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wlr_seat destroy: fix use-after-free when destroying clients 

wl_resource_for_each_safe isn't safe to use here because it accesses
the list's head memory one last time at the end of the loop. Work
around this by breaking out early.

==19880==ERROR: AddressSanitizer: heap-use-after-free on address 0x60d0000e6368 at pc 0x7fab68619de2 bp 0x7ffd5c91cee0 sp 0x7ffd5c91ced0
READ of size 8 at 0x60d0000e6368 thread T0
    #0 0x7fab68619de1 in wlr_seat_destroy ../types/seat/wlr_seat.c:179
    #1 0x7fab68619fb9 in handle_display_destroy ../types/seat/wlr_seat.c:196
    #2 0x7fab688e4f8f in wl_priv_signal_emit src/wayland-server.c:2024
    #3 0x7fab688e56ca in wl_display_destroy src/wayland-server.c:1092
    #4 0x40c11e in server_fini ../sway/server.c:138
    #5 0x40b1a8 in main ../sway/main.c:438
    #6 0x7fab67b5e18a in __libc_start_main ../csu/libc-start.c:308
    #7 0x409359 in _start (/opt/wayland/bin/sway+0x409359)

0x60d0000e6368 is located 24 bytes inside of 144-byte region [0x60d0000e6350,0x60d0000e63e0)
freed by thread T0 here:
    #0 0x7fab6a7d6880 in __interceptor_free (/lib64/libasan.so.5+0xee880)
    #1 0x7fab68619805 in seat_client_handle_resource_destroy ../types/seat/wlr_seat.c:97
    #2 0x7fab688e5025 in destroy_resource src/wayland-server.c:688

previously allocated by thread T0 here:
    #0 0x7fab6a7d6e50 in calloc (/lib64/libasan.so.5+0xeee50)
    #1 0x7fab686198df in seat_handle_bind ../types/seat/wlr_seat.c:127
    #2 0x7fab6530503d in ffi_call_unix64 (/lib64/libffi.so.6+0x603d)
This commit is contained in:
Dominique Martinet 2018-07-04 14:37:41 +09:00
parent 12dd9544f9
commit 48e8da851d
1 changed files with 10 additions and 2 deletions
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12
types/seat/wlr_seat.c
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@ -175,10 +175,18 @@ void wlr_seat_destroy(struct wlr_seat *seat) {
struct wlr_seat_client *client, *tmp; struct wlr_seat_client *client, *tmp;
wl_list_for_each_safe(client, tmp, &seat->clients, link) { wl_list_for_each_safe(client, tmp, &seat->clients, link) {
struct wl_resource *resource, *next_resource; struct wl_resource *resource, *next;
wl_resource_for_each_safe(resource, next_resource, &client->wl_resources) { /* wl_resource_for_each_safe isn't safe to use here, because the last
* wl_resource_destroy will also destroy the head we cannot do the last
* 'next' update that usually is harmless here.
* Work around this by breaking one step ahead
*/
wl_resource_for_each_safe(resource, next, &client->wl_resources) {
// will destroy other resources as well // will destroy other resources as well
wl_resource_destroy(resource); wl_resource_destroy(resource);
if (wl_resource_get_link(next) == &client->wl_resources) {
break;
}
} }
} }