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.
Fixes: bd70a8fb7ca4 ("bpf: Allow all printable characters in BTF DATASEC names")
Signed-off-by: Jeongjun Park <aha310510@xxxxxxxxx>
---
kernel/bpf/btf.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 520f49f422fe..5c24ea1a65a4 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -823,6 +823,9 @@ 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++;
--
