From 082f1db02c8034fee787ea9809775ea861c50430 Mon Sep 17 00:00:00 2001 From: Blaise Boscaccy Date: Mon, 10 Mar 2025 15:17:11 -0700 Subject: security: Propagate caller information in bpf hooks Certain bpf syscall subcommands are available for usage from both userspace and the kernel. LSM modules or eBPF gatekeeper programs may need to take a different course of action depending on whether or not a BPF syscall originated from the kernel or userspace. Additionally, some of the bpf_attr struct fields contain pointers to arbitrary memory. Currently the functionality to determine whether or not a pointer refers to kernel memory or userspace memory is exposed to the bpf verifier, but that information is missing from various LSM hooks. Here we augment the LSM hooks to provide this data, by simply passing a boolean flag indicating whether or not the call originated in the kernel, in any hook that contains a bpf_attr struct that corresponds to a subcommand that may be called from the kernel. Signed-off-by: Blaise Boscaccy Acked-by: Song Liu Acked-by: Paul Moore Link: https://lore.kernel.org/r/20250310221737.821889-2-bboscaccy@linux.microsoft.com Signed-off-by: Alexei Starovoitov --- include/linux/lsm_hook_defs.h | 6 +++--- include/linux/security.h | 12 ++++++------ 2 files changed, 9 insertions(+), 9 deletions(-) (limited to 'include/linux') diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index e2f1ce37c41e..f5aafd3ba5d4 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -426,14 +426,14 @@ LSM_HOOK(void, LSM_RET_VOID, audit_rule_free, void *lsmrule) #endif /* CONFIG_AUDIT */ #ifdef CONFIG_BPF_SYSCALL -LSM_HOOK(int, 0, bpf, int cmd, union bpf_attr *attr, unsigned int size) +LSM_HOOK(int, 0, bpf, int cmd, union bpf_attr *attr, unsigned int size, bool kernel) LSM_HOOK(int, 0, bpf_map, struct bpf_map *map, fmode_t fmode) LSM_HOOK(int, 0, bpf_prog, struct bpf_prog *prog) LSM_HOOK(int, 0, bpf_map_create, struct bpf_map *map, union bpf_attr *attr, - struct bpf_token *token) + struct bpf_token *token, bool kernel) LSM_HOOK(void, LSM_RET_VOID, bpf_map_free, struct bpf_map *map) LSM_HOOK(int, 0, bpf_prog_load, struct bpf_prog *prog, union bpf_attr *attr, - struct bpf_token *token) + struct bpf_token *token, bool kernel) LSM_HOOK(void, LSM_RET_VOID, bpf_prog_free, struct bpf_prog *prog) LSM_HOOK(int, 0, bpf_token_create, struct bpf_token *token, union bpf_attr *attr, const struct path *path) diff --git a/include/linux/security.h b/include/linux/security.h index 980b6c207cad..b2010034f82b 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -2249,14 +2249,14 @@ struct bpf_map; struct bpf_prog; struct bpf_token; #ifdef CONFIG_SECURITY -extern int security_bpf(int cmd, union bpf_attr *attr, unsigned int size); +extern int security_bpf(int cmd, union bpf_attr *attr, unsigned int size, bool kernel); extern int security_bpf_map(struct bpf_map *map, fmode_t fmode); extern int security_bpf_prog(struct bpf_prog *prog); extern int security_bpf_map_create(struct bpf_map *map, union bpf_attr *attr, - struct bpf_token *token); + struct bpf_token *token, bool kernel); extern void security_bpf_map_free(struct bpf_map *map); extern int security_bpf_prog_load(struct bpf_prog *prog, union bpf_attr *attr, - struct bpf_token *token); + struct bpf_token *token, bool kernel); extern void security_bpf_prog_free(struct bpf_prog *prog); extern int security_bpf_token_create(struct bpf_token *token, union bpf_attr *attr, const struct path *path); @@ -2265,7 +2265,7 @@ extern int security_bpf_token_cmd(const struct bpf_token *token, enum bpf_cmd cm extern int security_bpf_token_capable(const struct bpf_token *token, int cap); #else static inline int security_bpf(int cmd, union bpf_attr *attr, - unsigned int size) + unsigned int size, bool kernel) { return 0; } @@ -2281,7 +2281,7 @@ static inline int security_bpf_prog(struct bpf_prog *prog) } static inline int security_bpf_map_create(struct bpf_map *map, union bpf_attr *attr, - struct bpf_token *token) + struct bpf_token *token, bool kernel) { return 0; } @@ -2290,7 +2290,7 @@ static inline void security_bpf_map_free(struct bpf_map *map) { } static inline int security_bpf_prog_load(struct bpf_prog *prog, union bpf_attr *attr, - struct bpf_token *token) + struct bpf_token *token, bool kernel) { return 0; } -- cgit v1.2.3