From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Fastabend Subject: Re: KASAN: stack-out-of-bounds Read in bpf_tcp_close Date: Tue, 31 Jul 2018 08:25:06 -0700 Message-ID: <9d8024eb-8797-28d6-76f1-4b5de00423a7@gmail.com> References: <0000000000002f5daa05714d739b@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit To: syzbot , ast@kernel.org, daniel@iogearbox.net, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com Return-path: In-Reply-To: <0000000000002f5daa05714d739b@google.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 07/18/2018 03:19 PM, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit:    8ae71e76cf1f Merge branch 'bpf-offload-sharing' > git tree:       bpf-next > console output: https://syzkaller.appspot.com/x/log.txt?x=1379a978400000 > kernel config:  https://syzkaller.appspot.com/x/.config?x=89129667b46496c3 > dashboard link: https://syzkaller.appspot.com/bug?extid=65a97319fd875ea52b73 > compiler:       gcc (GCC) 8.0.1 20180413 (experimental) > syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=114f4b2c400000 > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1774932c400000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+65a97319fd875ea52b73@syzkaller.appspotmail.com > > random: sshd: uninitialized urandom read (32 bytes read) > random: sshd: uninitialized urandom read (32 bytes read) > IPVS: ftp: loaded support on port[0] = 21 > ================================================================== > swap_info_get: Bad swap file entry 8007fffc400d72b > BUG: KASAN: stack-out-of-bounds in __read_once_size include/linux/compiler.h:188 [inline] > BUG: KASAN: stack-out-of-bounds in smap_psock_sk kernel/bpf/sockmap.c:149 [inline] > BUG: KASAN: stack-out-of-bounds in bpf_tcp_close+0xf10/0x1050 kernel/bpf/sockmap.c:316 > Read of size 8 at addr ffff8801adcc4428 by task syz-executor115/24313 > BUG: Bad page map in process syz-executor115  pte:1ffff10035cac810 pmd:1ae564067 > > CPU: 0 PID: 24313 Comm: syz-executor115 Not tainted 4.18.0-rc3+ #58 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > > addr:(____ptrval____) vm_flags:00000875 anon_vma:          (null) mapping:(____ptrval____) index:0 > Allocated by task 2294230744: > usercopy: Kernel memory overwrite attempt detected to SLAB object 'task_struct(17:syz0)' (offset 6088, size 2)! > file:syz-executor115250413 fault:ext4_filemap_fault mmap:ext4_file_mmap readpage:ext4_readpage > ------------[ cut here ]------------ > Bad or missing usercopy whitelist? Kernel memory overwrite attempt detected to SLAB object 'task_struct(17:syz0)' (offset 4936, size 2)! > WARNING: CPU: 0 PID: 24313 at mm/usercopy.c:81 usercopy_warn+0xf5/0x120 mm/usercopy.c:76 > CPU: 1 PID: 4479 Comm: syz-executor115 Not tainted 4.18.0-rc3+ #58 > Kernel panic - not syncing: panic_on_warn set ... > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: >  __dump_stack lib/dump_stack.c:77 [inline] >  dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113 >  print_bad_pte.cold.116+0x1cd/0x22b mm/memory.c:774 >  zap_pte_range mm/memory.c:1380 [inline] >  zap_pmd_range mm/memory.c:1437 [inline] >  zap_pud_range mm/memory.c:1466 [inline] >  zap_p4d_range mm/memory.c:1487 [inline] >  unmap_page_range+0x1cb9/0x2220 mm/memory.c:1508 >  unmap_single_vma+0x1a0/0x310 mm/memory.c:1553 >  unmap_vmas+0x120/0x1f0 mm/memory.c:1583 >  exit_mmap+0x2c2/0x5b0 mm/mmap.c:3105 >  __mmput kernel/fork.c:970 [inline] >  mmput+0x265/0x620 kernel/fork.c:991 >  exit_mm kernel/exit.c:544 [inline] >  do_exit+0xea9/0x2750 kernel/exit.c:852 >  do_group_exit+0x177/0x440 kernel/exit.c:968 >  get_signal+0x88e/0x1970 kernel/signal.c:2468 >  do_signal+0x9c/0x21c0 arch/x86/kernel/signal.c:816 >  exit_to_usermode_loop+0x2e0/0x370 arch/x86/entry/common.c:162 >  prepare_exit_to_usermode+0x342/0x3b0 arch/x86/entry/common.c:197 >  retint_user+0x8/0x18 > RIP: 0033:0x4731e0 > Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > RSP: 002b:00007ffd426a9928 EFLAGS: 00010246 > RAX: 0000000000000000 RBX: 0000000000002e7e RCX: 00000000004731e0 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007ffd426a9930 > RBP: 0000000000002e7e R08: 0000000000000001 R09: 0000000000e2a880 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000f7e > R13: 000000000003ab5f R14: 0000000000000000 R15: 0000000000000000 > CPU: 0 PID: 24313 Comm: syz-executor115 Not tainted 4.18.0-rc3+ #58 > swap_info_get: Bad swap file entry 403fffe200725fc > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > Dumping ftrace buffer: >    (ftrace buffer empty) > Kernel Offset: disabled > Rebooting in 86400 seconds.. > Seems KCM and ULPs are colliding here, sockmap/tls need some extra checks. I'll have a fix shortly. Thanks, John