On 1/24/20 4:49 PM, Casey Schaufler wrote:
On 1/24/2020 1:04 PM, Stephen Smalley wrote:
On 1/23/20 7:22 PM, Casey Schaufler wrote:
This patchset provides the changes required for
the AppArmor security module to stack safely with any other.
v14: Rebase to 5.5-rc5
Incorporate feedback from v13
- Use an array of audit rules (patch 0002)
- Significant change, removed Acks (patch 0002)
- Remove unneeded include (patch 0013)
- Use context.len correctly (patch 0015)
- Reorder code to be more sensible (patch 0016)
- Drop SO_PEERCONTEXT as it's not needed yet (patch 0023)
I don't know for sure if this is your bug, but it happens every time I boot with your patches applied and not at all on stock v5.5-rc5 so here it is. Will try to bisect as time permits but not until next week. Trigger seems to be loading the tun driver.
Thanks. I will have a look as well.
Bisection led to the first patch in the series, "LSM: Infrastructure
management of the sock security". Still not sure if the bug is in the
patch itself or just being surfaced by it.
[ 67.726834] tun: Universal TUN/TAP device driver, 1.6
[ 67.736657] ==================================================================
[ 67.741335] BUG: KASAN: slab-out-of-bounds in sock_init_data+0x14a/0x5a0
[ 67.745037] Read of size 4 at addr ffff88870afe8928 by task libvirtd/1238
[ 67.751861] CPU: 4 PID: 1238 Comm: libvirtd Tainted: G T 5.5.0-rc5+ #54
[ 67.756250] Call Trace:
[ 67.759510] dump_stack+0xb8/0x110
[ 67.761604] print_address_description.constprop.0+0x1f/0x280
[ 67.763768] __kasan_report.cold+0x75/0x8f
[ 67.765895] ? sock_init_data+0x14a/0x5a0
[ 67.768282] kasan_report+0xe/0x20
[ 67.770397] sock_init_data+0x14a/0x5a0
[ 67.772511] tun_chr_open+0x1de/0x280 [tun]
[ 67.774644] misc_open+0x1cb/0x210
[ 67.776820] chrdev_open+0x15b/0x350
[ 67.778917] ? cdev_put.part.0+0x30/0x30
[ 67.781030] do_dentry_open+0x2cb/0x800
[ 67.783135] ? cdev_put.part.0+0x30/0x30
[ 67.785225] ? devcgroup_check_permission+0x11a/0x260
[ 67.787321] ? __x64_sys_fchdir+0xf0/0xf0
[ 67.789418] ? security_inode_permission+0x5b/0x70
[ 67.791513] path_openat+0x858/0x14a0
[ 67.793589] ? path_mountpoint+0x5e0/0x5e0
[ 67.795719] ? mark_lock+0xb8/0xb00
[ 67.797786] do_filp_open+0x11e/0x1b0
[ 67.799840] ? may_open_dev+0x60/0x60
[ 67.801871] ? match_held_lock+0x1b/0x240
[ 67.803968] ? lock_downgrade+0x360/0x360
[ 67.805997] ? do_raw_spin_lock+0x119/0x1d0
[ 67.808041] ? rwlock_bug.part.0+0x60/0x60
[ 67.810099] ? do_raw_spin_unlock+0xa3/0x130
[ 67.812244] ? _raw_spin_unlock+0x1f/0x30
[ 67.814287] ? __alloc_fd+0x143/0x2f0
[ 67.816324] do_sys_open+0x1f0/0x2d0
[ 67.818358] ? filp_open+0x50/0x50
[ 67.820404] ? trace_hardirqs_on_thunk+0x1a/0x1c
[ 67.822447] ? lockdep_hardirqs_off+0xbe/0x100
[ 67.824473] ? mark_held_locks+0x24/0x90
[ 67.826484] do_syscall_64+0x74/0xd0
[ 67.828480] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 67.830478] RIP: 0033:0x7f1a2cce6074
[ 67.832495] Code: 24 20 eb 8f 66 90 44 89 54 24 0c e8 86 f4 ff ff 44 8b 54 24 0c 44 89 e2 48 89 ee 41 89 c0 bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 77 32 44 89 c7 89 44 24 0c e8 b8 f4 ff ff 8b 44
[ 67.834760] RSP: 002b:00007f19e4af46d0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
[ 67.837032] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f1a2cce6074
[ 67.839318] RDX: 0000000000000002 RSI: 00007f1a2d0bfb67 RDI: 00000000ffffff9c
[ 67.841598] RBP: 00007f1a2d0bfb67 R08: 0000000000000000 R09: 00007f19e4af4914
[ 67.843941] R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000002
[ 67.846283] R13: 000000000000000d R14: 00007f19e4af4920 R15: 00007f1a2d0bfb67
[ 67.850936] Allocated by task 1238:
[ 67.853241] save_stack+0x1b/0x80
[ 67.855533] __kasan_kmalloc.constprop.0+0xc2/0xd0
[ 67.857935] sk_prot_alloc+0x115/0x170
[ 67.860235] sk_alloc+0x2f/0xa10
[ 67.862541] tun_chr_open+0x4d/0x280 [tun]
[ 67.864894] misc_open+0x1cb/0x210
[ 67.867164] chrdev_open+0x15b/0x350
[ 67.869448] do_dentry_open+0x2cb/0x800
[ 67.871768] path_openat+0x858/0x14a0
[ 67.874041] do_filp_open+0x11e/0x1b0
[ 67.876328] do_sys_open+0x1f0/0x2d0
[ 67.878592] do_syscall_64+0x74/0xd0
[ 67.880899] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 67.885431] Freed by task 726:
[ 67.887689] save_stack+0x1b/0x80
[ 67.889967] __kasan_slab_free+0x12c/0x170
[ 67.892197] kfree+0xff/0x430
[ 67.894444] uevent_show+0x176/0x1b0
[ 67.896709] dev_attr_show+0x37/0x70
[ 67.898940] sysfs_kf_seq_show+0x119/0x210
[ 67.901159] seq_read+0x29d/0x720
[ 67.903367] vfs_read+0xf9/0x1f0
[ 67.905538] ksys_read+0xc9/0x160
[ 67.907736] do_syscall_64+0x74/0xd0
[ 67.909889] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 67.914100] The buggy address belongs to the object at ffff88870afe8000
which belongs to the cache kmalloc-4k of size 4096
[ 67.918357] The buggy address is located 2344 bytes inside of
4096-byte region [ffff88870afe8000, ffff88870afe9000)
[ 67.922562] The buggy address belongs to the page:
[ 67.924725] page:ffffea001c2bfa00 refcount:1 mapcount:0 mapping:ffff88881f00de00 index:0x0 compound_mapcount: 0
[ 67.926926] raw: 0017ffe000010200 ffffea001c167a00 0000000200000002 ffff88881f00de00
[ 67.929144] raw: 0000000000000000 0000000080040004 00000001ffffffff 0000000000000000
[ 67.931362] page dumped because: kasan: bad access detected
[ 67.936192] Memory state around the buggy address:
[ 67.938438] ffff88870afe8800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ 67.941078] ffff88870afe8880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 67.943393] >ffff88870afe8900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 67.945709] ^
[ 67.948000] ffff88870afe8980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 67.950311] ffff88870afe8a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 67.952629] ==================================================================
