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author | David Monniaux <david.monniaux@univ-grenoble-alpes.fr> | 2020-03-03 08:17:40 +0100 |
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committer | David Monniaux <david.monniaux@univ-grenoble-alpes.fr> | 2020-03-03 08:17:40 +0100 |
commit | 1ab7b51c30e1b10ac45b0bd64cefdc01da0f7f68 (patch) | |
tree | 210ffc156c83f04fb0c61a40b4f9037d7ba8a7e1 /test/monniaux/BearSSL/src/rsa/rsa_pss_sig_pad.c | |
parent | 222c9047d61961db9c6b19fed5ca49829223fd33 (diff) | |
parent | 12be46d59a2483a10d77fa8ee67f7e0ca1bd702f (diff) | |
download | compcert-kvx-1ab7b51c30e1b10ac45b0bd64cefdc01da0f7f68.tar.gz compcert-kvx-1ab7b51c30e1b10ac45b0bd64cefdc01da0f7f68.zip |
Merge branch 'mppa-cse2' of gricad-gitlab.univ-grenoble-alpes.fr:sixcy/CompCert into mppa-work
Diffstat (limited to 'test/monniaux/BearSSL/src/rsa/rsa_pss_sig_pad.c')
-rw-r--r-- | test/monniaux/BearSSL/src/rsa/rsa_pss_sig_pad.c | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/test/monniaux/BearSSL/src/rsa/rsa_pss_sig_pad.c b/test/monniaux/BearSSL/src/rsa/rsa_pss_sig_pad.c new file mode 100644 index 00000000..13e90274 --- /dev/null +++ b/test/monniaux/BearSSL/src/rsa/rsa_pss_sig_pad.c @@ -0,0 +1,106 @@ +/* + * Copyright (c) 2018 Thomas Pornin <pornin@bolet.org> + * + * Permission is hereby granted, free of charge, to any person obtaining + * a copy of this software and associated documentation files (the + * "Software"), to deal in the Software without restriction, including + * without limitation the rights to use, copy, modify, merge, publish, + * distribute, sublicense, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice shall be + * included in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ + +#include "inner.h" + +/* see inner.h */ +uint32_t +br_rsa_pss_sig_pad(const br_prng_class **rng, + const br_hash_class *hf_data, const br_hash_class *hf_mgf1, + const unsigned char *hash, size_t salt_len, + uint32_t n_bitlen, unsigned char *x) +{ + size_t xlen, hash_len; + br_hash_compat_context hc; + unsigned char *salt, *seed; + + hash_len = br_digest_size(hf_data); + + /* + * The padded string is one bit smaller than the modulus; + * notably, if the modulus length is equal to 1 modulo 8, then + * the padded string will be one _byte_ smaller, and the first + * byte will be set to 0. We apply these transformations here. + */ + n_bitlen --; + if ((n_bitlen & 7) == 0) { + *x ++ = 0; + } + xlen = (n_bitlen + 7) >> 3; + + /* + * Check that the modulus is large enough for the hash value + * length combined with the intended salt length. + */ + if (hash_len > xlen || salt_len > xlen + || (hash_len + salt_len + 2) > xlen) + { + return 0; + } + + /* + * Produce a random salt. + */ + salt = x + xlen - hash_len - salt_len - 1; + if (salt_len != 0) { + (*rng)->generate(rng, salt, salt_len); + } + + /* + * Compute the seed for MGF1. + */ + seed = x + xlen - hash_len - 1; + hf_data->init(&hc.vtable); + memset(seed, 0, 8); + hf_data->update(&hc.vtable, seed, 8); + hf_data->update(&hc.vtable, hash, hash_len); + hf_data->update(&hc.vtable, salt, salt_len); + hf_data->out(&hc.vtable, seed); + + /* + * Prepare string PS (padded salt). The salt is already at the + * right place. + */ + memset(x, 0, xlen - salt_len - hash_len - 2); + x[xlen - salt_len - hash_len - 2] = 0x01; + + /* + * Generate the mask and XOR it into PS. + */ + br_mgf1_xor(x, xlen - hash_len - 1, hf_mgf1, seed, hash_len); + + /* + * Clear the top bits to ensure the value is lower than the + * modulus. + */ + x[0] &= 0xFF >> (((uint32_t)xlen << 3) - n_bitlen); + + /* + * The seed (H) is already in the right place. We just set the + * last byte. + */ + x[xlen - 1] = 0xBC; + + return 1; +} |