Mercurial > dropbear
view libtomcrypt/src/pk/pkcs1/pkcs_1_v1_5_encode.c @ 447:278805938dcf
Patch from Nicolai Ehemann to try binding before going to the background,
so that if it exits early (because something's already listening etc)
then it will return an exitcode of 1.
author | Matt Johnston <matt@ucc.asn.au> |
---|---|
date | Thu, 19 Jul 2007 15:54:18 +0000 |
parents | 0cbe8f6dbf9e |
children | f849a5ca2efc |
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/* LibTomCrypt, modular cryptographic library -- Tom St Denis * * LibTomCrypt is a library that provides various cryptographic * algorithms in a highly modular and flexible manner. * * The library is free for all purposes without any express * guarantee it works. * * Tom St Denis, [email protected], http://libtomcrypt.com */ #include "tomcrypt.h" /*! \file pkcs_1_v1_5_encode.c * * PKCS #1 v1.5 Padding (Andreas Lange) */ #ifdef PKCS_1 /*! \brief PKCS #1 v1.5 encode. * * \param msg The data to encode * \param msglen The length of the data to encode (octets) * \param block_type Block type to use in padding (\sa ltc_pkcs_1_v1_5_blocks) * \param modulus_bitlen The bit length of the RSA modulus * \param prng An active PRNG state (only for LTC_PKCS_1_EME) * \param prng_idx The index of the PRNG desired (only for LTC_PKCS_1_EME) * \param out [out] The destination for the encoded data * \param outlen [in/out] The max size and resulting size of the encoded data * * \return CRYPT_OK if successful */ int pkcs_1_v1_5_encode(const unsigned char *msg, unsigned long msglen, int block_type, unsigned long modulus_bitlen, prng_state *prng, int prng_idx, unsigned char *out, unsigned long *outlen) { unsigned long modulus_len, ps_len, i; unsigned char *ps; int result; /* valid block_type? */ if ((block_type != LTC_PKCS_1_EMSA) && (block_type != LTC_PKCS_1_EME)) { return CRYPT_PK_INVALID_PADDING; } if (block_type == LTC_PKCS_1_EME) { /* encryption padding, we need a valid PRNG */ if ((result = prng_is_valid(prng_idx)) != CRYPT_OK) { return result; } } modulus_len = (modulus_bitlen >> 3) + (modulus_bitlen & 7 ? 1 : 0); /* test message size */ if ((msglen + 11) > modulus_len) { return CRYPT_PK_INVALID_SIZE; } if (*outlen < modulus_len) { *outlen = modulus_len; result = CRYPT_BUFFER_OVERFLOW; goto bail; } /* generate an octets string PS */ ps = &out[2]; ps_len = modulus_len - msglen - 3; if (block_type == LTC_PKCS_1_EME) { /* now choose a random ps */ if (prng_descriptor[prng_idx].read(ps, ps_len, prng) != ps_len) { result = CRYPT_ERROR_READPRNG; goto bail; } /* transform zero bytes (if any) to non-zero random bytes */ for (i = 0; i < ps_len; i++) { while (ps[i] == 0) { if (prng_descriptor[prng_idx].read(&ps[i], 1, prng) != 1) { result = CRYPT_ERROR_READPRNG; goto bail; } } } } else { XMEMSET(ps, 0xFF, ps_len); } /* create string of length modulus_len */ out[0] = 0x00; out[1] = (unsigned char)block_type; /* block_type 1 or 2 */ out[2 + ps_len] = 0x00; XMEMCPY(&out[2 + ps_len + 1], msg, msglen); *outlen = modulus_len; result = CRYPT_OK; bail: return result; } /* pkcs_1_v1_5_encode */ #endif /* #ifdef PKCS_1 */ /* $Source: /cvs/libtom/libtomcrypt/src/pk/pkcs1/pkcs_1_v1_5_encode.c,v $ */ /* $Revision: 1.2 $ */ /* $Date: 2006/11/01 09:12:06 $ */