octeontx2-af: avoid off-by-one read from userspace

We try to access count + 1 byte from userspace with memdup_user(buffer,
count + 1). However, the userspace only provides buffer of count bytes and
only these count bytes are verified to be okay to access. To ensure the
copied buffer is NUL terminated, we use memdup_user_nul instead.

Fixes: 3a2eb515d1 ("octeontx2-af: Fix an off by one in rvu_dbg_qsize_write()")
Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com>
Link: https://lore.kernel.org/r/20240424-fix-oob-read-v2-6-f1f1b53a10f4@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Bui Quang Minh 2024-04-24 21:44:23 +07:00 committed by Jakub Kicinski
parent 8c34096c7f
commit f299ee709f

View File

@ -999,12 +999,10 @@ static ssize_t rvu_dbg_qsize_write(struct file *filp,
u16 pcifunc;
int ret, lf;
cmd_buf = memdup_user(buffer, count + 1);
cmd_buf = memdup_user_nul(buffer, count);
if (IS_ERR(cmd_buf))
return -ENOMEM;
cmd_buf[count] = '\0';
cmd_buf_tmp = strchr(cmd_buf, '\n');
if (cmd_buf_tmp) {
*cmd_buf_tmp = '\0';