This is a note to let you know that I've just added the patch titled
bpf: Take return from set_memory_ro() into account with bpf_prog_lock_ro()
to the 6.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bpf-take-return-from-set_memory_ro-into-account-with.patch
and it can be found in the queue-6.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit a3d6b8a49a5e83bc5070c6c0f5f32163249febf4
Author: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Date: Fri Mar 8 06:38:07 2024 +0100
bpf: Take return from set_memory_ro() into account with bpf_prog_lock_ro()
[ 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@xxxxxxxxxx>
Cc: linux-hardening@xxxxxxxxxxxxxxx <linux-hardening@xxxxxxxxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Message-ID: <286def78955e04382b227cb3e4b6ba272a7442e3.1709850515.git.christophe.leroy@xxxxxxxxxx>
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 219ee7a768744..35791b1c61c7d 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 1ea5ce5bb5993..9985988845e36 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 ab558eea1c9ee..d5fca9deac5a1 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -19354,10 +19354,14 @@ 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.
