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Diffstat (limited to 'libbb/md5.c')
-rw-r--r--libbb/md5.c129
1 files changed, 42 insertions, 87 deletions
diff --git a/libbb/md5.c b/libbb/md5.c
index b5aa89f..584f5fe 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.