diff mbox series

[bpf,v2,1/2] bpf: add check for invalid name in btf_name_valid_section()

Message ID 20240831054702.364455-1-aha310510@gmail.com (mailing list archive)
State Accepted
Commit bb6705c3f93bed2af03d43691743d4c43e3c8e6f
Delegated to: BPF
Headers show
Series bpf: fix incorrect name check pass logic in btf_name_valid_section | expand

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Commit Message

Jeongjun Park Aug. 31, 2024, 5:47 a.m. UTC 
If the length of the name string is 1 and the value of name[0] is NULL
byte, an OOB vulnerability occurs in btf_name_valid_section() and the
return value is true, so the invalid name passes the check.

To solve this, you need to check if the first position is NULL byte and 
if the first character is printable.

Suggested-by: Eduard Zingerman <eddyz87@gmail.com>
Fixes: bd70a8fb7ca4 ("bpf: Allow all printable characters in BTF DATASEC names")
Signed-off-by: Jeongjun Park <aha310510@gmail.com>
---
 kernel/bpf/btf.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--
diff mbox series

Patch

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 520f49f422fe..f1e91bf367fa 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -823,9 +823,11 @@  static bool btf_name_valid_section(const struct btf *btf, u32 offset)
 	const char *src = btf_str_by_offset(btf, offset);
 	const char *src_limit;
 
+	if (!*src)
+		return false;
+
 	/* set a limit on identifier length */
 	src_limit = src + KSYM_NAME_LEN;
-	src++;
 	while (*src && src < src_limit) {
 		if (!isprint(*src))
 			return false;