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| author | Phillip Lougher <phillip@lougher.demon.co.uk> | 2011-05-24 07:05:22 +0400 |
|---|---|---|
| committer | Phillip Lougher <phillip@lougher.demon.co.uk> | 2011-05-25 21:21:32 +0400 |
| commit | 37986f63c81bf23c856f65fc5e4830550e7f3d5b (patch) | |
| tree | aafcc2078b469fb8fdb6e43255e136fcc7059dc9 /fs/squashfs/super.c | |
| parent | 6f04864515365e135adc9f1cee4ac1251bb0ed35 (diff) | |
| download | linux-37986f63c81bf23c856f65fc5e4830550e7f3d5b.tar.xz | |
Squashfs: add sanity checks to id reading at mount time
Fsfuzzer generates corrupted filesystems which throw a warn_on in
kmalloc. One of these is due to a corrupted superblock no_ids field.
Fix this by checking that the number of bytes to be read (and allocated)
does not extend into the next filesystem structure.
Also add a couple of other sanity checks of the mount-time id table
structures.
Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
Diffstat (limited to 'fs/squashfs/super.c')
| -rw-r--r-- | fs/squashfs/super.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/fs/squashfs/super.c b/fs/squashfs/super.c index 401cc8c7608f..8f5f2781a60e 100644 --- a/fs/squashfs/super.c +++ b/fs/squashfs/super.c @@ -83,7 +83,7 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent) long long root_inode; unsigned short flags; unsigned int fragments; - u64 lookup_table_start, xattr_id_table_start; + u64 lookup_table_start, xattr_id_table_start, next_table; int err; TRACE("Entered squashfs_fill_superblock\n"); @@ -217,8 +217,10 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent) /* Handle xattrs */ sb->s_xattr = squashfs_xattr_handlers; xattr_id_table_start = le64_to_cpu(sblk->xattr_id_table_start); - if (xattr_id_table_start == SQUASHFS_INVALID_BLK) + if (xattr_id_table_start == SQUASHFS_INVALID_BLK) { + next_table = msblk->bytes_used; goto allocate_id_index_table; + } /* Allocate and read xattr id lookup table */ msblk->xattr_id_table = squashfs_read_xattr_id_table(sb, @@ -230,11 +232,13 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent) if (err != -ENOTSUPP) goto failed_mount; } + next_table = msblk->xattr_table; allocate_id_index_table: /* Allocate and read id index table */ msblk->id_table = squashfs_read_id_index_table(sb, - le64_to_cpu(sblk->id_table_start), le16_to_cpu(sblk->no_ids)); + le64_to_cpu(sblk->id_table_start), next_table, + le16_to_cpu(sblk->no_ids)); if (IS_ERR(msblk->id_table)) { ERROR("unable to read id index table\n"); err = PTR_ERR(msblk->id_table); |