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authorJason Cai (Xiang Feng) <jason.cai.kern@gmail.com>2019-01-20 17:39:13 +0300
committerMike Snitzer <snitzer@redhat.com>2019-03-05 22:53:49 +0300
commit70de2cbda8a5d788284469e755f8b097d339c240 (patch)
treeb209d028212c2289c2b296372a3d1f112e117dd1 /drivers/md/dm-thin.c
parent5941c621dc9eb61e3b22f934675577d559d1fa27 (diff)
downloadlinux-70de2cbda8a5d788284469e755f8b097d339c240.tar.xz
dm thin: add sanity checks to thin-pool and external snapshot creation
Invoking dm_get_device() twice on the same device path with different modes is dangerous. Because in that case, upgrade_mode() will alloc a new 'dm_dev' and free the old one, which may be referenced by a previous caller. Dereferencing the dangling pointer will trigger kernel NULL pointer dereference. The following two cases can reproduce this issue. Actually, they are invalid setups that must be disallowed, e.g.: 1. Creating a thin-pool with read_only mode, and the same device as both metadata and data. dmsetup create thinp --table \ "0 41943040 thin-pool /dev/vdb /dev/vdb 128 0 1 read_only" BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 ... Call Trace: new_read+0xfb/0x110 [dm_bufio] dm_bm_read_lock+0x43/0x190 [dm_persistent_data] ? kmem_cache_alloc_trace+0x15c/0x1e0 __create_persistent_data_objects+0x65/0x3e0 [dm_thin_pool] dm_pool_metadata_open+0x8c/0xf0 [dm_thin_pool] pool_ctr.cold.79+0x213/0x913 [dm_thin_pool] ? realloc_argv+0x50/0x70 [dm_mod] dm_table_add_target+0x14e/0x330 [dm_mod] table_load+0x122/0x2e0 [dm_mod] ? dev_status+0x40/0x40 [dm_mod] ctl_ioctl+0x1aa/0x3e0 [dm_mod] dm_ctl_ioctl+0xa/0x10 [dm_mod] do_vfs_ioctl+0xa2/0x600 ? handle_mm_fault+0xda/0x200 ? __do_page_fault+0x26c/0x4f0 ksys_ioctl+0x60/0x90 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x55/0x150 entry_SYSCALL_64_after_hwframe+0x44/0xa9 2. Creating a external snapshot using the same thin-pool device. dmsetup create thinp --table \ "0 41943040 thin-pool /dev/vdc /dev/vdb 128 0 2 ignore_discard" dmsetup message /dev/mapper/thinp 0 "create_thin 0" dmsetup create snap --table \ "0 204800 thin /dev/mapper/thinp 0 /dev/mapper/thinp" BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 ... Call Trace: ? __alloc_pages_nodemask+0x13c/0x2e0 retrieve_status+0xa5/0x1f0 [dm_mod] ? dm_get_live_or_inactive_table.isra.7+0x20/0x20 [dm_mod] table_status+0x61/0xa0 [dm_mod] ctl_ioctl+0x1aa/0x3e0 [dm_mod] dm_ctl_ioctl+0xa/0x10 [dm_mod] do_vfs_ioctl+0xa2/0x600 ksys_ioctl+0x60/0x90 ? ksys_write+0x4f/0xb0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x55/0x150 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Signed-off-by: Jason Cai (Xiang Feng) <jason.cai@linux.alibaba.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-thin.c')
-rw-r--r--drivers/md/dm-thin.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 0d9ded0f5e50..fcd887703f95 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -3283,6 +3283,13 @@ static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
as.argc = argc;
as.argv = argv;
+ /* make sure metadata and data are different devices */
+ if (!strcmp(argv[0], argv[1])) {
+ ti->error = "Error setting metadata or data device";
+ r = -EINVAL;
+ goto out_unlock;
+ }
+
/*
* Set default pool features.
*/
@@ -4167,6 +4174,12 @@ static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
tc->sort_bio_list = RB_ROOT;
if (argc == 3) {
+ if (!strcmp(argv[0], argv[2])) {
+ ti->error = "Error setting origin device";
+ r = -EINVAL;
+ goto bad_origin_dev;
+ }
+
r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev);
if (r) {
ti->error = "Error opening origin device";