+ unsigned char *out, const unsigned char *in,
+ size_t inlen, block128_f block)
+{
+ size_t ret;
+ unsigned char got_iv[8];
+
+ ret = crypto_128_unwrap_raw(key, got_iv, out, in, inlen, block);
+ if (ret != inlen)
+ return ret;
+
+ if (!iv)
+ iv = default_iv;
+ if (CRYPTO_memcmp(out, iv, 8)) {
+ OPENSSL_cleanse(out, inlen);
+ return 0;
+ }
+ return inlen;
+}
+
+/** Wrapping according to RFC 5649 section 4.1.
+ *
+ * @param[in] key Key value.
+ * @param[in] icv (Non-standard) IV, 4 bytes. NULL = use default_aiv.
+ * @param[out] out Cipher text. Minimal buffer length = (inlen + 15) bytes.
+ * Input and output buffers can overlap if block function
+ * supports that.
+ * @param[in] in Plain text as n 64-bit blocks, n >= 2.
+ * @param[in] inlen Length of in.
+ * @param[in] block Block processing function.
+ * @return 0 if inlen is out of range [1, CRYPTO128_WRAP_MAX].
+ * Output length if wrapping succeeded.
+ */
+size_t CRYPTO_128_wrap_pad(void *key, const unsigned char *icv,
+ unsigned char *out,
+ const unsigned char *in, size_t inlen,
+ block128_f block)
+{
+ /* n: number of 64-bit blocks in the padded key data
+ *
+ * If length of plain text is not a multiple of 8, pad the plain text octet
+ * string on the right with octets of zeros, where final length is the
+ * smallest multiple of 8 that is greater than length of plain text.
+ * If length of plain text is a multiple of 8, then there is no padding. */
+ const size_t blocks_padded = (inlen + 7) / 8; /* CEILING(m/8) */
+ const size_t padded_len = blocks_padded * 8;
+ const size_t padding_len = padded_len - inlen;
+ /* RFC 5649 section 3: Alternative Initial Value */
+ unsigned char aiv[8];
+ int ret;
+
+ /* Section 1: use 32-bit fixed field for plaintext octet length */
+ if (inlen == 0 || inlen >= CRYPTO128_WRAP_MAX)
+ return 0;
+
+ /* Section 3: Alternative Initial Value */
+ if (!icv)
+ memcpy(aiv, default_aiv, 4);
+ else
+ memcpy(aiv, icv, 4); /* Standard doesn't mention this. */
+
+ aiv[4] = (inlen >> 24) & 0xFF;
+ aiv[5] = (inlen >> 16) & 0xFF;
+ aiv[6] = (inlen >> 8) & 0xFF;
+ aiv[7] = inlen & 0xFF;
+
+ if (padded_len == 8) {
+ /*
+ * Section 4.1 - special case in step 2: If the padded plaintext
+ * contains exactly eight octets, then prepend the AIV and encrypt
+ * the resulting 128-bit block using AES in ECB mode.
+ */
+ memmove(out + 8, in, inlen);
+ memcpy(out, aiv, 8);
+ memset(out + 8 + inlen, 0, padding_len);
+ block(out, out, key);
+ ret = 16; /* AIV + padded input */
+ } else {
+ memmove(out, in, inlen);
+ memset(out + inlen, 0, padding_len); /* Section 4.1 step 1 */
+ ret = CRYPTO_128_wrap(key, aiv, out, out, padded_len, block);
+ }
+
+ return ret;
+}
+
+/** Unwrapping according to RFC 5649 section 4.2.
+ *
+ * @param[in] key Key value.
+ * @param[in] icv (Non-standard) IV, 4 bytes. NULL = use default_aiv.
+ * @param[out] out Plain text. Minimal buffer length = inlen bytes.
+ * Input and output buffers can overlap if block function
+ * supports that.
+ * @param[in] in Ciphertext text as n 64-bit blocks
+ * @param[in] inlen Length of in.
+ * @param[in] block Block processing function.
+ * @return 0 if inlen is out of range [16, CRYPTO128_WRAP_MAX],
+ * or if inlen is not multiply of 8
+ * or if IV and message length indicator doesn't match.
+ * Output length if unwrapping succeeded and IV matches.
+ */
+size_t CRYPTO_128_unwrap_pad(void *key, const unsigned char *icv,
+ unsigned char *out,
+ const unsigned char *in, size_t inlen,
+ block128_f block)
+{
+ /* n: number of 64-bit blocks in the padded key data */
+ size_t n = inlen / 8 - 1;
+ size_t padded_len;
+ size_t padding_len;
+ size_t ptext_len;
+ /* RFC 5649 section 3: Alternative Initial Value */
+ unsigned char aiv[8];
+ static unsigned char zeros[8] = { 0x0 };
+ size_t ret;
+
+ /* Section 4.2: Cipher text length has to be (n+1) 64-bit blocks. */
+ if ((inlen & 0x7) != 0 || inlen < 16 || inlen >= CRYPTO128_WRAP_MAX)
+ return 0;
+
+ memmove(out, in, inlen);
+ if (inlen == 16) {
+ /*
+ * Section 4.2 - special case in step 1: When n=1, the ciphertext
+ * contains exactly two 64-bit blocks and they are decrypted as a
+ * single AES block using AES in ECB mode: AIV | P[1] = DEC(K, C[0] |
+ * C[1])
+ */
+ block(out, out, key);
+ memcpy(aiv, out, 8);
+ /* Remove AIV */
+ memmove(out, out + 8, 8);
+ padded_len = 8;
+ } else {
+ padded_len = inlen - 8;
+ ret = crypto_128_unwrap_raw(key, aiv, out, out, inlen, block);
+ if (padded_len != ret) {
+ OPENSSL_cleanse(out, inlen);
+ return 0;
+ }
+ }
+
+ /*
+ * Section 3: AIV checks: Check that MSB(32,A) = A65959A6. Optionally a
+ * user-supplied value can be used (even if standard doesn't mention
+ * this).
+ */
+ if ((!icv && CRYPTO_memcmp(aiv, default_aiv, 4))
+ || (icv && CRYPTO_memcmp(aiv, icv, 4))) {
+ OPENSSL_cleanse(out, inlen);
+ return 0;
+ }
+
+ /*
+ * Check that 8*(n-1) < LSB(32,AIV) <= 8*n. If so, let ptext_len =
+ * LSB(32,AIV).
+ */
+
+ ptext_len = ((unsigned int)aiv[4] << 24)
+ | ((unsigned int)aiv[5] << 16)
+ | ((unsigned int)aiv[6] << 8)
+ | (unsigned int)aiv[7];
+ if (8 * (n - 1) >= ptext_len || ptext_len > 8 * n) {
+ OPENSSL_cleanse(out, inlen);
+ return 0;
+ }
+
+ /*
+ * Check that the rightmost padding_len octets of the output data are
+ * zero.
+ */
+ padding_len = padded_len - ptext_len;
+ if (CRYPTO_memcmp(out + ptext_len, zeros, padding_len) != 0) {
+ OPENSSL_cleanse(out, inlen);
+ return 0;
+ }
+
+ /* Section 4.2 step 3: Remove padding */
+ return ptext_len;
+}
projects / openssl.git / blobdiff