diff options
Diffstat (limited to 'libbb')
| -rw-r--r-- | libbb/md5.c | 129 |
1 files changed, 42 insertions, 87 deletions
diff --git a/libbb/md5.c b/libbb/md5.c index b5aa89fc6..584f5fe6f 100644 --- a/libbb/md5.c +++ b/libbb/md5.c @@ -33,15 +33,9 @@ # elif defined(bswap_32) # define SWAP(n) bswap_32(n) # else -# define SWAP(n) ((n << 24) | ((n&65280)<<8) | ((n&16711680)>>8) | (n>>24)) +# define SWAP(n) ((n << 24) | ((n&0xFF00)<<8) | ((n&0xFF0000)>>8) | (n>>24)) # endif -# if MD5_SIZE_VS_SPEED == 0 -/* This array contains the bytes used to pad the buffer to the next - 64-byte boundary. (RFC 1321, 3.1: Step 1) */ -static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ }; -# endif /* MD5_SIZE_VS_SPEED == 0 */ - /* Initialize structure containing state of computation. * (RFC 1321, 3.3: Step 3) */ @@ -52,7 +46,7 @@ void md5_begin(md5_ctx_t *ctx) ctx->C = 0x98badcfe; ctx->D = 0x10325476; - ctx->total[0] = ctx->total[1] = 0; + ctx->total = 0; ctx->buflen = 0; } @@ -66,17 +60,11 @@ void md5_begin(md5_ctx_t *ctx) # define FH(b, c, d) (b ^ c ^ d) # define FI(b, c, d) (c ^ (b | ~d)) -/* Starting with the result of former calls of this function (or the - * initialization function update the context for the next LEN bytes - * starting at BUFFER. - * It is necessary that LEN is a multiple of 64!!! - */ -static void md5_hash_block(const void *buffer, size_t len, md5_ctx_t *ctx) +/* Hash a single block, 64 bytes long and 4-byte aligned. */ +static void md5_hash_block(const void *buffer, md5_ctx_t *ctx) { uint32_t correct_words[16]; const uint32_t *words = buffer; - size_t nwords = len / sizeof(uint32_t); - const uint32_t *endp = words + nwords; # if MD5_SIZE_VS_SPEED > 0 static const uint32_t C_array[] = { @@ -126,16 +114,8 @@ static void md5_hash_block(const void *buffer, size_t len, md5_ctx_t *ctx) uint32_t C = ctx->C; uint32_t D = ctx->D; - /* First increment the byte count. RFC 1321 specifies the possible - length of the file up to 2^64 bits. Here we only compute the - number of bytes. Do a double word increment. */ - ctx->total[0] += len; - if (ctx->total[0] < len) - ++ctx->total[1]; - /* Process all bytes in the buffer with 64 bytes in each round of the loop. */ - while (words < endp) { uint32_t *cwp = correct_words; uint32_t A_save = A; uint32_t B_save = B; @@ -397,7 +377,6 @@ static void md5_hash_block(const void *buffer, size_t len, md5_ctx_t *ctx) B += B_save; C += C_save; D += D_save; - } /* Put checksum in context given as argument. */ ctx->A = A; @@ -406,55 +385,39 @@ static void md5_hash_block(const void *buffer, size_t len, md5_ctx_t *ctx) ctx->D = D; } -/* Starting with the result of former calls of this function (or the - * initialization function update the context for the next LEN bytes - * starting at BUFFER. - * It is NOT required that LEN is a multiple of 64. - */ +/* Feed data through a temporary buffer to call md5_hash_aligned_block() + * with chunks of data that are 4-byte aligned and a multiple of 64 bytes. + * This function's internal buffer remembers previous data until it has 64 + * bytes worth to pass on. Call md5_end() to flush this buffer. */ -static void md5_hash_bytes(const void *buffer, size_t len, md5_ctx_t *ctx) +void md5_hash(const void *buffer, size_t len, md5_ctx_t *ctx) { - /* When we already have some bits in our internal buffer concatenate - both inputs first. */ - if (ctx->buflen != 0) { - size_t left_over = ctx->buflen; - size_t add = 128 - left_over > len ? len : 128 - left_over; - - memcpy(&ctx->buffer[left_over], buffer, add); - ctx->buflen += add; - - if (left_over + add > 64) { - md5_hash_block(ctx->buffer, (left_over + add) & ~63, ctx); - /* The regions in the following copy operation cannot overlap. */ - memcpy(ctx->buffer, &ctx->buffer[(left_over + add) & ~63], - (left_over + add) & 63); - ctx->buflen = (left_over + add) & 63; - } + char *buf=(char *)buffer; - buffer = (const char *) buffer + add; - len -= add; - } + /* RFC 1321 specifies the possible length of the file up to 2^64 bits, + * Here we only track the number of bytes. */ - /* Process available complete blocks. */ - if (len > 64) { - md5_hash_block(buffer, len & ~63, ctx); - buffer = (const char *) buffer + (len & ~63); - len &= 63; - } + ctx->total += len; - /* Move remaining bytes in internal buffer. */ - if (len > 0) { - memcpy(ctx->buffer, buffer, len); - ctx->buflen = len; - } -} + // Process all input. -void md5_hash(const void *data, size_t length, md5_ctx_t *ctx) -{ - if (length % 64 == 0) { - md5_hash_block(data, length, ctx); - } else { - md5_hash_bytes(data, length, ctx); + while (len) { + int i = 64 - ctx->buflen; + + // Copy data into aligned buffer. + + if (i > len) i = len; + memcpy(ctx->buffer + ctx->buflen, buf, i); + len -= i; + ctx->buflen += i; + buf += i; + + // When buffer fills up, process it. + + if (ctx->buflen == 64) { + md5_hash_block(ctx->buffer, ctx); + ctx->buflen = 0; + } } } @@ -468,31 +431,23 @@ void md5_hash(const void *data, size_t length, md5_ctx_t *ctx) */ void *md5_end(void *resbuf, md5_ctx_t *ctx) { - /* Take yet unprocessed bytes into account. */ - uint32_t bytes = ctx->buflen; - size_t pad; + char *buf = ctx->buffer; + int i; - /* Now count remaining bytes. */ - ctx->total[0] += bytes; - if (ctx->total[0] < bytes) - ++ctx->total[1]; + /* Pad data to block size. */ - pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes; -# if MD5_SIZE_VS_SPEED > 0 - memset(&ctx->buffer[bytes], 0, pad); - ctx->buffer[bytes] = 0x80; -# else - memcpy(&ctx->buffer[bytes], fillbuf, pad); -# endif /* MD5_SIZE_VS_SPEED > 0 */ + buf[ctx->buflen++] = 0x80; + memset(buf + ctx->buflen, 0, 128 - ctx->buflen); /* Put the 64-bit file length in *bits* at the end of the buffer. */ - *(uint32_t *) & ctx->buffer[bytes + pad] = SWAP(ctx->total[0] << 3); - *(uint32_t *) & ctx->buffer[bytes + pad + 4] = - SWAP(((ctx->total[1] << 3) | (ctx->total[0] >> 29))); + ctx->total <<= 3; + if (ctx->buflen > 56) buf += 64; + for (i = 0; i < 8; i++) buf[56 + i] = ctx->total >> (i*8); /* Process last bytes. */ - md5_hash_block(ctx->buffer, bytes + pad + 8, ctx); - + if (buf != ctx->buffer) md5_hash_block(ctx->buffer, ctx); + md5_hash_block(buf, ctx); + /* Put result from CTX in first 16 bytes following RESBUF. The result is * always in little endian byte order, so that a byte-wise output yields * to the wanted ASCII representation of the message digest. |