smb: properly check incoming packet boundaries

Not all reply messages were properly checked for their lengths, which
made it possible to access uninitialized memory (but this does not lead
to out of boundary accesses).

Closes #1052

diff --git a/lib/smb.c b/lib/smb.c
index 56a38c2f28f84a054642e7282225a8cdc8f4e633..7cb0c9611c27c3c089e5e5e0ec9396f89bda449f 100644 (file)
--- a/lib/smb.c
+++ b/lib/smb.c
@@ -673,7 +673,7 @@ static CURLcode smb_connection_state(struct connectdata *conn, bool *done)
 
   switch(smbc->state) {
   case SMB_NEGOTIATE:
-    if(h->status) {
+    if(h->status || smbc->got < sizeof(*nrsp) + sizeof(smbc->challenge) - 1) {
       connclose(conn, "SMB: negotiation failed");
       return CURLE_COULDNT_CONNECT;
     }
@@ -712,6 +712,7 @@ static CURLcode smb_request_state(struct connectdata *conn, bool *done)
 {
   struct smb_request *req = conn->data->req.protop;
   struct smb_header *h;
+  struct smb_conn *smbc = &conn->proto.smbc;
   enum smb_req_state next_state = SMB_DONE;
   unsigned short len;
   unsigned short off;
@@ -754,7 +755,7 @@ static CURLcode smb_request_state(struct connectdata *conn, bool *done)
     break;
 
   case SMB_OPEN:
-    if(h->status) {
+    if(h->status || smbc->got < sizeof(struct smb_nt_create_response)) {
       req->result = CURLE_REMOTE_FILE_NOT_FOUND;
       next_state = SMB_TREE_DISCONNECT;
       break;
@@ -775,7 +776,7 @@ static CURLcode smb_request_state(struct connectdata *conn, bool *done)
     break;
 
   case SMB_DOWNLOAD:
-    if(h->status) {
+    if(h->status || smbc->got < sizeof(struct smb_header) + 14) {
       req->result = CURLE_RECV_ERROR;
       next_state = SMB_CLOSE;
       break;
@@ -785,7 +786,6 @@ static CURLcode smb_request_state(struct connectdata *conn, bool *done)
     off = Curl_read16_le(((unsigned char *) msg) +
                          sizeof(struct smb_header) + 13);
     if(len > 0) {
-      struct smb_conn *smbc = &conn->proto.smbc;
       if(off + sizeof(unsigned int) + len > smbc->got) {
         failf(conn->data, "Invalid input packet");
         result = CURLE_RECV_ERROR;
@@ -807,7 +807,7 @@ static CURLcode smb_request_state(struct connectdata *conn, bool *done)
     break;
 
   case SMB_UPLOAD:
-    if(h->status) {
+    if(h->status || smbc->got < sizeof(struct smb_header) + 6) {
       req->result = CURLE_UPLOAD_FAILED;
       next_state = SMB_CLOSE;
       break;