From: Vlad Buslov vladbu@nvidia.com
commit 396d7f23adf9e8c436dd81a69488b5b6a865acf8 upstream.
When police action is created by cls API tcf_exts_validate() first conditional that calls tcf_action_init_1() directly, the action idr is not updated according to latest changes in action API that require caller to commit newly created action to idr with tcf_idr_insert_many(). This results such action not being accessible through act API and causes crash reported by syzbot:
================================================================== BUG: KASAN: null-ptr-deref in instrument_atomic_read include/linux/instrumented.h:71 [inline] BUG: KASAN: null-ptr-deref in atomic_read include/asm-generic/atomic-instrumented.h:27 [inline] BUG: KASAN: null-ptr-deref in __tcf_idr_release net/sched/act_api.c:178 [inline] BUG: KASAN: null-ptr-deref in tcf_idrinfo_destroy+0x129/0x1d0 net/sched/act_api.c:598 Read of size 4 at addr 0000000000000010 by task kworker/u4:5/204
CPU: 0 PID: 204 Comm: kworker/u4:5 Not tainted 5.11.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:120 __kasan_report mm/kasan/report.c:400 [inline] kasan_report.cold+0x5f/0xd5 mm/kasan/report.c:413 check_memory_region_inline mm/kasan/generic.c:179 [inline] check_memory_region+0x13d/0x180 mm/kasan/generic.c:185 instrument_atomic_read include/linux/instrumented.h:71 [inline] atomic_read include/asm-generic/atomic-instrumented.h:27 [inline] __tcf_idr_release net/sched/act_api.c:178 [inline] tcf_idrinfo_destroy+0x129/0x1d0 net/sched/act_api.c:598 tc_action_net_exit include/net/act_api.h:151 [inline] police_exit_net+0x168/0x360 net/sched/act_police.c:390 ops_exit_list+0x10d/0x160 net/core/net_namespace.c:190 cleanup_net+0x4ea/0xb10 net/core/net_namespace.c:604 process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 ================================================================== Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 204 Comm: kworker/u4:5 Tainted: G B 5.11.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:120 panic+0x306/0x73d kernel/panic.c:231 end_report+0x58/0x5e mm/kasan/report.c:100 __kasan_report mm/kasan/report.c:403 [inline] kasan_report.cold+0x67/0xd5 mm/kasan/report.c:413 check_memory_region_inline mm/kasan/generic.c:179 [inline] check_memory_region+0x13d/0x180 mm/kasan/generic.c:185 instrument_atomic_read include/linux/instrumented.h:71 [inline] atomic_read include/asm-generic/atomic-instrumented.h:27 [inline] __tcf_idr_release net/sched/act_api.c:178 [inline] tcf_idrinfo_destroy+0x129/0x1d0 net/sched/act_api.c:598 tc_action_net_exit include/net/act_api.h:151 [inline] police_exit_net+0x168/0x360 net/sched/act_police.c:390 ops_exit_list+0x10d/0x160 net/core/net_namespace.c:190 cleanup_net+0x4ea/0xb10 net/core/net_namespace.c:604 process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Kernel Offset: disabled
Fix the issue by calling tcf_idr_insert_many() after successful action initialization.
Fixes: 0fedc63fadf0 ("net_sched: commit action insertions together") Reported-by: syzbot+151e3e714d34ae4ce7e8@syzkaller.appspotmail.com Signed-off-by: Vlad Buslov vladbu@nvidia.com Reviewed-by: Cong Wang xiyou.wangcong@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/net/act_api.h | 1 + net/sched/act_api.c | 2 +- net/sched/cls_api.c | 1 + 3 files changed, 3 insertions(+), 1 deletion(-)
--- a/include/net/act_api.h +++ b/include/net/act_api.h @@ -166,6 +166,7 @@ int tcf_idr_create_from_flags(struct tc_ struct nlattr *est, struct tc_action **a, const struct tc_action_ops *ops, int bind, u32 flags); +void tcf_idr_insert_many(struct tc_action *actions[]); void tcf_idr_cleanup(struct tc_action_net *tn, u32 index); int tcf_idr_check_alloc(struct tc_action_net *tn, u32 *index, struct tc_action **a, int bind); --- a/net/sched/act_api.c +++ b/net/sched/act_api.c @@ -908,7 +908,7 @@ static const struct nla_policy tcf_actio [TCA_ACT_HW_STATS] = NLA_POLICY_BITFIELD32(TCA_ACT_HW_STATS_ANY), };
-static void tcf_idr_insert_many(struct tc_action *actions[]) +void tcf_idr_insert_many(struct tc_action *actions[]) { int i;
--- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -3053,6 +3053,7 @@ int tcf_exts_validate(struct net *net, s act->type = exts->type = TCA_OLD_COMPAT; exts->actions[0] = act; exts->nr_actions = 1; + tcf_idr_insert_many(exts->actions); } else if (exts->action && tb[exts->action]) { int err;