From: Masami Hiramatsu Date: Tue, 17 Sep 2019 05:11:37 +0000 (+0900) Subject: tracing/kprobe: Fix NULL pointer access in trace_porbe_unlink() X-Git-Tag: v5.4-rc1~4^2~10 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=d59fae6fea39efe65bb3d3310aaa2a54b5f55c0d;p=platform%2Fkernel%2Flinux-rpi.git tracing/kprobe: Fix NULL pointer access in trace_porbe_unlink() Fix NULL pointer access in trace_probe_unlink() by initializing trace_probe.list correctly in trace_probe_init(). In the error case of trace_probe_init(), it can call trace_probe_unlink() before initializing trace_probe.list member. This causes NULL pointer dereference at list_del_init() in trace_probe_unlink(). Syzbot reported : kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 8633 Comm: syz-executor797 Not tainted 5.3.0-rc8-next-20190915 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__list_del_entry_valid+0x85/0xf5 lib/list_debug.c:51 Code: 0f 84 e1 00 00 00 48 b8 22 01 00 00 00 00 ad de 49 39 c4 0f 84 e2 00 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 e2 48 c1 ea 03 <80> 3c 02 00 75 53 49 8b 14 24 4c 39 f2 0f 85 99 00 00 00 49 8d 7d RSP: 0018:ffff888090a7f9d8 EFLAGS: 00010246 RAX: dffffc0000000000 RBX: ffff88809b6f90c0 RCX: ffffffff817c0ca9 RDX: 0000000000000000 RSI: ffffffff817c0a73 RDI: ffff88809b6f90c8 RBP: ffff888090a7f9f0 R08: ffff88809a04e600 R09: ffffed1015d26aed R10: ffffed1015d26aec R11: ffff8880ae935763 R12: 0000000000000000 R13: 0000000000000000 R14: ffff88809b6f90c0 R15: ffff88809b6f90d0 FS: 0000555556f99880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000006cc090 CR3: 00000000962b2000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __list_del_entry include/linux/list.h:131 [inline] list_del_init include/linux/list.h:190 [inline] trace_probe_unlink+0x1f/0x200 kernel/trace/trace_probe.c:959 trace_probe_cleanup+0xd3/0x110 kernel/trace/trace_probe.c:973 trace_probe_init+0x3f2/0x510 kernel/trace/trace_probe.c:1011 alloc_trace_uprobe+0x5e/0x250 kernel/trace/trace_uprobe.c:353 create_local_trace_uprobe+0x109/0x4a0 kernel/trace/trace_uprobe.c:1508 perf_uprobe_init+0x131/0x210 kernel/trace/trace_event_perf.c:314 perf_uprobe_event_init+0x106/0x1a0 kernel/events/core.c:8898 perf_try_init_event+0x135/0x590 kernel/events/core.c:10184 perf_init_event kernel/events/core.c:10228 [inline] perf_event_alloc.part.0+0x1b89/0x33d0 kernel/events/core.c:10505 perf_event_alloc kernel/events/core.c:10887 [inline] __do_sys_perf_event_open+0xa2d/0x2d00 kernel/events/core.c:10989 __se_sys_perf_event_open kernel/events/core.c:10871 [inline] __x64_sys_perf_event_open+0xbe/0x150 kernel/events/core.c:10871 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Link: http://lkml.kernel.org/r/156869709721.22406.5153754822203046939.stgit@devnote2 Reported-by: syzbot+2f807f4d3a2a4e87f18f@syzkaller.appspotmail.com Fixes: ca89bc071d5e ("tracing/kprobe: Add multi-probe per event support") Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index 1e67fef06e53..baf58a3612c0 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -986,6 +986,12 @@ int trace_probe_init(struct trace_probe *tp, const char *event, if (!tp->event) return -ENOMEM; + INIT_LIST_HEAD(&tp->event->files); + INIT_LIST_HEAD(&tp->event->class.fields); + INIT_LIST_HEAD(&tp->event->probes); + INIT_LIST_HEAD(&tp->list); + list_add(&tp->event->probes, &tp->list); + call = trace_probe_event_call(tp); call->class = &tp->event->class; call->name = kstrdup(event, GFP_KERNEL); @@ -999,11 +1005,6 @@ int trace_probe_init(struct trace_probe *tp, const char *event, ret = -ENOMEM; goto error; } - INIT_LIST_HEAD(&tp->event->files); - INIT_LIST_HEAD(&tp->event->class.fields); - INIT_LIST_HEAD(&tp->event->probes); - INIT_LIST_HEAD(&tp->list); - list_add(&tp->event->probes, &tp->list); return 0;