On Sat, Dec 9, 2017 at 7:35 PM, Xin Long <lucien.xin@xxxxxxxxx> wrote: > On Sat, Dec 9, 2017 at 6:40 PM, syzbot > <bot+0665d43fa62276c7a5e3372929aa0bab96260979@xxxxxxxxxxxxxxxxxxxxxxxxx> > wrote: >> Hello, >> >> syzkaller hit the following crash on >> 328b4ed93b69a6f2083d52f31a240a09e5de386a >> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/master >> compiler: gcc (GCC) 7.1.1 20170620 >> .config is attached >> Raw console output is attached. >> C reproducer is attached >> syzkaller reproducer is attached. See https://goo.gl/kgGztJ >> for information about syzkaller reproducers >> >> >> ================================================================== >> BUG: KASAN: slab-out-of-bounds in sctp_send_reset_streams+0xadf/0xc10 >> net/sctp/stream.c:314 >> Read of size 2 at addr ffff8801d8a6c048 by task syzkaller104411/3085 >> >> CPU: 0 PID: 3085 Comm: syzkaller104411 Not tainted 4.15.0-rc2+ #119 >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS >> Google 01/01/2011 >> Call Trace: >> __dump_stack lib/dump_stack.c:17 [inline] >> dump_stack+0x194/0x257 lib/dump_stack.c:53 >> print_address_description+0x73/0x250 mm/kasan/report.c:252 >> kasan_report_error mm/kasan/report.c:351 [inline] >> kasan_report+0x25b/0x340 mm/kasan/report.c:409 >> __asan_report_load2_noabort+0x14/0x20 mm/kasan/report.c:428 >> sctp_send_reset_streams+0xadf/0xc10 net/sctp/stream.c:314 >> sctp_setsockopt_reset_streams net/sctp/socket.c:3905 [inline] >> sctp_setsockopt+0x70d/0x5d50 net/sctp/socket.c:4195 >> compat_sock_common_setsockopt+0x104/0x140 net/core/sock.c:2981 >> C_SYSC_setsockopt net/compat.c:403 [inline] >> compat_SyS_setsockopt+0x17c/0x410 net/compat.c:386 >> do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline] >> do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389 >> entry_SYSENTER_compat+0x51/0x60 arch/x86/entry/entry_64_compat.S:125 >> RIP: 0023:0xf7f1bc79 >> RSP: 002b:00000000ff9893bc EFLAGS: 00000282 ORIG_RAX: 000000000000016e >> RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000000084 >> RDX: 0000000000000077 RSI: 000000002018b000 RDI: 0000000000000008 >> RBP: 000000000000001c R08: 0000000000000000 R09: 0000000000000000 >> R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 >> R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 >> >> Allocated by task 3085: >> save_stack+0x43/0xd0 mm/kasan/kasan.c:447 >> set_track mm/kasan/kasan.c:459 [inline] >> kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551 >> __do_kmalloc mm/slab.c:3711 [inline] >> __kmalloc_track_caller+0x15e/0x760 mm/slab.c:3726 >> memdup_user+0x2c/0x90 mm/util.c:164 >> sctp_setsockopt_reset_streams net/sctp/socket.c:3897 [inline] >> sctp_setsockopt+0x6a6/0x5d50 net/sctp/socket.c:4195 >> compat_sock_common_setsockopt+0x104/0x140 net/core/sock.c:2981 >> C_SYSC_setsockopt net/compat.c:403 [inline] >> compat_SyS_setsockopt+0x17c/0x410 net/compat.c:386 >> do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline] >> do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389 >> entry_SYSENTER_compat+0x51/0x60 arch/x86/entry/entry_64_compat.S:125 >> >> Freed by task 16: >> save_stack+0x43/0xd0 mm/kasan/kasan.c:447 >> set_track mm/kasan/kasan.c:459 [inline] >> kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524 >> __cache_free mm/slab.c:3491 [inline] >> kfree+0xca/0x250 mm/slab.c:3806 >> selinux_cred_free+0x48/0x70 security/selinux/hooks.c:3814 >> security_cred_free+0x48/0x80 security/security.c:995 >> put_cred_rcu+0x106/0x400 kernel/cred.c:117 >> __rcu_reclaim kernel/rcu/rcu.h:195 [inline] >> rcu_do_batch kernel/rcu/tree.c:2758 [inline] >> invoke_rcu_callbacks kernel/rcu/tree.c:3012 [inline] >> __rcu_process_callbacks kernel/rcu/tree.c:2979 [inline] >> rcu_process_callbacks+0xd74/0x17d0 kernel/rcu/tree.c:2996 >> __do_softirq+0x29d/0xbb2 kernel/softirq.c:285 >> >> The buggy address belongs to the object at ffff8801d8a6c040 >> which belongs to the cache kmalloc-32 of size 32 >> The buggy address is located 8 bytes inside of >> 32-byte region [ffff8801d8a6c040, ffff8801d8a6c060) >> The buggy address belongs to the page: >> page:000000006b05592a count:1 mapcount:0 mapping:000000001ca7267d >> index:0xffff8801d8a6cfc1 >> flags: 0x2fffc0000000100(slab) >> raw: 02fffc0000000100 ffff8801d8a6c000 ffff8801d8a6cfc1 000000010000003f >> raw: ffffea000762f920 ffffea00076133e0 ffff8801db0001c0 0000000000000000 >> page dumped because: kasan: bad access detected >> >> Memory state around the buggy address: >> ffff8801d8a6bf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >> ffff8801d8a6bf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >>> >>> ffff8801d8a6c000: fb fb fb fb fc fc fc fc 00 fc fc fc fc fc fc fc >> >> ^ >> ffff8801d8a6c080: fb fb fb fb fc fc fc fc 00 00 00 00 fc fc fc fc >> ffff8801d8a6c100: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc >> ================================================================== >> >> >> --- >> This bug is generated by a dumb bot. It may contain errors. >> See https://goo.gl/tpsmEJ for details. >> Direct all questions to syzkaller@xxxxxxxxxxxxxxxx. >> Please credit me with: Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx> >> >> syzbot will keep track of this bug report. >> Once a fix for this bug is merged into any tree, reply to this email with: >> #syz fix: exact-commit-title >> If you want to test a patch for this bug, please reply with: >> #syz test: git://repo/address.git branch >> and provide the patch inline or as an attachment. >> To mark this as a duplicate of another syzbot report, please reply with: >> #syz dup: exact-subject-of-another-report >> If it's a one-off invalid bug report, please reply with: >> #syz invalid >> Note: if the crash happens again, it will cause creation of a new bug >> report. >> Note: all commands must start from beginning of the line in the email body. > the check: > if (optlen < sizeof(struct sctp_reset_streams)) > in sctp_setsockopt_reset_streams() is not correct, the srs_stream_list > memory should have been counted as well. Fix: diff --git a/net/sctp/socket.c b/net/sctp/socket.c index ac6338f..1532a49 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -3930,6 +3930,10 @@ static int sctp_setsockopt_reset_streams(struct sock *sk, if (IS_ERR(params)) return PTR_ERR(params); + if (params->srs_number_streams * sizeof(__u16) > + optlen - sizeof(*params)) + goto out; + -- To unsubscribe from this list: send the line "unsubscribe linux-sctp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
