libcli/smb: parse the SMB2_TRANSFORM header and decrypt the SMB2 pdu

metze

diff --git a/libcli/smb/smbXcli_base.c b/libcli/smb/smbXcli_base.c
index 8458fdeaa6dfb9109486c18430d53fdb11879ef6..67d5f6a0eaa97d5527c923822beeb061a11c4dbd 100644 (file)
--- a/libcli/smb/smbXcli_base.c
+++ b/libcli/smb/smbXcli_base.c
@@ -2760,6 +2760,58 @@ static NTSTATUS smb2cli_inbuf_parse_compound(struct smbXcli_conn *conn,
                uint16_t body_size;
                struct iovec *iov_tmp;
 
+               if (len < 4) {
+                       DEBUG(10, ("%d bytes left, expected at least %d\n",
+                                  (int)len, 4));
+                       goto inval;
+               }
+               if (IVAL(hdr, 0) == SMB2_TF_MAGIC) {
+                       struct smbXcli_session *s;
+                       uint64_t uid;
+                       struct iovec tf_iov[2];
+                       NTSTATUS status;
+
+                       if (len < SMB2_TF_HDR_SIZE) {
+                               DEBUG(10, ("%d bytes left, expected at least %d\n",
+                                          (int)len, SMB2_TF_HDR_SIZE));
+                               goto inval;
+                       }
+                       tf = hdr;
+                       tf_len = SMB2_TF_HDR_SIZE;
+                       taken += tf_len;
+
+                       hdr = first_hdr + taken;
+                       len = IVAL(tf, SMB2_TF_MSG_SIZE);
+                       uid = BVAL(tf, SMB2_TF_SESSION_ID);
+
+                       s = conn->sessions;
+                       for (; s; s = s->next) {
+                               if (s->smb2.session_id != uid) {
+                                       continue;
+                               }
+                               break;
+                       }
+
+                       if (s == NULL) {
+                               DEBUG(10, ("unknown session_id %llu\n",
+                                          (unsigned long long)uid));
+                               goto inval;
+                       }
+
+                       tf_iov[0].iov_base = (void *)tf;
+                       tf_iov[0].iov_len = tf_len;
+                       tf_iov[1].iov_base = (void *)hdr;
+                       tf_iov[1].iov_len = len;
+
+                       status = smb2_signing_decrypt_pdu(s->smb2.decryption_key,
+                                                         conn->protocol,
+                                                         tf_iov, 2);
+                       if (!NT_STATUS_IS_OK(status)) {
+                               TALLOC_FREE(iov);
+                               return status;
+                       }
+               }
+
                /*
                 * We need the header plus the body length field
                 */
@@ -2791,6 +2843,9 @@ static NTSTATUS smb2cli_inbuf_parse_compound(struct smbXcli_conn *conn,
                        if (next_command_ofs > full_size) {
                                goto inval;
                        }
+                       if (tf && next_command_ofs < len) {
+                               goto inval;
+                       }
                        full_size = next_command_ofs;
                }
                if (body_size < 2) {
@@ -2950,6 +3005,14 @@ static NTSTATUS smb2cli_conn_dispatch_incoming(struct smbXcli_conn *conn,
                        }
                }
 
+               /*
+                * If we have a SMB2_TRANSFORM header we already verified
+                * a signature.
+                */
+               if (cur[0].iov_len == SMB2_TF_HDR_SIZE) {
+                       should_sign = false;
+               }
+
                if (should_sign) {
                        if (!(flags & SMB2_HDR_FLAG_SIGNED)) {
                                return NT_STATUS_ACCESS_DENIED;