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* [PATCH bpf-next v3 1/2] bpf: Take return from set_memory_ro() into account with bpf_prog_lock_ro()
@ 2024-03-08  5:38 Christophe Leroy
  2024-03-08  5:38 ` [PATCH bpf-next v3 2/2] bpf: Take return from set_memory_rox() into account with bpf_jit_binary_lock_ro() Christophe Leroy
  2024-03-15  2:30 ` [PATCH bpf-next v3 1/2] bpf: Take return from set_memory_ro() into account with bpf_prog_lock_ro() patchwork-bot+netdevbpf
  0 siblings, 2 replies; 3+ messages in thread
From: Christophe Leroy @ 2024-03-08  5:38 UTC (permalink / raw)
  To: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
	Martin KaFai Lau, Eduard Zingerman, Song Liu, Yonghong Song,
	John Fastabend, KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa
  Cc: Christophe Leroy, bpf, linux-arm-kernel, linux-kernel, loongarch,
	linux-mips, linux-parisc, linux-s390, sparclinux, netdev,
	linux-hardening @ vger . kernel . org, Kees Cook

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>
---
Note: next patch is autonomous, it is sent as a follow-up of this one to minimize risk of conflict on filter.h because the two changes are too close to each other.

v3: Perform bpf_prog_kallsyms_add() after protection of all subprog have succeeded.

v2: No modification (Just added link in patch message), patchwork discarded this series due to failed test of s390 but it seems unrelated, see https://lore.kernel.org/bpf/wvd5gzde5ejc2rzsbrtwqyof56uw5ea3rxntfrxtkdabzcuwt6@w7iczzhmay2i/T/#m2e61446f42d5dc3d78f2e0e8b7a783f15cfb109d
---
 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 36cc29a2934c..7dd59bccaeec 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -884,14 +884,15 @@ 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 9ee4536d0a09..ae28bab2b138 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -2393,7 +2393,9 @@ 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 ee86e4d7d5fc..c97108935c9a 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -19153,10 +19153,14 @@ 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.
-- 
2.43.0


^ permalink raw reply related	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2024-03-15  2:30 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2024-03-08  5:38 [PATCH bpf-next v3 1/2] bpf: Take return from set_memory_ro() into account with bpf_prog_lock_ro() Christophe Leroy
2024-03-08  5:38 ` [PATCH bpf-next v3 2/2] bpf: Take return from set_memory_rox() into account with bpf_jit_binary_lock_ro() Christophe Leroy
2024-03-15  2:30 ` [PATCH bpf-next v3 1/2] bpf: Take return from set_memory_ro() into account with bpf_prog_lock_ro() patchwork-bot+netdevbpf

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