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sha256: use memcpy() when result buffer is unaligned

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Fixes #23578.
This commit is contained in:
Yu Watanabe 2022-06-01 02:31:10 +09:00
parent b278cf2efd
commit c7a5eabeba
1 changed files with 20 additions and 19 deletions
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39
src/fundamental/sha256.c
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@ -49,6 +49,20 @@
# define SWAP64(n) (n)
#endif
/* The condition below is from glibc's string/string-inline.c.
* See definition of _STRING_INLINE_unaligned. */
#if !defined(__mc68020__) && !defined(__s390__) && !defined(__i386__)
/* To check alignment gcc has an appropriate operator. Other compilers don't. */
# if __GNUC__ >= 2
# define UNALIGNED_P(p) (((size_t) p) % __alignof__(uint32_t) != 0)
# else
# define UNALIGNED_P(p) (((size_t) p) % sizeof(uint32_t) != 0)
# endif
#else
# define UNALIGNED_P(p) false
#endif
/* This array contains the bytes used to pad the buffer to the next
64-byte boundary. (FIPS 180-2:5.1.1) */
static const uint8_t fillbuf[64] = {
@ -96,10 +110,7 @@ void sha256_init_ctx(struct sha256_ctx *ctx) {
}
/* Process the remaining bytes in the internal buffer and the usual
prolog according to the standard and write the result to RESBUF.
IMPORTANT: On some systems it is required that RESBUF is correctly
aligned for a 32 bits value. */
prolog according to the standard and write the result to RESBUF. */
void *sha256_finish_ctx(struct sha256_ctx *ctx, void *resbuf) {
/* Take yet unprocessed bytes into account. */
uint32_t bytes = ctx->buflen;
@ -124,7 +135,10 @@ void *sha256_finish_ctx(struct sha256_ctx *ctx, void *resbuf) {
/* Put result from CTX in first 32 bytes following RESBUF. */
for (size_t i = 0; i < 8; ++i)
((uint32_t *) resbuf)[i] = SWAP(ctx->H[i]);
if (UNALIGNED_P(resbuf))
memcpy((uint8_t*) resbuf + i * sizeof(uint32_t), (uint32_t[]) { SWAP(ctx->H[i]) }, sizeof(uint32_t));
else
((uint32_t *) resbuf)[i] = SWAP(ctx->H[i]);
return resbuf;
}
@ -158,17 +172,6 @@ void sha256_process_bytes(const void *buffer, size_t len, struct sha256_ctx *ctx
/* Process available complete blocks. */
if (len >= 64) {
/* The condition below is from glibc's string/string-inline.c.
* See definition of _STRING_INLINE_unaligned. */
#if !defined(__mc68020__) && !defined(__s390__) && !defined(__i386__)
/* To check alignment gcc has an appropriate operator. Other compilers don't. */
# if __GNUC__ >= 2
# define UNALIGNED_P(p) (((size_t) p) % __alignof__(uint32_t) != 0)
# else
# define UNALIGNED_P(p) (((size_t) p) % sizeof(uint32_t) != 0)
# endif
if (UNALIGNED_P(buffer))
while (len > 64) {
memcpy(ctx->buffer, buffer, 64);
@ -176,9 +179,7 @@ void sha256_process_bytes(const void *buffer, size_t len, struct sha256_ctx *ctx
buffer = (const char *) buffer + 64;
len -= 64;
}
else
#endif
{
else {
sha256_process_block(buffer, len & ~63, ctx);
buffer = (const char *) buffer + (len & ~63);
len &= 63;