| Message ID | 20210216162200.1834139-1-vladbu@nvidia.com (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] net: sched: fix police ext initialization | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Link |
| netdev/fixes_present | success | Link |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Clearly marked for net |
| netdev/subject_prefix | success | Link |
| netdev/cc_maintainers | success | CCed 6 of 6 maintainers |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 228 this patch: 228 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | warning | WARNING: Possible repeated word: 'Google' |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 232 this patch: 232 |
| netdev/header_inline | success | Link |
| netdev/stable | success | Stable not CCed |
On Tue, Feb 16, 2021 at 8:22 AM Vlad Buslov <vladbu@nvidia.com> wrote: > > 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: Good catch! This certainly makes sense to me, and I feed it to syzbot too, it is happy with this patch, so: Reported-and-tested-by: syzbot+151e3e714d34ae4ce7e8@syzkaller.appspotmail.com Reviewed-by: Cong Wang <xiyou.wangcong@gmail.com> Thanks.
diff --git a/include/net/act_api.h b/include/net/act_api.h index 55dab604861f..57be7c5d273b 100644 --- a/include/net/act_api.h +++ b/include/net/act_api.h @@ -166,6 +166,7 @@ int tcf_idr_create_from_flags(struct tc_action_net *tn, u32 index, 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); diff --git a/net/sched/act_api.c b/net/sched/act_api.c index 2e85b636b27b..ebc8f1413078 100644 --- a/net/sched/act_api.c +++ b/net/sched/act_api.c @@ -908,7 +908,7 @@ static const struct nla_policy tcf_action_policy[TCA_ACT_MAX + 1] = { [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; diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index 37b77bd30974..0b3900dd2354 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -3053,6 +3053,7 @@ int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb, 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;
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> --- 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(-)