On Thu 06-02-25 10:24:19, Theodore Ts'o wrote:
> On Thu, Feb 06, 2025 at 10:44:55AM +0100, Jan Kara wrote:
> > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> > index 7c54ae5fcbd4..64e280fed911 100644
> > --- a/fs/ext4/inode.c
> > +++ b/fs/ext4/inode.c
> > @@ -5007,8 +5007,16 @@ struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
> > inode->i_op = &ext4_encrypted_symlink_inode_operations;
> > } else if (ext4_inode_is_fast_symlink(inode)) {
> > inode->i_op = &ext4_fast_symlink_inode_operations;
> > - nd_terminate_link(ei->i_data, inode->i_size,
> > - sizeof(ei->i_data) - 1);
> > + if (inode->i_size == 0 ||
> > + inode->i_size >= sizeof(ei->i_data) ||
> > + strnlen((char *)ei->i_data, inode->i_size + 1) !=
> > + inode->i_size) {
> > + ext4_error_inode(inode, function, line, 0,
> > + "invalid fast symlink length %llu",
> > + (unsigned long long)inode->i_size);
> > + ret = -EFSCORRUPTED;
> > + goto bad_inode;
> > + }
> > inode_set_cached_link(inode, (char *)ei->i_data,
> > inode->i_size);
>
>
> I don't think this will do the right thing if the fast symlink is
> encrypted. See ext4_encrypted_get_link() in fs/ext4/symlink.c in the
> kernel sources, and also look at how e2fsck_pass1_check_symlink()
> handles checking the size of an encrypted, fast symlink.
Thanks for having a look but as Eric writes, there's:
if (IS_ENCRYPTED(inode)) {
inode->i_op = &ext4_encrypted_symlink_inode_operations;
} else if (ext4_inode_is_fast_symlink(inode)) {
just above the context of this hunk so I *think* encrypted symlinks cannot
get into this code?
Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
