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fscrypt updates for 5.14
A couple bug fixes for fs/crypto/: - Fix handling of major dirhash values that happen to be 0. - Fix cases where keys were derived differently on big endian systems than on little endian systems (affecting some newer features only). -----BEGIN PGP SIGNATURE----- iIoEABYIADIWIQSacvsUNc7UX4ntmEPzXCl4vpKOKwUCYNn+KhQcZWJpZ2dlcnNA Z29vZ2xlLmNvbQAKCRDzXCl4vpKOK595AP4hhu5pLLjPv+Okep+k+RTze5MzH9rH aXJK2T8J4TwGBgD/Qj+AjgLIJwjxk8mx3FliMsOjBxOIYiIpjHVNZect9AI= =+6JI -----END PGP SIGNATURE----- Merge tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt Pull fscrypt updates from Eric Biggers: "A couple bug fixes for fs/crypto/: - Fix handling of major dirhash values that happen to be 0. - Fix cases where keys were derived differently on big endian systems than on little endian systems (affecting some newer features only)" * tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt: fscrypt: fix derivation of SipHash keys on big endian CPUs fscrypt: don't ignore minor_hash when hash is 0
This commit is contained in:
commit
a58e203530
2 changed files with 35 additions and 15 deletions
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@ -344,13 +344,9 @@ int fscrypt_fname_disk_to_usr(const struct inode *inode,
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offsetof(struct fscrypt_nokey_name, sha256));
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offsetof(struct fscrypt_nokey_name, sha256));
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BUILD_BUG_ON(BASE64_CHARS(FSCRYPT_NOKEY_NAME_MAX) > NAME_MAX);
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BUILD_BUG_ON(BASE64_CHARS(FSCRYPT_NOKEY_NAME_MAX) > NAME_MAX);
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if (hash) {
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nokey_name.dirhash[0] = hash;
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nokey_name.dirhash[0] = hash;
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nokey_name.dirhash[1] = minor_hash;
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nokey_name.dirhash[1] = minor_hash;
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} else {
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nokey_name.dirhash[0] = 0;
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nokey_name.dirhash[1] = 0;
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}
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if (iname->len <= sizeof(nokey_name.bytes)) {
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if (iname->len <= sizeof(nokey_name.bytes)) {
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memcpy(nokey_name.bytes, iname->name, iname->len);
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memcpy(nokey_name.bytes, iname->name, iname->len);
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size = offsetof(struct fscrypt_nokey_name, bytes[iname->len]);
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size = offsetof(struct fscrypt_nokey_name, bytes[iname->len]);
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@ -210,15 +210,40 @@ static int setup_per_mode_enc_key(struct fscrypt_info *ci,
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return err;
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return err;
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}
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}
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/*
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* Derive a SipHash key from the given fscrypt master key and the given
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* application-specific information string.
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*
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* Note that the KDF produces a byte array, but the SipHash APIs expect the key
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* as a pair of 64-bit words. Therefore, on big endian CPUs we have to do an
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* endianness swap in order to get the same results as on little endian CPUs.
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*/
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static int fscrypt_derive_siphash_key(const struct fscrypt_master_key *mk,
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u8 context, const u8 *info,
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unsigned int infolen, siphash_key_t *key)
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{
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int err;
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err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf, context, info, infolen,
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(u8 *)key, sizeof(*key));
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if (err)
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return err;
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BUILD_BUG_ON(sizeof(*key) != 16);
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BUILD_BUG_ON(ARRAY_SIZE(key->key) != 2);
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le64_to_cpus(&key->key[0]);
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le64_to_cpus(&key->key[1]);
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return 0;
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}
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int fscrypt_derive_dirhash_key(struct fscrypt_info *ci,
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int fscrypt_derive_dirhash_key(struct fscrypt_info *ci,
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const struct fscrypt_master_key *mk)
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const struct fscrypt_master_key *mk)
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{
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{
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int err;
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int err;
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err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf, HKDF_CONTEXT_DIRHASH_KEY,
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err = fscrypt_derive_siphash_key(mk, HKDF_CONTEXT_DIRHASH_KEY,
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ci->ci_nonce, FSCRYPT_FILE_NONCE_SIZE,
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ci->ci_nonce, FSCRYPT_FILE_NONCE_SIZE,
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(u8 *)&ci->ci_dirhash_key,
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&ci->ci_dirhash_key);
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sizeof(ci->ci_dirhash_key));
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if (err)
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if (err)
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return err;
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return err;
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ci->ci_dirhash_key_initialized = true;
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ci->ci_dirhash_key_initialized = true;
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@ -253,10 +278,9 @@ static int fscrypt_setup_iv_ino_lblk_32_key(struct fscrypt_info *ci,
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if (mk->mk_ino_hash_key_initialized)
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if (mk->mk_ino_hash_key_initialized)
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goto unlock;
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goto unlock;
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err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf,
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err = fscrypt_derive_siphash_key(mk,
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HKDF_CONTEXT_INODE_HASH_KEY, NULL, 0,
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HKDF_CONTEXT_INODE_HASH_KEY,
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(u8 *)&mk->mk_ino_hash_key,
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NULL, 0, &mk->mk_ino_hash_key);
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sizeof(mk->mk_ino_hash_key));
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if (err)
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if (err)
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goto unlock;
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goto unlock;
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/* pairs with smp_load_acquire() above */
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/* pairs with smp_load_acquire() above */
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