Improve AMI long line error handling

In AMI's parser, when it receives a long line (> 1024 characters), it discards
that line, but continues to process the message normally.

Typically, this is not a problem because a) who has lines that long and b)
usually a discarded line results in an invalid message. But if that line is
specifying an optional field, then the message will be processed, you get a
'Response: Success', but things don't work the way you expected them to.

This patch changes the behavior when a line-too-long parse error occurs.

* Changes the log message to avoid way-too-long (and truncated anyways) log
  messages
* Adds a 'parsing' status flag to Response: Success
* Sets parsing = MESSAGE_LINE_TOO_LONG if, well, a line is too long
* Responds with an appropriate error if parsing != MESSAGE_OKAY

(closes issue AST-961)
Reported by: John Bigelow
Review: https://reviewboard.asterisk.org/r/2142/

git-svn-id: https://origsvn.digium.com/svn/asterisk/certified/branches/1.8.15@374569 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/main/manager.c b/main/manager.c
index dafc0c0f1e4f56f545ab626e5bd22317c11900d7..e8cd52adc4ea718c2cc7b23fc59a31c2d85d28be 100644 (file)
--- a/main/manager.c
+++ b/main/manager.c
@@ -992,6 +992,11 @@ struct mansession_session {
        AST_LIST_ENTRY(mansession_session) list;
 };
 
+enum mansession_message_parsing {
+       MESSAGE_OKAY,
+       MESSAGE_LINE_TOO_LONG
+};
+
 /* In case you didn't read that giant block of text above the mansession_session struct, the
  * 'mansession' struct is named this solely to keep the API the same in Asterisk. This structure really
  * represents data that is different from Manager action to Manager action. The mansession_session pointer
@@ -1002,6 +1007,7 @@ struct mansession {
        struct ast_tcptls_session_instance *tcptls_session;
        FILE *f;
        int fd;
+       enum mansession_message_parsing parsing;
        int write_error:1;
        struct manager_custom_hook *hook;
        ast_mutex_t lock;
@@ -4783,8 +4789,9 @@ static int get_input(struct mansession *s, char *output)
        }
        if (s->session->inlen >= maxlen) {
                /* no crlf found, and buffer full - sorry, too long for us */
-               ast_log(LOG_WARNING, "Dumping long line with no return from %s: %s\n", ast_inet_ntoa(s->session->sin.sin_addr), src);
+               ast_log(LOG_WARNING, "Discarding message from %s. Line too long: %.25s...\n", ast_inet_ntoa(s->session->sin.sin_addr), src);
                s->session->inlen = 0;
+               s->parsing = MESSAGE_LINE_TOO_LONG;
        }
        res = 0;
        while (res == 0) {
@@ -4841,6 +4848,23 @@ static int get_input(struct mansession *s, char *output)
        return res;
 }
 
+/*!
+ * \internal
+ * \brief Error handling for sending parse errors. This function handles locking, and clearing the
+ * parse error flag.
+ *
+ * \param s AMI session to process action request.
+ * \param m Message that's in error.
+ * \param error Error message to send.
+ */
+static void handle_parse_error(struct mansession *s, struct message *m, char *error)
+{
+       mansession_lock(s);
+       astman_send_error(s, m, error);
+       s->parsing = MESSAGE_OKAY;
+       mansession_unlock(s);
+}
+
 /*!
  * \internal
  * \brief Read and process an AMI action request.
@@ -4894,7 +4918,15 @@ static int do_message(struct mansession *s)
                                        mansession_unlock(s);
                                        res = 0;
                                } else {
-                                       res = process_message(s, &m) ? -1 : 0;
+                                       switch (s->parsing) {
+                                       case MESSAGE_OKAY:
+                                               res = process_message(s, &m) ? -1 : 0;
+                                               break;
+                                       case MESSAGE_LINE_TOO_LONG:
+                                               handle_parse_error(s, &m, "Failed to parse message: line too long");
+                                               res = 0;
+                                               break;
+                                       }
                                }
                                break;
                        } else if (m.hdrcount < ARRAY_LEN(m.headers)) {