pidgin/pidgin

Fix an out of bounds write in purple_markup_linkify.
release-2.x.y
2021-07-08, Gary Kramlich
71df0a528a5a
Fix an out of bounds write in purple_markup_linkify.

This was found by Thomas Roth , Dominik Maier
, and Fabian Freyer .

Testing Done:
Compiled and ran the `purple_markup_linkify_fuzzer` from the google oss-fuzz project to verify the fix.

Reviewed at https://reviews.imfreedom.org/r/781/
#define PIDGIN_ICON 104
#define PIDGIN_TRAY_AVAILABLE_4BIT 105
#define PIDGIN_TRAY_AWAY_4BIT 106
#define PIDGIN_TRAY_BUSY_4BIT 107
#define PIDGIN_TRAY_XA_4BIT 108
#define PIDGIN_TRAY_OFFLINE_4BIT 109
#define PIDGIN_TRAY_CONNECTING_4BIT 110
#define PIDGIN_TRAY_PENDING_4BIT 111
#define PIDGIN_TRAY_INVISIBLE_4BIT 112