From 9dea5a397111f1e049f10b9e1a2d6f70a9db6a95 Mon Sep 17 00:00:00 2001 From: Sverker Eriksson Date: Thu, 21 Mar 2013 11:59:42 +0100 Subject: crypto: Refactor mod_exp_nif As a preparation for the new mod_exp_prime and in the quest to reduce to use of the old mpint format. --- lib/crypto/c_src/crypto.c | 24 +++++++++----- lib/crypto/src/crypto.erl | 79 ++++++++++++++++++++++++++--------------------- 2 files changed, 60 insertions(+), 43 deletions(-) (limited to 'lib/crypto') diff --git a/lib/crypto/c_src/crypto.c b/lib/crypto/c_src/crypto.c index e77e5fb8f0..8139b331bf 100644 --- a/lib/crypto/c_src/crypto.c +++ b/lib/crypto/c_src/crypto.c @@ -304,7 +304,7 @@ static ErlNifFunc nif_funcs[] = { {"rand_bytes", 3, rand_bytes_3}, {"strong_rand_mpint_nif", 3, strong_rand_mpint_nif}, {"rand_uniform_nif", 2, rand_uniform_nif}, - {"mod_exp_nif", 3, mod_exp_nif}, + {"mod_exp_nif", 4, mod_exp_nif}, {"dss_verify", 4, dss_verify}, {"rsa_verify_nif", 4, rsa_verify_nif}, {"aes_cbc_crypt", 4, aes_cbc_crypt}, @@ -1543,16 +1543,19 @@ static ERL_NIF_TERM rand_uniform_nif(ErlNifEnv* env, int argc, const ERL_NIF_TER } static ERL_NIF_TERM mod_exp_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) -{/* (Base,Exponent,Modulo) */ +{/* (Base,Exponent,Modulo,bin_hdr) */ BIGNUM *bn_base=NULL, *bn_exponent=NULL, *bn_modulo, *bn_result; BN_CTX *bn_ctx; unsigned char* ptr; unsigned dlen; + unsigned bin_hdr; /* return type: 0=plain binary, 4: mpint */ + unsigned extra_byte; ERL_NIF_TERM ret; - if (!get_bn_from_mpint(env, argv[0], &bn_base) - || !get_bn_from_mpint(env, argv[1], &bn_exponent) - || !get_bn_from_mpint(env, argv[2], &bn_modulo)) { + if (!get_bn_from_bin(env, argv[0], &bn_base) + || !get_bn_from_bin(env, argv[1], &bn_exponent) + || !get_bn_from_bin(env, argv[2], &bn_modulo) + || !enif_get_uint(env,argv[3],&bin_hdr) || (bin_hdr & ~4)) { if (bn_base) BN_free(bn_base); if (bn_exponent) BN_free(bn_exponent); @@ -1562,9 +1565,14 @@ static ERL_NIF_TERM mod_exp_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM arg bn_ctx = BN_CTX_new(); BN_mod_exp(bn_result, bn_base, bn_exponent, bn_modulo, bn_ctx); dlen = BN_num_bytes(bn_result); - ptr = enif_make_new_binary(env, dlen+4, &ret); - put_int32(ptr, dlen); - BN_bn2bin(bn_result, ptr+4); + extra_byte = bin_hdr && BN_is_bit_set(bn_result, dlen*8-1); + ptr = enif_make_new_binary(env, bin_hdr+extra_byte+dlen, &ret); + if (bin_hdr) { + put_int32(ptr, extra_byte+dlen); + ptr[4] = 0; /* extra zeroed byte to ensure a positive mpint */ + ptr += bin_hdr + extra_byte; + } + BN_bn2bin(bn_result, ptr); BN_free(bn_result); BN_CTX_free(bn_ctx); BN_free(bn_modulo); diff --git a/lib/crypto/src/crypto.erl b/lib/crypto/src/crypto.erl index 1328a95e87..f5c1cd2845 100644 --- a/lib/crypto/src/crypto.erl +++ b/lib/crypto/src/crypto.erl @@ -787,17 +787,15 @@ rand_uniform_nif(_From,_To) -> ?nif_stub. %% mod_exp(Base, Exponent, Modulo) when is_integer(Base), is_integer(Exponent), is_integer(Modulo) -> - erlint(mod_exp(mpint(Base), mpint(Exponent), mpint(Modulo))); + bin_to_int(mod_exp_nif(int_to_bin(Base), int_to_bin(Exponent), int_to_bin(Modulo), 0)); mod_exp(Base, Exponent, Modulo) -> - case mod_exp_nif(Base,Exponent,Modulo) of - <> when MSB > 127 -> - <<(Len + 1):32/integer, 0, MSB, Rest/binary>>; - Whatever -> - Whatever + mod_exp_nif(mpint_to_bin(Base),mpint_to_bin(Exponent),mpint_to_bin(Modulo), 4). + end. -mod_exp_nif(_Base,_Exp,_Mod) -> ?nif_stub. + +mod_exp_nif(_Base,_Exp,_Mod,_bin_hdr) -> ?nif_stub. %% %% DSS, RSA - verify @@ -1071,43 +1069,54 @@ dh_compute_key_nif(_OthersPublicKey, _MyPrivateKey, _DHParameters) -> ?nif_stub. %% large integer in a binary with 32bit length %% MP representaion (SSH2) -mpint(X) when X < 0 -> - case X of - -1 -> - <<0,0,0,1,16#ff>>; - _ -> - mpint_neg(X,0,[]) - end; -mpint(X) -> - case X of - 0 -> - <<0,0,0,0>>; - _ -> - mpint_pos(X,0,[]) - end. +mpint(X) when X < 0 -> mpint_neg(X); +mpint(X) -> mpint_pos(X). -define(UINT32(X), X:32/unsigned-big-integer). -mpint_neg(-1,I,Ds=[MSB|_]) -> - if MSB band 16#80 =/= 16#80 -> - <>; - true -> - (<>) - end; -mpint_neg(X,I,Ds) -> - mpint_neg(X bsr 8,I+1,[(X band 255)|Ds]). + +mpint_neg(X) -> + Bin = int_to_bin_neg(X, []), + Sz = byte_size(Bin), + <>. -mpint_pos(0,I,Ds=[MSB|_]) -> +mpint_pos(X) -> + Bin = int_to_bin_pos(X, []), + <> = Bin, + Sz = byte_size(Bin), if MSB band 16#80 == 16#80 -> - <>; + <>; true -> - (<>) - end; -mpint_pos(X,I,Ds) -> - mpint_pos(X bsr 8,I+1,[(X band 255)|Ds]). + <> + end. + +int_to_bin(X) when X < 0 -> int_to_bin_neg(X, []); +int_to_bin(X) -> int_to_bin_pos(X, []). + +int_to_bin_pos(X) when X >= 0 -> + int_to_bin_pos(X, []). + +int_to_bin_pos(0,Ds=[_|_]) -> + list_to_binary(Ds); +int_to_bin_pos(X,Ds) -> + int_to_bin_pos(X bsr 8, [(X band 255)|Ds]). + +int_to_bin_neg(-1, Ds=[MSB|_]) when MSB >= 16#80 -> + list_to_binary(Ds); +int_to_bin_neg(X,Ds) -> + int_to_bin_neg(X bsr 8, [(X band 255)|Ds]). + + +bin_to_int(Bin) -> + Bits = bit_size(Bin), + <> = Bin, + Integer. %% int from integer in a binary with 32bit length erlint(<>) -> Bits= MPIntSize * 8, <> = MPIntValue, Integer. + +mpint_to_bin(<>) -> + Bin. -- cgit v1.2.3