This is a note to let you know that I've just added the patch titled
bpf: Fix a erroneous check after snprintf()
to the 6.5-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-fix-a-erroneous-check-after-snprintf.patch
and it can be found in the queue-6.5 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 700110c16d4e27592beb2a16f606263856bba573
Author: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
Date: Fri Sep 8 18:33:35 2023 +0200
bpf: Fix a erroneous check after snprintf()
[ Upstream commit a8f12572860ad8ba659d96eee9cf09e181f6ebcc ]
snprintf() does not return negative error code on error, it returns the
number of characters which *would* be generated for the given input.
Fix the error handling check.
Fixes: 57539b1c0ac2 ("bpf: Enable annotating trusted nested pointers")
Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
Link: https://lore.kernel.org/r/393bdebc87b22563c08ace094defa7160eb7a6c0.1694190795.git.christophe.jaillet@xxxxxxxxxx
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 4b38c97990872..197d8252ffc65 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -8498,7 +8498,7 @@ bool btf_nested_type_is_trusted(struct bpf_verifier_log *log,
tname = btf_name_by_offset(btf, walk_type->name_off);
ret = snprintf(safe_tname, sizeof(safe_tname), "%s%s", tname, suffix);
- if (ret < 0)
+ if (ret >= sizeof(safe_tname))
return false;
safe_id = btf_find_by_name_kind(btf, safe_tname, BTF_INFO_KIND(walk_type->info));
