diff options
| author | Jamie Iles <jamie@nuviainc.com> | 2020-10-12 14:13:09 +0100 |
|---|---|---|
| committer | Andreas Gruenbacher <agruenba@redhat.com> | 2020-10-14 23:54:43 +0200 |
| commit | c2a04b02c060c4858762edce4674d5cba3e5a96f (patch) | |
| tree | 07835b8712c6e981f718a89a449397f555dce156 /fs/gfs2/ops_fstype.c | |
| parent | 0e539ca1bbbe85a86549c97a30a765ada4a09df9 (diff) | |
gfs2: use-after-free in sysfs deregistration
syzkaller found the following splat with CONFIG_DEBUG_KOBJECT_RELEASE=y:
Read of size 1 at addr ffff000028e896b8 by task kworker/1:2/228
CPU: 1 PID: 228 Comm: kworker/1:2 Tainted: G S 5.9.0-rc8+ #101
Hardware name: linux,dummy-virt (DT)
Workqueue: events kobject_delayed_cleanup
Call trace:
dump_backtrace+0x0/0x4d8
show_stack+0x34/0x48
dump_stack+0x174/0x1f8
print_address_description.constprop.0+0x5c/0x550
kasan_report+0x13c/0x1c0
__asan_report_load1_noabort+0x34/0x60
memcmp+0xd0/0xd8
gfs2_uevent+0xc4/0x188
kobject_uevent_env+0x54c/0x1240
kobject_uevent+0x2c/0x40
__kobject_del+0x190/0x1d8
kobject_delayed_cleanup+0x2bc/0x3b8
process_one_work+0x96c/0x18c0
worker_thread+0x3f0/0xc30
kthread+0x390/0x498
ret_from_fork+0x10/0x18
Allocated by task 1110:
kasan_save_stack+0x28/0x58
__kasan_kmalloc.isra.0+0xc8/0xe8
kasan_kmalloc+0x10/0x20
kmem_cache_alloc_trace+0x1d8/0x2f0
alloc_super+0x64/0x8c0
sget_fc+0x110/0x620
get_tree_bdev+0x190/0x648
gfs2_get_tree+0x50/0x228
vfs_get_tree+0x84/0x2e8
path_mount+0x1134/0x1da8
do_mount+0x124/0x138
__arm64_sys_mount+0x164/0x238
el0_svc_common.constprop.0+0x15c/0x598
do_el0_svc+0x60/0x150
el0_svc+0x34/0xb0
el0_sync_handler+0xc8/0x5b4
el0_sync+0x15c/0x180
Freed by task 228:
kasan_save_stack+0x28/0x58
kasan_set_track+0x28/0x40
kasan_set_free_info+0x24/0x48
__kasan_slab_free+0x118/0x190
kasan_slab_free+0x14/0x20
slab_free_freelist_hook+0x6c/0x210
kfree+0x13c/0x460
Use the same pattern as f2fs + ext4 where the kobject destruction must
complete before allowing the FS itself to be freed. This means that we
need an explicit free_sbd in the callers.
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Jamie Iles <jamie@nuviainc.com>
[Also go to fail_free when init_names fails.]
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Diffstat (limited to 'fs/gfs2/ops_fstype.c')
| -rw-r--r-- | fs/gfs2/ops_fstype.c | 22 |
1 files changed, 5 insertions, 17 deletions
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c index 6d18d2c91add..5bd602a290f7 100644 --- a/fs/gfs2/ops_fstype.c +++ b/fs/gfs2/ops_fstype.c @@ -1062,26 +1062,14 @@ static int gfs2_fill_super(struct super_block *sb, struct fs_context *fc) } error = init_names(sdp, silent); - if (error) { - /* In this case, we haven't initialized sysfs, so we have to - manually free the sdp. */ - free_sbd(sdp); - sb->s_fs_info = NULL; - return error; - } + if (error) + goto fail_free; snprintf(sdp->sd_fsname, sizeof(sdp->sd_fsname), "%s", sdp->sd_table_name); error = gfs2_sys_fs_add(sdp); - /* - * If we hit an error here, gfs2_sys_fs_add will have called function - * kobject_put which causes the sysfs usage count to go to zero, which - * causes sysfs to call function gfs2_sbd_release, which frees sdp. - * Subsequent error paths here will call gfs2_sys_fs_del, which also - * kobject_put to free sdp. - */ if (error) - return error; + goto fail_free; gfs2_create_debugfs_file(sdp); @@ -1179,9 +1167,9 @@ fail_lm: gfs2_lm_unmount(sdp); fail_debug: gfs2_delete_debugfs_file(sdp); - /* gfs2_sys_fs_del must be the last thing we do, since it causes - * sysfs to call function gfs2_sbd_release, which frees sdp. */ gfs2_sys_fs_del(sdp); +fail_free: + free_sbd(sdp); sb->s_fs_info = NULL; return error; } |