*
* All algorithms are implemented in portable C code to avoid depending on
* libcrypto (OpenSSL), and because some fscrypt-supported algorithms aren't
- * available in libcrypto anyway (e.g. Adiantum). For simplicity, all crypto
- * code here tries to follow the mathematical definitions directly, without
- * optimizing for performance or worrying about following security best
- * practices such as mitigating side-channel attacks. So, only use this program
- * for testing!
+ * available in libcrypto anyway (e.g. Adiantum), or are only supported in
+ * recent versions (e.g. HKDF-SHA512). For simplicity, all crypto code here
+ * tries to follow the mathematical definitions directly, without optimizing for
+ * performance or worrying about following security best practices such as
+ * mitigating side-channel attacks. So, only use this program for testing!
*/
#include <asm/byteorder.h>
#include <linux/types.h>
#include <stdarg.h>
#include <stdbool.h>
+#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
"WARNING: this program is only meant for testing, not for \"real\" use!\n"
"\n"
"Options:\n"
+" --block-number=BNUM Starting block number for IV generation.\n"
+" Default: 0\n"
" --block-size=BLOCK_SIZE Encrypt each BLOCK_SIZE bytes independently.\n"
" Default: 4096 bytes\n"
" --decrypt Decrypt instead of encrypt\n"
" --file-nonce=NONCE File's nonce as a 32-character hex string\n"
+" --fs-uuid=UUID The filesystem UUID as a 32-character hex string.\n"
+" Required for --iv-ino-lblk-32 and\n"
+" --iv-ino-lblk-64; otherwise is unused.\n"
" --help Show this help\n"
-" --kdf=KDF Key derivation function to use: AES-128-ECB\n"
-" or none. Default: none\n"
+" --inode-number=INUM The file's inode number. Required for\n"
+" --iv-ino-lblk-32 and --iv-ino-lblk-64;\n"
+" otherwise is unused.\n"
+" --iv-ino-lblk-32 Similar to --iv-ino-lblk-64, but selects the\n"
+" 32-bit variant.\n"
+" --iv-ino-lblk-64 Use the format where the IVs include the inode\n"
+" number and the same key is shared across files.\n"
+" Requires --kdf=HKDF-SHA512, --fs-uuid,\n"
+" --inode-number, and --mode-num.\n"
+" --kdf=KDF Key derivation function to use: AES-128-ECB,\n"
+" HKDF-SHA512, or none. Default: none\n"
+" --mode-num=NUM Derive per-mode key using mode number NUM\n"
" --padding=PADDING If last block is partial, zero-pad it to next\n"
" PADDING-byte boundary. Default: BLOCK_SIZE\n"
, fp);
return (v >> n) | (v << (32 - n));
}
+static inline u64 rol64(u64 v, int n)
+{
+ return (v << n) | (v >> (64 - n));
+}
+
+static inline u64 ror64(u64 v, int n)
+{
+ return (v >> n) | (v << (64 - n));
+}
+
static inline void xor(u8 *res, const u8 *a, const u8 *b, size_t count)
{
while (count--)
#endif /* ENABLE_ALG_TESTS */
/*----------------------------------------------------------------------------*
- * SHA-256 *
+ * SHA-512 and SHA-256 *
*----------------------------------------------------------------------------*/
/*
* https://csrc.nist.gov/csrc/media/publications/fips/180/2/archive/2002-08-01/documents/fips180-2withchangenotice.pdf
*/
+#define SHA512_DIGEST_SIZE 64
+#define SHA512_BLOCK_SIZE 128
+
#define SHA256_DIGEST_SIZE 32
#define SHA256_BLOCK_SIZE 64
#define Ch(x, y, z) (((x) & (y)) ^ (~(x) & (z)))
#define Maj(x, y, z) (((x) & (y)) ^ ((x) & (z)) ^ ((y) & (z)))
+
+#define Sigma512_0(x) (ror64((x), 28) ^ ror64((x), 34) ^ ror64((x), 39))
+#define Sigma512_1(x) (ror64((x), 14) ^ ror64((x), 18) ^ ror64((x), 41))
+#define sigma512_0(x) (ror64((x), 1) ^ ror64((x), 8) ^ ((x) >> 7))
+#define sigma512_1(x) (ror64((x), 19) ^ ror64((x), 61) ^ ((x) >> 6))
+
#define Sigma256_0(x) (ror32((x), 2) ^ ror32((x), 13) ^ ror32((x), 22))
#define Sigma256_1(x) (ror32((x), 6) ^ ror32((x), 11) ^ ror32((x), 25))
#define sigma256_0(x) (ror32((x), 7) ^ ror32((x), 18) ^ ((x) >> 3))
#define sigma256_1(x) (ror32((x), 17) ^ ror32((x), 19) ^ ((x) >> 10))
-static const u32 sha256_iv[8] = {
- 0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c,
- 0x1f83d9ab, 0x5be0cd19,
+static const u64 sha512_iv[8] = {
+ 0x6a09e667f3bcc908, 0xbb67ae8584caa73b, 0x3c6ef372fe94f82b,
+ 0xa54ff53a5f1d36f1, 0x510e527fade682d1, 0x9b05688c2b3e6c1f,
+ 0x1f83d9abfb41bd6b, 0x5be0cd19137e2179,
};
-static const u32 sha256_round_constants[64] = {
- 0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1,
- 0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
- 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786,
- 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
- 0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147,
- 0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
- 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b,
- 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
- 0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a,
- 0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
- 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2,
+static const u64 sha512_round_constants[80] = {
+ 0x428a2f98d728ae22, 0x7137449123ef65cd, 0xb5c0fbcfec4d3b2f,
+ 0xe9b5dba58189dbbc, 0x3956c25bf348b538, 0x59f111f1b605d019,
+ 0x923f82a4af194f9b, 0xab1c5ed5da6d8118, 0xd807aa98a3030242,
+ 0x12835b0145706fbe, 0x243185be4ee4b28c, 0x550c7dc3d5ffb4e2,
+ 0x72be5d74f27b896f, 0x80deb1fe3b1696b1, 0x9bdc06a725c71235,
+ 0xc19bf174cf692694, 0xe49b69c19ef14ad2, 0xefbe4786384f25e3,
+ 0x0fc19dc68b8cd5b5, 0x240ca1cc77ac9c65, 0x2de92c6f592b0275,
+ 0x4a7484aa6ea6e483, 0x5cb0a9dcbd41fbd4, 0x76f988da831153b5,
+ 0x983e5152ee66dfab, 0xa831c66d2db43210, 0xb00327c898fb213f,
+ 0xbf597fc7beef0ee4, 0xc6e00bf33da88fc2, 0xd5a79147930aa725,
+ 0x06ca6351e003826f, 0x142929670a0e6e70, 0x27b70a8546d22ffc,
+ 0x2e1b21385c26c926, 0x4d2c6dfc5ac42aed, 0x53380d139d95b3df,
+ 0x650a73548baf63de, 0x766a0abb3c77b2a8, 0x81c2c92e47edaee6,
+ 0x92722c851482353b, 0xa2bfe8a14cf10364, 0xa81a664bbc423001,
+ 0xc24b8b70d0f89791, 0xc76c51a30654be30, 0xd192e819d6ef5218,
+ 0xd69906245565a910, 0xf40e35855771202a, 0x106aa07032bbd1b8,
+ 0x19a4c116b8d2d0c8, 0x1e376c085141ab53, 0x2748774cdf8eeb99,
+ 0x34b0bcb5e19b48a8, 0x391c0cb3c5c95a63, 0x4ed8aa4ae3418acb,
+ 0x5b9cca4f7763e373, 0x682e6ff3d6b2b8a3, 0x748f82ee5defb2fc,
+ 0x78a5636f43172f60, 0x84c87814a1f0ab72, 0x8cc702081a6439ec,
+ 0x90befffa23631e28, 0xa4506cebde82bde9, 0xbef9a3f7b2c67915,
+ 0xc67178f2e372532b, 0xca273eceea26619c, 0xd186b8c721c0c207,
+ 0xeada7dd6cde0eb1e, 0xf57d4f7fee6ed178, 0x06f067aa72176fba,
+ 0x0a637dc5a2c898a6, 0x113f9804bef90dae, 0x1b710b35131c471b,
+ 0x28db77f523047d84, 0x32caab7b40c72493, 0x3c9ebe0a15c9bebc,
+ 0x431d67c49c100d4c, 0x4cc5d4becb3e42b6, 0x597f299cfc657e2a,
+ 0x5fcb6fab3ad6faec, 0x6c44198c4a475817,
};
+/* Compute the SHA-512 digest of the given buffer */
+static void sha512(const u8 *in, size_t inlen, u8 out[SHA512_DIGEST_SIZE])
+{
+ const size_t msglen = ROUND_UP(inlen + 17, SHA512_BLOCK_SIZE);
+ u8 * const msg = xmalloc(msglen);
+ u64 H[8];
+ int i;
+
+ /* super naive way of handling the padding */
+ memcpy(msg, in, inlen);
+ memset(&msg[inlen], 0, msglen - inlen);
+ msg[inlen] = 0x80;
+ put_unaligned_be64((u64)inlen * 8, &msg[msglen - sizeof(__be64)]);
+ in = msg;
+
+ memcpy(H, sha512_iv, sizeof(H));
+ do {
+ u64 a = H[0], b = H[1], c = H[2], d = H[3],
+ e = H[4], f = H[5], g = H[6], h = H[7];
+ u64 W[80];
+
+ for (i = 0; i < 16; i++)
+ W[i] = get_unaligned_be64(&in[i * sizeof(__be64)]);
+ for (; i < ARRAY_SIZE(W); i++)
+ W[i] = sigma512_1(W[i - 2]) + W[i - 7] +
+ sigma512_0(W[i - 15]) + W[i - 16];
+ for (i = 0; i < ARRAY_SIZE(W); i++) {
+ u64 T1 = h + Sigma512_1(e) + Ch(e, f, g) +
+ sha512_round_constants[i] + W[i];
+ u64 T2 = Sigma512_0(a) + Maj(a, b, c);
+
+ h = g; g = f; f = e; e = d + T1;
+ d = c; c = b; b = a; a = T1 + T2;
+ }
+ H[0] += a; H[1] += b; H[2] += c; H[3] += d;
+ H[4] += e; H[5] += f; H[6] += g; H[7] += h;
+ } while ((in += SHA512_BLOCK_SIZE) != &msg[msglen]);
+
+ for (i = 0; i < ARRAY_SIZE(H); i++)
+ put_unaligned_be64(H[i], &out[i * sizeof(__be64)]);
+ free(msg);
+}
+
/* Compute the SHA-256 digest of the given buffer */
static void sha256(const u8 *in, size_t inlen, u8 out[SHA256_DIGEST_SIZE])
{
put_unaligned_be64((u64)inlen * 8, &msg[msglen - sizeof(__be64)]);
in = msg;
- memcpy(H, sha256_iv, sizeof(H));
+ for (i = 0; i < ARRAY_SIZE(H); i++)
+ H[i] = (u32)(sha512_iv[i] >> 32);
do {
u32 a = H[0], b = H[1], c = H[2], d = H[3],
e = H[4], f = H[5], g = H[6], h = H[7];
sigma256_0(W[i - 15]) + W[i - 16];
for (i = 0; i < ARRAY_SIZE(W); i++) {
u32 T1 = h + Sigma256_1(e) + Ch(e, f, g) +
- sha256_round_constants[i] + W[i];
+ (u32)(sha512_round_constants[i] >> 32) + W[i];
u32 T2 = Sigma256_0(a) + Maj(a, b, c);
h = g; g = f; f = e; e = d + T1;
while (num_tests--) {
u8 in[4096];
- u8 digest[SHA256_DIGEST_SIZE];
- u8 ref_digest[SHA256_DIGEST_SIZE];
+ u8 digest[SHA512_DIGEST_SIZE];
+ u8 ref_digest[SHA512_DIGEST_SIZE];
const size_t inlen = rand() % (1 + sizeof(in));
rand_bytes(in, inlen);
sha256(in, inlen, digest);
SHA256(in, inlen, ref_digest);
ASSERT(memcmp(digest, ref_digest, SHA256_DIGEST_SIZE) == 0);
+
+ sha512(in, inlen, digest);
+ SHA512(in, inlen, ref_digest);
+ ASSERT(memcmp(digest, ref_digest, SHA512_DIGEST_SIZE) == 0);
+ }
+}
+#endif /* ENABLE_ALG_TESTS */
+
+/*----------------------------------------------------------------------------*
+ * HKDF implementation *
+ *----------------------------------------------------------------------------*/
+
+static void hmac_sha512(const u8 *key, size_t keylen, const u8 *msg,
+ size_t msglen, u8 mac[SHA512_DIGEST_SIZE])
+{
+ u8 *ibuf = xmalloc(SHA512_BLOCK_SIZE + msglen);
+ u8 obuf[SHA512_BLOCK_SIZE + SHA512_DIGEST_SIZE];
+
+ ASSERT(keylen <= SHA512_BLOCK_SIZE); /* keylen > bs not implemented */
+
+ memset(ibuf, 0x36, SHA512_BLOCK_SIZE);
+ xor(ibuf, ibuf, key, keylen);
+ memcpy(&ibuf[SHA512_BLOCK_SIZE], msg, msglen);
+
+ memset(obuf, 0x5c, SHA512_BLOCK_SIZE);
+ xor(obuf, obuf, key, keylen);
+ sha512(ibuf, SHA512_BLOCK_SIZE + msglen, &obuf[SHA512_BLOCK_SIZE]);
+ sha512(obuf, sizeof(obuf), mac);
+
+ free(ibuf);
+}
+
+static void hkdf_sha512(const u8 *ikm, size_t ikmlen,
+ const u8 *salt, size_t saltlen,
+ const u8 *info, size_t infolen,
+ u8 *output, size_t outlen)
+{
+ static const u8 default_salt[SHA512_DIGEST_SIZE];
+ u8 prk[SHA512_DIGEST_SIZE]; /* pseudorandom key */
+ u8 *buf = xmalloc(1 + infolen + SHA512_DIGEST_SIZE);
+ u8 counter = 1;
+ size_t i;
+
+ if (saltlen == 0) {
+ salt = default_salt;
+ saltlen = sizeof(default_salt);
+ }
+
+ /* HKDF-Extract */
+ ASSERT(ikmlen > 0);
+ hmac_sha512(salt, saltlen, ikm, ikmlen, prk);
+
+ /* HKDF-Expand */
+ for (i = 0; i < outlen; i += SHA512_DIGEST_SIZE) {
+ u8 *p = buf;
+ u8 tmp[SHA512_DIGEST_SIZE];
+
+ ASSERT(counter != 0);
+ if (i > 0) {
+ memcpy(p, &output[i - SHA512_DIGEST_SIZE],
+ SHA512_DIGEST_SIZE);
+ p += SHA512_DIGEST_SIZE;
+ }
+ memcpy(p, info, infolen);
+ p += infolen;
+ *p++ = counter++;
+ hmac_sha512(prk, sizeof(prk), buf, p - buf, tmp);
+ memcpy(&output[i], tmp, MIN(sizeof(tmp), outlen - i));
+ }
+ free(buf);
+}
+
+#ifdef ENABLE_ALG_TESTS
+#include <openssl/evp.h>
+#include <openssl/kdf.h>
+static void openssl_hkdf_sha512(const u8 *ikm, size_t ikmlen,
+ const u8 *salt, size_t saltlen,
+ const u8 *info, size_t infolen,
+ u8 *output, size_t outlen)
+{
+ EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
+ size_t actual_outlen = outlen;
+
+ ASSERT(pctx != NULL);
+ ASSERT(EVP_PKEY_derive_init(pctx) > 0);
+ ASSERT(EVP_PKEY_CTX_set_hkdf_md(pctx, EVP_sha512()) > 0);
+ ASSERT(EVP_PKEY_CTX_set1_hkdf_key(pctx, ikm, ikmlen) > 0);
+ ASSERT(EVP_PKEY_CTX_set1_hkdf_salt(pctx, salt, saltlen) > 0);
+ ASSERT(EVP_PKEY_CTX_add1_hkdf_info(pctx, info, infolen) > 0);
+ ASSERT(EVP_PKEY_derive(pctx, output, &actual_outlen) > 0);
+ ASSERT(actual_outlen == outlen);
+ EVP_PKEY_CTX_free(pctx);
+}
+
+static void test_hkdf_sha512(void)
+{
+ unsigned long num_tests = NUM_ALG_TEST_ITERATIONS;
+
+ while (num_tests--) {
+ u8 ikm[SHA512_DIGEST_SIZE];
+ u8 salt[SHA512_DIGEST_SIZE];
+ u8 info[128];
+ u8 actual_output[512];
+ u8 expected_output[sizeof(actual_output)];
+ size_t ikmlen = 1 + (rand() % sizeof(ikm));
+ size_t saltlen = rand() % (1 + sizeof(salt));
+ size_t infolen = rand() % (1 + sizeof(info));
+ size_t outlen = rand() % (1 + sizeof(actual_output));
+
+ rand_bytes(ikm, ikmlen);
+ rand_bytes(salt, saltlen);
+ rand_bytes(info, infolen);
+
+ hkdf_sha512(ikm, ikmlen, salt, saltlen, info, infolen,
+ actual_output, outlen);
+ openssl_hkdf_sha512(ikm, ikmlen, salt, saltlen, info, infolen,
+ expected_output, outlen);
+ ASSERT(memcmp(actual_output, expected_output, outlen) == 0);
}
}
#endif /* ENABLE_ALG_TESTS */
}
#endif /* ENABLE_ALG_TESTS */
+/*----------------------------------------------------------------------------*
+ * SipHash-2-4 *
+ *----------------------------------------------------------------------------*/
+
+/*
+ * Reference: "SipHash: a fast short-input PRF"
+ * https://cr.yp.to/siphash/siphash-20120918.pdf
+ */
+
+#define SIPROUND \
+ do { \
+ v0 += v1; v2 += v3; \
+ v1 = rol64(v1, 13); v3 = rol64(v3, 16); \
+ v1 ^= v0; v3 ^= v2; \
+ v0 = rol64(v0, 32); \
+ v2 += v1; v0 += v3; \
+ v1 = rol64(v1, 17); v3 = rol64(v3, 21); \
+ v1 ^= v2; v3 ^= v0; \
+ v2 = rol64(v2, 32); \
+ } while (0)
+
+/* Compute the SipHash-2-4 of a 64-bit number when formatted as little endian */
+static u64 siphash_1u64(const u64 key[2], u64 data)
+{
+ u64 v0 = key[0] ^ 0x736f6d6570736575ULL;
+ u64 v1 = key[1] ^ 0x646f72616e646f6dULL;
+ u64 v2 = key[0] ^ 0x6c7967656e657261ULL;
+ u64 v3 = key[1] ^ 0x7465646279746573ULL;
+ u64 m[2] = {data, (u64)sizeof(data) << 56};
+ size_t i;
+
+ for (i = 0; i < ARRAY_SIZE(m); i++) {
+ v3 ^= m[i];
+ SIPROUND;
+ SIPROUND;
+ v0 ^= m[i];
+ }
+
+ v2 ^= 0xff;
+ for (i = 0; i < 4; i++)
+ SIPROUND;
+ return v0 ^ v1 ^ v2 ^ v3;
+}
+
/*----------------------------------------------------------------------------*
* Main program *
*----------------------------------------------------------------------------*/
#define FILE_NONCE_SIZE 16
+#define UUID_SIZE 16
#define MAX_KEY_SIZE 64
+#define MAX_IV_SIZE ADIANTUM_IV_SIZE
static const struct fscrypt_cipher {
const char *name;
return NULL;
}
-struct fscrypt_iv {
- union {
- __le64 block_num;
- u8 bytes[32];
+union fscrypt_iv {
+ /* usual IV format */
+ struct {
+ /* logical block number within the file */
+ __le64 block_number;
+
+ /* per-file nonce; only set in DIRECT_KEY mode */
+ u8 nonce[FILE_NONCE_SIZE];
+ };
+ /* IV format for IV_INO_LBLK_* modes */
+ struct {
+ /*
+ * IV_INO_LBLK_64: logical block number within the file
+ * IV_INO_LBLK_32: hashed inode number + logical block number
+ * within the file, mod 2^32
+ */
+ __le32 block_number32;
+
+ /* IV_INO_LBLK_64: inode number */
+ __le32 inode_number;
};
+ /* Any extra bytes up to the algorithm's IV size must be zeroed */
+ u8 bytes[MAX_IV_SIZE];
};
static void crypt_loop(const struct fscrypt_cipher *cipher, const u8 *key,
- struct fscrypt_iv *iv, bool decrypting,
- size_t block_size, size_t padding)
+ union fscrypt_iv *iv, bool decrypting,
+ size_t block_size, size_t padding, bool is_bnum_32bit)
{
u8 *buf = xmalloc(block_size);
size_t res;
full_write(STDOUT_FILENO, buf, crypt_len);
- iv->block_num = cpu_to_le64(le64_to_cpu(iv->block_num) + 1);
+ if (is_bnum_32bit)
+ iv->block_number32 = cpu_to_le32(
+ le32_to_cpu(iv->block_number32) + 1);
+ else
+ iv->block_number = cpu_to_le64(
+ le64_to_cpu(iv->block_number) + 1);
}
free(buf);
}
enum kdf_algorithm {
KDF_NONE,
KDF_AES_128_ECB,
+ KDF_HKDF_SHA512,
};
static enum kdf_algorithm parse_kdf_algorithm(const char *arg)
return KDF_NONE;
if (strcmp(arg, "AES-128-ECB") == 0)
return KDF_AES_128_ECB;
+ if (strcmp(arg, "HKDF-SHA512") == 0)
+ return KDF_HKDF_SHA512;
die("Unknown KDF: %s", arg);
}
+static u8 parse_mode_number(const char *arg)
+{
+ char *tmp;
+ long num = strtol(arg, &tmp, 10);
+
+ if (num <= 0 || *tmp || (u8)num != num)
+ die("Invalid mode number: %s", arg);
+ return num;
+}
+
+struct key_and_iv_params {
+ u8 master_key[MAX_KEY_SIZE];
+ int master_key_size;
+ enum kdf_algorithm kdf;
+ u8 mode_num;
+ u8 file_nonce[FILE_NONCE_SIZE];
+ bool file_nonce_specified;
+ bool iv_ino_lblk_64;
+ bool iv_ino_lblk_32;
+ u64 block_number;
+ u64 inode_number;
+ u8 fs_uuid[UUID_SIZE];
+ bool fs_uuid_specified;
+};
+
+#define HKDF_CONTEXT_KEY_IDENTIFIER 1
+#define HKDF_CONTEXT_PER_FILE_ENC_KEY 2
+#define HKDF_CONTEXT_DIRECT_KEY 3
+#define HKDF_CONTEXT_IV_INO_LBLK_64_KEY 4
+#define HKDF_CONTEXT_DIRHASH_KEY 5
+#define HKDF_CONTEXT_IV_INO_LBLK_32_KEY 6
+#define HKDF_CONTEXT_INODE_HASH_KEY 7
+
+/* Hash the file's inode number using SipHash keyed by a derived key */
+static u32 hash_inode_number(const struct key_and_iv_params *params)
+{
+ u8 info[9] = "fscrypt";
+ union {
+ u64 words[2];
+ u8 bytes[16];
+ } hash_key;
+
+ info[8] = HKDF_CONTEXT_INODE_HASH_KEY;
+ hkdf_sha512(params->master_key, params->master_key_size,
+ NULL, 0, info, sizeof(info),
+ hash_key.bytes, sizeof(hash_key));
+
+ hash_key.words[0] = get_unaligned_le64(&hash_key.bytes[0]);
+ hash_key.words[1] = get_unaligned_le64(&hash_key.bytes[8]);
+
+ return (u32)siphash_1u64(hash_key.words, params->inode_number);
+}
+
/*
* Get the key and starting IV with which the encryption will actually be done.
- * If a KDF was specified, a subkey is derived from the master key and file
- * nonce. Otherwise, the master key is used directly.
+ * If a KDF was specified, a subkey is derived from the master key and the mode
+ * number or file nonce. Otherwise, the master key is used directly.
*/
-static void get_key_and_iv(const u8 *master_key, size_t master_key_size,
- enum kdf_algorithm kdf,
- const u8 nonce[FILE_NONCE_SIZE],
+static void get_key_and_iv(const struct key_and_iv_params *params,
u8 *real_key, size_t real_key_size,
- struct fscrypt_iv *iv)
+ union fscrypt_iv *iv)
{
+ bool file_nonce_in_iv = false;
struct aes_key aes_key;
+ u8 info[8 + 1 + 1 + UUID_SIZE] = "fscrypt";
+ size_t infolen = 8;
size_t i;
- ASSERT(real_key_size <= master_key_size);
+ ASSERT(real_key_size <= params->master_key_size);
memset(iv, 0, sizeof(*iv));
- switch (kdf) {
+ /* Overridden later for iv_ino_lblk_{64,32} */
+ iv->block_number = cpu_to_le64(params->block_number);
+
+ if (params->iv_ino_lblk_64 || params->iv_ino_lblk_32) {
+ const char *opt = params->iv_ino_lblk_64 ? "--iv-ino-lblk-64" :
+ "--iv-ino-lblk-32";
+ if (params->iv_ino_lblk_64 && params->iv_ino_lblk_32)
+ die("--iv-ino-lblk-64 and --iv-ino-lblk-32 are mutually exclusive");
+ if (params->kdf != KDF_HKDF_SHA512)
+ die("%s requires --kdf=HKDF-SHA512", opt);
+ if (!params->fs_uuid_specified)
+ die("%s requires --fs-uuid", opt);
+ if (params->inode_number == 0)
+ die("%s requires --inode-number", opt);
+ if (params->mode_num == 0)
+ die("%s requires --mode-num", opt);
+ if (params->block_number > UINT32_MAX)
+ die("%s can't use --block-number > UINT32_MAX", opt);
+ if (params->inode_number > UINT32_MAX)
+ die("%s can't use --inode-number > UINT32_MAX", opt);
+ }
+
+ switch (params->kdf) {
case KDF_NONE:
- memcpy(real_key, master_key, real_key_size);
- if (nonce != NULL)
- memcpy(&iv->bytes[8], nonce, FILE_NONCE_SIZE);
+ if (params->mode_num != 0)
+ die("--mode-num isn't supported with --kdf=none");
+ memcpy(real_key, params->master_key, real_key_size);
+ file_nonce_in_iv = true;
break;
case KDF_AES_128_ECB:
- if (nonce == NULL)
+ if (!params->file_nonce_specified)
die("--file-nonce is required with --kdf=AES-128-ECB");
+ if (params->mode_num != 0)
+ die("--mode-num isn't supported with --kdf=AES-128-ECB");
STATIC_ASSERT(FILE_NONCE_SIZE == AES_128_KEY_SIZE);
ASSERT(real_key_size % AES_BLOCK_SIZE == 0);
- aes_setkey(&aes_key, nonce, AES_128_KEY_SIZE);
+ aes_setkey(&aes_key, params->file_nonce, AES_128_KEY_SIZE);
for (i = 0; i < real_key_size; i += AES_BLOCK_SIZE)
- aes_encrypt(&aes_key, &master_key[i], &real_key[i]);
+ aes_encrypt(&aes_key, ¶ms->master_key[i],
+ &real_key[i]);
+ break;
+ case KDF_HKDF_SHA512:
+ if (params->iv_ino_lblk_64) {
+ info[infolen++] = HKDF_CONTEXT_IV_INO_LBLK_64_KEY;
+ info[infolen++] = params->mode_num;
+ memcpy(&info[infolen], params->fs_uuid, UUID_SIZE);
+ infolen += UUID_SIZE;
+ iv->block_number32 = cpu_to_le32(params->block_number);
+ iv->inode_number = cpu_to_le32(params->inode_number);
+ } else if (params->iv_ino_lblk_32) {
+ info[infolen++] = HKDF_CONTEXT_IV_INO_LBLK_32_KEY;
+ info[infolen++] = params->mode_num;
+ memcpy(&info[infolen], params->fs_uuid, UUID_SIZE);
+ infolen += UUID_SIZE;
+ iv->block_number32 =
+ cpu_to_le32(hash_inode_number(params) +
+ params->block_number);
+ iv->inode_number = 0;
+ } else if (params->mode_num != 0) {
+ info[infolen++] = HKDF_CONTEXT_DIRECT_KEY;
+ info[infolen++] = params->mode_num;
+ file_nonce_in_iv = true;
+ } else if (params->file_nonce_specified) {
+ info[infolen++] = HKDF_CONTEXT_PER_FILE_ENC_KEY;
+ memcpy(&info[infolen], params->file_nonce,
+ FILE_NONCE_SIZE);
+ infolen += FILE_NONCE_SIZE;
+ } else {
+ die("With --kdf=HKDF-SHA512, at least one of --file-nonce and --mode-num must be specified");
+ }
+ hkdf_sha512(params->master_key, params->master_key_size,
+ NULL, 0, info, infolen, real_key, real_key_size);
break;
default:
ASSERT(0);
}
+
+ if (file_nonce_in_iv && params->file_nonce_specified)
+ memcpy(iv->nonce, params->file_nonce, FILE_NONCE_SIZE);
}
enum {
+ OPT_BLOCK_NUMBER,
OPT_BLOCK_SIZE,
OPT_DECRYPT,
OPT_FILE_NONCE,
+ OPT_FS_UUID,
OPT_HELP,
+ OPT_INODE_NUMBER,
+ OPT_IV_INO_LBLK_32,
+ OPT_IV_INO_LBLK_64,
OPT_KDF,
+ OPT_MODE_NUM,
OPT_PADDING,
};
static const struct option longopts[] = {
+ { "block-number", required_argument, NULL, OPT_BLOCK_NUMBER },
{ "block-size", required_argument, NULL, OPT_BLOCK_SIZE },
{ "decrypt", no_argument, NULL, OPT_DECRYPT },
{ "file-nonce", required_argument, NULL, OPT_FILE_NONCE },
+ { "fs-uuid", required_argument, NULL, OPT_FS_UUID },
{ "help", no_argument, NULL, OPT_HELP },
+ { "inode-number", required_argument, NULL, OPT_INODE_NUMBER },
+ { "iv-ino-lblk-32", no_argument, NULL, OPT_IV_INO_LBLK_32 },
+ { "iv-ino-lblk-64", no_argument, NULL, OPT_IV_INO_LBLK_64 },
{ "kdf", required_argument, NULL, OPT_KDF },
+ { "mode-num", required_argument, NULL, OPT_MODE_NUM },
{ "padding", required_argument, NULL, OPT_PADDING },
{ NULL, 0, NULL, 0 },
};
{
size_t block_size = 4096;
bool decrypting = false;
- u8 _file_nonce[FILE_NONCE_SIZE];
- u8 *file_nonce = NULL;
- enum kdf_algorithm kdf = KDF_NONE;
+ struct key_and_iv_params params;
size_t padding = 0;
const struct fscrypt_cipher *cipher;
- u8 master_key[MAX_KEY_SIZE];
- int master_key_size;
u8 real_key[MAX_KEY_SIZE];
- struct fscrypt_iv iv;
+ union fscrypt_iv iv;
char *tmp;
int c;
+ memset(¶ms, 0, sizeof(params));
+
aes_init();
#ifdef ENABLE_ALG_TESTS
test_aes();
test_sha2();
+ test_hkdf_sha512();
test_aes_256_xts();
test_aes_256_cts_cbc();
test_adiantum();
while ((c = getopt_long(argc, argv, "", longopts, NULL)) != -1) {
switch (c) {
+ case OPT_BLOCK_NUMBER:
+ errno = 0;
+ params.block_number = strtoull(optarg, &tmp, 10);
+ if (*tmp || errno)
+ die("Invalid block number: %s", optarg);
+ break;
case OPT_BLOCK_SIZE:
+ errno = 0;
block_size = strtoul(optarg, &tmp, 10);
- if (block_size <= 0 || *tmp)
+ if (block_size <= 0 || *tmp || errno)
die("Invalid block size: %s", optarg);
break;
case OPT_DECRYPT:
decrypting = true;
break;
case OPT_FILE_NONCE:
- if (hex2bin(optarg, _file_nonce, FILE_NONCE_SIZE) !=
- FILE_NONCE_SIZE)
+ if (hex2bin(optarg, params.file_nonce, FILE_NONCE_SIZE)
+ != FILE_NONCE_SIZE)
die("Invalid file nonce: %s", optarg);
- file_nonce = _file_nonce;
+ params.file_nonce_specified = true;
+ break;
+ case OPT_FS_UUID:
+ if (hex2bin(optarg, params.fs_uuid, UUID_SIZE)
+ != UUID_SIZE)
+ die("Invalid filesystem UUID: %s", optarg);
+ params.fs_uuid_specified = true;
break;
case OPT_HELP:
usage(stdout);
return 0;
+ case OPT_INODE_NUMBER:
+ errno = 0;
+ params.inode_number = strtoull(optarg, &tmp, 10);
+ if (params.inode_number <= 0 || *tmp || errno)
+ die("Invalid inode number: %s", optarg);
+ break;
+ case OPT_IV_INO_LBLK_32:
+ params.iv_ino_lblk_32 = true;
+ break;
+ case OPT_IV_INO_LBLK_64:
+ params.iv_ino_lblk_64 = true;
+ break;
case OPT_KDF:
- kdf = parse_kdf_algorithm(optarg);
+ params.kdf = parse_kdf_algorithm(optarg);
+ break;
+ case OPT_MODE_NUM:
+ params.mode_num = parse_mode_number(optarg);
break;
case OPT_PADDING:
padding = strtoul(optarg, &tmp, 10);
die("Block size of %zu bytes is too small for cipher %s",
block_size, cipher->name);
- master_key_size = hex2bin(argv[1], master_key, MAX_KEY_SIZE);
- if (master_key_size < 0)
+ params.master_key_size = hex2bin(argv[1], params.master_key,
+ MAX_KEY_SIZE);
+ if (params.master_key_size < 0)
die("Invalid master_key: %s", argv[1]);
- if (master_key_size < cipher->keysize)
+ if (params.master_key_size < cipher->keysize)
die("Master key is too short for cipher %s", cipher->name);
- get_key_and_iv(master_key, master_key_size, kdf, file_nonce,
- real_key, cipher->keysize, &iv);
+ get_key_and_iv(¶ms, real_key, cipher->keysize, &iv);
- crypt_loop(cipher, real_key, &iv, decrypting, block_size, padding);
+ crypt_loop(cipher, real_key, &iv, decrypting, block_size, padding,
+ params.iv_ino_lblk_64 || params.iv_ino_lblk_32);
return 0;
}