{
__u16 mid = 0;
__u16 last_mid;
- int collision;
-
- if (server == NULL)
- return mid;
+ bool collision;
spin_lock(&GlobalMid_Lock);
last_mid = server->CurrentMid; /* we do not want to loop forever */
(and it would also have to have been a request that
did not time out) */
while (server->CurrentMid != last_mid) {
- struct list_head *tmp;
struct mid_q_entry *mid_entry;
+ unsigned int num_mids;
- collision = 0;
+ collision = false;
if (server->CurrentMid == 0)
server->CurrentMid++;
- list_for_each(tmp, &server->pending_mid_q) {
- mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
-
- if ((mid_entry->mid == server->CurrentMid) &&
- (mid_entry->midState == MID_REQUEST_SUBMITTED)) {
+ num_mids = 0;
+ list_for_each_entry(mid_entry, &server->pending_mid_q, qhead) {
+ ++num_mids;
+ if (mid_entry->mid == server->CurrentMid &&
+ mid_entry->midState == MID_REQUEST_SUBMITTED) {
/* This mid is in use, try a different one */
- collision = 1;
+ collision = true;
break;
}
}
- if (collision == 0) {
+
+ /*
+ * if we have more than 32k mids in the list, then something
+ * is very wrong. Possibly a local user is trying to DoS the
+ * box by issuing long-running calls and SIGKILL'ing them. If
+ * we get to 2^16 mids then we're in big trouble as this
+ * function could loop forever.
+ *
+ * Go ahead and assign out the mid in this situation, but force
+ * an eventual reconnect to clean out the pending_mid_q.
+ */
+ if (num_mids > 32768)
+ server->tcpStatus = CifsNeedReconnect;
+
+ if (!collision) {
mid = server->CurrentMid;
break;
}
}
static int
-checkSMBhdr(struct smb_hdr *smb, __u16 mid)
+check_smb_hdr(struct smb_hdr *smb, __u16 mid)
{
- /* Make sure that this really is an SMB, that it is a response,
- and that the message ids match */
- if ((*(__le32 *) smb->Protocol == cpu_to_le32(0x424d53ff)) &&
- (mid == smb->Mid)) {
- if (smb->Flags & SMBFLG_RESPONSE)
- return 0;
- else {
- /* only one valid case where server sends us request */
- if (smb->Command == SMB_COM_LOCKING_ANDX)
- return 0;
- else
- cERROR(1, "Received Request not response");
- }
- } else { /* bad signature or mid */
- if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff))
- cERROR(1, "Bad protocol string signature header %x",
- *(unsigned int *) smb->Protocol);
- if (mid != smb->Mid)
- cERROR(1, "Mids do not match");
+ /* does it have the right SMB "signature" ? */
+ if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
+ cERROR(1, "Bad protocol string signature header 0x%x",
+ *(unsigned int *)smb->Protocol);
+ return 1;
+ }
+
+ /* Make sure that message ids match */
+ if (mid != smb->Mid) {
+ cERROR(1, "Mids do not match. received=%u expected=%u",
+ smb->Mid, mid);
+ return 1;
}
- cERROR(1, "bad smb detected. The Mid=%d", smb->Mid);
+
+ /* if it's a response then accept */
+ if (smb->Flags & SMBFLG_RESPONSE)
+ return 0;
+
+ /* only one valid case where server sends us request */
+ if (smb->Command == SMB_COM_LOCKING_ANDX)
+ return 0;
+
+ cERROR(1, "Server sent request, not response. mid=%u", smb->Mid);
return 1;
}
return 1;
}
- if (checkSMBhdr(smb, mid))
+ if (check_smb_hdr(smb, mid))
return 1;
clc_len = smbCalcSize_LE(smb);
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;
projects / mv-sheeva.git / blobdiff