[PATCH 6.8 155/158] ksmbd: fix slab-out-of-bounds in smb2_allocate_rsp_buf

Greg Kroah-Hartman
2024-04-23T21:42:33Z

From: Namjae Jeon <linkinjeon@kernel.org>

commit c119f4ede3fa90a9463f50831761c28f989bfb20 upstream.

If ->ProtocolId is SMB2_TRANSFORM_PROTO_NUM, smb2 request size
validation could be skipped. if request size is smaller than
sizeof(struct smb2_query_info_req), slab-out-of-bounds read can happen in
smb2_allocate_rsp_buf(). This patch allocate response buffer after
decrypting transform request. smb3_decrypt_req() will validate transform
request size and avoid slab-out-of-bound in smb2_allocate_rsp_buf().

Reported-by: Norbert Szetei <norbert@doyensec.com>
Cc: stable@vger.kernel.org
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/smb/server/server.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)

--- a/fs/smb/server/server.c
+++ b/fs/smb/server/server.c
@@ -167,20 +167,17 @@ static void __handle_ksmbd_work(struct k
int rc;
bool is_chained = false;

- if (conn->ops->allocate_rsp_buf(work))
- return;
-
if (conn->ops->is_transform_hdr &&
conn->ops->is_transform_hdr(work->request_buf)) {
rc = conn->ops->decrypt_req(work);
- if (rc < 0) {
- conn->ops->set_rsp_status(work, STATUS_DATA_ERROR);
- goto send;
- }
-
+ if (rc < 0)
+ return;
work->encrypted = true;
}

+ if (conn->ops->allocate_rsp_buf(work))
+ return;
+
rc = conn->ops->init_rsp_hdr(work);
if (rc) {
/* either uid or tid is not correct */