This is a note to let you know that I've just added the patch titled cifs: fix underflow in parse_server_interfaces() to the 6.1-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: cifs-fix-underflow-in-parse_server_interfaces.patch and it can be found in the queue-6.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit b3aa555197b5378d2ef7099e0e8dd6c0e3752b91 Author: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Date: Thu Feb 8 13:18:46 2024 +0300 cifs: fix underflow in parse_server_interfaces() [ Upstream commit cffe487026be13eaf37ea28b783d9638ab147204 ] In this loop, we step through the buffer and after each item we check if the size_left is greater than the minimum size we need. However, the problem is that "bytes_left" is type ssize_t while sizeof() is type size_t. That means that because of type promotion, the comparison is done as an unsigned and if we have negative bytes left the loop continues instead of ending. Fixes: fe856be475f7 ("CIFS: parse and store info on iface queries") Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Reviewed-by: Shyam Prasad N <sprasad@xxxxxxxxxxxxx> Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c index 5a157000bdfe..34d1262004df 100644 --- a/fs/smb/client/smb2ops.c +++ b/fs/smb/client/smb2ops.c @@ -613,7 +613,7 @@ parse_server_interfaces(struct network_interface_info_ioctl_rsp *buf, goto out; } - while (bytes_left >= sizeof(*p)) { + while (bytes_left >= (ssize_t)sizeof(*p)) { memset(&tmp_iface, 0, sizeof(tmp_iface)); tmp_iface.speed = le64_to_cpu(p->LinkSpeed); tmp_iface.rdma_capable = le32_to_cpu(p->Capability & RDMA_CAPABLE) ? 1 : 0;