Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6

* git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6:
  cifs: handle errors from coalesce_t2
  cifs: refactor mid finding loop in cifs_demultiplex_thread
  cifs: sanitize length checking in coalesce_t2 (try #3)
  cifs: check for bytes_remaining going to zero in CIFS_SessSetup
  cifs: change bleft in decode_unicode_ssetup back to signed type

2 files changed, 71 insertions, 68 deletions

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 4bc862a80efa..05f1dcf7d79a 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -274,7 +274,8 @@ static int coalesce_t2(struct smb_hdr *psecond, struct smb_hdr *pTargetSMB)
         char *data_area_of_target;
         char *data_area_of_buf2;
         int remaining;
-        __u16 byte_count, total_data_size, total_in_buf, total_in_buf2;
+        unsigned int byte_count, total_in_buf;
+        __u16 total_data_size, total_in_buf2;
 
         total_data_size = get_unaligned_le16(&pSMBt->t2_rsp.TotalDataCount);
 
@@ -287,7 +288,7 @@ static int coalesce_t2(struct smb_hdr *psecond, struct smb_hdr *pTargetSMB)
         remaining = total_data_size - total_in_buf;
 
         if (remaining < 0)
-                return -EINVAL;
+                return -EPROTO;
 
         if (remaining == 0) /* nothing to do, ignore */
                 return 0;
@@ -308,20 +309,29 @@ static int coalesce_t2(struct smb_hdr *psecond, struct smb_hdr *pTargetSMB)
         data_area_of_target += total_in_buf;
 
         /* copy second buffer into end of first buffer */
-        memcpy(data_area_of_target, data_area_of_buf2, total_in_buf2);
         total_in_buf += total_in_buf2;
+        /* is the result too big for the field? */
+        if (total_in_buf > USHRT_MAX)
+                return -EPROTO;
         put_unaligned_le16(total_in_buf, &pSMBt->t2_rsp.DataCount);
+
+        /* fix up the BCC */
         byte_count = get_bcc_le(pTargetSMB);
         byte_count += total_in_buf2;
+        /* is the result too big for the field? */
+        if (byte_count > USHRT_MAX)
+                return -EPROTO;
         put_bcc_le(byte_count, pTargetSMB);
 
         byte_count = pTargetSMB->smb_buf_length;
         byte_count += total_in_buf2;
-
-        /* BB also add check that we are not beyond maximum buffer size */
-
+        /* don't allow buffer to overflow */
+        if (byte_count > CIFSMaxBufSize)
+                return -ENOBUFS;
         pTargetSMB->smb_buf_length = byte_count;
 
+        memcpy(data_area_of_target, data_area_of_buf2, total_in_buf2);
+
         if (remaining == total_in_buf2) {
                 cFYI(1, "found the last secondary response");
                 return 0; /* we are done */
@@ -607,59 +617,63 @@ incomplete_rcv:
                 list_for_each_safe(tmp, tmp2, &server->pending_mid_q) {
                         mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
 
-                        if ((mid_entry->mid == smb_buffer->Mid) &&
-                            (mid_entry->midState == MID_REQUEST_SUBMITTED) &&
-                            (mid_entry->command == smb_buffer->Command)) {
-                                if (length == 0 &&
-                                   check2ndT2(smb_buffer, server->maxBuf) > 0) {
-                                        /* We have a multipart transact2 resp */
-                                        isMultiRsp = true;
-                                        if (mid_entry->resp_buf) {
-                                                /* merge response - fix up 1st*/
-                                                if (coalesce_t2(smb_buffer,
-                                                        mid_entry->resp_buf)) {
-                                                        mid_entry->multiRsp =
-                                                                 true;
-                                                        break;
-                                                } else {
-                                                        /* all parts received */
-                                                        mid_entry->multiEnd =
-                                                                 true;
-                                                        goto multi_t2_fnd;
-                                                }
+                        if (mid_entry->mid != smb_buffer->Mid ||
+                            mid_entry->midState != MID_REQUEST_SUBMITTED ||
+                            mid_entry->command != smb_buffer->Command) {
+                                mid_entry = NULL;
+                                continue;
+                        }
+
+                        if (length == 0 &&
+                            check2ndT2(smb_buffer, server->maxBuf) > 0) {
+                                /* We have a multipart transact2 resp */
+                                isMultiRsp = true;
+                                if (mid_entry->resp_buf) {
+                                        /* merge response - fix up 1st*/
+                                        length = coalesce_t2(smb_buffer,
+                                                        mid_entry->resp_buf);
+                                        if (length > 0) {
+                                                length = 0;
+                                                mid_entry->multiRsp = true;
+                                                break;
                                         } else {
-                                                if (!isLargeBuf) {
-                                                        cERROR(1, "1st trans2 resp needs bigbuf");
-                                        /* BB maybe we can fix this up,  switch
-                                           to already allocated large buffer? */
-                                                } else {
-                                                        /* Have first buffer */
-                                                        mid_entry->resp_buf =
-                                                                 smb_buffer;
-                                                        mid_entry->largeBuf =
-                                                                 true;
-                                                        bigbuf = NULL;
-                                                }
+                                                /* all parts received or
+                                                 * packet is malformed
+                                                 */
+                                                mid_entry->multiEnd = true;
+                                                goto multi_t2_fnd;
+                                        }
+                                } else {
+                                        if (!isLargeBuf) {
+                                                /*
+                                                 * FIXME: switch to already
+                                                 *        allocated largebuf?
+                                                 */
+                                                cERROR(1, "1st trans2 resp "
+                                                          "needs bigbuf");
+                                        } else {
+                                                /* Have first buffer */
+                                                mid_entry->resp_buf =
+                                                         smb_buffer;
+                                                mid_entry->largeBuf = true;
+                                                bigbuf = NULL;
                                         }
-                                        break;
                                 }
-                                mid_entry->resp_buf = smb_buffer;
-                                mid_entry->largeBuf = isLargeBuf;
+                                break;
+                        }
+                        mid_entry->resp_buf = smb_buffer;
+                        mid_entry->largeBuf = isLargeBuf;
 multi_t2_fnd:
-                                if (length == 0)
-                                        mid_entry->midState =
-                                                        MID_RESPONSE_RECEIVED;
-                                else
-                                        mid_entry->midState =
-                                                        MID_RESPONSE_MALFORMED;
+                        if (length == 0)
+                                mid_entry->midState = MID_RESPONSE_RECEIVED;
+                        else
+                                mid_entry->midState = MID_RESPONSE_MALFORMED;
 #ifdef CONFIG_CIFS_STATS2
-                                mid_entry->when_received = jiffies;
+                        mid_entry->when_received = jiffies;
 #endif
-                                list_del_init(&mid_entry->qhead);
-                                mid_entry->callback(mid_entry);
-                                break;
-                        }
-                        mid_entry = NULL;
+                        list_del_init(&mid_entry->qhead);
+                        mid_entry->callback(mid_entry);
+                        break;
                 }
                 spin_unlock(&GlobalMid_Lock);
 
diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index f6728eb6f4b9..645114ad0a10 100644
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -276,7 +276,7 @@ static void ascii_ssetup_strings(char **pbcc_area, struct cifsSesInfo *ses,
 }
 
 static void
-decode_unicode_ssetup(char **pbcc_area, __u16 bleft, struct cifsSesInfo *ses,
+decode_unicode_ssetup(char **pbcc_area, int bleft, struct cifsSesInfo *ses,
                       const struct nls_table *nls_cp)
 {
         int len;
@@ -284,19 +284,6 @@ decode_unicode_ssetup(char **pbcc_area, __u16 bleft, struct cifsSesInfo *ses,
 
         cFYI(1, "bleft %d", bleft);
 
-        /*
-         * Windows servers do not always double null terminate their final
-         * Unicode string. Check to see if there are an uneven number of bytes
-         * left. If so, then add an extra NULL pad byte to the end of the
-         * response.
-         *
-         * See section 2.7.2 in "Implementing CIFS" for details
-         */
-        if (bleft % 2) {
-                data[bleft] = 0;
-                ++bleft;
-        }
-
         kfree(ses->serverOS);
         ses->serverOS = cifs_strndup_from_ucs(data, bleft, true, nls_cp);
         cFYI(1, "serverOS=%s", ses->serverOS);
@@ -929,7 +916,9 @@ ssetup_ntlmssp_authenticate:
         }
 
         /* BB check if Unicode and decode strings */
-        if (smb_buf->Flags2 & SMBFLG2_UNICODE) {
+        if (bytes_remaining == 0) {
+                /* no string area to decode, do nothing */
+        } else if (smb_buf->Flags2 & SMBFLG2_UNICODE) {
                 /* unicode string area must be word-aligned */
                 if (((unsigned long) bcc_ptr - (unsigned long) smb_buf) % 2) {
                         ++bcc_ptr;