3.16.74-rc1 review patch. If anyone has any objections, please let me know.
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From: YueHaibing yuehaibing@huawei.com
commit 6377f787aeb945cae7abbb6474798de129e1f3ac upstream.
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 will trgger use-after-free in pde_subdir_find while unload the module.This patch fix error cleanup path of atalk_init
Reported-by: Hulk Robot hulkci@huawei.com Signed-off-by: YueHaibing yuehaibing@huawei.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Ben Hutchings ben@decadent.org.uk --- include/linux/atalk.h | 2 +- net/appletalk/atalk_proc.c | 2 +- net/appletalk/ddp.c | 37 ++++++++++++++++++++++++++------ net/appletalk/sysctl_net_atalk.c | 5 ++++- 4 files changed, 37 insertions(+), 9 deletions(-)
--- a/include/linux/atalk.h +++ b/include/linux/atalk.h @@ -150,7 +150,7 @@ extern int sysctl_aarp_retransmit_limit; extern int sysctl_aarp_resolve_time;
#ifdef CONFIG_SYSCTL -extern void atalk_register_sysctl(void); +extern int atalk_register_sysctl(void); extern void atalk_unregister_sysctl(void); #else #define atalk_register_sysctl() do { } while(0) --- a/net/appletalk/atalk_proc.c +++ b/net/appletalk/atalk_proc.c @@ -293,7 +293,7 @@ out_interface: goto out; }
-void __exit atalk_proc_exit(void) +void atalk_proc_exit(void) { remove_proc_entry("interface", atalk_proc_dir); remove_proc_entry("route", atalk_proc_dir); --- a/net/appletalk/ddp.c +++ b/net/appletalk/ddp.c @@ -1913,12 +1913,16 @@ static const char atalk_err_snap[] __ini /* Called by proto.c on kernel start up */ static int __init atalk_init(void) { - int rc = proto_register(&ddp_proto, 0); + int rc;
- if (rc != 0) + rc = proto_register(&ddp_proto, 0); + if (rc) goto out;
- (void)sock_register(&atalk_family_ops); + rc = sock_register(&atalk_family_ops); + if (rc) + goto out_proto; + ddp_dl = register_snap_client(ddp_snap_id, atalk_rcv); if (!ddp_dl) printk(atalk_err_snap); @@ -1926,12 +1930,33 @@ static int __init atalk_init(void) dev_add_pack(<alk_packet_type); dev_add_pack(&ppptalk_packet_type);
- register_netdevice_notifier(&ddp_notifier); + rc = register_netdevice_notifier(&ddp_notifier); + if (rc) + goto out_sock; + aarp_proto_init(); - atalk_proc_init(); - atalk_register_sysctl(); + rc = atalk_proc_init(); + if (rc) + goto out_aarp; + + rc = atalk_register_sysctl(); + if (rc) + goto out_proc; out: return rc; +out_proc: + atalk_proc_exit(); +out_aarp: + aarp_cleanup_module(); + unregister_netdevice_notifier(&ddp_notifier); +out_sock: + dev_remove_pack(&ppptalk_packet_type); + dev_remove_pack(<alk_packet_type); + unregister_snap_client(ddp_dl); + sock_unregister(PF_APPLETALK); +out_proto: + proto_unregister(&ddp_proto); + goto out; } module_init(atalk_init);
--- a/net/appletalk/sysctl_net_atalk.c +++ b/net/appletalk/sysctl_net_atalk.c @@ -44,9 +44,12 @@ static struct ctl_table atalk_table[] =
static struct ctl_table_header *atalk_table_header;
-void atalk_register_sysctl(void) +int __init atalk_register_sysctl(void) { atalk_table_header = register_net_sysctl(&init_net, "net/appletalk", atalk_table); + if (!atalk_table_header) + return -ENOMEM; + return 0; }
void atalk_unregister_sysctl(void)