6.6-stable review patch. If anyone has any objections, please let me know.
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From: Christophe Leroy christophe.leroy@csgroup.eu
[ Upstream commit 7d2cc63eca0c993c99d18893214abf8f85d566d8 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/filter.h | 5 +++-- kernel/bpf/core.c | 4 +++- 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 5090e940ba3e4..5a2800ec94ea6 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -842,14 +842,15 @@ 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 05445a4d55181..bdbce41d1bb4a 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -2373,7 +2373,9 @@ 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 171045b6956d9..aa546355918cb 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -18625,10 +18625,14 @@ 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.