linux-stable.git/fs/crypto, branch v5.10.78 Linux kernel stable tree fscrypt: add fscrypt_symlink_getattr() for computing st_size 2021-09-08T06:48:59+00:00 Eric Biggers ebiggers@google.com 2021-09-01T16:27:18+00:00 b8c298cf57dcb5b18855f11437199fd0eb1ea388 commit d18760560593e5af921f51a8c9b64b6109d634c2 upstream. Add a helper function fscrypt_symlink_getattr() which will be called from the various filesystems' ->getattr() methods to read and decrypt the target of encrypted symlinks in order to report the correct st_size. Detailed explanation: As required by POSIX and as documented in various man pages, st_size for a symlink is supposed to be the length of the symlink target. Unfortunately, st_size has always been wrong for encrypted symlinks because st_size is populated from i_size from disk, which intentionally contains the length of the encrypted symlink target. That's slightly greater than the length of the decrypted symlink target (which is the symlink target that userspace usually sees), and usually won't match the length of the no-key encoded symlink target either. This hadn't been fixed yet because reporting the correct st_size would require reading the symlink target from disk and decrypting or encoding it, which historically has been considered too heavyweight to do in ->getattr(). Also historically, the wrong st_size had only broken a test (LTP lstat03) and there were no known complaints from real users. (This is probably because the st_size of symlinks isn't used too often, and when it is, typically it's for a hint for what buffer size to pass to readlink() -- which a slightly-too-large size still works for.) However, a couple things have changed now. First, there have recently been complaints about the current behavior from real users: - Breakage in rpmbuild: https://github.com/rpm-software-management/rpm/issues/1682 https://github.com/google/fscrypt/issues/305 - Breakage in toybox cpio: https://www.mail-archive.com/toybox@lists.landley.net/msg07193.html - Breakage in libgit2: https://issuetracker.google.com/issues/189629152 (on Android public issue tracker, requires login) Second, we now cache decrypted symlink targets in ->i_link. Therefore, taking the performance hit of reading and decrypting the symlink target in ->getattr() wouldn't be as big a deal as it used to be, since usually it will just save having to do the same thing later. Also note that eCryptfs ended up having to read and decrypt symlink targets in ->getattr() as well, to fix this same issue; see commit 3a60a1686f0d ("eCryptfs: Decrypt symlink target for stat size"). So, let's just bite the bullet, and read and decrypt the symlink target in ->getattr() in order to report the correct st_size. Add a function fscrypt_symlink_getattr() which the filesystems will call to do this. (Alternatively, we could store the decrypted size of symlinks on-disk. But there isn't a great place to do so, and encryption is meant to hide the original size to some extent; that property would be lost.) Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210702065350.209646-2-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit d18760560593e5af921f51a8c9b64b6109d634c2 upstream.

Add a helper function fscrypt_symlink_getattr() which will be called
from the various filesystems' ->getattr() methods to read and decrypt
the target of encrypted symlinks in order to report the correct st_size.

Detailed explanation:

As required by POSIX and as documented in various man pages, st_size for
a symlink is supposed to be the length of the symlink target.
Unfortunately, st_size has always been wrong for encrypted symlinks
because st_size is populated from i_size from disk, which intentionally
contains the length of the encrypted symlink target.  That's slightly
greater than the length of the decrypted symlink target (which is the
symlink target that userspace usually sees), and usually won't match the
length of the no-key encoded symlink target either.

This hadn't been fixed yet because reporting the correct st_size would
require reading the symlink target from disk and decrypting or encoding
it, which historically has been considered too heavyweight to do in
->getattr().  Also historically, the wrong st_size had only broken a
test (LTP lstat03) and there were no known complaints from real users.
(This is probably because the st_size of symlinks isn't used too often,
and when it is, typically it's for a hint for what buffer size to pass
to readlink() -- which a slightly-too-large size still works for.)

However, a couple things have changed now.  First, there have recently
been complaints about the current behavior from real users:

- Breakage in rpmbuild:
  https://github.com/rpm-software-management/rpm/issues/1682
  https://github.com/google/fscrypt/issues/305

- Breakage in toybox cpio:
  https://www.mail-archive.com/toybox@lists.landley.net/msg07193.html

- Breakage in libgit2: https://issuetracker.google.com/issues/189629152
  (on Android public issue tracker, requires login)

Second, we now cache decrypted symlink targets in ->i_link.  Therefore,
taking the performance hit of reading and decrypting the symlink target
in ->getattr() wouldn't be as big a deal as it used to be, since usually
it will just save having to do the same thing later.

Also note that eCryptfs ended up having to read and decrypt symlink
targets in ->getattr() as well, to fix this same issue; see
commit 3a60a1686f0d ("eCryptfs: Decrypt symlink target for stat size").

So, let's just bite the bullet, and read and decrypt the symlink target
in ->getattr() in order to report the correct st_size.  Add a function
fscrypt_symlink_getattr() which the filesystems will call to do this.

(Alternatively, we could store the decrypted size of symlinks on-disk.
But there isn't a great place to do so, and encryption is meant to hide
the original size to some extent; that property would be lost.)

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210702065350.209646-2-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fscrypt: fix derivation of SipHash keys on big endian CPUs 2021-07-14T14:56:53+00:00 Eric Biggers ebiggers@google.com 2021-06-05T07:50:33+00:00 b5a2b5b64237b9d1bdb002ff96b5f3b8e142b2b2 commit 2fc2b430f559fdf32d5d1dd5ceaa40e12fb77bdf upstream. Typically, the cryptographic APIs that fscrypt uses take keys as byte arrays, which avoids endianness issues. However, siphash_key_t is an exception. It is defined as 'u64 key[2];', i.e. the 128-bit key is expected to be given directly as two 64-bit words in CPU endianness. fscrypt_derive_dirhash_key() and fscrypt_setup_iv_ino_lblk_32_key() forgot to take this into account. Therefore, the SipHash keys used to index encrypted+casefolded directories differ on big endian vs. little endian platforms, as do the SipHash keys used to hash inode numbers for IV_INO_LBLK_32-encrypted directories. This makes such directories non-portable between these platforms. Fix this by always using the little endian order. This is a breaking change for big endian platforms, but this should be fine in practice since these features (encrypt+casefold support, and the IV_INO_LBLK_32 flag) aren't known to actually be used on any big endian platforms yet. Fixes: aa408f835d02 ("fscrypt: derive dirhash key for casefolded directories") Fixes: e3b1078bedd3 ("fscrypt: add support for IV_INO_LBLK_32 policies") Cc: <stable@vger.kernel.org> # v5.6+ Link: https://lore.kernel.org/r/20210605075033.54424-1-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 2fc2b430f559fdf32d5d1dd5ceaa40e12fb77bdf upstream.

Typically, the cryptographic APIs that fscrypt uses take keys as byte
arrays, which avoids endianness issues.  However, siphash_key_t is an
exception.  It is defined as 'u64 key[2];', i.e. the 128-bit key is
expected to be given directly as two 64-bit words in CPU endianness.

fscrypt_derive_dirhash_key() and fscrypt_setup_iv_ino_lblk_32_key()
forgot to take this into account.  Therefore, the SipHash keys used to
index encrypted+casefolded directories differ on big endian vs. little
endian platforms, as do the SipHash keys used to hash inode numbers for
IV_INO_LBLK_32-encrypted directories.  This makes such directories
non-portable between these platforms.

Fix this by always using the little endian order.  This is a breaking
change for big endian platforms, but this should be fine in practice
since these features (encrypt+casefold support, and the IV_INO_LBLK_32
flag) aren't known to actually be used on any big endian platforms yet.

Fixes: aa408f835d02 ("fscrypt: derive dirhash key for casefolded directories")
Fixes: e3b1078bedd3 ("fscrypt: add support for IV_INO_LBLK_32 policies")
Cc: <stable@vger.kernel.org> # v5.6+
Link: https://lore.kernel.org/r/20210605075033.54424-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fscrypt: don't ignore minor_hash when hash is 0 2021-07-14T14:56:53+00:00 Eric Biggers ebiggers@google.com 2021-05-27T23:52:36+00:00 089057af71d7456040aaf5e708d70d1537154f96 commit 77f30bfcfcf484da7208affd6a9e63406420bf91 upstream. When initializing a no-key name, fscrypt_fname_disk_to_usr() sets the minor_hash to 0 if the (major) hash is 0. This doesn't make sense because 0 is a valid hash code, so we shouldn't ignore the filesystem-provided minor_hash in that case. Fix this by removing the special case for 'hash == 0'. This is an old bug that appears to have originated when the encryption code in ext4 and f2fs was moved into fs/crypto/. The original ext4 and f2fs code passed the hash by pointer instead of by value. So 'if (hash)' actually made sense then, as it was checking whether a pointer was NULL. But now the hashes are passed by value, and filesystems just pass 0 for any hashes they don't have. There is no need to handle this any differently from the hashes actually being 0. It is difficult to reproduce this bug, as it only made a difference in the case where a filename's 32-bit major hash happened to be 0. However, it probably had the largest chance of causing problems on ubifs, since ubifs uses minor_hash to do lookups of no-key names, in addition to using it as a readdir cookie. ext4 only uses minor_hash as a readdir cookie, and f2fs doesn't use minor_hash at all. Fixes: 0b81d0779072 ("fs crypto: move per-file encryption from f2fs tree to fs/crypto") Cc: <stable@vger.kernel.org> # v4.6+ Link: https://lore.kernel.org/r/20210527235236.2376556-1-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 77f30bfcfcf484da7208affd6a9e63406420bf91 upstream.

When initializing a no-key name, fscrypt_fname_disk_to_usr() sets the
minor_hash to 0 if the (major) hash is 0.

This doesn't make sense because 0 is a valid hash code, so we shouldn't
ignore the filesystem-provided minor_hash in that case.  Fix this by
removing the special case for 'hash == 0'.

This is an old bug that appears to have originated when the encryption
code in ext4 and f2fs was moved into fs/crypto/.  The original ext4 and
f2fs code passed the hash by pointer instead of by value.  So
'if (hash)' actually made sense then, as it was checking whether a
pointer was NULL.  But now the hashes are passed by value, and
filesystems just pass 0 for any hashes they don't have.  There is no
need to handle this any differently from the hashes actually being 0.

It is difficult to reproduce this bug, as it only made a difference in
the case where a filename's 32-bit major hash happened to be 0.
However, it probably had the largest chance of causing problems on
ubifs, since ubifs uses minor_hash to do lookups of no-key names, in
addition to using it as a readdir cookie.  ext4 only uses minor_hash as
a readdir cookie, and f2fs doesn't use minor_hash at all.

Fixes: 0b81d0779072 ("fs crypto: move per-file encryption from f2fs tree to fs/crypto")
Cc: <stable@vger.kernel.org> # v4.6+
Link: https://lore.kernel.org/r/20210527235236.2376556-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fscrypt: add fscrypt_is_nokey_name() 2020-12-26T15:02:43+00:00 Eric Biggers ebiggers@google.com 2020-11-18T07:56:05+00:00 2da473e59e11a934bda13dae2cbdbe84cd32d758 commit 159e1de201b6fca10bfec50405a3b53a561096a8 upstream. It's possible to create a duplicate filename in an encrypted directory by creating a file concurrently with adding the encryption key. Specifically, sys_open(O_CREAT) (or sys_mkdir(), sys_mknod(), or sys_symlink()) can lookup the target filename while the directory's encryption key hasn't been added yet, resulting in a negative no-key dentry. The VFS then calls ->create() (or ->mkdir(), ->mknod(), or ->symlink()) because the dentry is negative. Normally, ->create() would return -ENOKEY due to the directory's key being unavailable. However, if the key was added between the dentry lookup and ->create(), then the filesystem will go ahead and try to create the file. If the target filename happens to already exist as a normal name (not a no-key name), a duplicate filename may be added to the directory. In order to fix this, we need to fix the filesystems to prevent ->create(), ->mkdir(), ->mknod(), and ->symlink() on no-key names. (->rename() and ->link() need it too, but those are already handled correctly by fscrypt_prepare_rename() and fscrypt_prepare_link().) In preparation for this, add a helper function fscrypt_is_nokey_name() that filesystems can use to do this check. Use this helper function for the existing checks that fs/crypto/ does for rename and link. Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20201118075609.120337-2-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 159e1de201b6fca10bfec50405a3b53a561096a8 upstream.

It's possible to create a duplicate filename in an encrypted directory
by creating a file concurrently with adding the encryption key.

Specifically, sys_open(O_CREAT) (or sys_mkdir(), sys_mknod(), or
sys_symlink()) can lookup the target filename while the directory's
encryption key hasn't been added yet, resulting in a negative no-key
dentry.  The VFS then calls ->create() (or ->mkdir(), ->mknod(), or
->symlink()) because the dentry is negative.  Normally, ->create() would
return -ENOKEY due to the directory's key being unavailable.  However,
if the key was added between the dentry lookup and ->create(), then the
filesystem will go ahead and try to create the file.

If the target filename happens to already exist as a normal name (not a
no-key name), a duplicate filename may be added to the directory.

In order to fix this, we need to fix the filesystems to prevent
->create(), ->mkdir(), ->mknod(), and ->symlink() on no-key names.
(->rename() and ->link() need it too, but those are already handled
correctly by fscrypt_prepare_rename() and fscrypt_prepare_link().)

In preparation for this, add a helper function fscrypt_is_nokey_name()
that filesystems can use to do this check.  Use this helper function for
the existing checks that fs/crypto/ does for rename and link.

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20201118075609.120337-2-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fscrypt: remove kernel-internal constants from UAPI header 2020-12-26T15:02:43+00:00 Eric Biggers ebiggers@google.com 2020-10-24T00:51:31+00:00 3b7c17a81426289ab3509af8a5dfe4d0d7926933 commit 3ceb6543e9cf6ed87cc1fbc6f23ca2db903564cd upstream. There isn't really any valid reason to use __FSCRYPT_MODE_MAX or FSCRYPT_POLICY_FLAGS_VALID in a userspace program. These constants are only meant to be used by the kernel internally, and they are defined in the UAPI header next to the mode numbers and flags only so that kernel developers don't forget to update them when adding new modes or flags. In https://lkml.kernel.org/r/20201005074133.1958633-2-satyat@google.com there was an example of someone wanting to use __FSCRYPT_MODE_MAX in a user program, and it was wrong because the program would have broken if __FSCRYPT_MODE_MAX were ever increased. So having this definition available is harmful. FSCRYPT_POLICY_FLAGS_VALID has the same problem. So, remove these definitions from the UAPI header. Replace FSCRYPT_POLICY_FLAGS_VALID with just listing the valid flags explicitly in the one kernel function that needs it. Move __FSCRYPT_MODE_MAX to fscrypt_private.h, remove the double underscores (which were only present to discourage use by userspace), and add a BUILD_BUG_ON() and comments to (hopefully) ensure it is kept in sync. Keep the old name FS_POLICY_FLAGS_VALID, since it's been around for longer and there's a greater chance that removing it would break source compatibility with some program. Indeed, mtd-utils is using it in an #ifdef, and removing it would introduce compiler warnings (about FS_POLICY_FLAGS_PAD_* being redefined) into the mtd-utils build. However, reduce its value to 0x07 so that it only includes the flags with old names (the ones present before Linux 5.4), and try to make it clear that it's now "frozen" and no new flags should be added to it. Fixes: 2336d0deb2d4 ("fscrypt: use FSCRYPT_ prefix for uapi constants") Cc: <stable@vger.kernel.org> # v5.4+ Link: https://lore.kernel.org/r/20201024005132.495952-1-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 3ceb6543e9cf6ed87cc1fbc6f23ca2db903564cd upstream.

There isn't really any valid reason to use __FSCRYPT_MODE_MAX or
FSCRYPT_POLICY_FLAGS_VALID in a userspace program.  These constants are
only meant to be used by the kernel internally, and they are defined in
the UAPI header next to the mode numbers and flags only so that kernel
developers don't forget to update them when adding new modes or flags.

In https://lkml.kernel.org/r/20201005074133.1958633-2-satyat@google.com
there was an example of someone wanting to use __FSCRYPT_MODE_MAX in a
user program, and it was wrong because the program would have broken if
__FSCRYPT_MODE_MAX were ever increased.  So having this definition
available is harmful.  FSCRYPT_POLICY_FLAGS_VALID has the same problem.

So, remove these definitions from the UAPI header.  Replace
FSCRYPT_POLICY_FLAGS_VALID with just listing the valid flags explicitly
in the one kernel function that needs it.  Move __FSCRYPT_MODE_MAX to
fscrypt_private.h, remove the double underscores (which were only
present to discourage use by userspace), and add a BUILD_BUG_ON() and
comments to (hopefully) ensure it is kept in sync.

Keep the old name FS_POLICY_FLAGS_VALID, since it's been around for
longer and there's a greater chance that removing it would break source
compatibility with some program.  Indeed, mtd-utils is using it in
an #ifdef, and removing it would introduce compiler warnings (about
FS_POLICY_FLAGS_PAD_* being redefined) into the mtd-utils build.
However, reduce its value to 0x07 so that it only includes the flags
with old names (the ones present before Linux 5.4), and try to make it
clear that it's now "frozen" and no new flags should be added to it.

Fixes: 2336d0deb2d4 ("fscrypt: use FSCRYPT_ prefix for uapi constants")
Cc: <stable@vger.kernel.org> # v5.4+
Link: https://lore.kernel.org/r/20201024005132.495952-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fscrypt: fix inline encryption not used on new files 2020-11-12T04:59:07+00:00 Eric Biggers ebiggers@google.com 2020-11-11T01:52:24+00:00 d19d8d345eecd9247cbe6cbf27aef271bd88aba7 The new helper function fscrypt_prepare_new_inode() runs before S_ENCRYPTED has been set on the new inode. This accidentally made fscrypt_select_encryption_impl() never enable inline encryption on newly created files, due to its use of fscrypt_needs_contents_encryption() which only returns true when S_ENCRYPTED is set. Fix this by using S_ISREG() directly instead of fscrypt_needs_contents_encryption(), analogous to what select_encryption_mode() does. I didn't notice this earlier because by design, the user-visible behavior is the same (other than performance, potentially) regardless of whether inline encryption is used or not. Fixes: a992b20cd4ee ("fscrypt: add fscrypt_prepare_new_inode() and fscrypt_set_context()") Reviewed-by: Satya Tangirala <satyat@google.com> Link: https://lore.kernel.org/r/20201111015224.303073-1-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> 
The new helper function fscrypt_prepare_new_inode() runs before
S_ENCRYPTED has been set on the new inode.  This accidentally made
fscrypt_select_encryption_impl() never enable inline encryption on newly
created files, due to its use of fscrypt_needs_contents_encryption()
which only returns true when S_ENCRYPTED is set.

Fix this by using S_ISREG() directly instead of
fscrypt_needs_contents_encryption(), analogous to what
select_encryption_mode() does.

I didn't notice this earlier because by design, the user-visible
behavior is the same (other than performance, potentially) regardless of
whether inline encryption is used or not.

Fixes: a992b20cd4ee ("fscrypt: add fscrypt_prepare_new_inode() and fscrypt_set_context()")
Reviewed-by: Satya Tangirala <satyat@google.com>
Link: https://lore.kernel.org/r/20201111015224.303073-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
fscrypt: remove reachable WARN in fscrypt_setup_iv_ino_lblk_32_key() 2020-11-06T17:48:55+00:00 Eric Biggers ebiggers@google.com 2020-10-31T00:45:56+00:00 92cfcd030e4b1de11a6b1edb0840e55c26332d31 I_CREATING isn't actually set until the inode has been assigned an inode number and inserted into the inode hash table. So the WARN_ON() in fscrypt_setup_iv_ino_lblk_32_key() is wrong, and it can trigger when creating an encrypted file on ext4. Remove it. This was sometimes causing xfstest generic/602 to fail on ext4. I didn't notice it before because due to a separate oversight, new inodes that haven't been assigned an inode number yet don't necessarily have i_ino == 0 as I had thought, so by chance I never saw the test fail. Fixes: a992b20cd4ee ("fscrypt: add fscrypt_prepare_new_inode() and fscrypt_set_context()") Reported-by: Theodore Y. Ts'o <tytso@mit.edu> Link: https://lore.kernel.org/r/20201031004556.87862-1-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> 
I_CREATING isn't actually set until the inode has been assigned an inode
number and inserted into the inode hash table.  So the WARN_ON() in
fscrypt_setup_iv_ino_lblk_32_key() is wrong, and it can trigger when
creating an encrypted file on ext4.  Remove it.

This was sometimes causing xfstest generic/602 to fail on ext4.  I
didn't notice it before because due to a separate oversight, new inodes
that haven't been assigned an inode number yet don't necessarily have
i_ino == 0 as I had thought, so by chance I never saw the test fail.

Fixes: a992b20cd4ee ("fscrypt: add fscrypt_prepare_new_inode() and fscrypt_set_context()")
Reported-by: Theodore Y. Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20201031004556.87862-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
fscrypt: export fscrypt_d_revalidate() 2020-09-28T21:44:51+00:00 Eric Biggers ebiggers@google.com 2020-09-24T05:47:21+00:00 5b2a828b98ec1872799b1b4d82113c76a12d594f Dentries that represent no-key names must have a dentry_operations that includes fscrypt_d_revalidate(). Currently, this is handled by fscrypt_prepare_lookup() installing fscrypt_d_ops. However, ceph support for encryption (https://lore.kernel.org/r/20200914191707.380444-1-jlayton@kernel.org) can't use fscrypt_d_ops, since ceph already has its own dentry_operations. Similarly, ext4 and f2fs support for directories that are both encrypted and casefolded (https://lore.kernel.org/r/20200923010151.69506-1-drosen@google.com) can't use fscrypt_d_ops either, since casefolding requires some dentry operations too. To satisfy both users, we need to move the responsibility of installing the dentry_operations to filesystems. In preparation for this, export fscrypt_d_revalidate() and give it a !CONFIG_FS_ENCRYPTION stub. Reviewed-by: Jeff Layton <jlayton@kernel.org> Link: https://lore.kernel.org/r/20200924054721.187797-1-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> 
Dentries that represent no-key names must have a dentry_operations that
includes fscrypt_d_revalidate().  Currently, this is handled by
fscrypt_prepare_lookup() installing fscrypt_d_ops.

However, ceph support for encryption
(https://lore.kernel.org/r/20200914191707.380444-1-jlayton@kernel.org)
can't use fscrypt_d_ops, since ceph already has its own
dentry_operations.

Similarly, ext4 and f2fs support for directories that are both encrypted
and casefolded
(https://lore.kernel.org/r/20200923010151.69506-1-drosen@google.com)
can't use fscrypt_d_ops either, since casefolding requires some dentry
operations too.

To satisfy both users, we need to move the responsibility of installing
the dentry_operations to filesystems.

In preparation for this, export fscrypt_d_revalidate() and give it a
!CONFIG_FS_ENCRYPTION stub.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20200924054721.187797-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
fscrypt: rename DCACHE_ENCRYPTED_NAME to DCACHE_NOKEY_NAME 2020-09-24T04:29:49+00:00 Eric Biggers ebiggers@google.com 2020-09-24T04:26:24+00:00 501e43fbea468fa93c1dff0ee744e69303ef5a43 Originally we used the term "encrypted name" or "ciphertext name" to mean the encoded filename that is shown when an encrypted directory is listed without its key. But these terms are ambiguous since they also mean the filename stored on-disk. "Encrypted name" is especially ambiguous since it could also be understood to mean "this filename is encrypted on-disk", similar to "encrypted file". So we've started calling these encoded names "no-key names" instead. Therefore, rename DCACHE_ENCRYPTED_NAME to DCACHE_NOKEY_NAME to avoid confusion about what this flag means. Link: https://lore.kernel.org/r/20200924042624.98439-3-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> 
Originally we used the term "encrypted name" or "ciphertext name" to
mean the encoded filename that is shown when an encrypted directory is
listed without its key.  But these terms are ambiguous since they also
mean the filename stored on-disk.  "Encrypted name" is especially
ambiguous since it could also be understood to mean "this filename is
encrypted on-disk", similar to "encrypted file".

So we've started calling these encoded names "no-key names" instead.

Therefore, rename DCACHE_ENCRYPTED_NAME to DCACHE_NOKEY_NAME to avoid
confusion about what this flag means.

Link: https://lore.kernel.org/r/20200924042624.98439-3-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
fscrypt: don't call no-key names "ciphertext names" 2020-09-24T04:29:49+00:00 Eric Biggers ebiggers@google.com 2020-09-24T04:26:23+00:00 70fb2612aab62d47e03f82eaa7384a8d30ca175d Currently we're using the term "ciphertext name" ambiguously because it can mean either the actual ciphertext filename, or the encoded filename that is shown when an encrypted directory is listed without its key. The latter we're now usually calling the "no-key name"; and while it's derived from the ciphertext name, it's not the same thing. To avoid this ambiguity, rename fscrypt_name::is_ciphertext_name to fscrypt_name::is_nokey_name, and update comments that say "ciphertext name" (or "encrypted name") to say "no-key name" instead when warranted. Link: https://lore.kernel.org/r/20200924042624.98439-2-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> 
Currently we're using the term "ciphertext name" ambiguously because it
can mean either the actual ciphertext filename, or the encoded filename
that is shown when an encrypted directory is listed without its key.
The latter we're now usually calling the "no-key name"; and while it's
derived from the ciphertext name, it's not the same thing.

To avoid this ambiguity, rename fscrypt_name::is_ciphertext_name to
fscrypt_name::is_nokey_name, and update comments that say "ciphertext
name" (or "encrypted name") to say "no-key name" instead when warranted.

Link: https://lore.kernel.org/r/20200924042624.98439-2-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>