Messages in this thread | | | Subject | Re: KASAN: stack-out-of-bounds Read in bpf_tcp_close | From | John Fastabend <> | Date | Tue, 31 Jul 2018 08:25:06 -0700 |
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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
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