--- /dev/null
+/*
+ * PKCS #1 (RSA Encryption)
+ * Copyright (c) 2006-2014, Jouni Malinen <j@w1.fi>
+ *
+ * This software may be distributed under the terms of the BSD license.
+ * See README for more details.
+ */
+
+#include "includes.h"
+
+#include "common.h"
+#include "crypto/crypto.h"
+#include "rsa.h"
+#include "asn1.h"
+#include "pkcs1.h"
+
+
+static int pkcs1_generate_encryption_block(u8 block_type, size_t modlen,
+ const u8 *in, size_t inlen,
+ u8 *out, size_t *outlen)
+{
+ size_t ps_len;
+ u8 *pos;
+
+ /*
+ * PKCS #1 v1.5, 8.1:
+ *
+ * EB = 00 || BT || PS || 00 || D
+ * BT = 00 or 01 for private-key operation; 02 for public-key operation
+ * PS = k-3-||D||; at least eight octets
+ * (BT=0: PS=0x00, BT=1: PS=0xff, BT=2: PS=pseudorandom non-zero)
+ * k = length of modulus in octets (modlen)
+ */
+
+ if (modlen < 12 || modlen > *outlen || inlen > modlen - 11) {
+ wpa_printf(MSG_DEBUG, "PKCS #1: %s - Invalid buffer "
+ "lengths (modlen=%lu outlen=%lu inlen=%lu)",
+ __func__, (unsigned long) modlen,
+ (unsigned long) *outlen,
+ (unsigned long) inlen);
+ return -1;
+ }
+
+ pos = out;
+ *pos++ = 0x00;
+ *pos++ = block_type; /* BT */
+ ps_len = modlen - inlen - 3;
+ switch (block_type) {
+ case 0:
+ os_memset(pos, 0x00, ps_len);
+ pos += ps_len;
+ break;
+ case 1:
+ os_memset(pos, 0xff, ps_len);
+ pos += ps_len;
+ break;
+ case 2:
+ if (os_get_random(pos, ps_len) < 0) {
+ wpa_printf(MSG_DEBUG, "PKCS #1: %s - Failed to get "
+ "random data for PS", __func__);
+ return -1;
+ }
+ while (ps_len--) {
+ if (*pos == 0x00)
+ *pos = 0x01;
+ pos++;
+ }
+ break;
+ default:
+ wpa_printf(MSG_DEBUG, "PKCS #1: %s - Unsupported block type "
+ "%d", __func__, block_type);
+ return -1;
+ }
+ *pos++ = 0x00;
+ os_memcpy(pos, in, inlen); /* D */
+
+ return 0;
+}
+
+
+int pkcs1_encrypt(int block_type, struct crypto_rsa_key *key,
+ int use_private, const u8 *in, size_t inlen,
+ u8 *out, size_t *outlen)
+{
+ size_t modlen;
+
+ modlen = crypto_rsa_get_modulus_len(key);
+
+ if (pkcs1_generate_encryption_block(block_type, modlen, in, inlen,
+ out, outlen) < 0)
+ return -1;
+
+ return crypto_rsa_exptmod(out, modlen, out, outlen, key, use_private);
+}
+
+
+int pkcs1_v15_private_key_decrypt(struct crypto_rsa_key *key,
+ const u8 *in, size_t inlen,
+ u8 *out, size_t *outlen)
+{
+ int res;
+ u8 *pos, *end;
+
+ res = crypto_rsa_exptmod(in, inlen, out, outlen, key, 1);
+ if (res)
+ return res;
+
+ if (*outlen < 2 || out[0] != 0 || out[1] != 2)
+ return -1;
+
+ /* Skip PS (pseudorandom non-zero octets) */
+ pos = out + 2;
+ end = out + *outlen;
+ while (*pos && pos < end)
+ pos++;
+ if (pos == end)
+ return -1;
+ if (pos - out - 2 < 8) {
+ /* PKCS #1 v1.5, 8.1: At least eight octets long PS */
+ wpa_printf(MSG_INFO, "LibTomCrypt: Too short padding");
+ return -1;
+ }
+ pos++;
+
+ *outlen -= pos - out;
+
+ /* Strip PKCS #1 header */
+ os_memmove(out, pos, *outlen);
+
+ return 0;
+}
+
+
+int pkcs1_decrypt_public_key(struct crypto_rsa_key *key,
+ const u8 *crypt, size_t crypt_len,
+ u8 *plain, size_t *plain_len)
+{
+ size_t len;
+ u8 *pos;
+
+ len = *plain_len;
+ if (crypto_rsa_exptmod(crypt, crypt_len, plain, &len, key, 0) < 0)
+ return -1;
+
+ /*
+ * PKCS #1 v1.5, 8.1:
+ *
+ * EB = 00 || BT || PS || 00 || D
+ * BT = 00 or 01
+ * PS = k-3-||D|| times (00 if BT=00) or (FF if BT=01)
+ * k = length of modulus in octets
+ *
+ * Based on 10.1.3, "The block type shall be 01" for a signature.
+ */
+
+ if (len < 3 + 8 + 16 /* min hash len */ ||
+ plain[0] != 0x00 || plain[1] != 0x01) {
+ wpa_printf(MSG_INFO, "LibTomCrypt: Invalid signature EB "
+ "structure");
+ return -1;
+ }
+
+ pos = plain + 3;
+ /* BT = 01 */
+ if (plain[2] != 0xff) {
+ wpa_printf(MSG_INFO, "LibTomCrypt: Invalid signature "
+ "PS (BT=01)");
+ return -1;
+ }
+ while (pos < plain + len && *pos == 0xff)
+ pos++;
+
+ if (pos - plain - 2 < 8) {
+ /* PKCS #1 v1.5, 8.1: At least eight octets long PS */
+ wpa_printf(MSG_INFO, "LibTomCrypt: Too short signature "
+ "padding");
+ return -1;
+ }
+
+ if (pos + 16 /* min hash len */ >= plain + len || *pos != 0x00) {
+ wpa_printf(MSG_INFO, "LibTomCrypt: Invalid signature EB "
+ "structure (2)");
+ return -1;
+ }
+ pos++;
+ len -= pos - plain;
+
+ /* Strip PKCS #1 header */
+ os_memmove(plain, pos, len);
+ *plain_len = len;
+
+ return 0;
+}
+
+
+int pkcs1_v15_sig_ver(struct crypto_public_key *pk,
+ const u8 *s, size_t s_len,
+ const struct asn1_oid *hash_alg,
+ const u8 *hash, size_t hash_len)
+{
+ int res;
+ u8 *decrypted;
+ size_t decrypted_len;
+ const u8 *pos, *end, *next, *da_end;
+ struct asn1_hdr hdr;
+ struct asn1_oid oid;
+
+ decrypted = os_malloc(s_len);
+ if (decrypted == NULL)
+ return -1;
+ decrypted_len = s_len;
+ res = crypto_public_key_decrypt_pkcs1(pk, s, s_len, decrypted,
+ &decrypted_len);
+ if (res < 0) {
+ wpa_printf(MSG_INFO, "PKCS #1: RSA decrypt failed");
+ os_free(decrypted);
+ return -1;
+ }
+ wpa_hexdump(MSG_DEBUG, "Decrypted(S)", decrypted, decrypted_len);
+
+ /*
+ * PKCS #1 v1.5, 10.1.2:
+ *
+ * DigestInfo ::= SEQUENCE {
+ * digestAlgorithm DigestAlgorithmIdentifier,
+ * digest Digest
+ * }
+ *
+ * DigestAlgorithmIdentifier ::= AlgorithmIdentifier
+ *
+ * Digest ::= OCTET STRING
+ *
+ */
+ if (asn1_get_next(decrypted, decrypted_len, &hdr) < 0 ||
+ hdr.class != ASN1_CLASS_UNIVERSAL ||
+ hdr.tag != ASN1_TAG_SEQUENCE) {
+ wpa_printf(MSG_DEBUG,
+ "PKCS #1: Expected SEQUENCE (DigestInfo) - found class %d tag 0x%x",
+ hdr.class, hdr.tag);
+ os_free(decrypted);
+ return -1;
+ }
+
+ pos = hdr.payload;
+ end = pos + hdr.length;
+
+ /*
+ * X.509:
+ * AlgorithmIdentifier ::= SEQUENCE {
+ * algorithm OBJECT IDENTIFIER,
+ * parameters ANY DEFINED BY algorithm OPTIONAL
+ * }
+ */
+
+ if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
+ hdr.class != ASN1_CLASS_UNIVERSAL ||
+ hdr.tag != ASN1_TAG_SEQUENCE) {
+ wpa_printf(MSG_DEBUG,
+ "PKCS #1: Expected SEQUENCE (AlgorithmIdentifier) - found class %d tag 0x%x",
+ hdr.class, hdr.tag);
+ os_free(decrypted);
+ return -1;
+ }
+ da_end = hdr.payload + hdr.length;
+
+ if (asn1_get_oid(hdr.payload, hdr.length, &oid, &next)) {
+ wpa_printf(MSG_DEBUG,
+ "PKCS #1: Failed to parse digestAlgorithm");
+ os_free(decrypted);
+ return -1;
+ }
+
+ if (!asn1_oid_equal(&oid, hash_alg)) {
+ char txt[100], txt2[100];
+ asn1_oid_to_str(&oid, txt, sizeof(txt));
+ asn1_oid_to_str(hash_alg, txt2, sizeof(txt2));
+ wpa_printf(MSG_DEBUG,
+ "PKCS #1: Hash alg OID mismatch: was %s, expected %s",
+ txt, txt2);
+ os_free(decrypted);
+ return -1;
+ }
+
+ /* Digest ::= OCTET STRING */
+ pos = da_end;
+ end = decrypted + decrypted_len;
+
+ if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
+ hdr.class != ASN1_CLASS_UNIVERSAL ||
+ hdr.tag != ASN1_TAG_OCTETSTRING) {
+ wpa_printf(MSG_DEBUG,
+ "PKCS #1: Expected OCTETSTRING (Digest) - found class %d tag 0x%x",
+ hdr.class, hdr.tag);
+ os_free(decrypted);
+ return -1;
+ }
+ wpa_hexdump(MSG_MSGDUMP, "PKCS #1: Decrypted Digest",
+ hdr.payload, hdr.length);
+
+ if (hdr.length != hash_len ||
+ os_memcmp_const(hdr.payload, hash, hdr.length) != 0) {
+ wpa_printf(MSG_INFO, "PKCS #1: Digest value does not match calculated hash");
+ os_free(decrypted);
+ return -1;
+ }
+
+ os_free(decrypted);
+
+ if (hdr.payload + hdr.length != end) {
+ wpa_printf(MSG_INFO,
+ "PKCS #1: Extra data after signature - reject");
+
+ wpa_hexdump(MSG_DEBUG, "PKCS #1: Extra data",
+ hdr.payload + hdr.length,
+ end - hdr.payload - hdr.length);
+ return -1;
+ }
+
+ return 0;
+}
projects / mech_eap.git / blobdiff