lkml.org 
[lkml]   [2019]   [Feb]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] appletalk: Fix use-after-free in atalk_proc_exit
Date
From: YueHaibing <yuehaibing@huawei.com>

KASAN report this:

BUG: KASAN: use-after-free in pde_subdir_find+0x12d/0x150 fs/proc/generic.c:71
Read of size 8 at addr ffff8881f41fe5b0 by task syz-executor.0/2806

CPU: 0 PID: 2806 Comm: syz-executor.0 Not tainted 5.0.0-rc7+ #45
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xfa/0x1ce lib/dump_stack.c:113
print_address_description+0x65/0x270 mm/kasan/report.c:187
kasan_report+0x149/0x18d mm/kasan/report.c:317
pde_subdir_find+0x12d/0x150 fs/proc/generic.c:71
remove_proc_entry+0xe8/0x420 fs/proc/generic.c:667
atalk_proc_exit+0x18/0x820 [appletalk]
atalk_exit+0xf/0x5a [appletalk]
__do_sys_delete_module kernel/module.c:1018 [inline]
__se_sys_delete_module kernel/module.c:961 [inline]
__x64_sys_delete_module+0x3dc/0x5e0 kernel/module.c:961
do_syscall_64+0x147/0x600 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x462e99
Code: f7 d8 64 89 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb2de6b9c58 EFLAGS: 00000246 ORIG_RAX: 00000000000000b0
RAX: ffffffffffffffda RBX: 000000000073bf00 RCX: 0000000000462e99
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000200001c0
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb2de6ba6bc
R13: 00000000004bccaa R14: 00000000006f6bc8 R15: 00000000ffffffff

Allocated by task 2806:
set_track mm/kasan/common.c:85 [inline]
__kasan_kmalloc.constprop.3+0xa0/0xd0 mm/kasan/common.c:496
slab_post_alloc_hook mm/slab.h:444 [inline]
slab_alloc_node mm/slub.c:2739 [inline]
slab_alloc mm/slub.c:2747 [inline]
kmem_cache_alloc+0xcf/0x250 mm/slub.c:2752
kmem_cache_zalloc include/linux/slab.h:730 [inline]
__proc_create+0x30f/0xa20 fs/proc/generic.c:408
proc_mkdir_data+0x47/0x190 fs/proc/generic.c:469
0xffffffffc10c01bb
0xffffffffc10c0166
do_one_initcall+0xfa/0x5ca init/main.c:887
do_init_module+0x204/0x5f6 kernel/module.c:3460
load_module+0x66b2/0x8570 kernel/module.c:3808
__do_sys_finit_module+0x238/0x2a0 kernel/module.c:3902
do_syscall_64+0x147/0x600 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 2806:
set_track mm/kasan/common.c:85 [inline]
__kasan_slab_free+0x130/0x180 mm/kasan/common.c:458
slab_free_hook mm/slub.c:1409 [inline]
slab_free_freelist_hook mm/slub.c:1436 [inline]
slab_free mm/slub.c:2986 [inline]
kmem_cache_free+0xa6/0x2a0 mm/slub.c:3002
pde_put+0x6e/0x80 fs/proc/generic.c:647
remove_proc_entry+0x1d3/0x420 fs/proc/generic.c:684
0xffffffffc10c031c
0xffffffffc10c0166
do_one_initcall+0xfa/0x5ca init/main.c:887
do_init_module+0x204/0x5f6 kernel/module.c:3460
load_module+0x66b2/0x8570 kernel/module.c:3808
__do_sys_finit_module+0x238/0x2a0 kernel/module.c:3902
do_syscall_64+0x147/0x600 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8881f41fe500
which belongs to the cache proc_dir_entry of size 256
The buggy address is located 176 bytes inside of
256-byte region [ffff8881f41fe500, ffff8881f41fe600)
The buggy address belongs to the page:
page:ffffea0007d07f80 count:1 mapcount:0 mapping:ffff8881f6e69a00 index:0x0
flags: 0x2fffc0000000200(slab)
raw: 02fffc0000000200 dead000000000100 dead000000000200 ffff8881f6e69a00
raw: 0000000000000000 00000000800c000c 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8881f41fe480: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff8881f41fe500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881f41fe580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8881f41fe600: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
ffff8881f41fe680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

It should check the return value of atalk_proc_init fails,
otherwise atalk_exit calls pde_subdir_find will trgger
use-after-free while unloading the module.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
---
net/appletalk/ddp.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/appletalk/ddp.c b/net/appletalk/ddp.c
index 9b6bc5a..75075fe 100644
--- a/net/appletalk/ddp.c
+++ b/net/appletalk/ddp.c
@@ -1925,7 +1925,10 @@ static int __init atalk_init(void)

register_netdevice_notifier(&ddp_notifier);
aarp_proto_init();
- atalk_proc_init();
+ rc = atalk_proc_init();
+ if (rc)
+ goto out;
+
atalk_register_sysctl();
out:
return rc;
--
2.7.0

\
 
 \ /
  Last update: 2019-02-27 16:00    [W:0.032 / U:5.144 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site