From: Xiubo Li <xiubli@xxxxxxxxxx> When there has new osdmap comes, it will replace and release the old osdmap memory, but if the mount is still on the way without the osdc->lock wrappers, we will hit use after free bug, like: <3>[ 3797.775970] BUG: KASAN: use-after-free in __ceph_open_session+0x2a9/0x370 [libceph] <3>[ 3797.775974] Read of size 4 at addr ffff8883d8b8a110 by task mount.ceph/64782 <3>[ 3797.775975] <4>[ 3797.775980] CPU: 0 PID: 64782 Comm: mount.ceph Tainted: G E 5.5.0+ #16 <4>[ 3797.775982] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/19/2017 <4>[ 3797.775984] Call Trace: <4>[ 3797.775992] dump_stack+0x8c/0xc0 <4>[ 3797.775997] print_address_description.constprop.0+0x1b/0x210 <4>[ 3797.776029] ? __ceph_open_session+0x2a9/0x370 [libceph] <4>[ 3797.776062] ? __ceph_open_session+0x2a9/0x370 [libceph] <4>[ 3797.776065] __kasan_report.cold+0x1a/0x33 <4>[ 3797.776098] ? __ceph_open_session+0x2a9/0x370 [libceph] <4>[ 3797.776101] kasan_report+0xe/0x20 <4>[ 3797.776133] __ceph_open_session+0x2a9/0x370 [libceph] <4>[ 3797.776170] ? ceph_reset_client_addr+0x30/0x30 [libceph] <4>[ 3797.776173] ? _raw_spin_lock+0x7a/0xd0 <4>[ 3797.776178] ? finish_wait+0x100/0x100 <4>[ 3797.776182] ? __mutex_lock_slowpath+0x10/0x10 <4>[ 3797.776227] ceph_get_tree+0x65b/0xa40 [ceph] <4>[ 3797.776236] vfs_get_tree+0x46/0x120 <4>[ 3797.776240] do_mount+0xa2c/0xd70 <4>[ 3797.776245] ? __list_add_valid+0x2f/0x60 <4>[ 3797.776249] ? copy_mount_string+0x20/0x20 <4>[ 3797.776254] ? __kasan_kmalloc.constprop.0+0xc2/0xd0 <4>[ 3797.776258] __x64_sys_mount+0xbe/0x100 <4>[ 3797.776263] do_syscall_64+0x73/0x210 <4>[ 3797.776268] entry_SYSCALL_64_after_hwframe+0x44/0xa9 <4>[ 3797.776271] RIP: 0033:0x7f8f026e5b8e <4>[ 3797.776275] Code: 48 8b 0d fd 42 0c 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 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d ca 42 0c 00 f7 d8 64 89 01 48 <4>[ 3797.776277] RSP: 002b:00007ffc2d7cccd8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5 <4>[ 3797.776281] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f8f026e5b8e <4>[ 3797.776283] RDX: 00005582afb2a558 RSI: 00007ffc2d7cef0d RDI: 00005582b01707a0 <4>[ 3797.776285] RBP: 00007ffc2d7ccda0 R08: 00005582b0173250 R09: 0000000000000067 <4>[ 3797.776287] R10: 0000000000000000 R11: 0000000000000206 R12: 00005582afb043a0 <4>[ 3797.776289] R13: 00007ffc2d7cce80 R14: 0000000000000000 R15: 0000000000000000 <3>[ 3797.776293] <3>[ 3797.776295] Allocated by task 64782: <4>[ 3797.776299] save_stack+0x1b/0x80 <4>[ 3797.776302] __kasan_kmalloc.constprop.0+0xc2/0xd0 <4>[ 3797.776336] ceph_osdmap_alloc+0x29/0xd0 [libceph] <4>[ 3797.776368] ceph_osdc_init+0x1ff/0x490 [libceph] <4>[ 3797.776399] ceph_create_client+0x154/0x1b0 [libceph] <4>[ 3797.776427] ceph_get_tree+0x97/0xa40 [ceph] <4>[ 3797.776430] vfs_get_tree+0x46/0x120 <4>[ 3797.776433] do_mount+0xa2c/0xd70 <4>[ 3797.776436] __x64_sys_mount+0xbe/0x100 <4>[ 3797.776439] do_syscall_64+0x73/0x210 <4>[ 3797.776443] entry_SYSCALL_64_after_hwframe+0x44/0xa9 <3>[ 3797.776443] <3>[ 3797.776445] Freed by task 55184: <4>[ 3797.776461] save_stack+0x1b/0x80 <4>[ 3797.776464] __kasan_slab_free+0x12c/0x170 <4>[ 3797.776467] kfree+0xa3/0x290 <4>[ 3797.776500] handle_one_map+0x1f4/0x3c0 [libceph] <4>[ 3797.776533] ceph_osdc_handle_map+0x910/0xa90 [libceph] <4>[ 3797.776567] dispatch+0x826/0xde0 [libceph] <4>[ 3797.776599] ceph_con_workfn+0x18c1/0x3b30 [libceph] <4>[ 3797.776603] process_one_work+0x3b1/0x6a0 <4>[ 3797.776606] worker_thread+0x78/0x5d0 <4>[ 3797.776609] kthread+0x191/0x1e0 <4>[ 3797.776612] ret_from_fork+0x35/0x40 <3>[ 3797.776613] <3>[ 3797.776616] The buggy address belongs to the object at ffff8883d8b8a100 <3>[ 3797.776616] which belongs to the cache kmalloc-192 of size 192 <3>[ 3797.776836] The buggy address is located 16 bytes inside of <3>[ 3797.776836] 192-byte region [ffff8883d8b8a100, ffff8883d8b8a1c0) <3>[ 3797.776838] The buggy address belongs to the page: <4>[ 3797.776842] page:ffffea000f62e280 refcount:1 mapcount:0 mapping:ffff8883ec80f000 index:0xffff8883d8b8bf00 compound_mapcount: 0 <4>[ 3797.776847] raw: 0017ffe000010200 ffffea000f6c6780 0000000200000002 ffff8883ec80f000 <4>[ 3797.776851] raw: ffff8883d8b8bf00 000000008020001b 00000001ffffffff 0000000000000000 <4>[ 3797.776852] page dumped because: kasan: bad access detected <3>[ 3797.776853] <3>[ 3797.776854] Memory state around the buggy address: <3>[ 3797.776857] ffff8883d8b8a000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <3>[ 3797.776859] ffff8883d8b8a080: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc <3>[ 3797.776862] >ffff8883d8b8a100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb <3>[ 3797.776863] ^ <3>[ 3797.776866] ffff8883d8b8a180: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc <3>[ 3797.776868] ffff8883d8b8a200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb <3>[ 3797.776869] ================================================================== URL: https://tracker.ceph.com/issues/44177 Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx> --- net/ceph/ceph_common.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/net/ceph/ceph_common.c b/net/ceph/ceph_common.c index a0e97f6c1072..5c6230b56e02 100644 --- a/net/ceph/ceph_common.c +++ b/net/ceph/ceph_common.c @@ -682,8 +682,14 @@ EXPORT_SYMBOL(ceph_reset_client_addr); */ static bool have_mon_and_osd_map(struct ceph_client *client) { + bool have_osd_map = false; + + down_read(&client->osdc.lock); + have_osd_map = !!(client->osdc.osdmap && client->osdc.osdmap->epoch); + up_read(&client->osdc.lock); + return client->monc.monmap && client->monc.monmap->epoch && - client->osdc.osdmap && client->osdc.osdmap->epoch; + have_osd_map; } /* -- 2.21.0
