/* Size of an SSL signature: MD5+SHA1 */
#define SSL_SIG_LENGTH 36
-int RSA_sign(int type, const unsigned char *m, unsigned int m_len,
- unsigned char *sigret, unsigned int *siglen, RSA *rsa)
+/*
+ * encode_pkcs1 encodes a DigestInfo prefix of hash |type| and digest |m|, as
+ * described in EMSA-PKCS1-v1_5-ENCODE, RFC 3447 section 9.2 step 2. This
+ * encodes the DigestInfo (T and tLen) but does not add the padding.
+ *
+ * On success, it returns one and sets |*out| to a newly allocated buffer
+ * containing the result and |*out_len| to its length. The caller must free
+ * |*out| with |OPENSSL_free|. Otherwise, it returns zero.
+ */
+static int encode_pkcs1(unsigned char **out, int *out_len, int type,
+ const unsigned char *m, unsigned int m_len)
{
X509_SIG sig;
- ASN1_TYPE parameter;
- int i, j, ret = 1;
- unsigned char *p, *tmps = NULL;
- const unsigned char *s = NULL;
X509_ALGOR algor;
+ ASN1_TYPE parameter;
ASN1_OCTET_STRING digest;
+ uint8_t *der = NULL;
+ int len;
+
+ sig.algor = &algor;
+ sig.algor->algorithm = OBJ_nid2obj(type);
+ if (sig.algor->algorithm == NULL) {
+ RSAerr(RSA_F_ENCODE_PKCS1, RSA_R_UNKNOWN_ALGORITHM_TYPE);
+ return 0;
+ }
+ if (OBJ_length(sig.algor->algorithm) == 0) {
+ RSAerr(RSA_F_ENCODE_PKCS1,
+ RSA_R_THE_ASN1_OBJECT_IDENTIFIER_IS_NOT_KNOWN_FOR_THIS_MD);
+ return 0;
+ }
+ parameter.type = V_ASN1_NULL;
+ parameter.value.ptr = NULL;
+ sig.algor->parameter = ¶meter;
+
+ sig.digest = &digest;
+ sig.digest->data = (unsigned char *)m;
+ sig.digest->length = m_len;
+
+ len = i2d_X509_SIG(&sig, &der);
+ if (len < 0)
+ return 0;
+
+ *out = der;
+ *out_len = len;
+ return 1;
+}
+
+int RSA_sign(int type, const unsigned char *m, unsigned int m_len,
+ unsigned char *sigret, unsigned int *siglen, RSA *rsa)
+{
+ int encrypt_len, encoded_len = 0, ret = 0;
+ unsigned char *tmps = NULL;
+ const unsigned char *encoded = NULL;
+
if (rsa->meth->rsa_sign) {
return rsa->meth->rsa_sign(type, m, m_len, sigret, siglen, rsa);
}
- /* Special case: SSL signature, just check the length */
+
+ /* Compute the encoded digest. */
if (type == NID_md5_sha1) {
+ /*
+ * NID_md5_sha1 corresponds to the MD5/SHA1 combination in TLS 1.1 and
+ * earlier. It has no DigestInfo wrapper but otherwise is
+ * RSASSA-PKCS1-v1_5.
+ */
if (m_len != SSL_SIG_LENGTH) {
RSAerr(RSA_F_RSA_SIGN, RSA_R_INVALID_MESSAGE_LENGTH);
- return (0);
+ return 0;
}
- i = SSL_SIG_LENGTH;
- s = m;
+ encoded_len = SSL_SIG_LENGTH;
+ encoded = m;
} else {
- sig.algor = &algor;
- sig.algor->algorithm = OBJ_nid2obj(type);
- if (sig.algor->algorithm == NULL) {
- RSAerr(RSA_F_RSA_SIGN, RSA_R_UNKNOWN_ALGORITHM_TYPE);
- return (0);
- }
- if (OBJ_length(sig.algor->algorithm) == 0) {
- RSAerr(RSA_F_RSA_SIGN,
- RSA_R_THE_ASN1_OBJECT_IDENTIFIER_IS_NOT_KNOWN_FOR_THIS_MD);
- return (0);
- }
- parameter.type = V_ASN1_NULL;
- parameter.value.ptr = NULL;
- sig.algor->parameter = ¶meter;
-
- sig.digest = &digest;
- sig.digest->data = (unsigned char *)m; /* TMP UGLY CAST */
- sig.digest->length = m_len;
-
- i = i2d_X509_SIG(&sig, NULL);
+ if (!encode_pkcs1(&tmps, &encoded_len, type, m, m_len))
+ goto err;
+ encoded = tmps;
}
- j = RSA_size(rsa);
- if (i > (j - RSA_PKCS1_PADDING_SIZE)) {
+
+ if (encoded_len > RSA_size(rsa) - RSA_PKCS1_PADDING_SIZE) {
RSAerr(RSA_F_RSA_SIGN, RSA_R_DIGEST_TOO_BIG_FOR_RSA_KEY);
- return (0);
- }
- if (type != NID_md5_sha1) {
- tmps = OPENSSL_malloc((unsigned int)j + 1);
- if (tmps == NULL) {
- RSAerr(RSA_F_RSA_SIGN, ERR_R_MALLOC_FAILURE);
- return (0);
- }
- p = tmps;
- i2d_X509_SIG(&sig, &p);
- s = tmps;
+ goto err;
}
- i = RSA_private_encrypt(i, s, sigret, rsa, RSA_PKCS1_PADDING);
- if (i <= 0)
- ret = 0;
- else
- *siglen = i;
-
- if (type != NID_md5_sha1)
- OPENSSL_clear_free(tmps, (unsigned int)j + 1);
- return (ret);
-}
+ encrypt_len = RSA_private_encrypt(encoded_len, encoded, sigret, rsa,
+ RSA_PKCS1_PADDING);
+ if (encrypt_len <= 0)
+ goto err;
-/*
- * Check DigestInfo structure does not contain extraneous data by reencoding
- * using DER and checking encoding against original.
- */
-static int rsa_check_digestinfo(X509_SIG *sig, const unsigned char *dinfo,
- int dinfolen)
-{
- unsigned char *der = NULL;
- int derlen;
- int ret = 0;
- derlen = i2d_X509_SIG(sig, &der);
- if (derlen <= 0)
- return 0;
- if (derlen == dinfolen && !memcmp(dinfo, der, derlen))
- ret = 1;
- OPENSSL_clear_free(der, derlen);
+ *siglen = encrypt_len;
+ ret = 1;
+
+err:
+ OPENSSL_clear_free(tmps, (size_t)encoded_len);
return ret;
}
-int int_rsa_verify(int dtype, const unsigned char *m,
- unsigned int m_len,
+/*
+ * int_rsa_verify verifies an RSA signature in |sigbuf| using |rsa|. It may be
+ * called in two modes. If |rm| is NULL, it verifies the signature for digest
+ * |m|. Otherwise, it recovers the digest from the signature, writing the digest
+ * to |rm| and the length to |*prm_len|. |type| is the NID of the digest
+ * algorithm to use. It returns one on successful verification and zero
+ * otherwise.
+ */
+int int_rsa_verify(int type, const unsigned char *m, unsigned int m_len,
unsigned char *rm, size_t *prm_len,
const unsigned char *sigbuf, size_t siglen, RSA *rsa)
{
- int i, ret = 0, sigtype;
- unsigned char *s;
- X509_SIG *sig = NULL;
+ int decrypt_len, ret = 0, encoded_len = 0;
+ unsigned char *decrypt_buf = NULL, *encoded = NULL;
- if (siglen != (unsigned int)RSA_size(rsa)) {
+ if (siglen != (size_t)RSA_size(rsa)) {
RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_WRONG_SIGNATURE_LENGTH);
- return (0);
- }
-
- if ((dtype == NID_md5_sha1) && rm) {
- i = RSA_public_decrypt((int)siglen,
- sigbuf, rm, rsa, RSA_PKCS1_PADDING);
- if (i <= 0)
- return 0;
- *prm_len = i;
- return 1;
+ return 0;
}
- s = OPENSSL_malloc((unsigned int)siglen);
- if (s == NULL) {
+ /* Recover the encoded digest. */
+ decrypt_buf = OPENSSL_malloc(siglen);
+ if (decrypt_buf == NULL) {
RSAerr(RSA_F_INT_RSA_VERIFY, ERR_R_MALLOC_FAILURE);
goto err;
}
- if ((dtype == NID_md5_sha1) && (m_len != SSL_SIG_LENGTH)) {
- RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_INVALID_MESSAGE_LENGTH);
- goto err;
- }
- i = RSA_public_decrypt((int)siglen, sigbuf, s, rsa, RSA_PKCS1_PADDING);
- if (i <= 0)
+ decrypt_len = RSA_public_decrypt((int)siglen, sigbuf, decrypt_buf, rsa,
+ RSA_PKCS1_PADDING);
+ if (decrypt_len <= 0)
goto err;
- /*
- * Oddball MDC2 case: signature can be OCTET STRING. check for correct
- * tag and length octets.
- */
- if (dtype == NID_mdc2 && i == 18 && s[0] == 0x04 && s[1] == 0x10) {
- if (rm) {
- memcpy(rm, s + 2, 16);
- *prm_len = 16;
- ret = 1;
- } else if (memcmp(m, s + 2, 16)) {
+
+ if (type == NID_md5_sha1) {
+ /*
+ * NID_md5_sha1 corresponds to the MD5/SHA1 combination in TLS 1.1 and
+ * earlier. It has no DigestInfo wrapper but otherwise is
+ * RSASSA-PKCS1-v1_5.
+ */
+ if (decrypt_len != SSL_SIG_LENGTH) {
RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_BAD_SIGNATURE);
- } else {
- ret = 1;
+ goto err;
}
- } else if (dtype == NID_md5_sha1) {
- /* Special case: SSL signature */
- if ((i != SSL_SIG_LENGTH) || memcmp(s, m, SSL_SIG_LENGTH))
- RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_BAD_SIGNATURE);
- else
- ret = 1;
- } else {
- const unsigned char *p = s;
- sig = d2i_X509_SIG(NULL, &p, (long)i);
- if (sig == NULL)
- goto err;
+ if (rm != NULL) {
+ memcpy(rm, decrypt_buf, SSL_SIG_LENGTH);
+ *prm_len = SSL_SIG_LENGTH;
+ } else {
+ if (m_len != SSL_SIG_LENGTH) {
+ RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_INVALID_MESSAGE_LENGTH);
+ goto err;
+ }
- /* Excess data can be used to create forgeries */
- if (p != s + i || !rsa_check_digestinfo(sig, s, i)) {
- RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_BAD_SIGNATURE);
- goto err;
+ if (memcmp(decrypt_buf, m, SSL_SIG_LENGTH) != 0) {
+ RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_BAD_SIGNATURE);
+ goto err;
+ }
}
+ } else if (type == NID_mdc2 && decrypt_len == 2 + 16
+ && decrypt_buf[0] == 0x04 && decrypt_buf[1] == 0x10) {
+ /*
+ * Oddball MDC2 case: signature can be OCTET STRING. check for correct
+ * tag and length octets.
+ */
+ if (rm != NULL) {
+ memcpy(rm, decrypt_buf + 2, 16);
+ *prm_len = 16;
+ } else {
+ if (m_len != 16) {
+ RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_INVALID_MESSAGE_LENGTH);
+ goto err;
+ }
+ if (memcmp(m, decrypt_buf + 2, 16) != 0) {
+ RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_BAD_SIGNATURE);
+ goto err;
+ }
+ }
+ } else {
/*
- * Parameters to the signature algorithm can also be used to create
- * forgeries
+ * If recovering the digest, extract a digest-sized output from the end
+ * of |decrypt_buf| for |encode_pkcs1|, then compare the decryption
+ * output as in a standard verification.
*/
- if (sig->algor->parameter
- && ASN1_TYPE_get(sig->algor->parameter) != V_ASN1_NULL) {
- RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_BAD_SIGNATURE);
- goto err;
+ if (rm != NULL) {
+ const EVP_MD *md = EVP_get_digestbynid(type);
+ if (md == NULL) {
+ RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_UNKNOWN_ALGORITHM_TYPE);
+ goto err;
+ }
+
+ m_len = EVP_MD_size(md);
+ if (m_len > (size_t)decrypt_len) {
+ RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_INVALID_DIGEST_LENGTH);
+ goto err;
+ }
+ m = decrypt_buf + decrypt_len - m_len;
}
- sigtype = OBJ_obj2nid(sig->algor->algorithm);
+ /* Construct the encoded digest and ensure it matches. */
+ if (!encode_pkcs1(&encoded, &encoded_len, type, m, m_len))
+ goto err;
- if (sigtype != dtype) {
- RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_ALGORITHM_MISMATCH);
+ if (encoded_len != decrypt_len
+ || memcmp(encoded, decrypt_buf, encoded_len) != 0) {
+ RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_BAD_SIGNATURE);
goto err;
}
- if (rm) {
- const EVP_MD *md;
- md = EVP_get_digestbynid(dtype);
- if (md && (EVP_MD_size(md) != sig->digest->length))
- RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_INVALID_DIGEST_LENGTH);
- else {
- memcpy(rm, sig->digest->data, sig->digest->length);
- *prm_len = sig->digest->length;
- ret = 1;
- }
- } else if (((unsigned int)sig->digest->length != m_len) ||
- (memcmp(m, sig->digest->data, m_len) != 0)) {
- RSAerr(RSA_F_INT_RSA_VERIFY, RSA_R_BAD_SIGNATURE);
- } else
- ret = 1;
+
+ /* Output the recovered digest. */
+ if (rm != NULL) {
+ memcpy(rm, m, m_len);
+ *prm_len = m_len;
+ }
}
- err:
- X509_SIG_free(sig);
- OPENSSL_clear_free(s, (unsigned int)siglen);
- return (ret);
+
+ ret = 1;
+
+err:
+ OPENSSL_clear_free(encoded, (size_t)encoded_len);
+ OPENSSL_clear_free(decrypt_buf, siglen);
+ return ret;
}
-int RSA_verify(int dtype, const unsigned char *m, unsigned int m_len,
+int RSA_verify(int type, const unsigned char *m, unsigned int m_len,
const unsigned char *sigbuf, unsigned int siglen, RSA *rsa)
{
if (rsa->meth->rsa_verify) {
- return rsa->meth->rsa_verify(dtype, m, m_len, sigbuf, siglen, rsa);
+ return rsa->meth->rsa_verify(type, m, m_len, sigbuf, siglen, rsa);
}
- return int_rsa_verify(dtype, m, m_len, NULL, NULL, sigbuf, siglen, rsa);
+ return int_rsa_verify(type, m, m_len, NULL, NULL, sigbuf, siglen, rsa);
}
projects / oweals / openssl.git / commitdiff