btrfs: fix possible NULL-pointer dereference in integrity checks

[ Upstream commit 3dbd351df42109902fbcebf27104149226a4fcd9 ]

A user reports a possible NULL-pointer dereference in
btrfsic_process_superblock(). We are assigning state->fs_info to a local
fs_info variable and afterwards checking for the presence of state.

While we would BUG_ON() a NULL state anyways, we can also just remove
the local fs_info copy, as fs_info is only used once as the first
argument for btrfs_num_copies(). There we can just pass in
state->fs_info as well.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=205003
Signed-off-by: Johannes Thumshirn <jth@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Johannes Thumshirn 2019-12-05 14:19:57 +01:00 committed by Greg Kroah-Hartman
parent 50b9336966
commit ebf8e54118

View File

@ -629,7 +629,6 @@ static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(dev_t dev,
static int btrfsic_process_superblock(struct btrfsic_state *state,
struct btrfs_fs_devices *fs_devices)
{
struct btrfs_fs_info *fs_info = state->fs_info;
struct btrfs_super_block *selected_super;
struct list_head *dev_head = &fs_devices->devices;
struct btrfs_device *device;
@ -700,7 +699,7 @@ static int btrfsic_process_superblock(struct btrfsic_state *state,
break;
}
num_copies = btrfs_num_copies(fs_info, next_bytenr,
num_copies = btrfs_num_copies(state->fs_info, next_bytenr,
state->metablock_size);
if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
pr_info("num_copies(log_bytenr=%llu) = %d\n",