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authorNathan Huckleberry <nhuck@google.com>2022-05-20 21:15:01 +0300
committerHerbert Xu <herbert@gondor.apana.org.au>2022-06-10 11:40:18 +0300
commit6b2a51ff03bf0c54cbc699ee85a9a49eb203ebfc (patch)
tree8110bcd6c9baaedb35a031ae2529b2e47fa74269 /fs/crypto/fscrypt_private.h
parent9d2c0b485c46c7c5f781067c60300def5d1365cb (diff)
downloadlinux-6b2a51ff03bf0c54cbc699ee85a9a49eb203ebfc.tar.xz
fscrypt: Add HCTR2 support for filename encryption
HCTR2 is a tweakable, length-preserving encryption mode that is intended for use on CPUs with dedicated crypto instructions. HCTR2 has the property that a bitflip in the plaintext changes the entire ciphertext. This property fixes a known weakness with filename encryption: when two filenames in the same directory share a prefix of >= 16 bytes, with AES-CTS-CBC their encrypted filenames share a common substring, leaking information. HCTR2 does not have this problem. More information on HCTR2 can be found here: "Length-preserving encryption with HCTR2": https://eprint.iacr.org/2021/1441.pdf Signed-off-by: Nathan Huckleberry <nhuck@google.com> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'fs/crypto/fscrypt_private.h')
-rw-r--r--fs/crypto/fscrypt_private.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index 6b4c8094cc7b..f5be777d8279 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -31,7 +31,7 @@
#define FSCRYPT_CONTEXT_V2 2
/* Keep this in sync with include/uapi/linux/fscrypt.h */
-#define FSCRYPT_MODE_MAX FSCRYPT_MODE_ADIANTUM
+#define FSCRYPT_MODE_MAX FSCRYPT_MODE_AES_256_HCTR2
struct fscrypt_context_v1 {
u8 version; /* FSCRYPT_CONTEXT_V1 */