Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753462AbdGXQ2I (ORCPT ); Mon, 24 Jul 2017 12:28:08 -0400 Received: from mail-ua0-f182.google.com ([209.85.217.182]:34424 "EHLO mail-ua0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752807AbdGXQ2A (ORCPT ); Mon, 24 Jul 2017 12:28:00 -0400 MIME-Version: 1.0 In-Reply-To: References: <20170718145557.89616-1-glider@google.com> From: Alexander Potapenko Date: Mon, 24 Jul 2017 18:27:58 +0200 Message-ID: Subject: Re: [PATCH] sctp: fully initialize the IPv6 address in sctp_v6_to_addr() To: Xin Long Cc: Dmitriy Vyukov , Kostya Serebryany , Eric Dumazet , David Miller , Vladislav Yasevich , LKML , linux-sctp@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id v6OGSCq6018679 Content-Length: 3114 Lines: 72 On Wed, Jul 19, 2017 at 2:58 AM, Xin Long wrote: > On Wed, Jul 19, 2017 at 3:02 AM, Alexander Potapenko wrote: >> On Tue, Jul 18, 2017 at 4:55 PM, Alexander Potapenko wrote: >>> KMSAN reported use of uninitialized sctp_addr->v4.sin_addr.s_addr and >>> sctp_addr->v6.sin6_scope_id in sctp_v6_cmp_addr() (see below). >>> Make sure all fields of an IPv6 address are initialized, which >>> guarantees that the IPv4 fields are also initialized. >> I'm assuming here that the IPv4 address is known to overlap with the >> IPv6 one and doesn't need separate initialization. >> > > Ok, addr->v6.sin6_scope_id = 0 will fix the call trace you posted here. Sorry for the delay, I somehow missed your question. > addr->v6.sin6_flowinfo = 0 is to fix uninitialized > sctp_addr->v4.sin_addr.s_addr, > I couldn't see how this happens, can you also post the call trace for > v4.sin_addr.s_addr ? Here it is: ================================================================== BUG: KMSAN: use of uninitialized memory in sctp_v6_cmp_addr+0x8d4/0x9f0 net/sctp/ipv6.c:535 CPU: 2 PID: 17306 Comm: syz-executor1 Not tainted 4.11.0-rc5+ #2944 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: dump_stack+0x172/0x1c0 lib/dump_stack.c:42 is_logbuf_locked mm/kmsan/kmsan.c:59 [inline] kmsan_report+0x12a/0x180 mm/kmsan/kmsan.c:938 native_save_fl arch/x86/include/asm/irqflags.h:18 [inline] arch_local_save_flags arch/x86/include/asm/irqflags.h:72 [inline] arch_local_irq_save arch/x86/include/asm/irqflags.h:113 [inline] __msan_warning_32+0x61/0xb0 mm/kmsan/kmsan_instr.c:467 sctp_v6_cmp_addr+0x8d4/0x9f0 net/sctp/ipv6.c:535 sctp_v6_get_dst+0x8c7/0x1630 net/sctp/ipv6.c:297 sctp_transport_route+0x101/0x570 net/sctp/transport.c:292 sctp_assoc_add_peer+0x66d/0x16f0 net/sctp/associola.c:651 sctp_sendmsg+0x35a5/0x4f90 net/sctp/socket.c:1871 inet_sendmsg+0x498/0x670 net/ipv4/af_inet.c:762 sock_sendmsg_nosec net/socket.c:633 [inline] sock_sendmsg net/socket.c:643 [inline] SYSC_sendto+0x608/0x710 net/socket.c:1696 SyS_sendto+0x8a/0xb0 net/socket.c:1664 entry_SYSCALL_64_fastpath+0x13/0x94 RIP: 0033:0x44b479 RSP: 002b:00007f28a5bb2c08 EFLAGS: 00000286 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000020000000 RCX: 000000000044b479 RDX: 0000000000000001 RSI: 0000000020036000 RDI: 0000000000000005 RBP: 0000000000708000 R08: 00000000206e4000 R09: 000000000000001c R10: 0000000000000000 R11: 0000000000000286 R12: 00000000ffffffff R13: 0000000000003760 R14: 00000000006e5820 R15: 0000000000ff9000 origin description: ----dst_saddr@sctp_v6_get_dst local variable created at: sctp_v6_get_dst+0x91/0x1630 net/sctp/ipv6.c:236 sctp_transport_route+0x101/0x570 net/sctp/transport.c:292 ================================================================== > Thanks -- Alexander Potapenko Software Engineer Google Germany GmbH Erika-Mann-Straße, 33 80636 München Geschäftsführer: Matthew Scott Sucherman, Paul Terence Manicle Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg