imap: COMPRESS - Fail if client pipelines data without waiting for OK reply

diff --git a/src/imap/cmd-compress.c b/src/imap/cmd-compress.c
index 52c74b5a8214e159e512bdf4d6a29b2f61d035e5..0c3042cc290ce3d35c6927abdd29f7377ece2d63 100644 (file)
--- a/src/imap/cmd-compress.c
+++ b/src/imap/cmd-compress.c
@@ -75,6 +75,14 @@ bool cmd_compress(struct client_command_context *cmd)
        }
 
        client_skip_line(client);
+
+       /* Client cannot assume that COMPRESS works and just start sending
+          compressed data pipelined. Add an explicit sanity check for this. */
+       if (i_stream_get_data_size(client->input) > 0) {
+               client_send_tagline(cmd, "BAD Client did not wait for COMPRESS reply before sending more data");
+               return TRUE;
+       }
+
        client_send_tagline(cmd, "OK Begin compression.");
 
        uoff_t prev_out_offset = client->output->offset;