From: Chandan Rajendra <chandan@linux.ibm.com>
To: Zorro Lang <zlang@redhat.com>
Cc: linux-xfs@vger.kernel.org
Subject: Re: [PATCH] xfs: fix invalid pointer dereference in xfs_attr3_node_inactive
Date: Tue, 04 Feb 2020 14:49:23 +0530 [thread overview]
Message-ID: <68736876.BgoadosnfD@localhost.localdomain> (raw)
In-Reply-To: <20200204070636.25572-1-zlang@redhat.com>
On Tuesday, February 4, 2020 12:36 PM Zorro Lang wrote:
> 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);
May be add a Fixes tag. The bug was introduced by the commit
2911edb653b9c64e0aad461f308cae8ce030eb7b (xfs: remove the mappedbno argument
to xfs_da_get_buf).
Apart from that, I don't see any other issue with your patch.
Reviewed-by: Chandan Rajendra <chandanrlinux@gmail.com>
>
> [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@redhat.com>
> ---
> 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;
>
--
chandan
next prev parent reply other threads:[~2020-02-04 9:16 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-04 7:06 [PATCH] xfs: fix invalid pointer dereference in xfs_attr3_node_inactive Zorro Lang
2020-02-04 9:19 ` Chandan Rajendra [this message]
2020-02-04 10:29 ` Zorro Lang
2020-02-04 21:39 ` Dave Chinner
2020-02-05 0:09 ` Darrick J. Wong
2020-02-05 4:02 ` Zorro Lang
2020-10-26 5:19 ` Zorro Lang
2020-10-26 15:51 ` Darrick J. Wong
2020-02-05 3:58 ` Zorro Lang
2020-02-05 6:02 ` Darrick J. Wong
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