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-rw-r--r--lib/crypto/c_src/crypto.c24
-rw-r--r--lib/crypto/src/crypto.erl79
2 files changed, 60 insertions, 43 deletions
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
- <<Len:32/integer, MSB, Rest/binary>> 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 ->
- <<?UINT32((I+1)), (list_to_binary([255|Ds]))/binary>>;
- true ->
- (<<?UINT32(I), (list_to_binary(Ds))/binary>>)
- 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),
+ <<?UINT32(Sz), Bin/binary>>.
-mpint_pos(0,I,Ds=[MSB|_]) ->
+mpint_pos(X) ->
+ Bin = int_to_bin_pos(X, []),
+ <<MSB,_/binary>> = Bin,
+ Sz = byte_size(Bin),
if MSB band 16#80 == 16#80 ->
- <<?UINT32((I+1)), (list_to_binary([0|Ds]))/binary>>;
+ <<?UINT32((Sz+1)), 0, Bin/binary>>;
true ->
- (<<?UINT32(I), (list_to_binary(Ds))/binary>>)
- end;
-mpint_pos(X,I,Ds) ->
- mpint_pos(X bsr 8,I+1,[(X band 255)|Ds]).
+ <<?UINT32(Sz), Bin/binary>>
+ 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),
+ <<Integer:Bits/integer>> = Bin,
+ Integer.
%% int from integer in a binary with 32bit length
erlint(<<MPIntSize:32/integer,MPIntValue/binary>>) ->
Bits= MPIntSize * 8,
<<Integer:Bits/integer>> = MPIntValue,
Integer.
+
+mpint_to_bin(<<Len:32, Bin:Len/binary>>) ->
+ Bin.