From: Markus Theil <markus.theil@xxxxxxxxxxxxx> commit 3bd801b14e0c5d29eeddc7336558beb3344efaa3 upstream. Clear beacon ie pointer and ie length after free in order to prevent double free. ================================================================== BUG: KASAN: double-free or invalid-free \ in ieee80211_ibss_leave+0x83/0xe0 net/mac80211/ibss.c:1876 CPU: 0 PID: 8472 Comm: syz-executor100 Not tainted 5.11.0-rc6-syzkaller #0 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:120 print_address_description.constprop.0.cold+0x5b/0x2c6 mm/kasan/report.c:230 kasan_report_invalid_free+0x51/0x80 mm/kasan/report.c:355 ____kasan_slab_free+0xcc/0xe0 mm/kasan/common.c:341 kasan_slab_free include/linux/kasan.h:192 [inline] __cache_free mm/slab.c:3424 [inline] kfree+0xed/0x270 mm/slab.c:3760 ieee80211_ibss_leave+0x83/0xe0 net/mac80211/ibss.c:1876 rdev_leave_ibss net/wireless/rdev-ops.h:545 [inline] __cfg80211_leave_ibss+0x19a/0x4c0 net/wireless/ibss.c:212 __cfg80211_leave+0x327/0x430 net/wireless/core.c:1172 cfg80211_leave net/wireless/core.c:1221 [inline] cfg80211_netdev_notifier_call+0x9e8/0x12c0 net/wireless/core.c:1335 notifier_call_chain+0xb5/0x200 kernel/notifier.c:83 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:2040 call_netdevice_notifiers_extack net/core/dev.c:2052 [inline] call_netdevice_notifiers net/core/dev.c:2066 [inline] __dev_close_many+0xee/0x2e0 net/core/dev.c:1586 __dev_close net/core/dev.c:1624 [inline] __dev_change_flags+0x2cb/0x730 net/core/dev.c:8476 dev_change_flags+0x8a/0x160 net/core/dev.c:8549 dev_ifsioc+0x210/0xa70 net/core/dev_ioctl.c:265 dev_ioctl+0x1b1/0xc40 net/core/dev_ioctl.c:511 sock_do_ioctl+0x148/0x2d0 net/socket.c:1060 sock_ioctl+0x477/0x6a0 net/socket.c:1177 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported-by: syzbot+93976391bf299d425f44@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Markus Theil <markus.theil@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20210213133653.367130-1-markus.theil@xxxxxxxxxxxxx Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/mac80211/ibss.c | 2 ++ 1 file changed, 2 insertions(+) --- a/net/mac80211/ibss.c +++ b/net/mac80211/ibss.c @@ -1860,6 +1860,8 @@ int ieee80211_ibss_leave(struct ieee8021 /* remove beacon */ kfree(sdata->u.ibss.ie); + sdata->u.ibss.ie = NULL; + sdata->u.ibss.ie_len = 0; /* on the next join, re-program HT parameters */ memset(&ifibss->ht_capa, 0, sizeof(ifibss->ht_capa));
