Convert MessageID in smb2_hdr to LE

We have encountered failures when When testing smb2 mounts on ppc64
machines when using both Samba as well as Windows 2012.

On poking around, the problem was determined to be caused by the
high endian MessageID passed in the header for smb2. On checking the
corresponding MID for smb1 is converted to LE before being sent on the
wire.

We have tested this patch successfully on a ppc64 machine.

Signed-off-by: Sachin Prabhu <sprabhu@redhat.com>

1 files changed, 7 insertions, 5 deletions

diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
index f1cefc9763ed..689f035915cf 100644
--- a/fs/cifs/smb2misc.c
+++ b/fs/cifs/smb2misc.c
@@ -32,12 +32,14 @@
 static int
 check_smb2_hdr(struct smb2_hdr *hdr, __u64 mid)
 {
+	__u64 wire_mid = le64_to_cpu(hdr->MessageId);
+
 	/*
 	 * Make sure that this really is an SMB, that it is a response,
 	 * and that the message ids match.
 	 */
 	if ((*(__le32 *)hdr->ProtocolId == SMB2_PROTO_NUMBER) &&
-	    (mid == hdr->MessageId)) {
+	    (mid == wire_mid)) {
 		if (hdr->Flags & SMB2_FLAGS_SERVER_TO_REDIR)
 			return 0;
 		else {
@@ -51,11 +53,11 @@ check_smb2_hdr(struct smb2_hdr *hdr, __u64 mid)
 		if (*(__le32 *)hdr->ProtocolId != SMB2_PROTO_NUMBER)
 			cifs_dbg(VFS, "Bad protocol string signature header %x\n",
 				 *(unsigned int *) hdr->ProtocolId);
-		if (mid != hdr->MessageId)
+		if (mid != wire_mid)
 			cifs_dbg(VFS, "Mids do not match: %llu and %llu\n",
-				 mid, hdr->MessageId);
+				 mid, wire_mid);
 	}
-	cifs_dbg(VFS, "Bad SMB detected. The Mid=%llu\n", hdr->MessageId);
+	cifs_dbg(VFS, "Bad SMB detected. The Mid=%llu\n", wire_mid);
 	return 1;
 }
 
@@ -95,7 +97,7 @@ smb2_check_message(char *buf, unsigned int length)
 {
 	struct smb2_hdr *hdr = (struct smb2_hdr *)buf;
 	struct smb2_pdu *pdu = (struct smb2_pdu *)hdr;
-	__u64 mid = hdr->MessageId;
+	__u64 mid = le64_to_cpu(hdr->MessageId);
 	__u32 len = get_rfc1002_length(buf);
 	__u32 clc_len;  /* calculated length */
 	int command;