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authorQianchang Zhao <pioooooooooip@gmail.com>2025-10-22 15:27:47 +0900
committerSteve French <stfrench@microsoft.com>2025-10-26 20:47:32 -0500
commit6f40e50ceb99fc8ef37e5c56e2ec1d162733fef0 (patch)
treef5bef11181e818212eca4088fa3f5084cddd1f17
parentdcb6fa37fd7bc9c3d2b066329b0d27dedf8becaa (diff)
ksmbd: transport_ipc: validate payload size before reading handle
handle_response() dereferences the payload as a 4-byte handle without verifying that the declared payload size is at least 4 bytes. A malformed or truncated message from ksmbd.mountd can lead to a 4-byte read past the declared payload size. Validate the size before dereferencing. This is a minimal fix to guard the initial handle read. Fixes: 0626e6641f6b ("cifsd: add server handler for central processing and tranport layers") Cc: stable@vger.kernel.org Reported-by: Qianchang Zhao <pioooooooooip@gmail.com> Signed-off-by: Qianchang Zhao <pioooooooooip@gmail.com> Acked-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
-rw-r--r--fs/smb/server/transport_ipc.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/fs/smb/server/transport_ipc.c b/fs/smb/server/transport_ipc.c
index 46f87fd1ce1c..2c08cccfa680 100644
--- a/fs/smb/server/transport_ipc.c
+++ b/fs/smb/server/transport_ipc.c
@@ -263,10 +263,16 @@ static void ipc_msg_handle_free(int handle)
static int handle_response(int type, void *payload, size_t sz)
{
- unsigned int handle = *(unsigned int *)payload;
+ unsigned int handle;
struct ipc_msg_table_entry *entry;
int ret = 0;
+ /* Prevent 4-byte read beyond declared payload size */
+ if (sz < sizeof(unsigned int))
+ return -EINVAL;
+
+ handle = *(unsigned int *)payload;
+
ipc_update_last_active();
down_read(&ipc_msg_table_lock);
hash_for_each_possible(ipc_msg_table, entry, ipc_table_hlist, handle) {