d784b65be
Denys Vlasenko
2009-11-02
Subject
btrfs.c: check first two superblocks, for additional robustness
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util-linux/volume_id/btrfs.c+15 -8
| @@ -80,19 +80,26 @@ struct btrfs_super_block { | |
| int FAST_FUNC volume_id_probe_btrfs(struct volume_id *id /*,uint64_t off*/) | |
| { | |
| - | #define off ((uint64_t) (64 * 1024)) |
| + | // btrfs has superblocks at 64K, 64M and 256G |
| + | // minimum btrfs size is 256M |
| + | // so we never step out the device if we analyze |
| + | // the first and the second superblocks |
| struct btrfs_super_block *sb; | |
| + | unsigned off = 64; |
| - | dbg("btrfs: probing at offset 0x%llx", (unsigned long long) off); |
| + | while (off < 64*1024*1024) { |
| + | off *= 1024; |
| + | dbg("btrfs: probing at offset 0x%x", off); |
| - | sb = volume_id_get_buffer(id, off, sizeof(*sb)); |
| - | if (sb == NULL) |
| - | return -1; |
| + | sb = volume_id_get_buffer(id, off, sizeof(*sb)); |
| + | if (sb == NULL) |
| + | return -1; |
| - | if (memcmp(sb->magic, BTRFS_MAGIC, 8) != 0) |
| - | return -1; |
| + | if (memcmp(sb->magic, BTRFS_MAGIC, 8) != 0) |
| + | return -1; |
| + | } |
| - | // N.B.: btrfs supports 256-byte labels |
| + | // N.B.: btrfs natively supports 256 (>VOLUME_ID_LABEL_SIZE) size labels |
| volume_id_set_label_string(id, sb->label, VOLUME_ID_LABEL_SIZE); | |
| volume_id_set_uuid(id, sb->fsid, UUID_DCE); | |