lkml.org 
[lkml]   [2019]   [Dec]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[v3 PATCH] fscrypt: Allow modular crypto algorithms
On Sun, Dec 22, 2019 at 10:45:45AM -0600, Eric Biggers wrote:
>
> Okay, this approach looks fine. But can you rename the option to something more
> self-explanatory like FS_ENCRYPTION_ALGS, and add a comment? Like:
>
> # Filesystems supporting encryption must select this if FS_ENCRYPTION. This
> # allows the algorithms to be built as modules when all the filesystems are.

Sure, here's a third revision.

---8<---
The commit 643fa9612bf1 ("fscrypt: remove filesystem specific
build config option") removed modular support for fs/crypto. This
causes the Crypto API to be built-in whenever fscrypt is enabled.
This makes it very difficult for me to test modular builds of
the Crypto API without disabling fscrypt which is a pain.

As fscrypt is still evolving and it's developing new ties with the
fs layer, it's hard to build it as a module for now.

However, the actual algorithms are not required until a filesystem
is mounted. Therefore we can allow them to be built as modules.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/fs/crypto/Kconfig b/fs/crypto/Kconfig
index ff5a1746cbae..02df95b44331 100644
--- a/fs/crypto/Kconfig
+++ b/fs/crypto/Kconfig
@@ -2,13 +2,8 @@
config FS_ENCRYPTION
bool "FS Encryption (Per-file encryption)"
select CRYPTO
- select CRYPTO_AES
- select CRYPTO_CBC
- select CRYPTO_ECB
- select CRYPTO_XTS
- select CRYPTO_CTS
- select CRYPTO_SHA512
- select CRYPTO_HMAC
+ select CRYPTO_HASH
+ select CRYPTO_SKCIPHER
select KEYS
help
Enable encryption of files and directories. This
@@ -16,3 +11,15 @@ config FS_ENCRYPTION
efficient since it avoids caching the encrypted and
decrypted pages in the page cache. Currently Ext4,
F2FS and UBIFS make use of this feature.
+
+# Filesystems supporting encryption must select this if FS_ENCRYPTION. This
+# allows the algorithms to be built as modules when all the filesystems are.
+config FS_ENCRYPTION_ALGS
+ tristate
+ select CRYPTO_AES
+ select CRYPTO_CBC
+ select CRYPTO_CTS
+ select CRYPTO_ECB
+ select CRYPTO_HMAC
+ select CRYPTO_SHA512
+ select CRYPTO_XTS
diff --git a/fs/ext4/Kconfig b/fs/ext4/Kconfig
index ef42ab040905..930793456d3a 100644
--- a/fs/ext4/Kconfig
+++ b/fs/ext4/Kconfig
@@ -10,6 +10,7 @@ config EXT3_FS
select CRC16
select CRYPTO
select CRYPTO_CRC32C
+ select FS_ENCRYPTION_ALGS if FS_ENCRYPTION
help
This config option is here only for backward compatibility. ext3
filesystem is now handled by the ext4 driver.
diff --git a/fs/f2fs/Kconfig b/fs/f2fs/Kconfig
index 652fd2e2b23d..599fb9194c6a 100644
--- a/fs/f2fs/Kconfig
+++ b/fs/f2fs/Kconfig
@@ -6,6 +6,7 @@ config F2FS_FS
select CRYPTO
select CRYPTO_CRC32
select F2FS_FS_XATTR if FS_ENCRYPTION
+ select FS_ENCRYPTION_ALGS if FS_ENCRYPTION
help
F2FS is based on Log-structured File System (LFS), which supports
versatile "flash-friendly" features. The design has been focused on
diff --git a/fs/ubifs/Kconfig b/fs/ubifs/Kconfig
index 69932bcfa920..45d3d207fb99 100644
--- a/fs/ubifs/Kconfig
+++ b/fs/ubifs/Kconfig
@@ -12,6 +12,7 @@ config UBIFS_FS
select CRYPTO_ZSTD if UBIFS_FS_ZSTD
select CRYPTO_HASH_INFO
select UBIFS_FS_XATTR if FS_ENCRYPTION
+ select FS_ENCRYPTION_ALGS if FS_ENCRYPTION
depends on MTD_UBI
help
UBIFS is a file system for flash devices which works on top of UBI.
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
\
 
 \ /
  Last update: 2019-12-23 08:46    [W:0.052 / U:16.888 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site