[PATCH] mm: huge_memory: Handle strsep not finding delimiter

Leo Stone
2024-12-16T04:28:12Z

split_huge_pages_write does not handle the case where strsep finds no
delimiter in the given string and sets the input buffer to NULL,
which allows this reproducer to trigger a protection fault.

Reported-by: syzbot+8a3da2f1bbf59227c289@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=8a3da2f1bbf59227c289
Signed-off-by: Leo Stone <leocstone@gmail.com>
---
mm/huge_memory.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index ee335d96fc39..361319f749f0 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -4168,7 +4168,7 @@ static ssize_t split_huge_pages_write(struct file *file, const char __user *buf,
size_t input_len = strlen(input_buf);

tok = strsep(&buf, ",");
- if (tok) {
+ if (tok && buf) {
strscpy(file_path, tok);
} else {
ret = -EINVAL;
--
2.43.0