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nuttx-update/crypto/poly1305.c
Alin Jerpelea 97827ab26b crypto/poly1305: migrate to SPDX identifier 
Most tools used for compliance and SBOM generation use SPDX identifiers
This change brings us a step closer to an easy SBOM generation.

define NuttX local NuttX-PublicDomain identifier

 “Public Domain” is a concept distinct from copyright licensing;
it generally means that the work no longer has any copyright protection
or ownership, and therefore requires no license permission in order to
use, copy, modify, distribute, perform, display, etc.
In the United States – and many jurisdictions – copyright protections
attach automatically to creative works upon creation if they satisfy
certain minimum criteria.
“Public Domain” would thus represent a significant change to the legal
status of the work.
The rules around “Public Domain” often vary or are unspecified
jurisdiction to jurisdiction. Adding to the confusion, some
jurisdictions may not even recognize the concept of “Public Domain”
(or similar). As such, a license may nevertheless be required or implied
in these cases. Even in the U.S., there is no clear,
officially-sanctioned procedure for affirmatively placing
copyright-eligible works into the “Public Domain” aside from natural
statutory expiration of copyright. The bottom-line is, there are few if
any objective, brightline rules for proactively placing
copyright-eligible works into the Public Domain that we can broadly
rely on.

Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
2024-12-17 08:37:13 +08:00

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/****************************************************************************
* crypto/poly1305.c
*
* SPDX-License-Identifier: NuttX-PublicDomain
*
* Public Domain poly1305 from Andrew Moon
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <sys/types.h>
#include <crypto/poly1305.h>
/* poly1305 implementation using 32 bit * 32 bit = 64 bit multiplication
* and 64 bit addition.
*/
/* interpret four 8 bit unsigned integers as a
* 32 bit unsigned integer in little endian
*/
static unsigned long U8TO32(FAR const unsigned char *p)
{
return (((unsigned long)(p[0] & 0xff)) |
((unsigned long)(p[1] & 0xff) << 8) |
((unsigned long)(p[2] & 0xff) << 16) |
((unsigned long)(p[3] & 0xff) << 24));
}
/* store a 32 bit unsigned integer as four
* 8 bit unsigned integers in little endian
*/
static void U32TO8(FAR unsigned char *p, unsigned long v)
{
p[0] = (v) & 0xff;
p[1] = (v >> 8) & 0xff;
p[2] = (v >> 16) & 0xff;
p[3] = (v >> 24) & 0xff;
}
/****************************************************************************
* Public Functions
****************************************************************************/
void poly1305_begin(FAR poly1305_state *st, FAR const unsigned char *key)
{
/* r &= 0xffffffc0ffffffc0ffffffc0fffffff */
st->r[0] = (U8TO32(&key[0])) & 0x3ffffff;
st->r[1] = (U8TO32(&key[3]) >> 2) & 0x3ffff03;
st->r[2] = (U8TO32(&key[6]) >> 4) & 0x3ffc0ff;
st->r[3] = (U8TO32(&key[9]) >> 6) & 0x3f03fff;
st->r[4] = (U8TO32(&key[12]) >> 8) & 0x00fffff;
/* h = 0 */
st->h[0] = 0;
st->h[1] = 0;
st->h[2] = 0;
st->h[3] = 0;
st->h[4] = 0;
/* save pad for later */
st->pad[0] = U8TO32(&key[16]);
st->pad[1] = U8TO32(&key[20]);
st->pad[2] = U8TO32(&key[24]);
st->pad[3] = U8TO32(&key[28]);
st->leftover = 0;
st->final = 0;
}
static void poly1305_blocks(FAR poly1305_state *st,
FAR const unsigned char *m,
size_t bytes)
{
const unsigned long hibit = (st->final) ? 0 : (1 << 24); /* 1 << 128 */
unsigned long r0;
unsigned long r1;
unsigned long r2;
unsigned long r3;
unsigned long r4;
unsigned long s1;
unsigned long s2;
unsigned long s3;
unsigned long s4;
unsigned long h0;
unsigned long h1;
unsigned long h2;
unsigned long h3;
unsigned long h4;
unsigned long long d0;
unsigned long long d1;
unsigned long long d2;
unsigned long long d3;
unsigned long long d4;
unsigned long c;
r0 = st->r[0];
r1 = st->r[1];
r2 = st->r[2];
r3 = st->r[3];
r4 = st->r[4];
s1 = r1 * 5;
s2 = r2 * 5;
s3 = r3 * 5;
s4 = r4 * 5;
h0 = st->h[0];
h1 = st->h[1];
h2 = st->h[2];
h3 = st->h[3];
h4 = st->h[4];
while (bytes >= poly1305_block_size)
{
/* h += m[i] */
h0 += (U8TO32(m + 0)) & 0x3ffffff;
h1 += (U8TO32(m + 3) >> 2) & 0x3ffffff;
h2 += (U8TO32(m + 6) >> 4) & 0x3ffffff;
h3 += (U8TO32(m + 9) >> 6) & 0x3ffffff;
h4 += (U8TO32(m + 12) >> 8) | hibit;
/* h *= r */
d0 = ((unsigned long long)h0 * r0) +
((unsigned long long)h1 * s4) +
((unsigned long long)h2 * s3) +
((unsigned long long)h3 * s2) +
((unsigned long long)h4 * s1);
d1 = ((unsigned long long)h0 * r1) +
((unsigned long long)h1 * r0) +
((unsigned long long)h2 * s4) +
((unsigned long long)h3 * s3) +
((unsigned long long)h4 * s2);
d2 = ((unsigned long long)h0 * r2) +
((unsigned long long)h1 * r1) +
((unsigned long long)h2 * r0) +
((unsigned long long)h3 * s4) +
((unsigned long long)h4 * s3);
d3 = ((unsigned long long)h0 * r3) +
((unsigned long long)h1 * r2) +
((unsigned long long)h2 * r1) +
((unsigned long long)h3 * r0) +
((unsigned long long)h4 * s4);
d4 = ((unsigned long long)h0 * r4) +
((unsigned long long)h1 * r3) +
((unsigned long long)h2 * r2) +
((unsigned long long)h3 * r1) +
((unsigned long long)h4 * r0);
/* (partial) h %= p */
c = (unsigned long)(d0 >> 26);
h0 = (unsigned long)d0 & 0x3ffffff;
d1 += c;
c = (unsigned long)(d1 >> 26);
h1 = (unsigned long)d1 & 0x3ffffff;
d2 += c;
c = (unsigned long)(d2 >> 26);
h2 = (unsigned long)d2 & 0x3ffffff;
d3 += c;
c = (unsigned long)(d3 >> 26);
h3 = (unsigned long)d3 & 0x3ffffff;
d4 += c;
c = (unsigned long)(d4 >> 26);
h4 = (unsigned long)d4 & 0x3ffffff;
h0 += c * 5;
c = (h0 >> 26);
h0 = h0 & 0x3ffffff;
h1 += c;
m += poly1305_block_size;
bytes -= poly1305_block_size;
}
st->h[0] = h0;
st->h[1] = h1;
st->h[2] = h2;
st->h[3] = h3;
st->h[4] = h4;
}
void poly1305_update(FAR poly1305_state *st,
FAR const unsigned char *m,
size_t bytes)
{
size_t i;
/* handle leftover */
if (st->leftover)
{
size_t want = (poly1305_block_size - st->leftover);
if (want > bytes)
{
want = bytes;
}
for (i = 0; i < want; i++)
{
st->buffer[st->leftover + i] = m[i];
}
bytes -= want;
m += want;
st->leftover += want;
if (st->leftover < poly1305_block_size)
{
return;
}
poly1305_blocks(st, st->buffer, poly1305_block_size);
st->leftover = 0;
}
/* process full blocks */
if (bytes >= poly1305_block_size)
{
size_t want = (bytes & ~(poly1305_block_size - 1));
poly1305_blocks(st, m, want);
m += want;
bytes -= want;
}
/* store leftover */
if (bytes)
{
for (i = 0; i < bytes && i < poly1305_block_size; i++)
{
st->buffer[i] = m[i];
}
st->leftover += bytes;
}
}
void poly1305_finish(FAR poly1305_state *st, FAR unsigned char *mac)
{
unsigned long h0;
unsigned long h1;
unsigned long h2;
unsigned long h3;
unsigned long h4;
unsigned long c;
unsigned long g0;
unsigned long g1;
unsigned long g2;
unsigned long g3;
unsigned long g4;
unsigned long long f;
unsigned long mask;
/* process the remaining block */
if (st->leftover)
{
size_t i = st->leftover;
st->buffer[i++] = 1;
for (; i < poly1305_block_size; i++)
st->buffer[i] = 0;
st->final = 1;
poly1305_blocks(st, st->buffer, poly1305_block_size);
}
/* fully carry h */
h0 = st->h[0];
h1 = st->h[1];
h2 = st->h[2];
h3 = st->h[3];
h4 = st->h[4];
c = h1 >> 26;
h1 = h1 & 0x3ffffff;
h2 += c;
c = h2 >> 26;
h2 = h2 & 0x3ffffff;
h3 += c;
c = h3 >> 26;
h3 = h3 & 0x3ffffff;
h4 += c;
c = h4 >> 26;
h4 = h4 & 0x3ffffff;
h0 += c * 5;
c = h0 >> 26;
h0 = h0 & 0x3ffffff;
h1 += c;
/* compute h + -p */
g0 = h0 + 5;
c = g0 >> 26;
g0 &= 0x3ffffff;
g1 = h1 + c;
c = g1 >> 26;
g1 &= 0x3ffffff;
g2 = h2 + c;
c = g2 >> 26;
g2 &= 0x3ffffff;
g3 = h3 + c;
c = g3 >> 26;
g3 &= 0x3ffffff;
g4 = h4 + c - (1 << 26);
/* select h if h < p, or h + -p if h >= p */
mask = (g4 >> ((sizeof(unsigned long) * 8) - 1)) - 1;
g0 &= mask;
g1 &= mask;
g2 &= mask;
g3 &= mask;
g4 &= mask;
mask = ~mask;
h0 = (h0 & mask) | g0;
h1 = (h1 & mask) | g1;
h2 = (h2 & mask) | g2;
h3 = (h3 & mask) | g3;
h4 = (h4 & mask) | g4;
/* h = h % (2^128) */
h0 = ((h0) | (h1 << 26)) & 0xffffffff;
h1 = ((h1 >> 6) | (h2 << 20)) & 0xffffffff;
h2 = ((h2 >> 12) | (h3 << 14)) & 0xffffffff;
h3 = ((h3 >> 18) | (h4 << 8)) & 0xffffffff;
/* mac = (h + pad) % (2^128) */
f = (unsigned long long)h0 + st->pad[0];
h0 = (unsigned long)f;
f = (unsigned long long)h1 + st->pad[1] + (f >> 32);
h1 = (unsigned long)f;
f = (unsigned long long)h2 + st->pad[2] + (f >> 32);
h2 = (unsigned long)f;
f = (unsigned long long)h3 + st->pad[3] + (f >> 32);
h3 = (unsigned long)f;
U32TO8(mac + 0, h0);
U32TO8(mac + 4, h1);
U32TO8(mac + 8, h2);
U32TO8(mac + 12, h3);
/* zero out the state */
st->h[0] = 0;
st->h[1] = 0;
st->h[2] = 0;
st->h[3] = 0;
st->h[4] = 0;
st->r[0] = 0;
st->r[1] = 0;
st->r[2] = 0;
st->r[3] = 0;
st->r[4] = 0;
st->pad[0] = 0;
st->pad[1] = 0;
st->pad[2] = 0;
st->pad[3] = 0;
}
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