From 226e6ea4df373b5f805e5acc81e2910d716ec77d Mon Sep 17 00:00:00 2001 From: Neil Brown Date: Sat, 9 Sep 2006 17:44:45 +0200 Subject: Have ext2 reject file handles with bad inode numbers early. This prevents bad inode numbers from triggering errors in ext2_get_inode. Signed-off-by: Neil Brown Signed-off-by: Adrian Bunk --- fs/ext2/super.c | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) (limited to 'fs') diff --git a/fs/ext2/super.c b/fs/ext2/super.c index cb6f9bd658de..a8fbef73ea99 100644 --- a/fs/ext2/super.c +++ b/fs/ext2/super.c @@ -253,6 +253,46 @@ static struct super_operations ext2_sops = { #endif }; +static struct dentry *ext2_get_dentry(struct super_block *sb, void *vobjp) +{ + __u32 *objp = vobjp; + unsigned long ino = objp[0]; + __u32 generation = objp[1]; + struct inode *inode; + struct dentry *result; + + if (ino != EXT2_ROOT_INO && ino < EXT2_FIRST_INO(sb)) + return ERR_PTR(-ESTALE); + if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count)) + return ERR_PTR(-ESTALE); + + /* iget isn't really right if the inode is currently unallocated!! + * ext2_read_inode currently does appropriate checks, but + * it might be "neater" to call ext2_get_inode first and check + * if the inode is valid..... + */ + inode = iget(sb, ino); + if (inode == NULL) + return ERR_PTR(-ENOMEM); + if (is_bad_inode(inode) + || (generation && inode->i_generation != generation) + ) { + /* we didn't find the right inode.. */ + iput(inode); + return ERR_PTR(-ESTALE); + } + /* now to find a dentry. + * If possible, get a well-connected one + */ + result = d_alloc_anon(inode); + if (!result) { + iput(inode); + return ERR_PTR(-ENOMEM); + } + return result; +} + + /* Yes, most of these are left as NULL!! * A NULL value implies the default, which works with ext2-like file * systems, but can be improved upon. @@ -261,6 +301,7 @@ static struct super_operations ext2_sops = { struct dentry *ext2_get_parent(struct dentry *child); static struct export_operations ext2_export_ops = { .get_parent = ext2_get_parent, + .get_dentry = ext2_get_dentry, }; static unsigned long get_sb_block(void **data) -- cgit v1.2.3