From e5ece5f8b3ec14bfdbea20597ff1db82369d6331 Mon Sep 17 00:00:00 2001 From: Dominique Martinet Date: Sun, 7 Oct 2018 16:33:26 +0900 Subject: [PATCH] swaynag: fix use-after-free in wl_display_dispatch When destroying swaynag from within wl_display_dispatch, we cannot disconnect the display as that will free the queue's event_list. Free it after running the loop instead. Fixes this use-after-free: ==7312==ERROR: AddressSanitizer: heap-use-after-free on address 0x612000000110 at pc 0x000000412a9f bp 0x7ffd4e811760 sp 0x7ffd4e811750 READ of size 8 at 0x612000000110 thread T0 #0 0x412a9e in wl_list_empty ../common/list.c:206 #1 0x7f5b58f0d42f in dispatch_queue src/wayland-client.c:1572 #2 0x7f5b58f0d42f in wl_display_dispatch_queue_pending src/wayland-client.c:1815 #3 0x40f465 in swaynag_run ../swaynag/swaynag.c:390 #4 0x407576 in main ../swaynag/main.c:123 #5 0x7f5b58bb9412 in __libc_start_main ../csu/libc-start.c:308 #6 0x404a3d in _start (/opt/wayland/bin/swaynag+0x404a3d) 0x612000000110 is located 208 bytes inside of 320-byte region [0x612000000040,0x612000000180) freed by thread T0 here: #0 0x7f5b594ab480 in free (/lib64/libasan.so.5+0xef480) #1 0x40faff in swaynag_destroy ../swaynag/swaynag.c:454 #2 0x40cbb4 in layer_surface_closed ../swaynag/swaynag.c:82 #3 0x7f5b583e1acd in ffi_call_unix64 (/lib64/libffi.so.6+0x6acd) previously allocated by thread T0 here: #0 0x7f5b594aba50 in __interceptor_calloc (/lib64/libasan.so.5+0xefa50) #1 0x7f5b58f0c902 in wl_display_connect_to_fd src/wayland-private.h:236 (you need a wayland compiled with asan, my wl_list hack, or running with valgrind to see this trace) --- swaynag/swaynag.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/swaynag/swaynag.c b/swaynag/swaynag.c index 26d3589e..69da851e 100644 --- a/swaynag/swaynag.c +++ b/swaynag/swaynag.c @@ -390,6 +390,10 @@ void swaynag_run(struct swaynag *swaynag) { && wl_display_dispatch(swaynag->display) != -1) { // This is intentionally left blank } + + if (swaynag->display) { + wl_display_disconnect(swaynag->display); + } } void swaynag_destroy(struct swaynag *swaynag) { @@ -449,8 +453,4 @@ void swaynag_destroy(struct swaynag *swaynag) { if (swaynag->shm) { wl_shm_destroy(swaynag->shm); } - - if (swaynag->display) { - wl_display_disconnect(swaynag->display); - } }