Add back support for RSA_X931_PADDING

This makes the custom stalt stack work again.

Tested by robert as part of a larger diff
ok jsing

diff --git a/lib/libcrypto/rsa/rsa_eay.c b/lib/libcrypto/rsa/rsa_eay.c
index e65319b..6db563f 100644 (file)
--- a/lib/libcrypto/rsa/rsa_eay.c
+++ b/lib/libcrypto/rsa/rsa_eay.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: rsa_eay.c,v 1.59 2023/04/15 18:48:52 tb Exp $ */
+/* $OpenBSD: rsa_eay.c,v 1.60 2023/05/05 12:21:44 tb Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -382,11 +382,14 @@ RSA_eay_private_encrypt(int flen, const unsigned char *from, unsigned char *to,
        case RSA_PKCS1_PADDING:
                i = RSA_padding_add_PKCS1_type_1(buf, num, from, flen);
                break;
+       case RSA_X931_PADDING:
+               i = RSA_padding_add_X931(buf, num, from, flen);
+               break;
        case RSA_NO_PADDING:
                i = RSA_padding_add_none(buf, num, from, flen);
                break;
        default:
-               RSAerror(RSA_R_ILLEGAL_OR_UNSUPPORTED_PADDING_MODE);
+               RSAerror(RSA_R_UNKNOWN_PADDING_TYPE);
                goto err;
        }
        if (i <= 0)
@@ -446,11 +449,14 @@ RSA_eay_private_encrypt(int flen, const unsigned char *from, unsigned char *to,
                        goto err;
 
        if (padding == RSA_X931_PADDING) {
-               RSAerror(RSA_R_ILLEGAL_OR_UNSUPPORTED_PADDING_MODE);
-               goto err;
-       }
-
-       res = ret;
+               if (!BN_sub(f, rsa->n, ret))
+                       goto err;
+               if (BN_cmp(ret, f) > 0)
+                       res = f;
+               else
+                       res = ret;
+       } else
+               res = ret;
 
        /* put in leading 0 bytes if the number is less than the
         * length of the modulus */
@@ -661,10 +667,9 @@ RSA_eay_public_decrypt(int flen, const unsigned char *from, unsigned char *to,
            rsa->_method_mod_n))
                goto err;
 
-       if (padding == RSA_X931_PADDING) {
-               RSAerror(RSA_R_ILLEGAL_OR_UNSUPPORTED_PADDING_MODE);
-               goto err;
-       }
+       if (padding == RSA_X931_PADDING && (ret->d[0] & 0xf) != 12)
+               if (!BN_sub(ret, rsa->n, ret))
+                       goto err;
 
        p = buf;
        i = BN_bn2bin(ret, p);
@@ -673,6 +678,9 @@ RSA_eay_public_decrypt(int flen, const unsigned char *from, unsigned char *to,
        case RSA_PKCS1_PADDING:
                r = RSA_padding_check_PKCS1_type_1(to, num, buf, i, num);
                break;
+       case RSA_X931_PADDING:
+               r = RSA_padding_check_X931(to, num, buf, i, num);
+               break;
        case RSA_NO_PADDING:
                r = RSA_padding_check_none(to, num, buf, i, num);
                break;

diff --git a/lib/libcrypto/rsa/rsa_local.h b/lib/libcrypto/rsa/rsa_local.h
index b438ab4..4bc2cee 100644 (file)
--- a/lib/libcrypto/rsa/rsa_local.h
+++ b/lib/libcrypto/rsa/rsa_local.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: rsa_local.h,v 1.1 2022/11/26 16:08:54 tb Exp $ */
+/* $OpenBSD: rsa_local.h,v 1.2 2023/05/05 12:21:44 tb Exp $ */
 
 __BEGIN_HIDDEN_DECLS
 
@@ -91,4 +91,10 @@ extern int int_rsa_verify(int dtype, 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 RSA_padding_add_X931(unsigned char *to, int tlen,
+    const unsigned char *f, int fl);
+int RSA_padding_check_X931(unsigned char *to, int tlen,
+    const unsigned char *f, int fl, int rsa_len);
+int RSA_X931_hash_id(int nid);
+
 __END_HIDDEN_DECLS

diff --git a/lib/libcrypto/rsa/rsa_pmeth.c b/lib/libcrypto/rsa/rsa_pmeth.c
index 8e06365..429524d 100644 (file)
--- a/lib/libcrypto/rsa/rsa_pmeth.c
+++ b/lib/libcrypto/rsa/rsa_pmeth.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: rsa_pmeth.c,v 1.37 2023/04/25 15:48:48 tb Exp $ */
+/* $OpenBSD: rsa_pmeth.c,v 1.38 2023/05/05 12:21:44 tb Exp $ */
 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project 2006.
  */
@@ -187,7 +187,7 @@ static int
 pkey_rsa_sign(EVP_PKEY_CTX *ctx, unsigned char *sig, size_t *siglen,
     const unsigned char *tbs, size_t tbslen)
 {
-       int ret = -1;
+       int ret;
        RSA_PKEY_CTX *rctx = ctx->data;
        RSA *rsa = ctx->pkey->pkey.rsa;
 
@@ -197,11 +197,21 @@ pkey_rsa_sign(EVP_PKEY_CTX *ctx, unsigned char *sig, size_t *siglen,
                        return -1;
                }
 
-               if (rctx->pad_mode != RSA_PKCS1_PADDING &&
-                   rctx->pad_mode != RSA_PKCS1_PSS_PADDING)
-                       return -1;
-
-               if (rctx->pad_mode == RSA_PKCS1_PADDING) {
+               if (rctx->pad_mode == RSA_X931_PADDING) {
+                       if ((size_t)EVP_PKEY_size(ctx->pkey) < tbslen + 1) {
+                               RSAerror(RSA_R_KEY_SIZE_TOO_SMALL);
+                               return -1;
+                       }
+                       if (!setup_tbuf(rctx, ctx)) {
+                               RSAerror(ERR_R_MALLOC_FAILURE);
+                               return -1;
+                       }
+                       memcpy(rctx->tbuf, tbs, tbslen);
+                       rctx->tbuf[tbslen] =
+                           RSA_X931_hash_id(EVP_MD_type(rctx->md));
+                       ret = RSA_private_encrypt(tbslen + 1, rctx->tbuf, sig,
+                           rsa, RSA_X931_PADDING);
+               } else if (rctx->pad_mode == RSA_PKCS1_PADDING) {
                        unsigned int sltmp;
 
                        ret = RSA_sign(EVP_MD_type(rctx->md), tbs, tbslen, sig,
@@ -217,6 +227,8 @@ pkey_rsa_sign(EVP_PKEY_CTX *ctx, unsigned char *sig, size_t *siglen,
                                return -1;
                        ret = RSA_private_encrypt(RSA_size(rsa), rctx->tbuf,
                            sig, rsa, RSA_NO_PADDING);
+               } else {
+                       return -1;
                }
        } else {
                ret = RSA_private_encrypt(tbslen, tbs, sig, ctx->pkey->pkey.rsa,
@@ -236,16 +248,36 @@ pkey_rsa_verifyrecover(EVP_PKEY_CTX *ctx, unsigned char *rout, size_t *routlen,
        RSA_PKEY_CTX *rctx = ctx->data;
 
        if (rctx->md) {
-               size_t sltmp;
+               if (rctx->pad_mode == RSA_X931_PADDING) {
+                       if (!setup_tbuf(rctx, ctx))
+                               return -1;
+                       ret = RSA_public_decrypt(siglen, sig, rctx->tbuf,
+                           ctx->pkey->pkey.rsa, RSA_X931_PADDING);
+                       if (ret < 1)
+                               return 0;
+                       ret--;
+                       if (rctx->tbuf[ret] !=
+                           RSA_X931_hash_id(EVP_MD_type(rctx->md))) {
+                               RSAerror(RSA_R_ALGORITHM_MISMATCH);
+                               return 0;
+                       }
+                       if (ret != EVP_MD_size(rctx->md)) {
+                               RSAerror(RSA_R_INVALID_DIGEST_LENGTH);
+                               return 0;
+                       }
+                       if (rout)
+                               memcpy(rout, rctx->tbuf, ret);
+               } else if (rctx->pad_mode == RSA_PKCS1_PADDING) {
+                       size_t sltmp;
 
-               if (rctx->pad_mode != RSA_PKCS1_PADDING)
+                       ret = int_rsa_verify(EVP_MD_type(rctx->md), NULL, 0,
+                           rout, &sltmp, sig, siglen, ctx->pkey->pkey.rsa);
+                       if (ret <= 0)
+                               return 0;
+                       ret = sltmp;
+               } else {
                        return -1;
-
-               ret = int_rsa_verify(EVP_MD_type(rctx->md), NULL, 0,
-                   rout, &sltmp, sig, siglen, ctx->pkey->pkey.rsa);
-               if (ret <= 0)
-                       return 0;
-               ret = sltmp;
+               }
        } else {
                ret = RSA_public_decrypt(siglen, sig, rout, ctx->pkey->pkey.rsa,
                    rctx->pad_mode);
@@ -263,7 +295,6 @@ pkey_rsa_verify(EVP_PKEY_CTX *ctx, const unsigned char *sig, size_t siglen,
        RSA_PKEY_CTX *rctx = ctx->data;
        RSA *rsa = ctx->pkey->pkey.rsa;
        size_t rslen;
-       int ret;
 
        if (rctx->md) {
                if (rctx->pad_mode == RSA_PKCS1_PADDING)
@@ -273,22 +304,30 @@ pkey_rsa_verify(EVP_PKEY_CTX *ctx, const unsigned char *sig, size_t siglen,
                        RSAerror(RSA_R_INVALID_DIGEST_LENGTH);
                        return -1;
                }
+               if (rctx->pad_mode == RSA_X931_PADDING) {
+                       if (pkey_rsa_verifyrecover(ctx, NULL, &rslen, sig,
+                           siglen) <= 0)
+                               return 0;
+               } else if (rctx->pad_mode == RSA_PKCS1_PSS_PADDING) {
+                       int ret;
 
-               if (rctx->pad_mode != RSA_PKCS1_PSS_PADDING)
-                       return -1;
-
-               if (!setup_tbuf(rctx, ctx))
+                       if (!setup_tbuf(rctx, ctx))
+                               return -1;
+                       ret = RSA_public_decrypt(siglen, sig, rctx->tbuf,
+                           rsa, RSA_NO_PADDING);
+                       if (ret <= 0)
+                               return 0;
+                       ret = RSA_verify_PKCS1_PSS_mgf1(rsa, tbs, rctx->md,
+                           rctx->mgf1md, rctx->tbuf, rctx->saltlen);
+                       if (ret <= 0)
+                               return 0;
+                       return 1;
+               } else {
                        return -1;
-               ret = RSA_public_decrypt(siglen, sig, rctx->tbuf,
-                   rsa, RSA_NO_PADDING);
-               if (ret <= 0)
-                       return 0;
-               ret = RSA_verify_PKCS1_PSS_mgf1(rsa, tbs, rctx->md,
-                   rctx->mgf1md, rctx->tbuf, rctx->saltlen);
-               if (ret <= 0)
-                       return 0;
-               return 1;
+               }
        } else {
+               int ret;
+
                if (!setup_tbuf(rctx, ctx))
                        return -1;
 
@@ -365,34 +404,41 @@ check_padding_md(const EVP_MD *md, int padding)
        if (md == NULL)
                return 1;
 
-       if (padding == RSA_NO_PADDING || padding == RSA_X931_PADDING) {
-               RSAerror(RSA_R_ILLEGAL_OR_UNSUPPORTED_PADDING_MODE);
+       if (padding == RSA_NO_PADDING) {
+               RSAerror(RSA_R_INVALID_PADDING_MODE);
                return 0;
        }
 
-       /* List of all supported RSA digests. */
-       /* RFC 8017 and NIST CSOR. */
-       switch(EVP_MD_type(md)) {
-       case NID_sha1:
-       case NID_sha224:
-       case NID_sha256:
-       case NID_sha384:
-       case NID_sha512:
-       case NID_sha512_224:
-       case NID_sha512_256:
-       case NID_sha3_224:
-       case NID_sha3_256:
-       case NID_sha3_384:
-       case NID_sha3_512:
-       case NID_md5:
-       case NID_md5_sha1:
-       case NID_md4:
-       case NID_ripemd160:
-               return 1;
+       if (padding == RSA_X931_PADDING) {
+               if (RSA_X931_hash_id(EVP_MD_type(md)) == -1) {
+                       RSAerror(RSA_R_INVALID_X931_DIGEST);
+                       return 0;
+               }
+       } else {
+               /* List of all supported RSA digests. */
+               /* RFC 8017 and NIST CSOR. */
+               switch(EVP_MD_type(md)) {
+               case NID_sha1:
+               case NID_sha224:
+               case NID_sha256:
+               case NID_sha384:
+               case NID_sha512:
+               case NID_sha512_224:
+               case NID_sha512_256:
+               case NID_sha3_224:
+               case NID_sha3_256:
+               case NID_sha3_384:
+               case NID_sha3_512:
+               case NID_md5:
+               case NID_md5_sha1:
+               case NID_md4:
+               case NID_ripemd160:
+                       return 1;
 
-       default:
-               RSAerror(RSA_R_INVALID_DIGEST);
-               return 0;
+               default:
+                       RSAerror(RSA_R_INVALID_DIGEST);
+                       return 0;
+               }
        }
 
        return 1;
@@ -598,6 +644,8 @@ pkey_rsa_ctrl_str(EVP_PKEY_CTX *ctx, const char *type, const char *value)
                        pm = RSA_PKCS1_OAEP_PADDING;
                else if (!strcmp(value, "oaep"))
                        pm = RSA_PKCS1_OAEP_PADDING;
+               else if (!strcmp(value, "x931"))
+                       pm = RSA_X931_PADDING;
                else if (!strcmp(value, "pss"))
                        pm = RSA_PKCS1_PSS_PADDING;
                else {