1 files changed, 17 insertions, 16 deletions

diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index 24f0a9d97ad8..2a930a752a78 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -478,25 +478,26 @@ checkSMB(struct smb_hdr *smb, __u16 mid, unsigned int length)
                         if (((4 + len) & 0xFFFF) == (clc_len & 0xFFFF))
                                 return 0; /* bcc wrapped */
                 }
-                cFYI(1, "Calculated size %d vs length %d mismatch for mid %d",
+                cFYI(1, "Calculated size %u vs length %u mismatch for mid=%u",
                                 clc_len, 4 + len, smb->Mid);
-                /* Windows XP can return a few bytes too much, presumably
-                an illegal pad, at the end of byte range lock responses
-                so we allow for that three byte pad, as long as actual
-                received length is as long or longer than calculated length */
-                /* We have now had to extend this more, since there is a
-                case in which it needs to be bigger still to handle a
-                malformed response to transact2 findfirst from WinXP when
-                access denied is returned and thus bcc and wct are zero
-                but server says length is 0x21 bytes too long as if the server
-                forget to reset the smb rfc1001 length when it reset the
-                wct and bcc to minimum size and drop the t2 parms and data */
-                if ((4+len > clc_len) && (len <= clc_len + 512))
-                        return 0;
-                else {
-                        cERROR(1, "RFC1001 size %d bigger than SMB for Mid=%d",
+
+                if (4 + len < clc_len) {
+                        cERROR(1, "RFC1001 size %u smaller than SMB for mid=%u",
                                         len, smb->Mid);
                         return 1;
+                } else if (len > clc_len + 512) {
+                        /*
+                         * Some servers (Windows XP in particular) send more
+                         * data than the lengths in the SMB packet would
+                         * indicate on certain calls (byte range locks and
+                         * trans2 find first calls in particular). While the
+                         * client can handle such a frame by ignoring the
+                         * trailing data, we choose limit the amount of extra
+                         * data to 512 bytes.
+                         */
+                        cERROR(1, "RFC1001 size %u more than 512 bytes larger "
+                                  "than SMB for mid=%u", len, smb->Mid);
+                        return 1;
                 }
         }
         return 0;