Fix some potential misuses of ast_str in the code.

Passing an ast_str pointer by value that then calls
ast_str_set(), ast_str_set_va(), ast_str_append(), or
ast_str_append_va() can result in the pointer originally
passed by value being invalidated if the ast_str had
to be reallocated.

This fixes places in the code that do this. Only the
example in ccss.c could result in pointer invalidation
though since the other cases use a stack-allocated ast_str
and cannot be reallocated.

I've also updated the doxygen in strings.h to include
notes about potential misuse of the functions mentioned
previously.

Review: https://reviewboard.asterisk.org/r/2161
........

Merged revisions 375025 from http://svn.asterisk.org/svn/asterisk/branches/1.8
........

Merged revisions 375026 from http://svn.asterisk.org/svn/asterisk/branches/10
........

Merged revisions 375027 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@375044 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 11 insertions, 11 deletions

diff --git a/channels/chan_iax2.c b/channels/chan_iax2.c
index b6b7e97c1..be0f2676b 100644
--- a/channels/chan_iax2.c
+++ b/channels/chan_iax2.c
@@ -1597,19 +1597,19 @@ static int send_ping(const void *data)
 	return 0;
 }
 
-static void encmethods_to_str(int e, struct ast_str *buf)
+static void encmethods_to_str(int e, struct ast_str **buf)
 {
-	ast_str_set(&buf, 0, "(");
+	ast_str_set(buf, 0, "(");
 	if (e & IAX_ENCRYPT_AES128) {
-		ast_str_append(&buf, 0, "aes128");
+		ast_str_append(buf, 0, "aes128");
 	}
 	if (e & IAX_ENCRYPT_KEYROTATE) {
-		ast_str_append(&buf, 0, ",keyrotate");
+		ast_str_append(buf, 0, ",keyrotate");
 	}
-	if (ast_str_strlen(buf) > 1) {
-		ast_str_append(&buf, 0, ")");
+	if (ast_str_strlen(*buf) > 1) {
+		ast_str_append(buf, 0, ")");
 	} else {
-		ast_str_set(&buf, 0, "No");
+		ast_str_set(buf, 0, "No");
 	}
 }
 
@@ -3829,7 +3829,7 @@ static char *handle_cli_iax2_show_peer(struct ast_cli_entry *e, int cmd, struct
 
 		ast_sockaddr_to_sin(&peer->addr, &peer_addr);
 
-		encmethods_to_str(peer->encmethods, encmethods);
+		encmethods_to_str(peer->encmethods, &encmethods);
 		ast_cli(a->fd, "\n\n");
 		ast_cli(a->fd, "  * Name       : %s\n", peer->name);
 		ast_cli(a->fd, "  Description  : %s\n", peer->description);
@@ -6811,7 +6811,7 @@ static int __iax2_show_peers(int fd, int *total, struct mansession *s, const int
 		else
 			ast_copy_string(name, peer->name, sizeof(name));
 
-		encmethods_to_str(peer->encmethods, encmethods);
+		encmethods_to_str(peer->encmethods, &encmethods);
 		retstatus = peer_status(peer, status, sizeof(status));
 		if (retstatus > 0)
 			online_peers++;
@@ -7116,7 +7116,7 @@ static int manager_iax2_show_peer_list(struct mansession *s, const struct messag
 
 	i = ao2_iterator_init(peers, 0);
 	for (; (peer = ao2_iterator_next(&i)); peer_unref(peer)) {
-		encmethods_to_str(peer->encmethods, encmethods);
+		encmethods_to_str(peer->encmethods, &encmethods);
 		astman_append(s, "Event: PeerEntry\r\n%sChanneltype: IAX\r\n", idtext);
 		if (!ast_strlen_zero(peer->username)) {
 			astman_append(s, "ObjectName: %s\r\nObjectUsername: %s\r\n", peer->name, peer->username);
@@ -14781,7 +14781,7 @@ static int peers_data_provider_get(const struct ast_data_search *search,
 
 		ast_data_add_bool(data_peer, "dynamic", ast_test_flag64(peer, IAX_DYNAMIC));
 
-		encmethods_to_str(peer->encmethods, encmethods);
+		encmethods_to_str(peer->encmethods, &encmethods);
 		ast_data_add_str(data_peer, "encryption", peer->encmethods ? ast_str_buffer(encmethods) : "no");
 
 		peer_unref(peer);