Currently, btf_name_valid_identifier() and btf_name_valid_section() are
written in a while loop and use pointer operations, so it takes a long
time to understand the operation of the code. Therefore, I suggest
refactoring the code to make it easier to maintain.
In addition, btf_name_valid_section() does not check for the case where
src[0] is a NULL value, resulting in an out-of-bounds vuln. Therefore, a
check for this should be added.
Reported-by: Jeongjun Park <aha310510@xxxxxxxxx>
Fixes: bd70a8fb7ca4 ("bpf: Allow all printable characters in BTF DATASEC names")
Signed-off-by: Jeongjun Park <aha310510@xxxxxxxxx>
---
kernel/bpf/btf.c | 27 ++++++++++++---------------
1 file changed, 12 insertions(+), 15 deletions(-)
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 674b38c33c74..c1e2aead9141 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -794,21 +794,18 @@ static bool btf_name_valid_identifier(const struct btf *btf, u32 offset)
{
/* offset must be valid */
const char *src = btf_str_by_offset(btf, offset);
- const char *src_limit;
+ int i;
- if (!__btf_name_char_ok(*src, true))
+ if (!__btf_name_char_ok(src[0], true))
return false;
/* set a limit on identifier length */
- src_limit = src + KSYM_NAME_LEN;
- src++;
- while (*src && src < src_limit) {
- if (!__btf_name_char_ok(*src, false))
+ for (i = 1; i < KSYM_NAME_LEN && src[i]; i++) {
+ if (!__btf_name_char_ok(src[i], false))
return false;
- src++;
}
- return !*src;
+ return !src[i];
}
/* Allow any printable character in DATASEC names */
@@ -816,18 +813,18 @@ static bool btf_name_valid_section(const struct btf *btf, u32 offset)
{
/* offset must be valid */
const char *src = btf_str_by_offset(btf, offset);
- const char *src_limit;
+ int i;
+
+ if (!src[0])
+ return false;
/* set a limit on identifier length */
- src_limit = src + KSYM_NAME_LEN;
- src++;
- while (*src && src < src_limit) {
- if (!isprint(*src))
+ for (i = 1; i < KSYM_NAME_LEN && src[i]; i++) {
+ if (!isprint(src[i]))
return false;
- src++;
}
- return !*src;
+ return !src[i];
}
static const char *__btf_name_by_offset(const struct btf *btf, u32 offset)
--
