[PATCH] Add sha256sum(1)

---
 Makefile      |   6 ++-
 sha256.h      |  18 +++++++
 sha256sum.1   |   8 ++++
 sha256sum.c   |  49 +++++++++++++++++++
 util/sha256.c | 152 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 231 insertions(+), 2 deletions(-)
 create mode 100644 sha256.h
 create mode 100644 sha256sum.1
 create mode 100644 sha256sum.c
 create mode 100644 util/sha256.c
diff --git a/Makefile b/Makefile
index bd0c38c..a904c47 100644
--- a/Makefile
+++ b/Makefile
_AT_@ -3,7 +3,7 @@ include config.mk
 .POSIX:
 .SUFFIXES: .c .o
 
-HDR = crypt.h fs.h text.h md5.h sha1.h util.h arg.h
+HDR = crypt.h fs.h text.h md5.h sha1.h sha256.h util.h arg.h
 LIB = \
 	util/afgets.o    \
 	util/agetcwd.o   \
_AT_@ -20,7 +20,8 @@ LIB = \
 	util/putword.o   \
 	util/recurse.o   \
 	util/rm.o        \
-	util/sha1.o
+	util/sha1.o      \
+	util/sha256.o
 
 SRC = \
 	basename.c \
_AT_@ -80,6 +81,7 @@ SRC = \
 	unlink.c   \
 	seq.c      \
 	sha1sum.c  \
+	sha256sum.c\
 	wc.c       \
 	who.c      \
 	yes.c
diff --git a/sha256.h b/sha256.h
new file mode 100644
index 0000000..5968b8e
--- /dev/null
+++ b/sha256.h
_AT_@ -0,0 +1,18 @@
+/* public domain sha256 implementation based on fips180-3 */
+
+struct sha256 {
+	uint64_t len;    /* processed message length */
+	uint32_t h[8];   /* hash state */
+	uint8_t buf[64]; /* message block buffer */
+};
+
+enum { SHA256_DIGEST_LENGTH = 32 };
+
+/* reset state */
+void sha256_init(void *ctx);
+/* process message */
+void sha256_update(void *ctx, const void *m, unsigned long len);
+/* get message digest */
+/* state is ruined after sum, keep a copy if multiple sum is needed */
+/* part of the message might be left in s, zero it if secrecy is needed */
+void sha256_sum(void *ctx, uint8_t md[SHA256_DIGEST_LENGTH]);
diff --git a/sha256sum.1 b/sha256sum.1
new file mode 100644
index 0000000..494b9df
--- /dev/null
+++ b/sha256sum.1
_AT_@ -0,0 +1,8 @@
+.TH SHA256SUM 1 sbase\-VERSION
+.SH NAME
+sha256sum \- compute SHA256 message digest
+.SH SYNOPSIS
+.B sha256sum
+.RI [ file ...]
+.SH DESCRIPTION
+Print SHA256 (256-bit) checksums. With no file, read standard input.
diff --git a/sha256sum.c b/sha256sum.c
new file mode 100644
index 0000000..ce97435
--- /dev/null
+++ b/sha256sum.c
_AT_@ -0,0 +1,49 @@
+/* See LICENSE file for copyright and license details. */
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include "util.h"
+#include "crypt.h"
+#include "sha256.h"
+
+struct sha256 s;
+struct crypt_ops sha256_ops = {
+	sha256_init,
+	sha256_update,
+	sha256_sum,
+	&s,
+};
+
+static void
+usage(void)
+{
+	eprintf("usage: %s [file...]\n", argv0);
+}
+
+int
+main(int argc, char *argv[])
+{
+	FILE *fp;
+	uint8_t md[SHA256_DIGEST_LENGTH];
+
+	ARGBEGIN {
+	default:
+		usage();
+	} ARGEND;
+
+	if (argc == 0) {
+		cryptsum(&sha256_ops, stdin, "<stdin>", md);
+		mdprint(md, "<stdin>", sizeof(md));
+	} else {
+		for (; argc > 0; argc--) {
+			if ((fp = fopen(*argv, "r")) == NULL)
+				eprintf("fopen %s:", *argv);
+			cryptsum(&sha256_ops, fp, *argv, md);
+			mdprint(md, *argv, sizeof(md));
+			fclose(fp);
+			argv++;
+		}
+	}
+
+	return 0;
+}
diff --git a/util/sha256.c b/util/sha256.c
new file mode 100644
index 0000000..94db29b
--- /dev/null
+++ b/util/sha256.c
_AT_@ -0,0 +1,152 @@
+/*
+ * public domain sha256 crypt implementation
+ *
+ * original sha crypt design: http://people.redhat.com/drepper/SHA-crypt.txt
+ * in this implementation at least 32bit int is assumed,
+ * key length is limited, the $5$ prefix is mandatory, '\n' and ':' is rejected
+ * in the salt and rounds= setting must contain a valid iteration count,
+ * on error "*" is returned.
+ */
+#include <ctype.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+#include "../sha256.h"
+
+/* public domain sha256 implementation based on fips180-3 */
+
+static uint32_t ror(uint32_t n, int k) { return (n >> k) | (n << (32-k)); }
+#define Ch(x,y,z)  (z ^ (x & (y ^ z)))
+#define Maj(x,y,z) ((x & y) | (z & (x | y)))
+#define S0(x)      (ror(x,2) ^ ror(x,13) ^ ror(x,22))
+#define S1(x)      (ror(x,6) ^ ror(x,11) ^ ror(x,25))
+#define R0(x)      (ror(x,7) ^ ror(x,18) ^ (x>>3))
+#define R1(x)      (ror(x,17) ^ ror(x,19) ^ (x>>10))
+
+static const uint32_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
+};
+
+static void processblock(struct sha256 *s, const uint8_t *buf)
+{
+	uint32_t W[64], t1, t2, a, b, c, d, e, f, g, h;
+	int i;
+
+	for (i = 0; i < 16; i++) {
+		W[i] = (uint32_t)buf[4*i]<<24;
+		W[i] |= (uint32_t)buf[4*i+1]<<16;
+		W[i] |= (uint32_t)buf[4*i+2]<<8;
+		W[i] |= buf[4*i+3];
+	}
+	for (; i < 64; i++)
+		W[i] = R1(W[i-2]) + W[i-7] + R0(W[i-15]) + W[i-16];
+	a = s->h[0];
+	b = s->h[1];
+	c = s->h[2];
+	d = s->h[3];
+	e = s->h[4];
+	f = s->h[5];
+	g = s->h[6];
+	h = s->h[7];
+	for (i = 0; i < 64; i++) {
+		t1 = h + S1(e) + Ch(e,f,g) + K[i] + W[i];
+		t2 = S0(a) + Maj(a,b,c);
+		h = g;
+		g = f;
+		f = e;
+		e = d + t1;
+		d = c;
+		c = b;
+		b = a;
+		a = t1 + t2;
+	}
+	s->h[0] += a;
+	s->h[1] += b;
+	s->h[2] += c;
+	s->h[3] += d;
+	s->h[4] += e;
+	s->h[5] += f;
+	s->h[6] += g;
+	s->h[7] += h;
+}
+
+static void pad(struct sha256 *s)
+{
+	unsigned r = s->len % 64;
+
+	s->buf[r++] = 0x80;
+	if (r > 56) {
+		memset(s->buf + r, 0, 64 - r);
+		r = 0;
+		processblock(s, s->buf);
+	}
+	memset(s->buf + r, 0, 56 - r);
+	s->len *= 8;
+	s->buf[56] = s->len >> 56;
+	s->buf[57] = s->len >> 48;
+	s->buf[58] = s->len >> 40;
+	s->buf[59] = s->len >> 32;
+	s->buf[60] = s->len >> 24;
+	s->buf[61] = s->len >> 16;
+	s->buf[62] = s->len >> 8;
+	s->buf[63] = s->len;
+	processblock(s, s->buf);
+}
+
+void sha256_init(void *ctx)
+{
+	struct sha256 *s = ctx;
+	s->len = 0;
+	s->h[0] = 0x6a09e667;
+	s->h[1] = 0xbb67ae85;
+	s->h[2] = 0x3c6ef372;
+	s->h[3] = 0xa54ff53a;
+	s->h[4] = 0x510e527f;
+	s->h[5] = 0x9b05688c;
+	s->h[6] = 0x1f83d9ab;
+	s->h[7] = 0x5be0cd19;
+}
+
+void sha256_sum(void *ctx, uint8_t md[SHA256_DIGEST_LENGTH])
+{
+	struct sha256 *s = ctx;
+	int i;
+
+	pad(s);
+	for (i = 0; i < 8; i++) {
+		md[4*i] = s->h[i] >> 24;
+		md[4*i+1] = s->h[i] >> 16;
+		md[4*i+2] = s->h[i] >> 8;
+		md[4*i+3] = s->h[i];
+	}
+}
+
+void sha256_update(void *ctx, const void *m, unsigned long len)
+{
+	struct sha256 *s = ctx;
+	const uint8_t *p = m;
+	unsigned r = s->len % 64;
+
+	s->len += len;
+	if (r) {
+		if (len < 64 - r) {
+			memcpy(s->buf + r, p, len);
+			return;
+		}
+		memcpy(s->buf + r, p, 64 - r);
+		len -= 64 - r;
+		p += 64 - r;
+		processblock(s, s->buf);
+	}
+	for (; len >= 64; len -= 64, p += 64)
+		processblock(s, p);
+	memcpy(s->buf, p, len);
+}
-- 
1.8.3.3
--BXVAT5kNtrzKuDFl--