/* $OpenBSD: rsa_pk1.c,v 1.17 2024/03/30 04:34:17 jsing Exp $ */ /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) * All rights reserved. * * This package is an SSL implementation written * by Eric Young (eay@cryptsoft.com). * The implementation was written so as to conform with Netscapes SSL. * * This library is free for commercial and non-commercial use as long as * the following conditions are aheared to. The following conditions * apply to all code found in this distribution, be it the RC4, RSA, * lhash, DES, etc., code; not just the SSL code. The SSL documentation * included with this distribution is covered by the same copyright terms * except that the holder is Tim Hudson (tjh@cryptsoft.com). * * Copyright remains Eric Young's, and as such any Copyright notices in * the code are not to be removed. * If this package is used in a product, Eric Young should be given attribution * as the author of the parts of the library used. * This can be in the form of a textual message at program startup or * in documentation (online or textual) provided with the package. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * "This product includes cryptographic software written by * Eric Young (eay@cryptsoft.com)" * The word 'cryptographic' can be left out if the rouines from the library * being used are not cryptographic related :-). * 4. If you include any Windows specific code (or a derivative thereof) from * the apps directory (application code) you must include an acknowledgement: * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" * * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * The licence and distribution terms for any publically available version or * derivative of this code cannot be changed. i.e. this code cannot simply be * copied and put under another distribution licence * [including the GNU Public Licence.] */ #include #include #include #include #include #include #include "bytestring.h" int RSA_padding_add_PKCS1_type_1(unsigned char *to, int tlen, const unsigned char *from, int flen) { CBB cbb; int i; int ret = 0; /* * Pad data block with PKCS1 type 1 padding - RFC 2313, section 8.1. */ memset(&cbb, 0, sizeof(cbb)); if (flen < 0 || tlen < 0) goto err; if (flen > tlen - RSA_PKCS1_PADDING_SIZE) { RSAerror(RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE); goto err; } if (!CBB_init_fixed(&cbb, to, tlen)) goto err; /* * Add leading NUL, block type (0x01), padding bytes (0xff) and * trailing NUL. */ if (!CBB_add_u8(&cbb, 0)) goto err; if (!CBB_add_u8(&cbb, 1)) goto err; for (i = 0; i < tlen - 3 - flen; i++) { if (!CBB_add_u8(&cbb, 0xff)) goto err; } if (!CBB_add_u8(&cbb, 0)) goto err; /* Now add the actual data. */ if (!CBB_add_bytes(&cbb, from, flen)) goto err; if (!CBB_finish(&cbb, NULL, NULL)) goto err; ret = 1; err: CBB_cleanup(&cbb); return ret; } LCRYPTO_ALIAS(RSA_padding_add_PKCS1_type_1); int RSA_padding_check_PKCS1_type_1(unsigned char *to, int tlen, const unsigned char *from, int flen, int num) { int i, j; const unsigned char *p; p = from; if (num != flen + 1 || *(p++) != 01) { RSAerror(RSA_R_BLOCK_TYPE_IS_NOT_01); return -1; } /* scan over padding data */ j = flen - 1; /* one for type. */ for (i = 0; i < j; i++) { if (*p != 0xff) { /* should decrypt to 0xff */ if (*p == 0) { p++; break; } else { RSAerror(RSA_R_BAD_FIXED_HEADER_DECRYPT); return -1; } } p++; } if (i == j) { RSAerror(RSA_R_NULL_BEFORE_BLOCK_MISSING); return -1; } if (i < 8) { RSAerror(RSA_R_BAD_PAD_BYTE_COUNT); return -1; } i++; /* Skip over the '\0' */ j -= i; if (j > tlen) { RSAerror(RSA_R_DATA_TOO_LARGE); return -1; } memcpy(to, p, j); return j; } LCRYPTO_ALIAS(RSA_padding_check_PKCS1_type_1); int RSA_padding_add_PKCS1_type_2(unsigned char *to, int tlen, const unsigned char *from, int flen) { uint8_t padding[256]; uint8_t pad; CBB cbb; CBS cbs; int i; int ret = 0; /* * Pad data block with PKCS1 type 2 padding - RFC 2313, section 8.1. */ memset(&cbb, 0, sizeof(cbb)); CBS_init(&cbs, NULL, 0); if (flen < 0 || tlen < 0) goto err; if (flen > tlen - RSA_PKCS1_PADDING_SIZE) { RSAerror(RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE); goto err; } if (!CBB_init_fixed(&cbb, to, tlen)) goto err; /* * Add leading NUL, block type (0x02), padding bytes (random non-zero * bytes) and trailing NUL. */ if (!CBB_add_u8(&cbb, 0)) goto err; if (!CBB_add_u8(&cbb, 2)) goto err; for (i = 0; i < tlen - 3 - flen; i++) { do { if (CBS_len(&cbs) == 0) { arc4random_buf(padding, sizeof(padding)); CBS_init(&cbs, padding, sizeof(padding)); } if (!CBS_get_u8(&cbs, &pad)) goto err; } while (pad == 0); if (!CBB_add_u8(&cbb, pad)) goto err; } if (!CBB_add_u8(&cbb, 0)) goto err; /* Now add the actual data. */ if (!CBB_add_bytes(&cbb, from, flen)) goto err; if (!CBB_finish(&cbb, NULL, NULL)) goto err; ret = 1; err: CBB_cleanup(&cbb); explicit_bzero(padding, sizeof(padding)); return ret; } LCRYPTO_ALIAS(RSA_padding_add_PKCS1_type_2); int RSA_padding_check_PKCS1_type_2(unsigned char *to, int tlen, const unsigned char *from, int flen, int num) { int i, j; const unsigned char *p; p = from; if (num != flen + 1 || *(p++) != 02) { RSAerror(RSA_R_BLOCK_TYPE_IS_NOT_02); return -1; } /* scan over padding data */ j = flen - 1; /* one for type. */ for (i = 0; i < j; i++) if (*(p++) == 0) break; if (i == j) { RSAerror(RSA_R_NULL_BEFORE_BLOCK_MISSING); return -1; } if (i < 8) { RSAerror(RSA_R_BAD_PAD_BYTE_COUNT); return -1; } i++; /* Skip over the '\0' */ j -= i; if (j > tlen) { RSAerror(RSA_R_DATA_TOO_LARGE); return -1; } memcpy(to, p, j); return j; } LCRYPTO_ALIAS(RSA_padding_check_PKCS1_type_2);