From: NeilBrown Inodes earlier than the 'first' inode (e.g. journal, resize) should be rejected early - except the root inode. Also inode numbers that are too big should be rejected early. Signed-off-by: Neil Brown Signed-off-by: Andrew Morton --- fs/ext3/super.c | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) diff -puN fs/ext3/super.c~knfsd-make-ext3-reject-filehandles-referring-to-invalid-inode-numbers fs/ext3/super.c --- a/fs/ext3/super.c~knfsd-make-ext3-reject-filehandles-referring-to-invalid-inode-numbers +++ a/fs/ext3/super.c @@ -554,6 +554,48 @@ static int ext3_show_options(struct seq_ return 0; } + +static struct dentry *ext3_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 != EXT3_ROOT_INO && ino < EXT3_FIRST_INO(sb)) + return ERR_PTR(-ESTALE); + if (ino > le32_to_cpu(EXT3_SB(sb)->s_es->s_inodes_count)) + return ERR_PTR(-ESTALE); + + /* iget isn't really right if the inode is currently unallocated!! + * + * ext3_read_inode will return a bad_inode if the inode had been deleted. + * so we should be safe. + * + * Currently we don't know the generation for parent directory, so + * a generation of 0 means "accept any" + */ + inode = iget(sb, ino); + if (inode == NULL) + return ERR_PTR(-ENOMEM); + if (is_bad_inode(inode) + || (generation && inode->i_generation != generation) + ) { + 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; +} + #ifdef CONFIG_QUOTA #define QTYPE2NAME(t) ((t)==USRQUOTA?"user":"group") #define QTYPE2MOPT(on, t) ((t)==USRQUOTA?((on)##USRJQUOTA):((on)##GRPJQUOTA)) @@ -622,6 +664,7 @@ static struct super_operations ext3_sops static struct export_operations ext3_export_ops = { .get_parent = ext3_get_parent, + .get_dentry = ext3_get_dentry, }; enum { _