Btrfs: add more validation checks for superblock

This adds validation checks for super_total_bytes, super_bytes_used and
super_stripesize, super_num_devices.

Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
Reported-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

2 files changed, 35 insertions, 0 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 6628fca9f4ed..2bd5f5e975cc 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -4130,6 +4130,17 @@ static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
          * Hint to catch really bogus numbers, bitflips or so, more exact checks are
          * done later
          */
+        if (btrfs_super_bytes_used(sb) < 6 * btrfs_super_nodesize(sb)) {
+                btrfs_err(fs_info, "bytes_used is too small %llu",
+                       btrfs_super_bytes_used(sb));
+                ret = -EINVAL;
+        }
+        if (!is_power_of_2(btrfs_super_stripesize(sb)) ||
+            btrfs_super_stripesize(sb) != sectorsize) {
+                btrfs_err(fs_info, "invalid stripesize %u",
+                       btrfs_super_stripesize(sb));
+                ret = -EINVAL;
+        }
         if (btrfs_super_num_devices(sb) > (1UL << 31))
                 printk(KERN_WARNING "BTRFS: suspicious number of devices: %llu\n",
                                 btrfs_super_num_devices(sb));
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 42ccde43053b..fd5c9e69894a 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -6651,6 +6651,7 @@ int btrfs_read_chunk_tree(struct btrfs_root *root)
         struct btrfs_key found_key;
         int ret;
         int slot;
+        u64 total_dev = 0;
 
         root = root->fs_info->chunk_root;
 
@@ -6692,6 +6693,7 @@ int btrfs_read_chunk_tree(struct btrfs_root *root)
                         ret = read_one_dev(root, leaf, dev_item);
                         if (ret)
                                 goto error;
+                        total_dev++;
                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
                         struct btrfs_chunk *chunk;
                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
@@ -6701,6 +6703,28 @@ int btrfs_read_chunk_tree(struct btrfs_root *root)
                 }
                 path->slots[0]++;
         }
+
+        /*
+         * After loading chunk tree, we've got all device information,
+         * do another round of validation checks.
+         */
+        if (total_dev != root->fs_info->fs_devices->total_devices) {
+                btrfs_err(root->fs_info,
+           "super_num_devices %llu mismatch with num_devices %llu found here",
+                          btrfs_super_num_devices(root->fs_info->super_copy),
+                          total_dev);
+                ret = -EINVAL;
+                goto error;
+        }
+        if (btrfs_super_total_bytes(root->fs_info->super_copy) <
+            root->fs_info->fs_devices->total_rw_bytes) {
+                btrfs_err(root->fs_info,
+        "super_total_bytes %llu mismatch with fs_devices total_rw_bytes %llu",
+                          btrfs_super_total_bytes(root->fs_info->super_copy),
+                          root->fs_info->fs_devices->total_rw_bytes);
+                ret = -EINVAL;
+                goto error;
+        }
         ret = 0;
 error:
         unlock_chunks(root);