* Makefile (OBJS): New objects chksum.o and chksums/sha256.o.

* chksum.c, chksum.h, chksums/sha256.c, chksums/sha256.h: New files.

* lib.c (init): Call chksum_init.

* txr.1: Documented.

* LICENSE: Add SHA-256 copyright notice.

2 files changed, 359 insertions, 0 deletions

diff --git a/chksums/sha256.c b/chksums/sha256.c
new file mode 100644
index 00000000..7c0cff73
--- /dev/null
+++ b/chksums/sha256.c
@@ -0,0 +1,319 @@
+/*-
+ * Copyright 2005 Colin Percival
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <string.h>
+#include <limits.h>
+#include <wchar.h>
+#include "config.h"
+#include "lib.h"
+#include "itypes.h"
+#include "sha256.h"
+
+#if HAVE_LITTLE_ENDIAN
+
+INLINE void be32enc(unsigned char *dst, u32_t v)
+{
+  dst[0] = (v >> 24) & 0xff;
+  dst[1] = (v >> 16) & 0xff;
+  dst[2] = (v >> 8) & 0xff;
+  dst[3] = v & 0xff;
+}
+
+INLINE u32_t be32dec(const unsigned char *src)
+{
+  return (convert(u32_t, src[0]) << 24 | convert(u32_t, src[1]) << 16 |
+          convert(u32_t, src[2]) << 8 | src[3]);
+}
+
+INLINE void be64enc(unsigned char *dst, u64_t v)
+{
+  dst[0] = (v >> 56) & 0xff;
+  dst[1] = (v >> 48) & 0xff;
+  dst[2] = (v >> 40) & 0xff;
+  dst[3] = (v >> 32) & 0xff;
+  dst[4] = (v >> 24) & 0xff;
+  dst[5] = (v >> 16) & 0xff;
+  dst[6] = (v >> 8) & 0xff;
+  dst[7] = v & 0xff;
+}
+
+/*
+ * Encode a length len/4 vector of (u32_t) into a length len vector of
+ * (unsigned char) in big-endian form.  Assumes len is a multiple of 4.
+ */
+static void be32enc_vect(unsigned char *dst, const u32_t *src, size_t len)
+{
+  size_t i;
+
+  for (i = 0; i < len / 4; i++)
+    be32enc(dst + i * 4, src[i]);
+}
+
+/*
+ * Decode a big-endian length len vector of (unsigned char) into a length
+ * len/4 vector of (u32_t).  Assumes len is a multiple of 4.
+ */
+static void be32dec_vect(u32_t *dst, const unsigned char *src, size_t len)
+{
+  size_t i;
+
+  for (i = 0; i < len / 4; i++)
+    dst[i] = be32dec(src + i * 4);
+}
+
+#else /* BYTE_ORDER != BIG_ENDIAN */
+
+/* Copy a vector of big-endian u32_t into a vector of bytes */
+#define be32enc_vect(dst, src, len) \
+  memcpy((void *)dst, (const void *)src, (size_t)len)
+
+/* Copy a vector of bytes into a vector of big-endian u32_t */
+#define be32dec_vect(dst, src, len) \
+  memcpy((void *)dst, (const void *)src, (size_t)len)
+
+INLINE void be64enc(unsigned char *dst, u64_t v)
+{
+  *coerce(u64_t *, dst) = v;
+}
+
+#endif /* BYTE_ORDER != BIG_ENDIAN */
+
+/* SHA256 round constants. */
+static const u32_t K[64] = {
+  0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
+  0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
+  0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
+  0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
+  0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
+  0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
+  0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
+  0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
+  0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
+  0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
+  0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
+  0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
+  0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
+  0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
+  0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
+  0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
+};
+
+/* Elementary functions used by SHA256 */
+#define Ch(x, y, z)     ((x & (y ^ z)) ^ z)
+#define Maj(x, y, z)    ((x & (y | z)) | (y & z))
+#define SHR(x, n)       (x >> n)
+#define ROTR(x, n)      ((x >> n) | (x << (32 - n)))
+#define S0(x)           (ROTR(x, 2) ^ ROTR(x, 13) ^ ROTR(x, 22))
+#define S1(x)           (ROTR(x, 6) ^ ROTR(x, 11) ^ ROTR(x, 25))
+#define s0(x)           (ROTR(x, 7) ^ ROTR(x, 18) ^ SHR(x, 3))
+#define s1(x)           (ROTR(x, 17) ^ ROTR(x, 19) ^ SHR(x, 10))
+
+/* SHA256 round function */
+#define RND(a, b, c, d, e, f, g, h, k)                  \
+        h += S1(e) + Ch(e, f, g) + k;                   \
+        d += h;                                         \
+        h += S0(a) + Maj(a, b, c);
+
+/* Adjusted round function for rotating state */
+#define RNDr(S, W, i, ii)                       \
+        RND(S[(64 - i) % 8], S[(65 - i) % 8],   \
+            S[(66 - i) % 8], S[(67 - i) % 8],   \
+            S[(68 - i) % 8], S[(69 - i) % 8],   \
+            S[(70 - i) % 8], S[(71 - i) % 8],   \
+            W[i + ii] + K[i + ii])
+
+/* Message schedule computation */
+#define MSCH(W, ii, i)                          \
+        W[i + ii + 16] = s1(W[i + ii + 14]) + W[i + ii + 9] + s0(W[i + ii + 1]) + W[i + ii]
+
+/*
+ * SHA256 block compression function.  The 256-bit state is transformed via
+ * the 512-bit input block to produce a new state.
+ */
+static void SHA256_transform(u32_t *state, const unsigned char block[64])
+{
+  u32_t W[64];
+  u32_t S[8];
+  int i;
+
+  /* 1. Prepare the first part of the message schedule W. */
+  be32dec_vect(W, block, 64);
+
+  /* 2. Initialize working variables. */
+  memcpy(S, state, 32);
+
+  /* 3. Mix. */
+  for (i = 0; i < 64; i += 16) {
+    RNDr(S, W, 0, i);
+    RNDr(S, W, 1, i);
+    RNDr(S, W, 2, i);
+    RNDr(S, W, 3, i);
+    RNDr(S, W, 4, i);
+    RNDr(S, W, 5, i);
+    RNDr(S, W, 6, i);
+    RNDr(S, W, 7, i);
+    RNDr(S, W, 8, i);
+    RNDr(S, W, 9, i);
+    RNDr(S, W, 10, i);
+    RNDr(S, W, 11, i);
+    RNDr(S, W, 12, i);
+    RNDr(S, W, 13, i);
+    RNDr(S, W, 14, i);
+    RNDr(S, W, 15, i);
+
+    if (i == 48)
+      break;
+    MSCH(W, 0, i);
+    MSCH(W, 1, i);
+    MSCH(W, 2, i);
+    MSCH(W, 3, i);
+    MSCH(W, 4, i);
+    MSCH(W, 5, i);
+    MSCH(W, 6, i);
+    MSCH(W, 7, i);
+    MSCH(W, 8, i);
+    MSCH(W, 9, i);
+    MSCH(W, 10, i);
+    MSCH(W, 11, i);
+    MSCH(W, 12, i);
+    MSCH(W, 13, i);
+    MSCH(W, 14, i);
+    MSCH(W, 15, i);
+  }
+
+  /* 4. Mix local working variables into global state */
+  for (i = 0; i < 8; i++)
+    state[i] += S[i];
+}
+
+static unsigned char PAD[64] = {
+  0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+};
+
+/* Add padding and terminating bit-count. */
+static void SHA256_pad(SHA256_t *ctx)
+{
+  size_t r;
+
+  /* Figure out how many bytes we have buffered. */
+  r = (ctx->count >> 3) & 0x3f;
+
+  /* Pad to 56 mod 64, transforming if we finish a block en route. */
+  if (r < 56) {
+    /* Pad to 56 mod 64. */
+    memcpy(&ctx->buf[r], PAD, 56 - r);
+  } else {
+    /* Finish the current block and mix. */
+    memcpy(&ctx->buf[r], PAD, 64 - r);
+    SHA256_transform(ctx->state, ctx->buf);
+
+    /* The start of the final block is all zeroes. */
+    memset(&ctx->buf[0], 0, 56);
+  }
+
+  /* Add the terminating bit-count. */
+  be64enc(&ctx->buf[56], ctx->count);
+
+  /* Mix in the final block. */
+  SHA256_transform(ctx->state, ctx->buf);
+}
+
+/* SHA-256 initialization.  Begins a SHA-256 operation. */
+void SHA256_init(SHA256_t *ctx)
+{
+  /* Zero bits processed so far */
+  ctx->count = 0;
+
+  /* Magic initialization constants */
+  ctx->state[0] = 0x6A09E667;
+  ctx->state[1] = 0xBB67AE85;
+  ctx->state[2] = 0x3C6EF372;
+  ctx->state[3] = 0xA54FF53A;
+  ctx->state[4] = 0x510E527F;
+  ctx->state[5] = 0x9B05688C;
+  ctx->state[6] = 0x1F83D9AB;
+  ctx->state[7] = 0x5BE0CD19;
+}
+
+/* Add bytes into the hash */
+void SHA256_update(SHA256_t *ctx, const void *in, size_t len)
+{
+  u64_t bitlen;
+  u32_t r;
+  const unsigned char *src = in;
+
+  /* Number of bytes left in the buffer from previous updates */
+  r = (ctx->count >> 3) & 0x3f;
+
+  /* Convert the length into a number of bits */
+  bitlen = len << 3;
+
+  /* Update number of bits */
+  ctx->count += bitlen;
+
+  /* Handle the case where we don't need to perform any transforms */
+  if (len < 64 - r) {
+    memcpy(&ctx->buf[r], src, len);
+    return;
+  }
+
+  /* Finish the current block */
+  memcpy(&ctx->buf[r], src, 64 - r);
+  SHA256_transform(ctx->state, ctx->buf);
+  src += 64 - r;
+  len -= 64 - r;
+
+  /* Perform complete blocks */
+  while (len >= 64) {
+    SHA256_transform(ctx->state, src);
+    src += 64;
+    len -= 64;
+  }
+
+  /* Copy left over data into buffer */
+  memcpy(ctx->buf, src, len);
+}
+
+/*
+ * SHA-256 finalization.  Pads the input data, exports the hash value,
+ * and clears the context state.
+ */
+void SHA256_final(SHA256_t *ctx, unsigned char *digest)
+{
+
+  /* Add padding */
+  SHA256_pad(ctx);
+
+  /* Write the hash */
+  be32enc_vect(digest, ctx->state, SHA256_DIGEST_LENGTH);
+
+  /* Clear the context state */
+  memset(ctx, 0, sizeof *ctx);
+}
diff --git a/chksums/sha256.h b/chksums/sha256.h
new file mode 100644
index 00000000..3cd57a4e
--- /dev/null
+++ b/chksums/sha256.h
@@ -0,0 +1,40 @@
+/*-
+ * Copyright 2005 Colin Percival
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#define SHA256_BLOCK_LENGTH 64
+#define SHA256_DIGEST_LENGTH 32
+#define SHA256_DIGEST_STRING_LENGTH (SHA256_DIGEST_LENGTH * 2 + 1)
+
+typedef struct SHA256 {
+  u32_t state[8];
+  u64_t count;
+  u8_t buf[SHA256_BLOCK_LENGTH];
+} SHA256_t;
+
+void SHA256_init(SHA256_t *);
+void SHA256_update(SHA256_t *, const void *, size_t);
+void SHA256_final(SHA256_t *, unsigned char *);