summaryrefslogtreecommitdiffstats
path: root/Documentation
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2022-12-12 20:03:50 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2022-12-12 20:03:50 -0800
commit8129bac60f30936d2339535841db5b66d0520a67 (patch)
treebad8c543cb71450eaa46327075c540dd6dad9111 /Documentation
parentdeb9acc12250b13e40f7133f189d8a0891da53f3 (diff)
parent41952551acb405080726aa38a8a7ce317d9de4bb (diff)
downloadlinux-8129bac60f30936d2339535841db5b66d0520a67.tar.bz2
Merge tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt
Pull fscrypt updates from Eric Biggers: "This release adds SM4 encryption support, contributed by Tianjia Zhang. SM4 is a Chinese block cipher that is an alternative to AES. I recommend against using SM4, but (according to Tianjia) some people are being required to use it. Since SM4 has been turning up in many other places (crypto API, wireless, TLS, OpenSSL, ARMv8 CPUs, etc.), it hasn't been very controversial, and some people have to use it, I don't think it would be fair for me to reject this optional feature. Besides the above, there are a couple cleanups" * tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt: fscrypt: add additional documentation for SM4 support fscrypt: remove unused Speck definitions fscrypt: Add SM4 XTS/CTS symmetric algorithm support blk-crypto: Add support for SM4-XTS blk crypto mode fscrypt: add comment for fscrypt_valid_enc_modes_v1() fscrypt: pass super_block to fscrypt_put_master_key_activeref()
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/filesystems/fscrypt.rst7
1 files changed, 7 insertions, 0 deletions
diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst
index 5ba5817c17c2..ef183387da20 100644
--- a/Documentation/filesystems/fscrypt.rst
+++ b/Documentation/filesystems/fscrypt.rst
@@ -338,6 +338,7 @@ Currently, the following pairs of encryption modes are supported:
- AES-128-CBC for contents and AES-128-CTS-CBC for filenames
- Adiantum for both contents and filenames
- AES-256-XTS for contents and AES-256-HCTR2 for filenames (v2 policies only)
+- SM4-XTS for contents and SM4-CTS-CBC for filenames (v2 policies only)
If unsure, you should use the (AES-256-XTS, AES-256-CTS-CBC) pair.
@@ -369,6 +370,12 @@ CONFIG_CRYPTO_HCTR2 must be enabled. Also, fast implementations of XCTR and
POLYVAL should be enabled, e.g. CRYPTO_POLYVAL_ARM64_CE and
CRYPTO_AES_ARM64_CE_BLK for ARM64.
+SM4 is a Chinese block cipher that is an alternative to AES. It has
+not seen as much security review as AES, and it only has a 128-bit key
+size. It may be useful in cases where its use is mandated.
+Otherwise, it should not be used. For SM4 support to be available, it
+also needs to be enabled in the kernel crypto API.
+
New encryption modes can be added relatively easily, without changes
to individual filesystems. However, authenticated encryption (AE)
modes are not currently supported because of the difficulty of dealing