[PATCH 6.1 059/197] cifs: fix underflow in parse_server_interfaces()

Greg Kroah-Hartman
2024-02-20T21:01:00Z

From: Dan Carpenter <dan.carpenter@linaro.org>

[ 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@linaro.org>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/smb/client/smb2ops.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

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;
--
2.43.0