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| author | Eric Biggers <ebiggers@google.com> | 2021-10-26 04:10:42 +0200 |
|---|---|---|
| committer | Eric Biggers <ebiggers@google.com> | 2021-10-26 04:11:50 +0200 |
| commit | b7e072f9b77f4c516df96e0c22ec09f8b2e76ba1 (patch) | |
| tree | 39facb75c31a17b894e1c74ecacee8eb899e2fae /fs/crypto | |
| parent | fscrypt: allow 256-bit master keys with AES-256-XTS (diff) | |
| download | linux-b7e072f9b77f4c516df96e0c22ec09f8b2e76ba1.tar.xz linux-b7e072f9b77f4c516df96e0c22ec09f8b2e76ba1.zip | |
fscrypt: improve a few comments
Improve a few comments. These were extracted from the patch
"fscrypt: add support for hardware-wrapped keys"
(https://lore.kernel.org/r/20211021181608.54127-4-ebiggers@kernel.org).
Link: https://lore.kernel.org/r/20211026021042.6581-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Diffstat (limited to 'fs/crypto')
| -rw-r--r-- | fs/crypto/fscrypt_private.h | 11 | ||||
| -rw-r--r-- | fs/crypto/keysetup.c | 5 |
2 files changed, 13 insertions, 3 deletions
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index cb25ef0cdf1f..5b0a9e6478b5 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -20,6 +20,11 @@ #define FSCRYPT_FILE_NONCE_SIZE 16 +/* + * Minimum size of an fscrypt master key. Note: a longer key will be required + * if ciphers with a 256-bit security strength are used. This is just the + * absolute minimum, which applies when only 128-bit encryption is used. + */ #define FSCRYPT_MIN_KEY_SIZE 16 #define FSCRYPT_CONTEXT_V1 1 @@ -413,7 +418,11 @@ struct fscrypt_master_key_secret { */ struct fscrypt_hkdf hkdf; - /* Size of the raw key in bytes. Set even if ->raw isn't set. */ + /* + * Size of the raw key in bytes. This remains set even if ->raw was + * zeroized due to no longer being needed. I.e. we still remember the + * size of the key even if we don't need to remember the key itself. + */ u32 size; /* For v1 policy keys: the raw key. Wiped for v2 policy keys. */ diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index 89cd533a88bf..eede186b04ce 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -122,8 +122,9 @@ err_free_tfm: /* * Prepare the crypto transform object or blk-crypto key in @prep_key, given the - * raw key, encryption mode, and flag indicating which encryption implementation - * (fs-layer or blk-crypto) will be used. + * raw key, encryption mode (@ci->ci_mode), flag indicating which encryption + * implementation (fs-layer or blk-crypto) will be used (@ci->ci_inlinecrypt), + * and IV generation method (@ci->ci_policy.flags). */ int fscrypt_prepare_key(struct fscrypt_prepared_key *prep_key, const u8 *raw_key, const struct fscrypt_info *ci) |