prevent memory leak in xmpp_stanza_new_from_string()

sjaeckel · sjaeckel · commit 62d1063560b8 · 2022-05-05T16:34:44.000+02:00
Only remember the first stanza in case the string contains
multiple stanzas.

Signed-off-by: Steffen Jaeckel &lt;jaeckel-floss@eyet-services.de&gt;
diff --git a/src/stanza.c b/src/stanza.c
@@ -1640,8 +1640,11 @@ static void _stub_stream_end(char *name, void *userdata)
 
 static void _stream_stanza(xmpp_stanza_t *stanza, void *userdata)
 {
-    stanza = xmpp_stanza_clone(stanza);
-    *(xmpp_stanza_t **)userdata = stanza;
+    xmpp_stanza_t **dest = userdata;
+    if (*dest == NULL) {
+        stanza = xmpp_stanza_clone(stanza);
+        *dest = stanza;
+    }
 }
 
 /** Create a stanza object from the string.
diff --git a/tests/test_stanza.c b/tests/test_stanza.c
@@ -99,7 +99,7 @@ static void test_stanza_from_string(xmpp_ctx_t *ctx)
     size_t buflen;
     int ret;
 
-    static const char *str =
+    const char *str =
         "<signcrypt xmlns=\"urn:xmpp:openpgp:0\"><to "
         "jid=\"user@domain.com\"/><time "
         "stamp=\"2020-06-03T21:26:24+0200\"/><rpad/><payload><body "
@@ -113,6 +113,22 @@ static void test_stanza_from_string(xmpp_ctx_t *ctx)
     xmpp_free(ctx, buf);
     xmpp_stanza_release(stanza);
 
+    /* create a string with two stanzas to make sure we don't
+     * leak any memory when we convert them to a xmpp_stanza_t
+     */
+    buf = malloc(strlen(str) * 2 + 1);
+    assert(buf != NULL);
+    memcpy(buf, str, strlen(str) + 1);
+    memcpy(&buf[strlen(str)], str, strlen(str) + 1);
+    stanza = xmpp_stanza_new_from_string(ctx, buf);
+    assert(stanza != NULL);
+    free(buf);
+    ret = xmpp_stanza_to_text(stanza, &buf, &buflen);
+    assert(ret == XMPP_EOK);
+    COMPARE(str, buf);
+    xmpp_free(ctx, buf);
+    xmpp_stanza_release(stanza);
+
     /* Error path. */
     stanza = xmpp_stanza_new_from_string(ctx, "<uu><uu>tt");
     assert(stanza == NULL);

Original file line number	Diff line number	Diff line change
`@@ -1640,8 +1640,11 @@ static void _stub_stream_end(char name, void userdata)`
`1640`	`1640`
`1641`	`1641`	`static void _stream_stanza(xmpp_stanza_t stanza, void userdata)`
`1642`	`1642`	`{`
`1643`		`- stanza = xmpp_stanza_clone(stanza);`
`1644`		`- (xmpp_stanza_t *)userdata = stanza;`
	`1643`	`+ xmpp_stanza_t **dest = userdata;`
	`1644`	`+ if (*dest == NULL) {`
	`1645`	`+ stanza = xmpp_stanza_clone(stanza);`
	`1646`	`+ *dest = stanza;`
	`1647`	`+ }`
`1645`	`1648`	`}`
`1646`	`1649`
`1647`	`1650`	`/** Create a stanza object from the string.`