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-rw-r--r--fs/cifs/misc.c33
1 files changed, 17 insertions, 16 deletions
diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index 24f0a9d97ad..2a930a752a7 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;