On Mon, Aug 24, 2020 at 9:37 PM syzbot <syzbot+f07cc9be8d1d226947ed@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > syzbot has found a reproducer for the following issue on: Looping in fsdevel and OverlayFS maintainers, as this seems to be FS/OverlayFS related... See also original report against 5.8-rc7: https://lore.kernel.org/linux-security-module/0000000000008caae305ab9a5318@xxxxxxxxxx/T/ > > HEAD commit: d012a719 Linux 5.9-rc2 > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=14aa130e900000 > kernel config: https://syzkaller.appspot.com/x/.config?x=891ca5711a9f1650 > dashboard link: https://syzkaller.appspot.com/bug?extid=f07cc9be8d1d226947ed > compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=104a650e900000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+f07cc9be8d1d226947ed@xxxxxxxxxxxxxxxxxxxxxxxxx > > general protection fault, probably for non-canonical address 0xdffffc000000000d: 0000 [#1] PREEMPT SMP KASAN > KASAN: null-ptr-deref in range [0x0000000000000068-0x000000000000006f] > CPU: 1 PID: 32288 Comm: syz-executor.3 Not tainted 5.9.0-rc2-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > RIP: 0010:d_backing_inode include/linux/dcache.h:549 [inline] > RIP: 0010:security_inode_getattr+0x42/0x140 security/security.c:1276 > Code: 1b fe 49 8d 5e 08 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 bc b4 5b fe 48 8b 1b 48 83 c3 68 48 89 d8 48 c1 e8 03 <42> 80 3c 38 00 74 08 48 89 df e8 9f b4 5b fe 48 8b 1b 48 83 c3 0c > RSP: 0018:ffffc9000a017750 EFLAGS: 00010202 > RAX: 000000000000000d RBX: 0000000000000068 RCX: ffff888093ec6180 > RDX: 0000000000000000 RSI: ffffc9000a017860 RDI: ffffc9000a017850 > RBP: ffffc9000a017850 R08: dffffc0000000000 R09: ffffc9000a017850 > R10: fffff52001402f0c R11: 0000000000000000 R12: ffffc9000a017860 > R13: 0000000000008401 R14: ffffc9000a017850 R15: dffffc0000000000 > FS: 00007f292d4ef700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000001b30920074 CR3: 00000000937fd000 CR4: 00000000001506e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > vfs_getattr+0x21/0x60 fs/stat.c:121 > ovl_copy_up_one fs/overlayfs/copy_up.c:850 [inline] > ovl_copy_up_flags+0x2ef/0x2a00 fs/overlayfs/copy_up.c:931 > ovl_maybe_copy_up+0x154/0x180 fs/overlayfs/copy_up.c:963 > ovl_open+0xa2/0x200 fs/overlayfs/file.c:147 > do_dentry_open+0x7c8/0x1010 fs/open.c:817 > do_open fs/namei.c:3251 [inline] > path_openat+0x2794/0x3840 fs/namei.c:3368 > do_filp_open+0x191/0x3a0 fs/namei.c:3395 > file_open_name+0x321/0x430 fs/open.c:1113 > acct_on kernel/acct.c:207 [inline] > __do_sys_acct kernel/acct.c:286 [inline] > __se_sys_acct+0x122/0x6f0 kernel/acct.c:273 > do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > RIP: 0033:0x45d579 > Code: 5d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007f292d4eec78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a3 > RAX: ffffffffffffffda RBX: 0000000000000700 RCX: 000000000045d579 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000040 > RBP: 000000000118cf70 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c > R13: 00007ffc8e04bc4f R14: 00007f292d4ef9c0 R15: 000000000118cf4c > Modules linked in: > ---[ end trace 7e4f1041b188e411 ]--- > RIP: 0010:d_backing_inode include/linux/dcache.h:549 [inline] > RIP: 0010:security_inode_getattr+0x42/0x140 security/security.c:1276 > Code: 1b fe 49 8d 5e 08 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 bc b4 5b fe 48 8b 1b 48 83 c3 68 48 89 d8 48 c1 e8 03 <42> 80 3c 38 00 74 08 48 89 df e8 9f b4 5b fe 48 8b 1b 48 83 c3 0c > RSP: 0018:ffffc9000a017750 EFLAGS: 00010202 > RAX: 000000000000000d RBX: 0000000000000068 RCX: ffff888093ec6180 > RDX: 0000000000000000 RSI: ffffc9000a017860 RDI: ffffc9000a017850 > RBP: ffffc9000a017850 R08: dffffc0000000000 R09: ffffc9000a017850 > R10: fffff52001402f0c R11: 0000000000000000 R12: ffffc9000a017860 > R13: 0000000000008401 R14: ffffc9000a017850 R15: dffffc0000000000 > FS: 00007f292d4ef700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007fef820e7000 CR3: 00000000937fd000 CR4: 00000000001506e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > -- Ondrej Mosnacek Software Engineer, Platform Security - SELinux kernel Red Hat, Inc.
