From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E2398C38145 for ; Wed, 7 Sep 2022 22:32:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229788AbiIGWc0 (ORCPT ); Wed, 7 Sep 2022 18:32:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43904 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229492AbiIGWcX (ORCPT ); Wed, 7 Sep 2022 18:32:23 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C33E098D11 for ; Wed, 7 Sep 2022 15:32:22 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 5152B61AEC for ; Wed, 7 Sep 2022 22:32:22 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E2ABFC433C1; Wed, 7 Sep 2022 22:32:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1662589941; bh=Gvbh4ii2SgD2Ghz1bC88kTpxfjJoLpKT/Ph/iJIwjUs=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=D7SGfQk2Cx0p1KtP6pgEECKWzJjcT0yUMZjKmMtAgEZ5lSdA/mE7G1VYRsp4yA7Px qYYnphZRU+95vz7vv0dbOvWmWqGjx82Cobqa26AEl4zuv2J4uVByMyCyuwYdQSu0HS t+KavQUzFMIqbQLFBNJrA11STqZ7AhDh4duW75VbXP+ehygyh9rq3Z7jUvz1jLyv9I W7x5ULCxLBD6NexlXgfIhANs48P79bt575qfwroGusMT2TTlgMhi2fXt2hrTONU7AI 4vDtghirj8gvlzrOwqrdwbS+mS5Zt3SRXE45ELCFEgcoltoCdHv8AKnUMYxJUYVLfc V7NFyDfsrE3Cg== Date: Thu, 8 Sep 2022 07:32:17 +0900 From: Masami Hiramatsu (Google) To: "Christian A. Ehrhardt" Cc: linux-kernel@vger.kernel.org, "Naveen N. Rao" , Anil S Keshavamurthy , "David S. Miller" , Masami Hiramatsu , Steven Rostedt Subject: Re: [PATCH] kprobes: prohibit probes in gate area Message-Id: <20220908073217.7ee9ecd48766507329fbcac2@kernel.org> In-Reply-To: <20220907200917.654103-1-lk@c--e.de> References: <20220907200917.654103-1-lk@c--e.de> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 7 Sep 2022 22:09:17 +0200 "Christian A. Ehrhardt" wrote: > The system call gate area counts as kernel text but trying > to install a kprobe in this area fails with an Oops later on. > To fix this explicitly disallow the gate area for kprobes. > > Found by syzkaller with the following reproducer: > perf_event_open$cgroup(&(0x7f00000001c0)={0x6, 0x80, 0x0, 0x0, 0x0, 0x0, 0x80ffff, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, @perf_config_ext={0x0, 0xffffffffff600000}}, 0xffffffffffffffff, 0x0, 0xffffffffffffffff, 0x0) > > Sample report: > BUG: unable to handle page fault for address: fffffbfff3ac6000 > PGD 6dfcb067 P4D 6dfcb067 PUD 6df8f067 PMD 6de4d067 PTE 0 > Oops: 0000 [#1] PREEMPT SMP KASAN NOPTI > CPU: 0 PID: 21978 Comm: syz-executor.2 Not tainted 6.0.0-rc3-00363-g7726d4c3e60b-dirty #6 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 > RIP: 0010:__insn_get_emulate_prefix arch/x86/lib/insn.c:91 [inline] > RIP: 0010:insn_get_emulate_prefix arch/x86/lib/insn.c:106 [inline] > RIP: 0010:insn_get_prefixes.part.0+0xa8/0x1110 arch/x86/lib/insn.c:134 > Code: 49 be 00 00 00 00 00 fc ff df 48 8b 40 60 48 89 44 24 08 e9 81 00 00 00 e8 e5 4b 39 ff 4c 89 fa 4c 89 f9 48 c1 ea 03 83 e1 07 <42> 0f b6 14 32 38 ca 7f 08 84 d2 0f 85 06 10 00 00 48 89 d8 48 89 > RSP: 0018:ffffc900088bf860 EFLAGS: 00010246 > RAX: 0000000000040000 RBX: ffffffff9b9bebc0 RCX: 0000000000000000 > RDX: 1ffffffff3ac6000 RSI: ffffc90002d82000 RDI: ffffc900088bf9e8 > RBP: ffffffff9d630001 R08: 0000000000000000 R09: ffffc900088bf9e8 > R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000001 > R13: ffffffff9d630000 R14: dffffc0000000000 R15: ffffffff9d630000 > FS: 00007f63eef63640(0000) GS:ffff88806d000000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: fffffbfff3ac6000 CR3: 0000000029d90005 CR4: 0000000000770ef0 > PKRU: 55555554 > Call Trace: > > insn_get_prefixes arch/x86/lib/insn.c:131 [inline] > insn_get_opcode arch/x86/lib/insn.c:272 [inline] > insn_get_modrm+0x64a/0x7b0 arch/x86/lib/insn.c:343 > insn_get_sib+0x29a/0x330 arch/x86/lib/insn.c:421 > insn_get_displacement+0x350/0x6b0 arch/x86/lib/insn.c:464 > insn_get_immediate arch/x86/lib/insn.c:632 [inline] > insn_get_length arch/x86/lib/insn.c:707 [inline] > insn_decode+0x43a/0x490 arch/x86/lib/insn.c:747 > can_probe+0xfc/0x1d0 arch/x86/kernel/kprobes/core.c:282 > arch_prepare_kprobe+0x79/0x1c0 arch/x86/kernel/kprobes/core.c:739 > prepare_kprobe kernel/kprobes.c:1160 [inline] > register_kprobe kernel/kprobes.c:1641 [inline] > register_kprobe+0xb6e/0x1690 kernel/kprobes.c:1603 > __register_trace_kprobe kernel/trace/trace_kprobe.c:509 [inline] > __register_trace_kprobe+0x26a/0x2d0 kernel/trace/trace_kprobe.c:477 > create_local_trace_kprobe+0x1f7/0x350 kernel/trace/trace_kprobe.c:1833 > perf_kprobe_init+0x18c/0x280 kernel/trace/trace_event_perf.c:271 > perf_kprobe_event_init+0xf8/0x1c0 kernel/events/core.c:9888 > perf_try_init_event+0x12d/0x570 kernel/events/core.c:11261 > perf_init_event kernel/events/core.c:11325 [inline] > perf_event_alloc.part.0+0xf7f/0x36a0 kernel/events/core.c:11619 > perf_event_alloc kernel/events/core.c:12059 [inline] > __do_sys_perf_event_open+0x4a8/0x2a00 kernel/events/core.c:12157 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x38/0x90 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > RIP: 0033:0x7f63ef7efaed > Code: 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007f63eef63028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a > RAX: ffffffffffffffda RBX: 00007f63ef90ff80 RCX: 00007f63ef7efaed > RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 00000000200001c0 > RBP: 00007f63ef86019c R08: 0000000000000000 R09: 0000000000000000 > R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000 > R13: 0000000000000002 R14: 00007f63ef90ff80 R15: 00007f63eef43000 > > Modules linked in: > CR2: fffffbfff3ac6000 > ---[ end trace 0000000000000000 ]--- > RIP: 0010:__insn_get_emulate_prefix arch/x86/lib/insn.c:91 [inline] > RIP: 0010:insn_get_emulate_prefix arch/x86/lib/insn.c:106 [inline] > RIP: 0010:insn_get_prefixes.part.0+0xa8/0x1110 arch/x86/lib/insn.c:134 > Code: 49 be 00 00 00 00 00 fc ff df 48 8b 40 60 48 89 44 24 08 e9 81 00 00 00 e8 e5 4b 39 ff 4c 89 fa 4c 89 f9 48 c1 ea 03 83 e1 07 <42> 0f b6 14 32 38 ca 7f 08 84 d2 0f 85 06 10 00 00 48 89 d8 48 89 > RSP: 0018:ffffc900088bf860 EFLAGS: 00010246 > RAX: 0000000000040000 RBX: ffffffff9b9bebc0 RCX: 0000000000000000 > RDX: 1ffffffff3ac6000 RSI: ffffc90002d82000 RDI: ffffc900088bf9e8 > RBP: ffffffff9d630001 R08: 0000000000000000 R09: ffffc900088bf9e8 > R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000001 > R13: ffffffff9d630000 R14: dffffc0000000000 R15: ffffffff9d630000 > FS: 00007f63eef63640(0000) GS:ffff88806d000000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: fffffbfff3ac6000 CR3: 0000000029d90005 CR4: 0000000000770ef0 > PKRU: 55555554 > ================================================================== > Good catch! kprobes should not probe vsyscall area. Acked-by: Masami Hiramatsu (Google) Cc: stable@vger.kernel.org Thank you, > cc: "Naveen N. Rao" > cc: Anil S Keshavamurthy > cc: "David S. Miller" > cc: Masami Hiramatsu > Signed-off-by: Christian A. Ehrhardt > --- > kernel/kprobes.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > index 08350e35aba2..ca9d834d0b84 100644 > --- a/kernel/kprobes.c > +++ b/kernel/kprobes.c > @@ -1562,6 +1562,7 @@ static int check_kprobe_address_safe(struct kprobe *p, > /* Ensure it is not in reserved area nor out of text */ > if (!(core_kernel_text((unsigned long) p->addr) || > is_module_text_address((unsigned long) p->addr)) || > + in_gate_area_no_mm((unsigned long) p->addr) || > within_kprobe_blacklist((unsigned long) p->addr) || > jump_label_text_reserved(p->addr, p->addr) || > static_call_text_reserved(p->addr, p->addr) || > -- > 2.34.1 > -- Masami Hiramatsu (Google)