Commit 4adf8282 authored May 22, 2021 by Daniel Rosenberg Committed by Greg Kroah-Hartman Jun 24, 2022

BACKPORT: ext4: fix no-key deletion for encrypt+casefold



[ Upstream commit 63e7f1289389c8dff3c766f01ac1cc1c874b2ba5 ]

commit 471fbbea7ff7 ("ext4: handle casefolding with encryption") is
missing a few checks for the encryption key which are needed to
support deleting enrypted casefolded files when the key is not
present.

This bug made it impossible to delete encrypted+casefolded directories
without the encryption key, due to errors like:

    W         : EXT4-fs warning (device vdc): __ext4fs_dirhash:270: inode #49202: comm Binder:378_4: Siphash requires key

Repro steps in kvm-xfstests test appliance:
      mkfs.ext4 -F -E encoding=utf8 -O encrypt /dev/vdc
      mount /vdc
      mkdir /vdc/dir
      chattr +F /vdc/dir
      keyid=$(head -c 64 /dev/zero | xfs_io -c add_enckey /vdc | awk '{print $NF}')
      xfs_io -c "set_encpolicy $keyid" /vdc/dir
      for i in `seq 1 100`; do
          mkdir /vdc/dir/$i
      done
      xfs_io -c "rm_enckey $keyid" /vdc
      rm -rf /vdc/dir # fails with the bug

Fixes: 471fbbea7ff7 ("ext4: handle casefolding with encryption")
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Link: https://lore.kernel.org/r/20210522004132.2142563-1-drosen@google.com


Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Change-Id: Idbf9a46ebac38df02603c13206b41459762d2b8b

parent 7f4133a5

fs/ext4/namei.c

+4 −2

Original line number	Original line	Diff line number	Diff line
	@@ -1389,7 +1389,8 @@ int ext4_fname_setup_ci_filename(struct inode dir, const struct qstr iname,
	struct dx_hash_info *hinfo = &name->hinfo;		struct dx_hash_info *hinfo = &name->hinfo;
	int len;		int len;

	if (!needs_casefold(dir)) {		if (!IS_CASEFOLDED(dir) \|\| !dir->i_sb->s_encoding \|\|
			(IS_ENCRYPTED(dir) && !fscrypt_has_encryption_key(dir))) {
	cf_name->name = NULL;		cf_name->name = NULL;
	return 0;		return 0;
	}		}
	@@ -1440,7 +1441,8 @@ static bool ext4_match(struct inode *parent,
	#endif		#endif

	#ifdef CONFIG_UNICODE		#ifdef CONFIG_UNICODE
	if (needs_casefold(parent)) {		if (parent->i_sb->s_encoding && IS_CASEFOLDED(parent) &&
			(!IS_ENCRYPTED(parent) \|\| fscrypt_has_encryption_key(parent))) {
	if (fname->cf_name.name) {		if (fname->cf_name.name) {
	struct qstr cf = {.name = fname->cf_name.name,		struct qstr cf = {.name = fname->cf_name.name,
	.len = fname->cf_name.len};		.len = fname->cf_name.len};