pidgin/pidgin

Fix leak that may occur when xmlnode_from_str fails
release-2.x.y
2021-09-13, Elliott Sales de Andrade
59a77978ca08
Fix leak that may occur when xmlnode_from_str fails

The failure may occur any time in the middle of parsing, and `xpd->current` may
not actually be pointing to the root of the parsed tree. Thus we need to walk
back up before freeing the xmlnode.

Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=34988

Testing Done:
Ran the reproducer testcase on `fuzz_xml`

Reviewed at https://reviews.imfreedom.org/r/911/
#error "This is file is not a valid C code"
/* This file contains some of the macros from other header files as
function declarations. This does not make sense in C, but it
provides type information for the dbus-analyze-functions.py
program, which makes these macros callable by DBUS. */
/* blist.h */
gboolean PURPLE_BLIST_NODE_IS_CHAT(PurpleBlistNode *node);
gboolean PURPLE_BLIST_NODE_IS_BUDDY(PurpleBlistNode *node);
gboolean PURPLE_BLIST_NODE_IS_CONTACT(PurpleBlistNode *node);
gboolean PURPLE_BLIST_NODE_IS_GROUP(PurpleBlistNode *node);
gboolean PURPLE_BUDDY_IS_ONLINE(PurpleBuddy *buddy);
gboolean PURPLE_BLIST_NODE_HAS_FLAG(PurpleBlistNode *node, int flags);
gboolean PURPLE_BLIST_NODE_SHOULD_SAVE(PurpleBlistNode *node);
/* connection.h */
gboolean PURPLE_CONNECTION_IS_CONNECTED(PurpleConnection *connection);
gboolean PURPLE_CONNECTION_IS_VALID(PurpleConnection *connection);
/* conversation.h */
PurpleConvIm *PURPLE_CONV_IM(const PurpleConversation *conversation);
PurpleConvIm *PURPLE_CONV_CHAT(const PurpleConversation *conversation);