From bb6705c3f93bed2af03d43691743d4c43e3c8e6f Mon Sep 17 00:00:00 2001 From: Jeongjun Park Date: Sat, 31 Aug 2024 14:47:02 +0900 Subject: [PATCH] bpf: add check for invalid name in btf_name_valid_section() 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 Fixes: bd70a8fb7ca4 ("bpf: Allow all printable characters in BTF DATASEC names") Signed-off-by: Jeongjun Park Link: https://lore.kernel.org/r/20240831054702.364455-1-aha310510@gmail.com Signed-off-by: Alexei Starovoitov Acked-by: Eduard Zingerman --- kernel/bpf/btf.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index e3377dd61f7e..a4e4f8d43ecf 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; -- 2.50.1