From: Li Nan linan122@huawei.com
[ Upstream commit 516b3eb8c8065f7465f87608d37a7ed08298c7a5 ]
The SMB2 Protocol requires that "The first byte of the Direct TCP transport packet header MUST be zero (0x00)"[1]. Commit 1c1bcf2d3ea0 ("ksmbd: validate smb request protocol id") removed the validation of this 1-byte zero. Add the validation back now.
[1]: [MS-SMB2] - v20230227, page 30. https://winprotocoldoc.blob.core.windows.net/productionwindowsarchives/MS-SM...
Fixes: 1c1bcf2d3ea0 ("ksmbd: validate smb request protocol id") Signed-off-by: Li Nan linan122@huawei.com Acked-by: Tom Talpey tom@talpey.com Acked-by: Namjae Jeon linkinjeon@kernel.org Signed-off-by: Steve French stfrench@microsoft.com --- fs/ksmbd/smb_common.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/fs/ksmbd/smb_common.c b/fs/ksmbd/smb_common.c index d160363c09eb..e90a1e8c1951 100644 --- a/fs/ksmbd/smb_common.c +++ b/fs/ksmbd/smb_common.c @@ -158,8 +158,12 @@ int ksmbd_verify_smb_message(struct ksmbd_work *work) */ bool ksmbd_smb_request(struct ksmbd_conn *conn) { - __le32 *proto = (__le32 *)smb2_get_msg(conn->request_buf); + __le32 *proto;
+ if (conn->request_buf[0] != 0) + return false; + + proto = (__le32 *)smb2_get_msg(conn->request_buf); if (*proto == SMB2_COMPRESSION_TRANSFORM_ID) { pr_err_ratelimited("smb2 compression not support yet"); return false;