Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751849AbbLIOnb (ORCPT ); Wed, 9 Dec 2015 09:43:31 -0500 Received: from mail-wm0-f46.google.com ([74.125.82.46]:38391 "EHLO mail-wm0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751004AbbLIOn3 (ORCPT ); Wed, 9 Dec 2015 09:43:29 -0500 MIME-Version: 1.0 In-Reply-To: References: Date: Wed, 9 Dec 2015 06:43:28 -0800 Message-ID: Subject: Re: use-after-free in inet6_destroy_sock From: Eric Dumazet To: Dmitry Vyukov Cc: "David S. Miller" , Alexey Kuznetsov , James Morris , Hideaki YOSHIFUJI , Patrick McHardy , netdev , LKML , Vlad Yasevich , Neil Horman , linux-sctp@vger.kernel.org, syzkaller , Kostya Serebryany , Alexander Potapenko , Sasha Levin 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-Length: 7871 Lines: 163 On Wed, Dec 9, 2015 at 6:15 AM, Dmitry Vyukov wrote: > Hello, > > The following program causes use-after-free in inet6_destroy_sock: > > // autogenerated by syzkaller (http://github.com/google/syzkaller) > #include > #include > #include > #include > #include > #include > #include > #include > > int cfd = -1; > > void *thr(void *arg) > { > cfd = syscall(SYS_socket, PF_INET6, SOCK_STREAM, IPPROTO_SCTP); > struct sockaddr_in6 sa = {}; > sa.sin6_family = AF_INET6; > sa.sin6_port = getpid(); > sa.sin6_addr.s6_addr[15] = 1; > syscall(SYS_connect, cfd, &sa, sizeof(sa), 0, 0, 0); > return 0; > } > > int main() > { > syscall(SYS_mmap, 0x20000000ul, 0x10000ul, 0x3ul, 0x32ul, > 0xfffffffffffffffful, 0x0ul); > int fd = syscall(SYS_socket, PF_INET6, SOCK_STREAM, IPPROTO_SCTP); > struct sockaddr_in6 sa = {}; > sa.sin6_family = AF_INET6; > sa.sin6_port = getpid(); > sa.sin6_addr.s6_addr[15] = 1; > syscall(SYS_bind, fd, &sa, sizeof(sa), 0, 0, 0); > syscall(SYS_listen, fd, 0x3ul, 0, 0, 0, 0); > memcpy((void*)0x20002ff6, > "\x10\x48\xe0\xad\x68\xc0\xce\x4c\xd0\xb5", 10); > syscall(SYS_setsockopt, fd, 0x29ul, 0x6ul, 0x20002ff6ul, 0xaul, 0); > pthread_t th; > pthread_create(&th, 0, thr, 0); > pthread_join(th, 0); > int sfd = syscall(SYS_accept4, fd, 0x20003f80ul, 0x20003ab4ul, > 0x80800ul, 0, 0); > dup3(fd, -1, 0x80000); > return 0; > } > > > ================================================================== > BUG: KASAN: use-after-free in inet6_destroy_sock+0x177/0x1c0 at addr > ffff8800349179b4 > Read of size 4 by task executor/7001 > ============================================================================= > BUG kmalloc-96 (Not tainted): kasan: bad access detected > ----------------------------------------------------------------------------- > > Disabling lock debugging due to kernel taint > INFO: Allocated in sock_kmalloc+0x93/0x100 age=20 cpu=0 pid=7064 > [< none >] ___slab_alloc+0x648/0x8c0 mm/slub.c:2468 > [< none >] __slab_alloc+0x4c/0x90 mm/slub.c:2497 > [< inline >] slab_alloc_node mm/slub.c:2560 > [< inline >] slab_alloc mm/slub.c:2602 > [< none >] __kmalloc+0x2d9/0x480 mm/slub.c:3562 > [< inline >] kmalloc include/linux/slab.h:463 > [< none >] sock_kmalloc+0x93/0x100 net/core/sock.c:1771 > [< none >] do_ipv6_setsockopt.isra.5+0x1f43/0x2e50 > net/ipv6/ipv6_sockglue.c:490 > [< none >] ipv6_setsockopt+0x4f/0x150 net/ipv6/ipv6_sockglue.c:895 > [< none >] sctp_setsockopt+0x194/0x4020 net/sctp/socket.c:3702 > [< none >] sock_common_setsockopt+0xb4/0x140 net/core/sock.c:2641 > [< inline >] SYSC_setsockopt net/socket.c:1750 > [< none >] SyS_setsockopt+0x161/0x290 net/socket.c:1729 > [< none >] entry_SYSCALL_64_fastpath+0x16/0x7a > arch/x86/entry/entry_64.S:185 > > INFO: Freed in rcu_process_callbacks+0x52c/0x19e0 age=16 cpu=0 pid=0 > [< none >] __slab_free+0x21e/0x3e0 mm/slub.c:2678 > [< inline >] slab_free mm/slub.c:2833 > [< none >] kfree+0x26f/0x3e0 mm/slub.c:3662 > [< inline >] __rcu_reclaim kernel/rcu/rcu.h:113 > [< inline >] rcu_do_batch kernel/rcu/tree.c:2693 > [< inline >] invoke_rcu_callbacks kernel/rcu/tree.c:2961 > [< inline >] __rcu_process_callbacks kernel/rcu/tree.c:2928 > [< none >] rcu_process_callbacks+0x52c/0x19e0 kernel/rcu/tree.c:2945 > [< none >] __do_softirq+0x2e5/0xb40 kernel/softirq.c:273 > [< inline >] invoke_softirq kernel/softirq.c:350 > [< none >] irq_exit+0x165/0x1e0 kernel/softirq.c:391 > [< inline >] exiting_irq ./arch/x86/include/asm/apic.h:653 > [< none >] smp_apic_timer_interrupt+0x88/0xc0 > arch/x86/kernel/apic/apic.c:926 > [< none >] apic_timer_interrupt+0x8c/0xa0 > arch/x86/entry/entry_64.S:520 > [< inline >] arch_safe_halt ./arch/x86/include/asm/paravirt.h:111 > [< none >] default_idle+0x22/0x300 arch/x86/kernel/process.c:304 > [< none >] arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:295 > [< none >] default_idle_call+0x4f/0x80 kernel/sched/idle.c:92 > [< inline >] cpuidle_idle_call kernel/sched/idle.c:156 > [< inline >] cpu_idle_loop kernel/sched/idle.c:251 > [< none >] cpu_startup_entry+0x481/0x690 kernel/sched/idle.c:299 > [< none >] rest_init+0x1c7/0x1d0 init/main.c:412 > [< none >] start_kernel+0x6cd/0x6f3 init/main.c:683 > [< none >] x86_64_start_reservations+0x2a/0x2c > arch/x86/kernel/head64.c:195 > [< none >] x86_64_start_kernel+0x176/0x185 > arch/x86/kernel/head64.c:184 > > INFO: Slab 0xffffea0000d24500 objects=28 used=26 fp=0xffff8800349179b0 > flags=0x1fffc0000004080 > INFO: Object 0xffff8800349179b0 @offset=14768 fp=0xffff880034914000 > CPU: 1 PID: 7001 Comm: executor Tainted: G B 4.4.0-rc4+ #158 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > 0000000000000001 ffff880062eef940 ffffffff82e0f6d8 0000000041b58ab3 > ffffffff87aa2c7d ffffffff82e0f626 ffff88006c051740 ffffffff87ac3e19 > ffff88003e804900 0000000000000008 ffff8800349179b0 ffff880062eef940 > > Call Trace: > [] __asan_report_load4_noabort+0x54/0x70 > mm/kasan/report.c:294 > [] inet6_destroy_sock+0x177/0x1c0 net/ipv6/af_inet6.c:433 > [] sctp_v6_destroy_sock+0x1d/0x20 net/sctp/socket.c:7389 > [] sk_common_release+0x7d/0x3e0 net/core/sock.c:2662 > [] sctp_close+0x5fe/0x9b0 net/sctp/socket.c:1541 > [] inet_release+0x111/0x270 net/ipv4/af_inet.c:413 > [] inet6_release+0x55/0x90 net/ipv6/af_inet6.c:406 > [] sock_release+0x96/0x260 net/socket.c:571 > [] sock_close+0x16/0x20 net/socket.c:1022 > [] __fput+0x244/0x860 fs/file_table.c:208 > [] ____fput+0x15/0x20 fs/file_table.c:244 > [] task_work_run+0x130/0x240 kernel/task_work.c:115 > [< inline >] exit_task_work include/linux/task_work.h:21 > [] do_exit+0x885/0x3050 kernel/exit.c:750 > [] do_group_exit+0xec/0x390 kernel/exit.c:880 > [< inline >] SYSC_exit_group kernel/exit.c:891 > [] SyS_exit_group+0x1d/0x20 kernel/exit.c:889 > [] entry_SYSCALL_64_fastpath+0x16/0x7a > arch/x86/entry/entry_64.S:185 > ================================================================== > > On commit aa53685549a2cfb5f175b0c4a20bc9aa1e5a1b85 (Nov 8). > Eric, this now includes your patches that you previously pointed me > to, and also https://patchwork.ozlabs.org/patch/553068/ on top of it. Sure, I believe SCTP crowd already know they are missing ipv6_dup_options() $ git grep -n ipv6_dup_options include/net/ipv6.h:300:struct ipv6_txoptions *ipv6_dup_options(struct sock *sk, net/dccp/ipv6.c:499: opt = ipv6_dup_options(newsk, opt); net/ipv6/exthdrs.c:714:ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt) net/ipv6/exthdrs.c:734:EXPORT_SYMBOL_GPL(ipv6_dup_options); net/ipv6/tcp_ipv6.c:1107: opt = ipv6_dup_options(newsk, opt); I can certainly send a patch, but maybe someone already cooked it and is testing it ? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/