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| author | Christophe Leroy <christophe.leroy@csgroup.eu> | 2024-03-08 06:38:07 +0100 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2024-03-15 03:28:52 +0100 |
| commit | 7d2cc63eca0c993c99d18893214abf8f85d566d8 (patch) | |
| tree | f76363657d57f38f950856a1c399dad1ad31780b | |
| parent | bpf: preserve sleepable bit in subprog info (diff) | |
| download | linux-7d2cc63eca0c993c99d18893214abf8f85d566d8.tar.xz linux-7d2cc63eca0c993c99d18893214abf8f85d566d8.zip | |
bpf: Take return from set_memory_ro() into account with bpf_prog_lock_ro()
set_memory_ro() can fail, leaving memory unprotected.
Check its return and take it into account as an error.
Link: https://github.com/KSPP/linux/issues/7
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: linux-hardening@vger.kernel.org <linux-hardening@vger.kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Message-ID: <286def78955e04382b227cb3e4b6ba272a7442e3.1709850515.git.christophe.leroy@csgroup.eu>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| -rw-r--r-- | include/linux/filter.h | 5 | ||||
| -rw-r--r-- | kernel/bpf/core.c | 4 | ||||
| -rw-r--r-- | kernel/bpf/verifier.c | 8 |
3 files changed, 12 insertions, 5 deletions
diff --git a/include/linux/filter.h b/include/linux/filter.h index c99bc3df2d28..9107ee1de66f 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -887,14 +887,15 @@ bpf_ctx_narrow_access_offset(u32 off, u32 size, u32 size_default) #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0])) -static inline void bpf_prog_lock_ro(struct bpf_prog *fp) +static inline int __must_check bpf_prog_lock_ro(struct bpf_prog *fp) { #ifndef CONFIG_BPF_JIT_ALWAYS_ON if (!fp->jited) { set_vm_flush_reset_perms(fp); - set_memory_ro((unsigned long)fp, fp->pages); + return set_memory_ro((unsigned long)fp, fp->pages); } #endif + return 0; } static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr) diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 696bc55de8e8..63f100def31b 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -2403,7 +2403,9 @@ struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) } finalize: - bpf_prog_lock_ro(fp); + *err = bpf_prog_lock_ro(fp); + if (*err) + return fp; /* The tail call compatibility check can only be done at * this late stage as we need to determine, if we deal diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 7b208e5d38f6..de7813947981 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -19263,10 +19263,14 @@ static int jit_subprogs(struct bpf_verifier_env *env) * bpf_prog_load will add the kallsyms for the main program. */ for (i = 1; i < env->subprog_cnt; i++) { - bpf_prog_lock_ro(func[i]); - bpf_prog_kallsyms_add(func[i]); + err = bpf_prog_lock_ro(func[i]); + if (err) + goto out_free; } + for (i = 1; i < env->subprog_cnt; i++) + bpf_prog_kallsyms_add(func[i]); + /* Last step: make now unused interpreter insns from main * prog consistent for later dump requests, so they can * later look the same as if they were interpreted only. |