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Fix keccak-tiny portability on exotic
platforms.
* SHA-3/SHAKE use little endian for certain things, so byteswap as needed. * The code was written under the assumption that unaligned access to quadwords is allowed, which isn't true particularly on non-Intel.
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changes/bug18943
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6
changes/bug18943
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@ -0,0 +1,6 @@
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o Major bugfixes (crypto, portability):
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- The SHA3 and SHAKE routines now produce the correct output on
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Big Endian systems, unbreaking the unit tests. No code calls
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either algorithm family yet, so this is primarily a build fix.
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Closes ticket 18943.
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@ -11,6 +11,29 @@
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#include <string.h>
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#include "crypto.h"
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/******** Endianness conversion helpers ********/
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static inline uint64_t
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loadu64le(const unsigned char *x) {
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uint64_t r = 0;
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size_t i;
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for (i = 0; i < 8; ++i) {
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r |= (uint64_t)x[i] << 8 * i;
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}
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return r;
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}
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static inline void
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storeu64le(uint8_t *x, uint64_t u) {
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size_t i;
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for(i=0; i<8; ++i) {
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x[i] = u;
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u >>= 8;
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}
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}
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/******** The Keccak-f[1600] permutation ********/
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/*** Constants. ***/
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@ -80,24 +103,26 @@ static inline void keccakf(void* state) {
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/*** Some helper macros. ***/
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#define _(S) do { S } while (0)
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#define FOR(i, ST, L, S) \
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_(for (size_t i = 0; i < L; i += ST) { S; })
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#define mkapply_ds(NAME, S) \
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static inline void NAME(uint8_t* dst, \
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const uint8_t* src, \
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size_t len) { \
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FOR(i, 1, len, S); \
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}
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#define mkapply_sd(NAME, S) \
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static inline void NAME(const uint8_t* src, \
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uint8_t* dst, \
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size_t len) { \
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FOR(i, 1, len, S); \
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// `xorin` modified to handle Big Endian systems, `buf` being unaligned on
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// systems that care about such things. Assumes that len is a multiple of 8,
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// which is always true for the rates we use, and the modified finalize.
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static inline void
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xorin8(uint8_t *dst, const uint8_t *src, size_t len) {
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uint64_t* a = (uint64_t*)dst; // Always aligned.
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for (size_t i = 0; i < len; i += 8) {
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a[i/8] ^= loadu64le(src + i);
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}
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}
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mkapply_ds(xorin, dst[i] ^= src[i]) // xorin
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mkapply_sd(setout, dst[i] = src[i]) // setout
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// `setout` likewise modified to handle Big Endian systems. Assumes that len
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// is a multiple of 8, which is true for every rate we use.
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static inline void
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setout8(const uint8_t *src, uint8_t *dst, size_t len) {
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const uint64_t *si = (const uint64_t*)src; // Always aligned.
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for (size_t i = 0; i < len; i+= 8) {
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storeu64le(dst+i, si[i/8]);
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}
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}
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#define P keccakf
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#define Plen KECCAK_MAX_RATE
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@ -118,7 +143,7 @@ static inline void
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keccak_absorb_blocks(keccak_state *s, const uint8_t *buf, size_t nr_blocks)
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{
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size_t blen = nr_blocks * s->rate;
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foldP(buf, blen, xorin);
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foldP(buf, blen, xorin8);
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}
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static int
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@ -161,10 +186,14 @@ static void
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keccak_finalize(keccak_state *s)
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{
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// Xor in the DS and pad frame.
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s->a[s->offset] ^= s->delim;
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s->a[s->rate - 1] ^= 0x80;
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s->block[s->offset++] = s->delim; // DS.
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for (size_t i = s->offset; i < s->rate; i++) {
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s->block[i] = 0;
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}
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s->block[s->rate - 1] |= 0x80; // Pad frame.
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// Xor in the last block.
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xorin(s->a, s->block, s->offset);
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xorin8(s->a, s->block, s->rate);
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memwipe(s->block, 0, sizeof(s->block));
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s->finalized = 1;
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@ -176,7 +205,7 @@ keccak_squeeze_blocks(keccak_state *s, uint8_t *out, size_t nr_blocks)
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{
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for (size_t n = 0; n < nr_blocks; n++) {
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keccakf(s->a);
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setout(s->a, out, s->rate);
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setout8(s->a, out, s->rate);
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out += s->rate;
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}
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}
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@ -321,6 +350,7 @@ static inline int hash(uint8_t* out, size_t outlen,
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int ret = 0;
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keccak_state s;
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keccak_cleanse(&s);
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switch (delim) {
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case KECCAK_DELIM_DIGEST:
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