PKCS 1: Add function for checking v1.5 RSA signature
This could be used as a step towards replacing more specific functions used in X.509 and TLS processing. Signed-off-by: Jouni Malinen <j@w1.fi>
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Jouni Malinen
parent
d3811845f3
commit
54ac6ff8c4
2 changed files with 137 additions and 1 deletions
131
src/tls/pkcs1.c
131
src/tls/pkcs1.c
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@ -1,6 +1,6 @@
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/*
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* PKCS #1 (RSA Encryption)
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* Copyright (c) 2006-2009, Jouni Malinen <j@w1.fi>
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* Copyright (c) 2006-2014, Jouni Malinen <j@w1.fi>
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*
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* This software may be distributed under the terms of the BSD license.
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* See README for more details.
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@ -9,7 +9,9 @@
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#include "includes.h"
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#include "common.h"
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#include "crypto/crypto.h"
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#include "rsa.h"
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#include "asn1.h"
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#include "pkcs1.h"
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@ -189,3 +191,130 @@ int pkcs1_decrypt_public_key(struct crypto_rsa_key *key,
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return 0;
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}
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int pkcs1_v15_sig_ver(struct crypto_public_key *pk,
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const u8 *s, size_t s_len,
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const struct asn1_oid *hash_alg,
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const u8 *hash, size_t hash_len)
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{
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int res;
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u8 *decrypted;
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size_t decrypted_len;
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const u8 *pos, *end, *next, *da_end;
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struct asn1_hdr hdr;
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struct asn1_oid oid;
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decrypted = os_malloc(s_len);
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if (decrypted == NULL)
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return -1;
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decrypted_len = s_len;
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res = crypto_public_key_decrypt_pkcs1(pk, s, s_len, decrypted,
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&decrypted_len);
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if (res < 0) {
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wpa_printf(MSG_INFO, "PKCS #1: RSA decrypt failed");
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os_free(decrypted);
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return -1;
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}
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wpa_hexdump(MSG_DEBUG, "Decrypted(S)", decrypted, decrypted_len);
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/*
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* PKCS #1 v1.5, 10.1.2:
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*
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* DigestInfo ::= SEQUENCE {
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* digestAlgorithm DigestAlgorithmIdentifier,
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* digest Digest
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* }
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*
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* DigestAlgorithmIdentifier ::= AlgorithmIdentifier
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*
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* Digest ::= OCTET STRING
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*
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*/
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if (asn1_get_next(decrypted, decrypted_len, &hdr) < 0 ||
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hdr.class != ASN1_CLASS_UNIVERSAL ||
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hdr.tag != ASN1_TAG_SEQUENCE) {
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wpa_printf(MSG_DEBUG,
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"PKCS #1: Expected SEQUENCE (DigestInfo) - found class %d tag 0x%x",
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hdr.class, hdr.tag);
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os_free(decrypted);
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return -1;
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}
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pos = hdr.payload;
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end = pos + hdr.length;
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/*
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* X.509:
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* AlgorithmIdentifier ::= SEQUENCE {
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* algorithm OBJECT IDENTIFIER,
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* parameters ANY DEFINED BY algorithm OPTIONAL
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* }
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*/
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if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
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hdr.class != ASN1_CLASS_UNIVERSAL ||
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hdr.tag != ASN1_TAG_SEQUENCE) {
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wpa_printf(MSG_DEBUG,
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"PKCS #1: Expected SEQUENCE (AlgorithmIdentifier) - found class %d tag 0x%x",
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hdr.class, hdr.tag);
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os_free(decrypted);
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return -1;
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}
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da_end = hdr.payload + hdr.length;
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if (asn1_get_oid(hdr.payload, hdr.length, &oid, &next)) {
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wpa_printf(MSG_DEBUG,
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"PKCS #1: Failed to parse digestAlgorithm");
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os_free(decrypted);
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return -1;
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}
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if (!asn1_oid_equal(&oid, hash_alg)) {
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char txt[100], txt2[100];
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asn1_oid_to_str(&oid, txt, sizeof(txt));
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asn1_oid_to_str(hash_alg, txt2, sizeof(txt2));
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wpa_printf(MSG_DEBUG,
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"PKCS #1: Hash alg OID mismatch: was %s, expected %s",
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txt, txt2);
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os_free(decrypted);
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return -1;
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}
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/* Digest ::= OCTET STRING */
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pos = da_end;
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end = decrypted + decrypted_len;
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if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
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hdr.class != ASN1_CLASS_UNIVERSAL ||
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hdr.tag != ASN1_TAG_OCTETSTRING) {
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wpa_printf(MSG_DEBUG,
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"PKCS #1: Expected OCTETSTRING (Digest) - found class %d tag 0x%x",
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hdr.class, hdr.tag);
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os_free(decrypted);
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return -1;
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}
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wpa_hexdump(MSG_MSGDUMP, "PKCS #1: Decrypted Digest",
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hdr.payload, hdr.length);
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if (hdr.length != hash_len ||
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os_memcmp(hdr.payload, hash, hdr.length) != 0) {
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wpa_printf(MSG_INFO, "PKCS #1: Digest value does not match calculated hash");
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os_free(decrypted);
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return -1;
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}
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os_free(decrypted);
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if (hdr.payload + hdr.length != end) {
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wpa_printf(MSG_INFO,
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"PKCS #1: Extra data after signature - reject");
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wpa_hexdump(MSG_DEBUG, "PKCS #1: Extra data",
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hdr.payload + hdr.length,
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end - hdr.payload - hdr.length);
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return -1;
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}
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return 0;
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}
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@ -9,6 +9,9 @@
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#ifndef PKCS1_H
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#define PKCS1_H
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struct crypto_public_key;
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struct asn1_oid;
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int pkcs1_encrypt(int block_type, struct crypto_rsa_key *key,
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int use_private, const u8 *in, size_t inlen,
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u8 *out, size_t *outlen);
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@ -18,5 +21,9 @@ int pkcs1_v15_private_key_decrypt(struct crypto_rsa_key *key,
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int pkcs1_decrypt_public_key(struct crypto_rsa_key *key,
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const u8 *crypt, size_t crypt_len,
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u8 *plain, size_t *plain_len);
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int pkcs1_v15_sig_ver(struct crypto_public_key *pk,
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const u8 *s, size_t s_len,
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const struct asn1_oid *hash_alg,
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const u8 *hash, size_t hash_len);
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#endif /* PKCS1_H */
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