mirror of
https://libwebsockets.org/repo/libwebsockets
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c9731c5f17
This is a huge patch that should be a global NOP. For unix type platforms it enables -Wconversion to issue warnings (-> error) for all automatic casts that seem less than ideal but are normally concealed by the toolchain. This is things like passing an int to a size_t argument. Once enabled, I went through all args on my default build (which build most things) and tried to make the removed default cast explicit. With that approach it neither change nor bloat the code, since it compiles to whatever it was doing before, just with the casts made explicit... in a few cases I changed some length args from int to size_t but largely left the causes alone. From now on, new code that is relying on less than ideal casting will complain and nudge me to improve it by warnings.
266 lines
6.7 KiB
C
266 lines
6.7 KiB
C
/* $OpenBSD: smult_curve25519_ref.c,v 1.2 2013/11/02 22:02:14 markus Exp $ */
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/*
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version 20081011
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Matthew Dempsky
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Public domain.
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Derived from public domain code by D. J. Bernstein.
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*/
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static void add(unsigned int out[32],const unsigned int a[32],const unsigned int b[32])
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{
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unsigned int j;
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unsigned int u;
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u = 0;
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for (j = 0;j < 31;++j) { u += a[j] + b[j]; out[j] = u & 255; u >>= 8; }
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u += a[31] + b[31]; out[31] = u;
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}
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static void sub(unsigned int out[32],const unsigned int a[32],const unsigned int b[32])
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{
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unsigned int j;
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unsigned int u;
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u = 218;
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for (j = 0;j < 31;++j) {
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u += a[j] + 65280 - b[j];
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out[j] = u & 255;
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u >>= 8;
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}
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u += a[31] - b[31];
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out[31] = u;
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}
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static void squeeze(unsigned int a[32])
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{
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unsigned int j;
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unsigned int u;
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u = 0;
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for (j = 0;j < 31;++j) { u += a[j]; a[j] = u & 255; u >>= 8; }
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u += a[31]; a[31] = u & 127;
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u = 19 * (u >> 7);
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for (j = 0;j < 31;++j) { u += a[j]; a[j] = u & 255; u >>= 8; }
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u += a[31]; a[31] = u;
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}
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static const unsigned int minusp[32] = {
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19, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 128
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} ;
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static void freeze(unsigned int a[32])
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{
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unsigned int aorig[32];
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unsigned int j;
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unsigned int negative;
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for (j = 0;j < 32;++j) aorig[j] = a[j];
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add(a,a,minusp);
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negative = (unsigned int)-(int)((a[31] >> 7) & 1);
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for (j = 0;j < 32;++j) a[j] ^= negative & (aorig[j] ^ a[j]);
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}
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static void mult(unsigned int out[32],const unsigned int a[32],const unsigned int b[32])
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{
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unsigned int i;
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for (i = 0;i < 32;++i) {
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unsigned int j;
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unsigned int u;
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u = 0;
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for (j = 0;j <= i;++j) u += a[j] * b[i - j];
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for (j = i + 1;j < 32;++j) u += 38 * a[j] * b[i + 32 - j];
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out[i] = u;
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}
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squeeze(out);
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}
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static void mult121665(unsigned int out[32],const unsigned int a[32])
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{
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unsigned int j;
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unsigned int u;
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u = 0;
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for (j = 0;j < 31;++j) { u += 121665 * a[j]; out[j] = u & 255; u >>= 8; }
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u += 121665 * a[31]; out[31] = u & 127;
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u = 19 * (u >> 7);
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for (j = 0;j < 31;++j) { u += out[j]; out[j] = u & 255; u >>= 8; }
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u += out[j]; out[j] = u;
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}
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static void square(unsigned int out[32],const unsigned int a[32])
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{
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unsigned int i;
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unsigned int j;
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unsigned int u;
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for (i = 0;i < 32;++i) {
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u = 0;
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for (j = 0;j < i - j;++j) u += a[j] * a[i - j];
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for (j = i + 1;j < i + 32 - j;++j)
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if (i + 32 - j < 32 && j < 32)
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u += 38 * a[j] * a[i + 32 - j];
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u *= 2;
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if ((i & 1) == 0) {
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u += a[i / 2] * a[i / 2];
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u += 38 * a[i / 2 + 16] * a[i / 2 + 16];
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}
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out[i] = u;
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}
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squeeze(out);
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}
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static void smc_select(unsigned int p[64],unsigned int q[64],const unsigned int r[64],const unsigned int s[64],unsigned int b)
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{
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unsigned int j;
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unsigned int t;
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unsigned int bminus1;
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bminus1 = b - 1;
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for (j = 0;j < 64;++j) {
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t = bminus1 & (r[j] ^ s[j]);
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p[j] = s[j] ^ t;
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q[j] = r[j] ^ t;
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}
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}
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static void mainloop(unsigned int work[64],const unsigned char e[32])
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{
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unsigned int xzm1[64];
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unsigned int xzm[64];
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unsigned int xzmb[64];
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unsigned int xzm1b[64];
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unsigned int xznb[64];
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unsigned int xzn1b[64];
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unsigned int a0[64];
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unsigned int a1[64];
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unsigned int b0[64];
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unsigned int b1[64];
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unsigned int c1[64];
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unsigned int r[32];
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unsigned int s[32];
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unsigned int t[32];
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unsigned int u[32];
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unsigned int j;
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unsigned int b;
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int pos;
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for (j = 0;j < 32;++j) xzm1[j] = work[j];
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xzm1[32] = 1;
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for (j = 33;j < 64;++j) xzm1[j] = 0;
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xzm[0] = 1;
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for (j = 1;j < 64;++j) xzm[j] = 0;
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for (pos = 254;pos >= 0;--pos) {
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b = (unsigned int)(e[pos / 8] >> (pos & 7));
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b &= 1;
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smc_select(xzmb,xzm1b,xzm,xzm1,b);
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add(a0,xzmb,xzmb + 32);
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sub(a0 + 32,xzmb,xzmb + 32);
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add(a1,xzm1b,xzm1b + 32);
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sub(a1 + 32,xzm1b,xzm1b + 32);
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square(b0,a0);
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square(b0 + 32,a0 + 32);
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mult(b1,a1,a0 + 32);
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mult(b1 + 32,a1 + 32,a0);
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add(c1,b1,b1 + 32);
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sub(c1 + 32,b1,b1 + 32);
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square(r,c1 + 32);
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sub(s,b0,b0 + 32);
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mult121665(t,s);
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add(u,t,b0);
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mult(xznb,b0,b0 + 32);
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mult(xznb + 32,s,u);
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square(xzn1b,c1);
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mult(xzn1b + 32,r,work);
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smc_select(xzm,xzm1,xznb,xzn1b,b);
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}
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for (j = 0;j < 64;++j) work[j] = xzm[j];
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}
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static void recip(unsigned int out[32],const unsigned int z[32])
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{
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unsigned int z2[32];
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unsigned int z9[32];
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unsigned int z11[32];
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unsigned int z2_5_0[32];
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unsigned int z2_10_0[32];
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unsigned int z2_20_0[32];
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unsigned int z2_50_0[32];
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unsigned int z2_100_0[32];
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unsigned int t0[32];
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unsigned int t1[32];
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int i;
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/* 2 */ square(z2,z);
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/* 4 */ square(t1,z2);
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/* 8 */ square(t0,t1);
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/* 9 */ mult(z9,t0,z);
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/* 11 */ mult(z11,z9,z2);
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/* 22 */ square(t0,z11);
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/* 2^5 - 2^0 = 31 */ mult(z2_5_0,t0,z9);
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/* 2^6 - 2^1 */ square(t0,z2_5_0);
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/* 2^7 - 2^2 */ square(t1,t0);
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/* 2^8 - 2^3 */ square(t0,t1);
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/* 2^9 - 2^4 */ square(t1,t0);
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/* 2^10 - 2^5 */ square(t0,t1);
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/* 2^10 - 2^0 */ mult(z2_10_0,t0,z2_5_0);
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/* 2^11 - 2^1 */ square(t0,z2_10_0);
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/* 2^12 - 2^2 */ square(t1,t0);
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/* 2^20 - 2^10 */ for (i = 2;i < 10;i += 2) { square(t0,t1); square(t1,t0); }
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/* 2^20 - 2^0 */ mult(z2_20_0,t1,z2_10_0);
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/* 2^21 - 2^1 */ square(t0,z2_20_0);
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/* 2^22 - 2^2 */ square(t1,t0);
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/* 2^40 - 2^20 */ for (i = 2;i < 20;i += 2) { square(t0,t1); square(t1,t0); }
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/* 2^40 - 2^0 */ mult(t0,t1,z2_20_0);
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/* 2^41 - 2^1 */ square(t1,t0);
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/* 2^42 - 2^2 */ square(t0,t1);
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/* 2^50 - 2^10 */ for (i = 2;i < 10;i += 2) { square(t1,t0); square(t0,t1); }
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/* 2^50 - 2^0 */ mult(z2_50_0,t0,z2_10_0);
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/* 2^51 - 2^1 */ square(t0,z2_50_0);
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/* 2^52 - 2^2 */ square(t1,t0);
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/* 2^100 - 2^50 */ for (i = 2;i < 50;i += 2) { square(t0,t1); square(t1,t0); }
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/* 2^100 - 2^0 */ mult(z2_100_0,t1,z2_50_0);
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/* 2^101 - 2^1 */ square(t1,z2_100_0);
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/* 2^102 - 2^2 */ square(t0,t1);
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/* 2^200 - 2^100 */ for (i = 2;i < 100;i += 2) { square(t1,t0); square(t0,t1); }
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/* 2^200 - 2^0 */ mult(t1,t0,z2_100_0);
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/* 2^201 - 2^1 */ square(t0,t1);
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/* 2^202 - 2^2 */ square(t1,t0);
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/* 2^250 - 2^50 */ for (i = 2;i < 50;i += 2) { square(t0,t1); square(t1,t0); }
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/* 2^250 - 2^0 */ mult(t0,t1,z2_50_0);
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/* 2^251 - 2^1 */ square(t1,t0);
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/* 2^252 - 2^2 */ square(t0,t1);
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/* 2^253 - 2^3 */ square(t1,t0);
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/* 2^254 - 2^4 */ square(t0,t1);
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/* 2^255 - 2^5 */ square(t1,t0);
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/* 2^255 - 21 */ mult(out,t1,z11);
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}
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int crypto_scalarmult_curve25519(unsigned char *q,
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const unsigned char *n,
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const unsigned char *p)
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{
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unsigned int work[96];
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unsigned char e[32];
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unsigned int i;
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for (i = 0;i < 32;++i) e[i] = n[i];
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e[0] &= 248;
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e[31] &= 127;
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e[31] |= 64;
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for (i = 0;i < 32;++i) work[i] = p[i];
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mainloop(work,e);
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recip(work + 32,work + 32);
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mult(work + 64,work,work + 32);
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freeze(work + 64);
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for (i = 0;i < 32;++i) q[i] = (unsigned char)work[64 + i];
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return 0;
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}
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