUREEXEC instead of 0x1ULL. > + > +BPF_CALL_2(bpf_lsm_set_bprm_opts, struct linux_binprm *, bprm, u64, flags) > +{ > + > + if (flags & ~BPF_LSM_F_BRPM_OPTS_MASK) > + return -EINVAL; > + > + bprm->secureexec = (flags & BPF_LSM_F_BPRM_SECUREEXEC); The intention of this helper is to set "or clear" a bit? It may be useful to clarify the "clear" part in the doc also. > + return 0; > +} > +
On Tue, Nov 17, 2020 at 1:11 AM Martin KaFai Lau <kafai@fb.com> wrote: > > On Mon, Nov 16, 2020 at 11:25:35PM +0000, KP Singh wrote: > > From: KP Singh <kpsingh@google.com> > > > > The helper allows modification of certain bits on the linux_binprm > > struct starting with the secureexec bit which can be updated using the > > BPF_LSM_F_BPRM_SECUREEXEC flag. > > > > secureexec can be set by the LSM for privilege gaining executions to set > > the AT_SECURE auxv for glibc. When set, the dynamic linker disables the > > use of certain environment variables (like LD_PRELOAD). > > > > Signed-off-by: KP Singh <kpsingh@google.com> > > --- > > include/uapi/linux/bpf.h | 14 ++++++++++++++ > > kernel/bpf/bpf_lsm.c | 27 +++++++++++++++++++++++++++ > > scripts/bpf_helpers_doc.py | 2 ++ > > tools/include/uapi/linux/bpf.h | 14 ++++++++++++++ > > 4 files changed, 57 insertions(+) > > > > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h > > index 162999b12790..7f1b6ba8246c 100644 > > --- a/include/uapi/linux/bpf.h > > +++ b/include/uapi/linux/bpf.h > > @@ -3787,6 +3787,14 @@ union bpf_attr { > > * *ARG_PTR_TO_BTF_ID* of type *task_struct*. > > * Return > > * Pointer to the current task. > > + * > > + * long bpf_lsm_set_bprm_opts(struct linux_binprm *bprm, u64 flags) > > + * > > + * Description > > + * Sets certain options on the *bprm*: > > + * > > + * **BPF_LSM_F_BPRM_SECUREEXEC** Set the secureexec bit > > + * which sets the **AT_SECURE** auxv for glibc. > The return value needs to be documented also. Done. > > > */ > > #define __BPF_FUNC_MAPPER(FN) \ > > FN(unspec), \ > > @@ -3948,6 +3956,7 @@ union bpf_attr { > > FN(task_storage_get), \ > > FN(task_storage_delete), \ > > FN(get_current_task_btf), \ > > + FN(lsm_set_bprm_opts), \ > > /* */ > > > > /* integer value in 'imm' field of BPF_CALL instruction selects which helper > > @@ -4119,6 +4128,11 @@ enum bpf_lwt_encap_mode { > > BPF_LWT_ENCAP_IP, > > }; > > > > +/* Flags for LSM helpers */ > > +enum { > > + BPF_LSM_F_BPRM_SECUREEXEC = (1ULL << 0), > > +}; > > + > > #define __bpf_md_ptr(type, name) \ > > union { \ > > type name; \ > > diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c > > index 553107f4706a..31f85474a0ef 100644 > > --- a/kernel/bpf/bpf_lsm.c > > +++ b/kernel/bpf/bpf_lsm.c > > @@ -7,6 +7,7 @@ > > #include <linux/filter.h> > > #include <linux/bpf.h> > > #include <linux/btf.h> > > +#include <linux/binfmts.h> > > #include <linux/lsm_hooks.h> > > #include <linux/bpf_lsm.h> > > #include <linux/kallsyms.h> > > @@ -51,6 +52,30 @@ int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog, > > return 0; > > } > > > > +/* Mask for all the currently supported BPRM option flags */ > > +#define BPF_LSM_F_BRPM_OPTS_MASK 0x1ULL > If there is a need to have v3, it will be better to use > BPF_LSM_F_BPRM_SECUREEXEC instead of 0x1ULL. Done. > > > + > > +BPF_CALL_2(bpf_lsm_set_bprm_opts, struct linux_binprm *, bprm, u64, flags) > > +{ > > + > > + if (flags & ~BPF_LSM_F_BRPM_OPTS_MASK) > > + return -EINVAL; > > + > > + bprm->secureexec = (flags & BPF_LSM_F_BPRM_SECUREEXEC); > The intention of this helper is to set "or clear" a bit? > It may be useful to clarify the "clear" part in the doc also. Updated the docs: * long bpf_lsm_set_bprm_opts(struct linux_binprm *bprm, u64 flags) * * Description * Set or clear certain options on *bprm*: * * **BPF_LSM_F_BPRM_SECUREEXEC** Set the secureexec bit * which sets the **AT_SECURE** auxv for glibc. The bit is * is cleared if the flag is not specified. * Return * **-EINVAL** if invalid *flags* are passed. > > > + return 0; > > +} > > +
On Tue, Nov 17, 2020 at 3:03 AM KP Singh <kpsingh@chromium.org> wrote: > > On Tue, Nov 17, 2020 at 1:11 AM Martin KaFai Lau <kafai@fb.com> wrote: > > > > On Mon, Nov 16, 2020 at 11:25:35PM +0000, KP Singh wrote: > > > From: KP Singh <kpsingh@google.com> > > > > > > The helper allows modification of certain bits on the linux_binprm > > > struct starting with the secureexec bit which can be updated using the > > > BPF_LSM_F_BPRM_SECUREEXEC flag. > > > > > > secureexec can be set by the LSM for privilege gaining executions to set > > > the AT_SECURE auxv for glibc. When set, the dynamic linker disables the > > > use of certain environment variables (like LD_PRELOAD). > > > > > > Signed-off-by: KP Singh <kpsingh@google.com> > > > --- > > > include/uapi/linux/bpf.h | 14 ++++++++++++++ > > > kernel/bpf/bpf_lsm.c | 27 +++++++++++++++++++++++++++ > > > scripts/bpf_helpers_doc.py | 2 ++ > > > tools/include/uapi/linux/bpf.h | 14 ++++++++++++++ > > > 4 files changed, 57 insertions(+) > > > > > > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h > > > index 162999b12790..7f1b6ba8246c 100644 > > > --- a/include/uapi/linux/bpf.h > > > +++ b/include/uapi/linux/bpf.h > > > @@ -3787,6 +3787,14 @@ union bpf_attr { > > > * *ARG_PTR_TO_BTF_ID* of type *task_struct*. > > > * Return > > > * Pointer to the current task. > > > + * > > > + * long bpf_lsm_set_bprm_opts(struct linux_binprm *bprm, u64 flags) > > > + * > > > + * Description > > > + * Sets certain options on the *bprm*: > > > + * > > > + * **BPF_LSM_F_BPRM_SECUREEXEC** Set the secureexec bit > > > + * which sets the **AT_SECURE** auxv for glibc. > > The return value needs to be documented also. > > Done. > > > > > > */ > > > #define __BPF_FUNC_MAPPER(FN) \ > > > FN(unspec), \ > > > @@ -3948,6 +3956,7 @@ union bpf_attr { > > > FN(task_storage_get), \ > > > FN(task_storage_delete), \ > > > FN(get_current_task_btf), \ > > > + FN(lsm_set_bprm_opts), \ > > > /* */ > > > > > > /* integer value in 'imm' field of BPF_CALL instruction selects which helper > > > @@ -4119,6 +4128,11 @@ enum bpf_lwt_encap_mode { > > > BPF_LWT_ENCAP_IP, > > > }; > > > > > > +/* Flags for LSM helpers */ > > > +enum { > > > + BPF_LSM_F_BPRM_SECUREEXEC = (1ULL << 0), > > > +}; > > > + > > > #define __bpf_md_ptr(type, name) \ > > > union { \ > > > type name; \ > > > diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c > > > index 553107f4706a..31f85474a0ef 100644 > > > --- a/kernel/bpf/bpf_lsm.c > > > +++ b/kernel/bpf/bpf_lsm.c > > > @@ -7,6 +7,7 @@ > > > #include <linux/filter.h> > > > #include <linux/bpf.h> > > > #include <linux/btf.h> > > > +#include <linux/binfmts.h> > > > #include <linux/lsm_hooks.h> > > > #include <linux/bpf_lsm.h> > > > #include <linux/kallsyms.h> > > > @@ -51,6 +52,30 @@ int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog, > > > return 0; > > > } > > > > > > +/* Mask for all the currently supported BPRM option flags */ > > > +#define BPF_LSM_F_BRPM_OPTS_MASK 0x1ULL > > If there is a need to have v3, it will be better to use > > BPF_LSM_F_BPRM_SECUREEXEC instead of 0x1ULL. > > Done. > > > > > > + > > > +BPF_CALL_2(bpf_lsm_set_bprm_opts, struct linux_binprm *, bprm, u64, flags) > > > +{ > > > + > > > + if (flags & ~BPF_LSM_F_BRPM_OPTS_MASK) > > > + return -EINVAL; > > > + > > > + bprm->secureexec = (flags & BPF_LSM_F_BPRM_SECUREEXEC); > > The intention of this helper is to set "or clear" a bit? > > It may be useful to clarify the "clear" part in the doc also. > > Updated the docs: > > * long bpf_lsm_set_bprm_opts(struct linux_binprm *bprm, u64 flags) > * > * Description > * Set or clear certain options on *bprm*: > * > * **BPF_LSM_F_BPRM_SECUREEXEC** Set the secureexec bit > * which sets the **AT_SECURE** auxv for glibc. The bit is > * is cleared if the flag is not specified. (-is) = cleared if the flag is not specified. (Thanks checkpatch!) > * Return > * **-EINVAL** if invalid *flags* are passed. > > > > > > + return 0; > > > +} > > > +
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 162999b12790..7f1b6ba8246c 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -3787,6 +3787,14 @@ union bpf_attr { * *ARG_PTR_TO_BTF_ID* of type *task_struct*. * Return * Pointer to the current task. + * + * long bpf_lsm_set_bprm_opts(struct linux_binprm *bprm, u64 flags) + * + * Description + * Sets certain options on the *bprm*: + * + * **BPF_LSM_F_BPRM_SECUREEXEC** Set the secureexec bit + * which sets the **AT_SECURE** auxv for glibc. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3948,6 +3956,7 @@ union bpf_attr { FN(task_storage_get), \ FN(task_storage_delete), \ FN(get_current_task_btf), \ + FN(lsm_set_bprm_opts), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper @@ -4119,6 +4128,11 @@ enum bpf_lwt_encap_mode { BPF_LWT_ENCAP_IP, }; +/* Flags for LSM helpers */ +enum { + BPF_LSM_F_BPRM_SECUREEXEC = (1ULL << 0), +}; + #define __bpf_md_ptr(type, name) \ union { \ type name; \ diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c index 553107f4706a..31f85474a0ef 100644 --- a/kernel/bpf/bpf_lsm.c +++ b/kernel/bpf/bpf_lsm.c @@ -7,6 +7,7 @@ #include <linux/filter.h> #include <linux/bpf.h> #include <linux/btf.h> +#include <linux/binfmts.h> #include <linux/lsm_hooks.h> #include <linux/bpf_lsm.h> #include <linux/kallsyms.h> @@ -51,6 +52,30 @@ int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog, return 0; } +/* Mask for all the currently supported BPRM option flags */ +#define BPF_LSM_F_BRPM_OPTS_MASK 0x1ULL + +BPF_CALL_2(bpf_lsm_set_bprm_opts, struct linux_binprm *, bprm, u64, flags) +{ + + if (flags & ~BPF_LSM_F_BRPM_OPTS_MASK) + return -EINVAL; + + bprm->secureexec = (flags & BPF_LSM_F_BPRM_SECUREEXEC); + return 0; +} + +BTF_ID_LIST_SINGLE(bpf_lsm_set_bprm_opts_btf_ids, struct, linux_binprm) + +const static struct bpf_func_proto bpf_lsm_set_bprm_opts_proto = { + .func = bpf_lsm_set_bprm_opts, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_BTF_ID, + .arg1_btf_id = &bpf_lsm_set_bprm_opts_btf_ids[0], + .arg2_type = ARG_ANYTHING, +}; + static const struct bpf_func_proto * bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { @@ -71,6 +96,8 @@ bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_task_storage_get_proto; case BPF_FUNC_task_storage_delete: return &bpf_task_storage_delete_proto; + case BPF_FUNC_lsm_set_bprm_opts: + return &bpf_lsm_set_bprm_opts_proto; default: return tracing_prog_func_proto(func_id, prog); } diff --git a/scripts/bpf_helpers_doc.py b/scripts/bpf_helpers_doc.py index 31484377b8b1..c5bc947a70ad 100755 --- a/scripts/bpf_helpers_doc.py +++ b/scripts/bpf_helpers_doc.py @@ -418,6 +418,7 @@ class PrinterHelpers(Printer): 'struct bpf_tcp_sock', 'struct bpf_tunnel_key', 'struct bpf_xfrm_state', + 'struct linux_binprm', 'struct pt_regs', 'struct sk_reuseport_md', 'struct sockaddr', @@ -465,6 +466,7 @@ class PrinterHelpers(Printer): 'struct bpf_tcp_sock', 'struct bpf_tunnel_key', 'struct bpf_xfrm_state', + 'struct linux_binprm', 'struct pt_regs', 'struct sk_reuseport_md', 'struct sockaddr', diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 162999b12790..7f1b6ba8246c 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -3787,6 +3787,14 @@ union bpf_attr { * *ARG_PTR_TO_BTF_ID* of type *task_struct*. * Return * Pointer to the current task. + * + * long bpf_lsm_set_bprm_opts(struct linux_binprm *bprm, u64 flags) + * + * Description + * Sets certain options on the *bprm*: + * + * **BPF_LSM_F_BPRM_SECUREEXEC** Set the secureexec bit + * which sets the **AT_SECURE** auxv for glibc. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3948,6 +3956,7 @@ union bpf_attr { FN(task_storage_get), \ FN(task_storage_delete), \ FN(get_current_task_btf), \ + FN(lsm_set_bprm_opts), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper @@ -4119,6 +4128,11 @@ enum bpf_lwt_encap_mode { BPF_LWT_ENCAP_IP, }; +/* Flags for LSM helpers */ +enum { + BPF_LSM_F_BPRM_SECUREEXEC = (1ULL << 0), +}; + #define __bpf_md_ptr(type, name) \ union { \ type name; \