path: root/fs/btrfs/volumes.h
diff options
authorQu Wenruo <wqu@suse.com>2019-03-08 14:20:03 +0800
committerDavid Sterba <dsterba@suse.com>2019-04-29 19:02:32 +0200
commitab4ba2e133463c702b37242560d7fabedd2dc750 (patch)
treec4308266c635ddecb044ee96ccd7ca7bb453e001 /fs/btrfs/volumes.h
parentbtrfs: tree-checker: Check chunk item at tree block read time (diff)
btrfs: tree-checker: Verify dev item
[BUG] For fuzzed image whose DEV_ITEM has invalid total_bytes as 0, then kernel will just panic: BUG: unable to handle kernel NULL pointer dereference at 0000000000000098 #PF error: [normal kernel read fault] PGD 800000022b2bd067 P4D 800000022b2bd067 PUD 22b2bc067 PMD 0 Oops: 0000 [#1] SMP PTI CPU: 0 PID: 1106 Comm: mount Not tainted 5.0.0-rc8+ #9 RIP: 0010:btrfs_verify_dev_extents+0x2a5/0x5a0 Call Trace: open_ctree+0x160d/0x2149 btrfs_mount_root+0x5b2/0x680 [CAUSE] If device extent verification finds a deivce with 0 total_bytes, then it assumes it's a seed dummy, then search for seed devices. But in this case, there is no seed device at all, causing NULL pointer. [FIX] Since this is caused by fuzzed image, let's go the tree-check way, just add a new verification for device item. Reported-by: Yoon Jungyeon <jungyeon@gatech.edu> Link: https://bugzilla.kernel.org/show_bug.cgi?id=202691 Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/volumes.h')
1 files changed, 9 insertions, 0 deletions
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 3ad9d58d1b66..38ed94b77202 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -258,6 +258,15 @@ struct btrfs_fs_devices {
+#define BTRFS_MAX_DEVS(info) ((BTRFS_MAX_ITEM_SIZE(info) \
+ - sizeof(struct btrfs_chunk)) \
+ / sizeof(struct btrfs_stripe) + 1)
+ - 2 * sizeof(struct btrfs_disk_key) \
+ - 2 * sizeof(struct btrfs_chunk)) \
+ / sizeof(struct btrfs_stripe) + 1)
* we need the mirror number and stripe index to be passed around
* the call chain while we are processing end_io (especially errors).