diff options
Diffstat (limited to 'fs/crypto/keysetup.c')
| -rw-r--r-- | fs/crypto/keysetup.c | 54 |
1 files changed, 40 insertions, 14 deletions
diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index 96074054bdbc..74d61d827d91 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -174,10 +174,24 @@ done: return 0; } +int fscrypt_derive_dirhash_key(struct fscrypt_info *ci, + const struct fscrypt_master_key *mk) +{ + int err; + + err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf, HKDF_CONTEXT_DIRHASH_KEY, + ci->ci_nonce, FS_KEY_DERIVATION_NONCE_SIZE, + (u8 *)&ci->ci_dirhash_key, + sizeof(ci->ci_dirhash_key)); + if (err) + return err; + ci->ci_dirhash_key_initialized = true; + return 0; +} + static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci, struct fscrypt_master_key *mk) { - u8 derived_key[FSCRYPT_MAX_KEY_SIZE]; int err; if (ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) { @@ -189,8 +203,8 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci, * This ensures that the master key is consistently used only * for HKDF, avoiding key reuse issues. */ - return setup_per_mode_key(ci, mk, mk->mk_direct_tfms, - HKDF_CONTEXT_DIRECT_KEY, false); + err = setup_per_mode_key(ci, mk, mk->mk_direct_tfms, + HKDF_CONTEXT_DIRECT_KEY, false); } else if (ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) { /* @@ -199,21 +213,33 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci, * the IVs. This format is optimized for use with inline * encryption hardware compliant with the UFS or eMMC standards. */ - return setup_per_mode_key(ci, mk, mk->mk_iv_ino_lblk_64_tfms, - HKDF_CONTEXT_IV_INO_LBLK_64_KEY, - true); + err = setup_per_mode_key(ci, mk, mk->mk_iv_ino_lblk_64_tfms, + HKDF_CONTEXT_IV_INO_LBLK_64_KEY, true); + } else { + u8 derived_key[FSCRYPT_MAX_KEY_SIZE]; + + err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf, + HKDF_CONTEXT_PER_FILE_KEY, + ci->ci_nonce, + FS_KEY_DERIVATION_NONCE_SIZE, + derived_key, ci->ci_mode->keysize); + if (err) + return err; + + err = fscrypt_set_derived_key(ci, derived_key); + memzero_explicit(derived_key, ci->ci_mode->keysize); } - - err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf, - HKDF_CONTEXT_PER_FILE_KEY, - ci->ci_nonce, FS_KEY_DERIVATION_NONCE_SIZE, - derived_key, ci->ci_mode->keysize); if (err) return err; - err = fscrypt_set_derived_key(ci, derived_key); - memzero_explicit(derived_key, ci->ci_mode->keysize); - return err; + /* Derive a secret dirhash key for directories that need it. */ + if (S_ISDIR(ci->ci_inode->i_mode) && IS_CASEFOLDED(ci->ci_inode)) { + err = fscrypt_derive_dirhash_key(ci, mk); + if (err) + return err; + } + + return 0; } /* |