When hfs was converted to the new mount api a bug was introduced by changing the allocation pattern of sb->s_fs_info. If setup_bdev_super() fails after a new superblock has been allocated by sget_fc(), but before hfs_fill_super() takes ownership of the filesystem-specific s_fs_info data it was leaked.
Fix this by freeing sb->s_fs_info in hfs_kill_super().
Cc: stable@vger.kernel.org Fixes: ffcd06b6d13b ("hfs: convert hfs to use the new mount api") Reported-by: syzbot+ad45f827c88778ff7df6@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=ad45f827c88778ff7df6 Tested-by: Viacheslav Dubeyko Slava.Dubeyko@ibm.com Signed-off-by: Christian Brauner brauner@kernel.org Signed-off-by: Mehdi Ben Hadj Khelifa mehdi.benhadjkhelifa@gmail.com --- fs/hfs/mdb.c | 35 ++++++++++++++--------------------- fs/hfs/super.c | 10 +++++++++- 2 files changed, 23 insertions(+), 22 deletions(-)
diff --git a/fs/hfs/mdb.c b/fs/hfs/mdb.c index 53f3fae60217..f28cd24dee84 100644 --- a/fs/hfs/mdb.c +++ b/fs/hfs/mdb.c @@ -92,7 +92,7 @@ int hfs_mdb_get(struct super_block *sb) /* See if this is an HFS filesystem */ bh = sb_bread512(sb, part_start + HFS_MDB_BLK, mdb); if (!bh) - goto out; + return -EIO;
if (mdb->drSigWord == cpu_to_be16(HFS_SUPER_MAGIC)) break; @@ -102,13 +102,14 @@ int hfs_mdb_get(struct super_block *sb) * (should do this only for cdrom/loop though) */ if (hfs_part_find(sb, &part_start, &part_size)) - goto out; + return -EIO; }
HFS_SB(sb)->alloc_blksz = size = be32_to_cpu(mdb->drAlBlkSiz); if (!size || (size & (HFS_SECTOR_SIZE - 1))) { pr_err("bad allocation block size %d\n", size); - goto out_bh; + brelse(bh); + return -EIO; }
size = min(HFS_SB(sb)->alloc_blksz, (u32)PAGE_SIZE); @@ -125,14 +126,16 @@ int hfs_mdb_get(struct super_block *sb) brelse(bh); if (!sb_set_blocksize(sb, size)) { pr_err("unable to set blocksize to %u\n", size); - goto out; + return -EIO; }
bh = sb_bread512(sb, part_start + HFS_MDB_BLK, mdb); if (!bh) - goto out; - if (mdb->drSigWord != cpu_to_be16(HFS_SUPER_MAGIC)) - goto out_bh; + return -EIO; + if (mdb->drSigWord != cpu_to_be16(HFS_SUPER_MAGIC)) { + brelse(bh); + return -EIO; + }
HFS_SB(sb)->mdb_bh = bh; HFS_SB(sb)->mdb = mdb; @@ -174,7 +177,7 @@ int hfs_mdb_get(struct super_block *sb)
HFS_SB(sb)->bitmap = kzalloc(8192, GFP_KERNEL); if (!HFS_SB(sb)->bitmap) - goto out; + return -EIO;
/* read in the bitmap */ block = be16_to_cpu(mdb->drVBMSt) + part_start; @@ -185,7 +188,7 @@ int hfs_mdb_get(struct super_block *sb) bh = sb_bread(sb, off >> sb->s_blocksize_bits); if (!bh) { pr_err("unable to read volume bitmap\n"); - goto out; + return -EIO; } off2 = off & (sb->s_blocksize - 1); len = min((int)sb->s_blocksize - off2, size); @@ -199,12 +202,12 @@ int hfs_mdb_get(struct super_block *sb) HFS_SB(sb)->ext_tree = hfs_btree_open(sb, HFS_EXT_CNID, hfs_ext_keycmp); if (!HFS_SB(sb)->ext_tree) { pr_err("unable to open extent tree\n"); - goto out; + return -EIO; } HFS_SB(sb)->cat_tree = hfs_btree_open(sb, HFS_CAT_CNID, hfs_cat_keycmp); if (!HFS_SB(sb)->cat_tree) { pr_err("unable to open catalog tree\n"); - goto out; + return -EIO; }
attrib = mdb->drAtrb; @@ -229,12 +232,6 @@ int hfs_mdb_get(struct super_block *sb) }
return 0; - -out_bh: - brelse(bh); -out: - hfs_mdb_put(sb); - return -EIO; }
/* @@ -359,8 +356,6 @@ void hfs_mdb_close(struct super_block *sb) * Release the resources associated with the in-core MDB. */ void hfs_mdb_put(struct super_block *sb) { - if (!HFS_SB(sb)) - return; /* free the B-trees */ hfs_btree_close(HFS_SB(sb)->ext_tree); hfs_btree_close(HFS_SB(sb)->cat_tree); @@ -373,6 +368,4 @@ void hfs_mdb_put(struct super_block *sb) unload_nls(HFS_SB(sb)->nls_disk);
kfree(HFS_SB(sb)->bitmap); - kfree(HFS_SB(sb)); - sb->s_fs_info = NULL; } diff --git a/fs/hfs/super.c b/fs/hfs/super.c index 47f50fa555a4..df289cbdd4e8 100644 --- a/fs/hfs/super.c +++ b/fs/hfs/super.c @@ -431,10 +431,18 @@ static int hfs_init_fs_context(struct fs_context *fc) return 0; }
+static void hfs_kill_super(struct super_block *sb) +{ + struct hfs_sb_info *hsb = HFS_SB(sb); + + kill_block_super(sb); + kfree(hsb); +} + static struct file_system_type hfs_fs_type = { .owner = THIS_MODULE, .name = "hfs", - .kill_sb = kill_block_super, + .kill_sb = hfs_kill_super, .fs_flags = FS_REQUIRES_DEV, .init_fs_context = hfs_init_fs_context, };