This patch fixes below KASAN report. The xfs_attr3_node_inactive()
gets 'child_bp' at there:
error = xfs_trans_get_buf(*trans, mp->m_ddev_targp,
child_blkno,
XFS_FSB_TO_BB(mp, mp->m_attr_geo->fsbcount), 0,
&child_bp);
if (error)
return error;
error = bp->b_error;
But it turns to use 'bp', not 'child_bp'. And the 'bp' has been freed by:
xfs_trans_brelse(*trans, bp);
[75626.212549] ==================================================================
[75626.245606] BUG: KASAN: use-after-free in xfs_attr3_node_inactive+0x61e/0x8a0 [xfs]
[75626.280164] Read of size 4 at addr ffff88881ffab004 by task rm/30390
[75626.315595] CPU: 13 PID: 30390 Comm: rm Tainted: G W 5.5.0+ #1
[75626.347856] Hardware name: HP ProLiant DL380p Gen8, BIOS P70 08/02/2014
[75626.377864] Call Trace:
[75626.388868] dump_stack+0x96/0xe0
[75626.403778] print_address_description.constprop.4+0x1f/0x300
[75626.429656] __kasan_report.cold.8+0x76/0xb0
[75626.448950] ? xfs_trans_ordered_buf+0x410/0x440 [xfs]
[75626.472393] ? xfs_attr3_node_inactive+0x61e/0x8a0 [xfs]
[75626.496705] kasan_report+0xe/0x20
[75626.512134] xfs_attr3_node_inactive+0x61e/0x8a0 [xfs]
[75626.535328] ? xfs_da_read_buf+0x235/0x2c0 [xfs]
[75626.557270] ? xfs_attr3_leaf_inactive+0x470/0x470 [xfs]
[75626.583199] ? xfs_da3_root_split+0x1050/0x1050 [xfs]
[75626.607952] ? lock_contended+0xd20/0xd20
[75626.626615] ? xfs_ilock+0x149/0x4c0 [xfs]
[75626.644661] ? down_write_nested+0x187/0x3c0
[75626.663892] ? down_write_trylock+0x2f0/0x2f0
[75626.683496] ? __sb_start_write+0x1c4/0x310
[75626.702389] ? down_read_trylock+0x360/0x360
[75626.721669] ? xfs_trans_buf_set_type+0x90/0x1e0 [xfs]
[75626.745171] xfs_attr_inactive+0x3e5/0x7b0 [xfs]
[75626.766097] ? xfs_attr3_node_inactive+0x8a0/0x8a0 [xfs]
[75626.790101] ? lock_downgrade+0x6d0/0x6d0
[75626.808122] ? do_raw_spin_trylock+0xb2/0x180
[75626.827859] ? lock_contended+0xd20/0xd20
[75626.846154] xfs_inactive+0x4b8/0x5b0 [xfs]
[75626.865504] xfs_fs_destroy_inode+0x3dc/0xb80 [xfs]
[75626.887615] destroy_inode+0xbc/0x1a0
[75626.904172] do_unlinkat+0x451/0x5d0
[75626.920325] ? __ia32_sys_rmdir+0x40/0x40
[75626.938485] ? __check_object_size+0x275/0x324
[75626.958819] ? strncpy_from_user+0x7d/0x350
[75626.977848] do_syscall_64+0x9f/0x4f0
[75626.994333] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[75627.017173] RIP: 0033:0x7f968239567b
[75627.033260] Code: 73 01 c3 48 8b 0d 0d d8 2c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 07 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d dd d7 2c 00 f7 d8 64 89 01 48
[75627.123796] RSP: 002b:00007ffcdf66ad38 EFLAGS: 00000246 ORIG_RAX: 0000000000000107
[75627.158521] RAX: ffffffffffffffda RBX: 0000562cd8b5d5b0 RCX: 00007f968239567b
[75627.190764] RDX: 0000000000000000 RSI: 0000562cd8b5c380 RDI: 00000000ffffff9c
[75627.222921] RBP: 0000562cd8b5c2f0 R08: 0000000000000003 R09: 0000000000000000
[75627.255236] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffcdf66af20
[75627.287435] R13: 0000000000000000 R14: 0000562cd8b5d5b0 R15: 0000000000000000
[75627.326616] Allocated by task 30390:
[75627.342780] save_stack+0x19/0x80
[75627.357980] __kasan_kmalloc.constprop.7+0xc1/0xd0
[75627.379553] kmem_cache_alloc+0xc8/0x300
[75627.397288] kmem_zone_alloc+0x10a/0x3f0 [xfs]
[75627.417376] _xfs_buf_alloc+0x56/0x1140 [xfs]
[75627.437051] xfs_buf_get_map+0x126/0x7c0 [xfs]
[75627.457103] xfs_buf_read_map+0xb2/0xaa0 [xfs]
[75627.477180] xfs_trans_read_buf_map+0x6c8/0x12d0 [xfs]
[75627.500420] xfs_da_read_buf+0x1d9/0x2c0 [xfs]
[75627.520579] xfs_da3_node_read+0x23/0x80 [xfs]
[75627.540620] xfs_attr_inactive+0x5c5/0x7b0 [xfs]
[75627.561609] xfs_inactive+0x4b8/0x5b0 [xfs]
[75627.581541] xfs_fs_destroy_inode+0x3dc/0xb80 [xfs]
[75627.605628] destroy_inode+0xbc/0x1a0
[75627.624025] do_unlinkat+0x451/0x5d0
[75627.641629] do_syscall_64+0x9f/0x4f0
[75627.658156] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[75627.687232] Freed by task 30390:
[75627.701882] save_stack+0x19/0x80
[75627.716821] __kasan_slab_free+0x125/0x170
[75627.735329] kmem_cache_free+0xcd/0x400
[75627.752745] xfs_buf_rele+0x30a/0xcb0 [xfs]
[75627.772731] xfs_attr3_node_inactive+0x1c7/0x8a0 [xfs]
[75627.797384] xfs_attr_inactive+0x3e5/0x7b0 [xfs]
[75627.818450] xfs_inactive+0x4b8/0x5b0 [xfs]
[75627.837455] xfs_fs_destroy_inode+0x3dc/0xb80 [xfs]
[75627.859765] destroy_inode+0xbc/0x1a0
[75627.876296] do_unlinkat+0x451/0x5d0
[75627.892466] do_syscall_64+0x9f/0x4f0
[75627.909015] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[75627.938572] The buggy address belongs to the object at ffff88881ffaad80
which belongs to the cache xfs_buf of size 680
[75627.994075] The buggy address is located 644 bytes inside of
680-byte region [ffff88881ffaad80, ffff88881ffab028)
[75628.047015] The buggy address belongs to the page:
[75628.069056] page:ffffea00207fea00 refcount:1 mapcount:0 mapping:ffff888098515400 index:0xffff88881ffa9d40 compound_mapcount: 0
[75628.124539] raw: 0057ffffc0010200 dead000000000100 dead000000000122 ffff888098515400
[75628.162598] raw: ffff88881ffa9d40 0000000080270025 00000001ffffffff 0000000000000000
[75628.197491] page dumped because: kasan: bad access detected
[75628.230389] Memory state around the buggy address:
[75628.252072] ffff88881ffaaf00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[75628.284801] ffff88881ffaaf80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[75628.317587] >ffff88881ffab000: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc
[75628.350592] ^
[75628.364746] ffff88881ffab080: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
[75628.397289] ffff88881ffab100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[75628.429955] ==================================================================
Signed-off-by: Zorro Lang <zlang@xxxxxxxxxx>
---
fs/xfs/xfs_attr_inactive.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/xfs/xfs_attr_inactive.c b/fs/xfs/xfs_attr_inactive.c
index bbfa6ba84dcd..26230d150bf2 100644
--- a/fs/xfs/xfs_attr_inactive.c
+++ b/fs/xfs/xfs_attr_inactive.c
@@ -211,7 +211,7 @@ xfs_attr3_node_inactive(
&child_bp);
if (error)
return error;
- error = bp->b_error;
+ error = child_bp->b_error;
if (error) {
xfs_trans_brelse(*trans, child_bp);
return error;
--
2.20.1
