Do not use a FILE handle when doing SIP TCP reads.

This is used to solve an issue where a poll on a file
descriptor does not necessarily correspond to the readiness
of a FILE handle to be read.

This change makes it so that for TCP connections, we do a
recv() on the file descriptor instead.

Because TCP does not guarantee that an entire message or even
just one single message will arrive during a read, a loop has
been introduced to ensure that we only attempt to handle a
single message at a time. The tcptls_session_instance structure
has also had an overflow buffer added to it so that if more
than one TCP message arrives in one go, there is a place to
throw the excess.

Huge thanks goes out to Walter Doekes for doing extensive review
on this change and finding edge cases where code could fail.

(closes issue ASTERISK-20212)
reported by Phil Ciccone

Review: https://reviewboard.asterisk.org/r/2123
........

Merged revisions 374905 from http://svn.asterisk.org/svn/asterisk/branches/1.8
........

Merged revisions 374906 from http://svn.asterisk.org/svn/asterisk/branches/10
........

Merged revisions 374914 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@374924 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 10 insertions, 2 deletions

diff --git a/main/tcptls.c b/main/tcptls.c
index 2e5cbf4c6..b52cdc491 100644
--- a/main/tcptls.c
+++ b/main/tcptls.c
@@ -142,6 +142,12 @@ HOOK_T ast_tcptls_server_write(struct ast_tcptls_session_instance *tcptls_sessio
 	return write(tcptls_session->fd, buf, count);
 }
 
+static void session_instance_destructor(void *obj)
+{
+	struct ast_tcptls_session_instance *i = obj;
+	ast_free(i->overflow_buf);
+}
+
 /*! \brief
 * creates a FILE * from the fd passed by the accept thread.
 * This operation is potentially expensive (certificate verification),
@@ -290,7 +296,7 @@ void *ast_tcptls_server_root(void *data)
 			}
 			continue;
 		}
-		tcptls_session = ao2_alloc(sizeof(*tcptls_session), NULL);
+		tcptls_session = ao2_alloc(sizeof(*tcptls_session), session_instance_destructor);
 		if (!tcptls_session) {
 			ast_log(LOG_WARNING, "No memory for new session: %s\n", strerror(errno));
 			if (close(fd)) {
@@ -299,6 +305,7 @@ void *ast_tcptls_server_root(void *data)
 			continue;
 		}
 
+		tcptls_session->overflow_buf = ast_str_create(128);
 		flags = fcntl(fd, F_GETFL);
 		fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);
 		tcptls_session->fd = fd;
@@ -498,10 +505,11 @@ struct ast_tcptls_session_instance *ast_tcptls_client_create(struct ast_tcptls_s
 		}
 	}
 
-	if (!(tcptls_session = ao2_alloc(sizeof(*tcptls_session), NULL))) {
+	if (!(tcptls_session = ao2_alloc(sizeof(*tcptls_session), session_instance_destructor))) {
 		goto error;
 	}
 
+	tcptls_session->overflow_buf = ast_str_create(128);
 	tcptls_session->client = 1;
 	tcptls_session->fd = desc->accept_fd;
 	tcptls_session->parent = desc;