On Thu, Sep 10, 2020 at 1:32 PM Dmitry Vyukov <dvyu...@google.com> wrote: > > On Thu, Sep 10, 2020 at 9:20 AM Anant Thazhemadam > <anant.thazhema...@gmail.com> wrote: > > Looks like this bug is no longer valid. I'm not sure which commit seems to > > have fixed it. Can this be marked as invalid or closed yet? > > You can see on the dashboard (or in mailing list archives) that B K > Karthik tested a patch for this bug in July: > https://syzkaller.appspot.com/bug?extid=72ff2fa98097767b5a27 > > So perhaps that patch fixes it? Karthik, did you send it? Was it > merged? Did the commit include the syzbot Reported-by tag? >
I did send it. I was taking a u32 spi value and casting it to a pointer to an IP address. Steffen Klassert <steffen.klass...@secunet.com> pointed out to me that the approach i was looking at was completely wrong. https://lkml.org/lkml/2020/7/27/361 is the conversation. hope this helps. thanks, karthik > > > On Thu, Jul 16, 2020 at 4:05 AM syzbot > <syzbot+72ff2fa98097767b5...@syzkaller.appspotmail.com> wrote: > > > > syzbot has found a reproducer for the following issue on: > > > > HEAD commit: ca0e494a Add linux-next specific files for 20200715 > > git tree: linux-next > > console output: https://syzkaller.appspot.com/x/log.txt?x=175099bf100000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=2c76d72659687242 > > dashboard link: https://syzkaller.appspot.com/bug?extid=72ff2fa98097767b5a27 > > compiler: gcc (GCC) 10.1.0-syz 20200507 > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=112e8dbf100000 > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=109429bf100000 > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > Reported-by: syzbot+72ff2fa98097767b5...@syzkaller.appspotmail.com > > > > netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0 > > netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0 > > netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0 > > ================================================================== > > BUG: KASAN: use-after-free in __xfrm6_tunnel_spi_lookup+0x3a9/0x3b0 > > net/ipv6/xfrm6_tunnel.c:79 > > Read of size 8 at addr ffff8880934578a8 by task syz-executor437/6811 > > CPU: 0 PID: 6811 Comm: syz-executor437 Not tainted > > 5.8.0-rc5-next-20200715-syzkaller #0 > > 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+0x18f/0x20d lib/dump_stack.c:118 > > print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383 > > __kasan_report mm/kasan/report.c:513 [inline] > > kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 > > __xfrm6_tunnel_spi_lookup+0x3a9/0x3b0 net/ipv6/xfrm6_tunnel.c:79 > > xfrm6_tunnel_spi_lookup+0x8a/0x1d0 net/ipv6/xfrm6_tunnel.c:95 > > xfrmi6_rcv_tunnel+0xb9/0x100 net/xfrm/xfrm_interface.c:824 > > tunnel6_rcv+0xef/0x2b0 net/ipv6/tunnel6.c:148 > > ip6_protocol_deliver_rcu+0x2e8/0x1670 net/ipv6/ip6_input.c:433 > > ip6_input_finish+0x7f/0x160 net/ipv6/ip6_input.c:474 > > NF_HOOK include/linux/netfilter.h:307 [inline] > > NF_HOOK include/linux/netfilter.h:301 [inline] > > ip6_input+0x9c/0xd0 net/ipv6/ip6_input.c:483 > > dst_input include/net/dst.h:449 [inline] > > ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline] > > NF_HOOK include/linux/netfilter.h:307 [inline] > > NF_HOOK include/linux/netfilter.h:301 [inline] > > ipv6_rcv+0x28e/0x3c0 net/ipv6/ip6_input.c:307 > > __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5287 > > __netif_receive_skb+0x27/0x1c0 net/core/dev.c:5401 > > netif_receive_skb_internal net/core/dev.c:5503 [inline] > > netif_receive_skb+0x159/0x990 net/core/dev.c:5562 > > tun_rx_batched.isra.0+0x460/0x720 drivers/net/tun.c:1518 > > tun_get_user+0x23b2/0x35b0 drivers/net/tun.c:1972 > > tun_chr_write_iter+0xba/0x151 drivers/net/tun.c:2001 > > call_write_iter include/linux/fs.h:1879 [inline] > > new_sync_write+0x422/0x650 fs/read_write.c:515 > > vfs_write+0x59d/0x6b0 fs/read_write.c:595 > > ksys_write+0x12d/0x250 fs/read_write.c:648 > > do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 > > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > RIP: 0033:0x403d50 > > Code: Bad RIP value. > > RSP: 002b:00007ffe8fe93368 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 > > RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000403d50 > > RDX: 000000000000005e RSI: 00000000200007c0 RDI: 00000000000000f0 > > RBP: 00007ffe8fe93390 R08: 0000000000000000 R09: 0000000000000000 > > R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe8fe93380 > > R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 > > Allocated by task 6811: > > kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 > > kasan_set_track mm/kasan/common.c:56 [inline] > > __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461 > > __do_kmalloc mm/slab.c:3655 [inline] > > __kmalloc+0x1a8/0x320 mm/slab.c:3664 > > kmalloc include/linux/slab.h:559 [inline] > > kzalloc include/linux/slab.h:666 [inline] > > tomoyo_init_log+0x1335/0x1e50 security/tomoyo/audit.c:275 > > tomoyo_supervisor+0x32f/0xeb0 security/tomoyo/common.c:2097 > > tomoyo_audit_path_number_log security/tomoyo/file.c:235 [inline] > > tomoyo_path_number_perm+0x3ed/0x4d0 security/tomoyo/file.c:734 > > security_file_ioctl+0x50/0xb0 security/security.c:1489 > > ksys_ioctl+0x50/0x180 fs/ioctl.c:747 > > __do_sys_ioctl fs/ioctl.c:762 [inline] > > __se_sys_ioctl fs/ioctl.c:760 [inline] > > __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760 > > do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 > > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > Freed by task 6811: > > kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 > > kasan_set_track+0x1c/0x30 mm/kasan/common.c:56 > > kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355 > > __kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422 > > __cache_free mm/slab.c:3418 [inline] > > kfree+0x103/0x2c0 mm/slab.c:3756 > > tomoyo_supervisor+0x350/0xeb0 security/tomoyo/common.c:2149 > > tomoyo_audit_path_number_log security/tomoyo/file.c:235 [inline] > > tomoyo_path_number_perm+0x3ed/0x4d0 security/tomoyo/file.c:734 > > security_file_ioctl+0x50/0xb0 security/security.c:1489 > > ksys_ioctl+0x50/0x180 fs/ioctl.c:747 > > __do_sys_ioctl fs/ioctl.c:762 [inline] > > __se_sys_ioctl fs/ioctl.c:760 [inline] > > __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760 > > do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 > > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > The buggy address belongs to the object at ffff888093457800 > > which belongs to the cache kmalloc-512 of size 512 > > The buggy address is located 168 bytes inside of > > 512-byte region [ffff888093457800, ffff888093457a00) > > The buggy address belongs to the page: > > page:000000005c2b5911 refcount:1 mapcount:0 mapping:0000000000000000 > > index:0x0 pfn:0x93457 > > flags: 0xfffe0000000200(slab) > > raw: 00fffe0000000200 ffffea00028d4308 ffffea0002834c88 ffff8880aa000600 > > raw: 0000000000000000 ffff888093457000 0000000100000004 0000000000000000 > > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > > ffff888093457780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > > ffff888093457800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > >ffff888093457880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > ^ > > ffff888093457900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > ffff888093457980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > ==================================================================