Support ChaCha20+Poly1305 cipher suites.

nss/lib/freebl/poly1305/poly1305.c

+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* This implementation of poly1305 is by Andrew Moon
+ * (https://github.com/floodyberry/poly1305-donna) and released as public
+ * domain. */
+
+#include <string.h>
+#include <stdint.h>
+
+#include "poly1305.h"
+
+#if defined(NSS_X86) || defined(NSS_X64)
+/* We can assume little-endian. */
+static uint32_t U8TO32_LE(const unsigned char *m) {
+        uint32_t r;
+        memcpy(&r, m, sizeof(r));
+        return r;
+}
+
+static void U32TO8_LE(unsigned char *m, uint32_t v) {
+        memcpy(m, &v, sizeof(v));
+}
+#else
+static void U8TO32_LE(const unsigned char *m) {
+        return (uint32_t)m[0] |
+               (uint32_t)m[1] << 8 |
+               (uint32_t)m[2] << 16 |
+               (uint32_t)m[3] << 24;
+}
+
+static void U32TO8_LE(unsigned char *m, uint32_t v) {
+        m[0] = v;
+        m[1] = v >> 8;
+        m[2] = v >> 16;
+        m[3] = v >> 24;
+}
+#endif
+
+static uint64_t
+mul32x32_64(uint32_t a, uint32_t b) {
+        return (uint64_t)a * b;
+}
+
+struct poly1305_state_st {
+        uint32_t r0,r1,r2,r3,r4;
+        uint32_t s1,s2,s3,s4;
+        uint32_t h0,h1,h2,h3,h4;
+        unsigned char buf[16];
+        unsigned int buf_used;
+        unsigned char key[16];
+};
+
+/* update updates |state| given some amount of input data. This function may
+ * only be called with a |len| that is not a multiple of 16 at the end of the
+ * data. Otherwise the input must be buffered into 16 byte blocks. */
+static void update(struct poly1305_state_st *state, const unsigned char *in,
+                   size_t len) {
+        uint32_t t0,t1,t2,t3;
+        uint64_t t[5];
+        uint32_t b;
+        uint64_t c;
+        size_t j;
+        unsigned char mp[16];
+
+        if (len < 16)
+                goto poly1305_donna_atmost15bytes;
+
+poly1305_donna_16bytes:
+        t0 = U8TO32_LE(in);
+        t1 = U8TO32_LE(in+4);
+        t2 = U8TO32_LE(in+8);
+        t3 = U8TO32_LE(in+12);
+
+        in += 16;
+        len -= 16;
+
+        state->h0 += t0 & 0x3ffffff;
+        state->h1 += ((((uint64_t)t1 << 32) | t0) >> 26) & 0x3ffffff;
+        state->h2 += ((((uint64_t)t2 << 32) | t1) >> 20) & 0x3ffffff;
+        state->h3 += ((((uint64_t)t3 << 32) | t2) >> 14) & 0x3ffffff;
+        state->h4 += (t3 >> 8) | (1 << 24);
+
+poly1305_donna_mul:
+        t[0] = mul32x32_64(state->h0,state->r0) +
+               mul32x32_64(state->h1,state->s4) +
+               mul32x32_64(state->h2,state->s3) +
+               mul32x32_64(state->h3,state->s2) +
+               mul32x32_64(state->h4,state->s1);
+        t[1] = mul32x32_64(state->h0,state->r1) +
+               mul32x32_64(state->h1,state->r0) +
+               mul32x32_64(state->h2,state->s4) +
+               mul32x32_64(state->h3,state->s3) +
+               mul32x32_64(state->h4,state->s2);
+        t[2] = mul32x32_64(state->h0,state->r2) +
+               mul32x32_64(state->h1,state->r1) +
+               mul32x32_64(state->h2,state->r0) +
+               mul32x32_64(state->h3,state->s4) +
+               mul32x32_64(state->h4,state->s3);
+        t[3] = mul32x32_64(state->h0,state->r3) +
+               mul32x32_64(state->h1,state->r2) +
+               mul32x32_64(state->h2,state->r1) +
+               mul32x32_64(state->h3,state->r0) +
+               mul32x32_64(state->h4,state->s4);
+        t[4] = mul32x32_64(state->h0,state->r4) +
+               mul32x32_64(state->h1,state->r3) +
+               mul32x32_64(state->h2,state->r2) +
+               mul32x32_64(state->h3,state->r1) +
+               mul32x32_64(state->h4,state->r0);
+
+                   state->h0 = (uint32_t)t[0] & 0x3ffffff; c =           (t[0] >> 26);
+        t[1] += c; state->h1 = (uint32_t)t[1] & 0x3ffffff; b = (uint32_t)(t[1] >> 26);
+        t[2] += b; state->h2 = (uint32_t)t[2] & 0x3ffffff; b = (uint32_t)(t[2] >> 26);
+        t[3] += b; state->h3 = (uint32_t)t[3] & 0x3ffffff; b = (uint32_t)(t[3] >> 26);
+        t[4] += b; state->h4 = (uint32_t)t[4] & 0x3ffffff; b = (uint32_t)(t[4] >> 26);
+        state->h0 += b * 5;
+
+        if (len >= 16)
+                goto poly1305_donna_16bytes;
+
+        /* final bytes */
+poly1305_donna_atmost15bytes:
+        if (!len)
+                return;
+
+        for (j = 0; j < len; j++)
+                mp[j] = in[j];
+        mp[j++] = 1;
+        for (; j < 16; j++)
+                mp[j] = 0;
+        len = 0;
+
+        t0 = U8TO32_LE(mp+0);
+        t1 = U8TO32_LE(mp+4);
+        t2 = U8TO32_LE(mp+8);
+        t3 = U8TO32_LE(mp+12);
+
+        state->h0 += t0 & 0x3ffffff;
+        state->h1 += ((((uint64_t)t1 << 32) | t0) >> 26) & 0x3ffffff;
+        state->h2 += ((((uint64_t)t2 << 32) | t1) >> 20) & 0x3ffffff;
+        state->h3 += ((((uint64_t)t3 << 32) | t2) >> 14) & 0x3ffffff;
+        state->h4 += (t3 >> 8);
+
+        goto poly1305_donna_mul;
+}
+
+void Poly1305Init(poly1305_state *statep, const unsigned char key[32]) {
+        struct poly1305_state_st *state = (struct poly1305_state_st*) statep;
+        uint32_t t0,t1,t2,t3;
+
+        t0 = U8TO32_LE(key+0);
+        t1 = U8TO32_LE(key+4);
+        t2 = U8TO32_LE(key+8);
+        t3 = U8TO32_LE(key+12);
+
+        /* precompute multipliers */
+        state->r0 = t0 & 0x3ffffff; t0 >>= 26; t0 |= t1 << 6;
+        state->r1 = t0 & 0x3ffff03; t1 >>= 20; t1 |= t2 << 12;
+        state->r2 = t1 & 0x3ffc0ff; t2 >>= 14; t2 |= t3 << 18;
+        state->r3 = t2 & 0x3f03fff; t3 >>= 8;
+        state->r4 = t3 & 0x00fffff;
+
+        state->s1 = state->r1 * 5;
+        state->s2 = state->r2 * 5;
+        state->s3 = state->r3 * 5;
+        state->s4 = state->r4 * 5;
+
+        /* init state */
+        state->h0 = 0;
+        state->h1 = 0;
+        state->h2 = 0;
+        state->h3 = 0;
+        state->h4 = 0;
+
+        state->buf_used = 0;
+        memcpy(state->key, key + 16, sizeof(state->key));
+}
+
+void Poly1305Update(poly1305_state *statep, const unsigned char *in,
+                     size_t in_len) {
+        unsigned int i;
+        struct poly1305_state_st *state = (struct poly1305_state_st*) statep;
+
+        if (state->buf_used) {
+                unsigned int todo = 16 - state->buf_used;
+                if (todo > in_len)
+                        todo = in_len;
+                for (i = 0; i < todo; i++)
+                        state->buf[state->buf_used + i] = in[i];
+                state->buf_used += todo;
+                in_len -= todo;
+                in += todo;
+
+                if (state->buf_used == 16) {
+                        update(state, state->buf, 16);
+                        state->buf_used = 0;
+                }
+        }
+
+        if (in_len >= 16) {
+                size_t todo = in_len & ~0xf;
+                update(state, in, todo);
+                in += todo;
+                in_len &= 0xf;
+        }
+
+        if (in_len) {
+                for (i = 0; i < in_len; i++)
+                        state->buf[i] = in[i];
+                state->buf_used = in_len;
+        }
+}
+
+void Poly1305Finish(poly1305_state *statep, unsigned char mac[16]) {
+        struct poly1305_state_st *state = (struct poly1305_state_st*) statep;
+        uint64_t f0,f1,f2,f3;
+        uint32_t g0,g1,g2,g3,g4;
+        uint32_t b, nb;
+
+        if (state->buf_used)
+                update(state, state->buf, state->buf_used);
+
+                            b = state->h0 >> 26; state->h0 = state->h0 & 0x3ffffff;
+        state->h1 +=     b; b = state->h1 >> 26; state->h1 = state->h1 & 0x3ffffff;
+        state->h2 +=     b; b = state->h2 >> 26; state->h2 = state->h2 & 0x3ffffff;
+        state->h3 +=     b; b = state->h3 >> 26; state->h3 = state->h3 & 0x3ffffff;
+        state->h4 +=     b; b = state->h4 >> 26; state->h4 = state->h4 & 0x3ffffff;
+        state->h0 += b * 5;
+
+        g0 = state->h0 + 5; b = g0 >> 26; g0 &= 0x3ffffff;
+        g1 = state->h1 + b; b = g1 >> 26; g1 &= 0x3ffffff;
+        g2 = state->h2 + b; b = g2 >> 26; g2 &= 0x3ffffff;
+        g3 = state->h3 + b; b = g3 >> 26; g3 &= 0x3ffffff;
+        g4 = state->h4 + b - (1 << 26);
+
+        b = (g4 >> 31) - 1;
+        nb = ~b;
+        state->h0 = (state->h0 & nb) | (g0 & b);
+        state->h1 = (state->h1 & nb) | (g1 & b);
+        state->h2 = (state->h2 & nb) | (g2 & b);
+        state->h3 = (state->h3 & nb) | (g3 & b);
+        state->h4 = (state->h4 & nb) | (g4 & b);
+
+        f0 = ((state->h0      ) | (state->h1 << 26)) + (uint64_t)U8TO32_LE(&state->key[0]);
+        f1 = ((state->h1 >>  6) | (state->h2 << 20)) + (uint64_t)U8TO32_LE(&state->key[4]);
+        f2 = ((state->h2 >> 12) | (state->h3 << 14)) + (uint64_t)U8TO32_LE(&state->key[8]);
+        f3 = ((state->h3 >> 18) | (state->h4 <<  8)) + (uint64_t)U8TO32_LE(&state->key[12]);
+
+        U32TO8_LE(&mac[ 0], f0); f1 += (f0 >> 32);
+        U32TO8_LE(&mac[ 4], f1); f2 += (f1 >> 32);
+        U32TO8_LE(&mac[ 8], f2); f3 += (f2 >> 32);
+        U32TO8_LE(&mac[12], f3);
+}