[PATCH 6.1 058/236] bna: ensure the copied buf is NUL terminated

Greg Kroah-Hartman
2024-05-14T11:30:05Z

From: Bui Quang Minh <minhquangbui99@gmail.com>

[ Upstream commit 8c34096c7fdf272fd4c0c37fe411cd2e3ed0ee9f ]

Currently, we allocate a nbytes-sized kernel buffer and copy nbytes from
userspace to that buffer. Later, we use sscanf on this buffer but we don't
ensure that the string is terminated inside the buffer, this can lead to
OOB read when using sscanf. Fix this issue by using memdup_user_nul
instead of memdup_user.

Fixes: 7afc5dbde091 ("bna: Add debugfs interface.")
Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com>
Link: https://lore.kernel.org/r/20240424-fix-oob-read-v2-2-f1f1b53a10f4@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/brocade/bna/bnad_debugfs.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/brocade/bna/bnad_debugfs.c b/drivers/net/ethernet/brocade/bna/bnad_debugfs.c
index 04ad0f2b9677e..777f0d7e48192 100644
--- a/drivers/net/ethernet/brocade/bna/bnad_debugfs.c
+++ b/drivers/net/ethernet/brocade/bna/bnad_debugfs.c
@@ -312,7 +312,7 @@ bnad_debugfs_write_regrd(struct file *file, const char __user *buf,
void *kern_buf;

/* Copy the user space buf */
- kern_buf = memdup_user(buf, nbytes);
+ kern_buf = memdup_user_nul(buf, nbytes);
if (IS_ERR(kern_buf))
return PTR_ERR(kern_buf);

@@ -372,7 +372,7 @@ bnad_debugfs_write_regwr(struct file *file, const char __user *buf,
void *kern_buf;

/* Copy the user space buf */
- kern_buf = memdup_user(buf, nbytes);
+ kern_buf = memdup_user_nul(buf, nbytes);
if (IS_ERR(kern_buf))
return PTR_ERR(kern_buf);

--
2.43.0