1 files changed, 16 insertions, 6 deletions

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 4bc862a80efa..8b75a8ec90b4 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 */