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authorJouni Malinen <j@w1.fi>2008-02-28 01:34:43 (GMT)
committerJouni Malinen <jm@jm.kir.nu>2008-02-28 01:34:43 (GMT)
commit6fc6879bd55a394f807cbbe927df736c190cb8ab (patch)
treecdf50da0c58f21510a808d53502a060d911ff243 /src/tls/rsa.c
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Re-initialize hostapd/wpa_supplicant git repository based on 0.6.3 release
Diffstat (limited to 'src/tls/rsa.c')
-rw-r--r--src/tls/rsa.c359
1 files changed, 359 insertions, 0 deletions
diff --git a/src/tls/rsa.c b/src/tls/rsa.c
new file mode 100644
index 0000000..bfc0d52
--- /dev/null
+++ b/src/tls/rsa.c
@@ -0,0 +1,359 @@
+/*
+ * RSA
+ * Copyright (c) 2006, Jouni Malinen <j@w1.fi>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Alternatively, this software may be distributed under the terms of BSD
+ * license.
+ *
+ * See README and COPYING for more details.
+ */
+
+#include "includes.h"
+
+#include "common.h"
+#include "crypto.h"
+#include "asn1.h"
+#include "bignum.h"
+#include "rsa.h"
+
+
+struct crypto_rsa_key {
+ int private_key; /* whether private key is set */
+ struct bignum *n; /* modulus (p * q) */
+ struct bignum *e; /* public exponent */
+ /* The following parameters are available only if private_key is set */
+ struct bignum *d; /* private exponent */
+ struct bignum *p; /* prime p (factor of n) */
+ struct bignum *q; /* prime q (factor of n) */
+ struct bignum *dmp1; /* d mod (p - 1); CRT exponent */
+ struct bignum *dmq1; /* d mod (q - 1); CRT exponent */
+ struct bignum *iqmp; /* 1 / q mod p; CRT coefficient */
+};
+
+
+static const u8 * crypto_rsa_parse_integer(const u8 *pos, const u8 *end,
+ struct bignum *num)
+{
+ struct asn1_hdr hdr;
+
+ if (pos == NULL)
+ return NULL;
+
+ if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
+ hdr.class != ASN1_CLASS_UNIVERSAL || hdr.tag != ASN1_TAG_INTEGER) {
+ wpa_printf(MSG_DEBUG, "RSA: Expected INTEGER - found class %d "
+ "tag 0x%x", hdr.class, hdr.tag);
+ return NULL;
+ }
+
+ if (bignum_set_unsigned_bin(num, hdr.payload, hdr.length) < 0) {
+ wpa_printf(MSG_DEBUG, "RSA: Failed to parse INTEGER");
+ return NULL;
+ }
+
+ return hdr.payload + hdr.length;
+}
+
+
+/**
+ * crypto_rsa_import_public_key - Import an RSA public key
+ * @buf: Key buffer (DER encoded RSA public key)
+ * @len: Key buffer length in bytes
+ * Returns: Pointer to the public key or %NULL on failure
+ */
+struct crypto_rsa_key *
+crypto_rsa_import_public_key(const u8 *buf, size_t len)
+{
+ struct crypto_rsa_key *key;
+ struct asn1_hdr hdr;
+ const u8 *pos, *end;
+
+ key = os_zalloc(sizeof(*key));
+ if (key == NULL)
+ return NULL;
+
+ key->n = bignum_init();
+ key->e = bignum_init();
+ if (key->n == NULL || key->e == NULL) {
+ crypto_rsa_free(key);
+ return NULL;
+ }
+
+ /*
+ * PKCS #1, 7.1:
+ * RSAPublicKey ::= SEQUENCE {
+ * modulus INTEGER, -- n
+ * publicExponent INTEGER -- e
+ * }
+ */
+
+ if (asn1_get_next(buf, len, &hdr) < 0 ||
+ hdr.class != ASN1_CLASS_UNIVERSAL ||
+ hdr.tag != ASN1_TAG_SEQUENCE) {
+ wpa_printf(MSG_DEBUG, "RSA: Expected SEQUENCE "
+ "(public key) - found class %d tag 0x%x",
+ hdr.class, hdr.tag);
+ goto error;
+ }
+ pos = hdr.payload;
+ end = pos + hdr.length;
+
+ pos = crypto_rsa_parse_integer(pos, end, key->n);
+ pos = crypto_rsa_parse_integer(pos, end, key->e);
+
+ if (pos == NULL)
+ goto error;
+
+ if (pos != end) {
+ wpa_hexdump(MSG_DEBUG,
+ "RSA: Extra data in public key SEQUENCE",
+ pos, end - pos);
+ goto error;
+ }
+
+ return key;
+
+error:
+ crypto_rsa_free(key);
+ return NULL;
+}
+
+
+/**
+ * crypto_rsa_import_private_key - Import an RSA private key
+ * @buf: Key buffer (DER encoded RSA private key)
+ * @len: Key buffer length in bytes
+ * Returns: Pointer to the private key or %NULL on failure
+ */
+struct crypto_rsa_key *
+crypto_rsa_import_private_key(const u8 *buf, size_t len)
+{
+ struct crypto_rsa_key *key;
+ struct bignum *zero;
+ struct asn1_hdr hdr;
+ const u8 *pos, *end;
+
+ key = os_zalloc(sizeof(*key));
+ if (key == NULL)
+ return NULL;
+
+ key->private_key = 1;
+
+ key->n = bignum_init();
+ key->e = bignum_init();
+ key->d = bignum_init();
+ key->p = bignum_init();
+ key->q = bignum_init();
+ key->dmp1 = bignum_init();
+ key->dmq1 = bignum_init();
+ key->iqmp = bignum_init();
+
+ if (key->n == NULL || key->e == NULL || key->d == NULL ||
+ key->p == NULL || key->q == NULL || key->dmp1 == NULL ||
+ key->dmq1 == NULL || key->iqmp == NULL) {
+ crypto_rsa_free(key);
+ return NULL;
+ }
+
+ /*
+ * PKCS #1, 7.2:
+ * RSAPrivateKey ::= SEQUENCE {
+ * version Version,
+ * modulus INTEGER, -- n
+ * publicExponent INTEGER, -- e
+ * privateExponent INTEGER, -- d
+ * prime1 INTEGER, -- p
+ * prime2 INTEGER, -- q
+ * exponent1 INTEGER, -- d mod (p-1)
+ * exponent2 INTEGER, -- d mod (q-1)
+ * coefficient INTEGER -- (inverse of q) mod p
+ * }
+ *
+ * Version ::= INTEGER -- shall be 0 for this version of the standard
+ */
+ if (asn1_get_next(buf, len, &hdr) < 0 ||
+ hdr.class != ASN1_CLASS_UNIVERSAL ||
+ hdr.tag != ASN1_TAG_SEQUENCE) {
+ wpa_printf(MSG_DEBUG, "RSA: Expected SEQUENCE "
+ "(public key) - found class %d tag 0x%x",
+ hdr.class, hdr.tag);
+ goto error;
+ }
+ pos = hdr.payload;
+ end = pos + hdr.length;
+
+ zero = bignum_init();
+ if (zero == NULL)
+ goto error;
+ pos = crypto_rsa_parse_integer(pos, end, zero);
+ if (pos == NULL || bignum_cmp_d(zero, 0) != 0) {
+ wpa_printf(MSG_DEBUG, "RSA: Expected zero INTEGER in the "
+ "beginning of private key; not found");
+ bignum_deinit(zero);
+ goto error;
+ }
+ bignum_deinit(zero);
+
+ pos = crypto_rsa_parse_integer(pos, end, key->n);
+ pos = crypto_rsa_parse_integer(pos, end, key->e);
+ pos = crypto_rsa_parse_integer(pos, end, key->d);
+ pos = crypto_rsa_parse_integer(pos, end, key->p);
+ pos = crypto_rsa_parse_integer(pos, end, key->q);
+ pos = crypto_rsa_parse_integer(pos, end, key->dmp1);
+ pos = crypto_rsa_parse_integer(pos, end, key->dmq1);
+ pos = crypto_rsa_parse_integer(pos, end, key->iqmp);
+
+ if (pos == NULL)
+ goto error;
+
+ if (pos != end) {
+ wpa_hexdump(MSG_DEBUG,
+ "RSA: Extra data in public key SEQUENCE",
+ pos, end - pos);
+ goto error;
+ }
+
+ return key;
+
+error:
+ crypto_rsa_free(key);
+ return NULL;
+}
+
+
+/**
+ * crypto_rsa_get_modulus_len - Get the modulus length of the RSA key
+ * @key: RSA key
+ * Returns: Modulus length of the key
+ */
+size_t crypto_rsa_get_modulus_len(struct crypto_rsa_key *key)
+{
+ return bignum_get_unsigned_bin_len(key->n);
+}
+
+
+/**
+ * crypto_rsa_exptmod - RSA modular exponentiation
+ * @in: Input data
+ * @inlen: Input data length
+ * @out: Buffer for output data
+ * @outlen: Maximum size of the output buffer and used size on success
+ * @key: RSA key
+ * @use_private: 1 = Use RSA private key, 0 = Use RSA public key
+ * Returns: 0 on success, -1 on failure
+ */
+int crypto_rsa_exptmod(const u8 *in, size_t inlen, u8 *out, size_t *outlen,
+ struct crypto_rsa_key *key, int use_private)
+{
+ struct bignum *tmp, *a = NULL, *b = NULL;
+ int ret = -1;
+ size_t modlen;
+
+ if (use_private && !key->private_key)
+ return -1;
+
+ tmp = bignum_init();
+ if (tmp == NULL)
+ return -1;
+
+ if (bignum_set_unsigned_bin(tmp, in, inlen) < 0)
+ goto error;
+ if (bignum_cmp(key->n, tmp) < 0) {
+ /* Too large input value for the RSA key modulus */
+ goto error;
+ }
+
+ if (use_private) {
+ /*
+ * Decrypt (or sign) using Chinese remainer theorem to speed
+ * up calculation. This is equivalent to tmp = tmp^d mod n
+ * (which would require more CPU to calculate directly).
+ *
+ * dmp1 = (1/e) mod (p-1)
+ * dmq1 = (1/e) mod (q-1)
+ * iqmp = (1/q) mod p, where p > q
+ * m1 = c^dmp1 mod p
+ * m2 = c^dmq1 mod q
+ * h = q^-1 (m1 - m2) mod p
+ * m = m2 + hq
+ */
+ a = bignum_init();
+ b = bignum_init();
+ if (a == NULL || b == NULL)
+ goto error;
+
+ /* a = tmp^dmp1 mod p */
+ if (bignum_exptmod(tmp, key->dmp1, key->p, a) < 0)
+ goto error;
+
+ /* b = tmp^dmq1 mod q */
+ if (bignum_exptmod(tmp, key->dmq1, key->q, b) < 0)
+ goto error;
+
+ /* tmp = (a - b) * (1/q mod p) (mod p) */
+ if (bignum_sub(a, b, tmp) < 0 ||
+ bignum_mulmod(tmp, key->iqmp, key->p, tmp) < 0)
+ goto error;
+
+ /* tmp = b + q * tmp */
+ if (bignum_mul(tmp, key->q, tmp) < 0 ||
+ bignum_add(tmp, b, tmp) < 0)
+ goto error;
+ } else {
+ /* Encrypt (or verify signature) */
+ /* tmp = tmp^e mod N */
+ if (bignum_exptmod(tmp, key->e, key->n, tmp) < 0)
+ goto error;
+ }
+
+ modlen = crypto_rsa_get_modulus_len(key);
+ if (modlen > *outlen) {
+ *outlen = modlen;
+ goto error;
+ }
+
+ if (bignum_get_unsigned_bin_len(tmp) > modlen)
+ goto error; /* should never happen */
+
+ *outlen = modlen;
+ os_memset(out, 0, modlen);
+ if (bignum_get_unsigned_bin(
+ tmp, out +
+ (modlen - bignum_get_unsigned_bin_len(tmp)), NULL) < 0)
+ goto error;
+
+ ret = 0;
+
+error:
+ bignum_deinit(tmp);
+ bignum_deinit(a);
+ bignum_deinit(b);
+ return ret;
+}
+
+
+/**
+ * crypto_rsa_free - Free RSA key
+ * @key: RSA key to be freed
+ *
+ * This function frees an RSA key imported with either
+ * crypto_rsa_import_public_key() or crypto_rsa_import_private_key().
+ */
+void crypto_rsa_free(struct crypto_rsa_key *key)
+{
+ if (key) {
+ bignum_deinit(key->n);
+ bignum_deinit(key->e);
+ bignum_deinit(key->d);
+ bignum_deinit(key->p);
+ bignum_deinit(key->q);
+ bignum_deinit(key->dmp1);
+ bignum_deinit(key->dmq1);
+ bignum_deinit(key->iqmp);
+ os_free(key);
+ }
+}