user: libc: Add crypto/sha256 support

Signed-off-by: Ian Moffett <ian@osmora.org>

3 files changed, 305 insertions, 0 deletions

diff --git a/lib/libc/Makefile b/lib/libc/Makefile
index b5bd01e..be693bd 100644
--- a/lib/libc/Makefile
+++ b/lib/libc/Makefile
@@ -30,6 +30,7 @@ headers: sys/include/machine
 	cp -f include/*.h $(USRDIR)/include/
 	cp -f include/stdlib/*.h $(USRDIR)/include/
 	cp -rf include/ousi $(USRDIR)/include/
+	cp -rf include/crypto $(USRDIR)/include/
 
 .PHONY:
 build/:
diff --git a/lib/libc/include/crypto/sha256.h b/lib/libc/include/crypto/sha256.h
new file mode 100644
index 0000000..6bd1077
--- /dev/null
+++ b/lib/libc/include/crypto/sha256.h
@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * 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.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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.
+ */
+
+#ifndef _CRYPTO_SHA256_H
+#define _CRYPTO_SHA256_H 1
+
+#include <stddef.h>
+#include <stdint.h>
+
+#define SHA256_HEX_SIZE (64 + 1)
+#define SHA256_BYTES_SIZE 32
+
+/*
+ * Compute the SHA-256 checksum of a memory region given a pointer and
+ * the size of that memory region.
+ * The output is a hexadecimal string of 65 characters.
+ * The last character will be the null-character.
+ */
+void sha256_hex(const void *src, size_t n_bytes, char *dst_hex65);
+
+void sha256_bytes(const void *src, size_t n_bytes, void *dst_bytes32);
+
+typedef struct sha256 {
+    uint32_t state[8];
+    uint8_t buffer[64];
+    uint64_t n_bits;
+    uint8_t buffer_counter;
+} sha256;
+
+/* Functions to compute streaming SHA-256 checksums. */
+void sha256_init(struct sha256 *sha);
+void sha256_append(struct sha256 *sha, const void *data, size_t n_bytes);
+void sha256_finalize_hex(struct sha256 *sha, char *dst_hex65);
+void sha256_finalize_bytes(struct sha256 *sha, void *dst_bytes32);
+
+#endif  /* !_CRYPTO_SHA256_H */
diff --git a/lib/libc/src/crypto/sha256.c b/lib/libc/src/crypto/sha256.c
new file mode 100644
index 0000000..c722026
--- /dev/null
+++ b/lib/libc/src/crypto/sha256.c
@@ -0,0 +1,242 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * 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.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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 <crypto/sha256.h>
+#include <stdint.h>
+#include <stddef.h>
+
+static inline uint32_t
+rotr(uint32_t x, int n)
+{
+    return (x >> n) | (x << (32 - n));
+}
+
+static inline uint32_t
+step1(uint32_t e, uint32_t f, uint32_t g)
+{
+    return (rotr(e, 6) ^ rotr(e, 11) ^ rotr(e, 25)) + ((e & f) ^ ((~ e) & g));
+}
+
+static inline uint32_t
+step2(uint32_t a, uint32_t b, uint32_t c)
+{
+    return (rotr(a, 2) ^ rotr(a, 13) ^ rotr(a, 22)) + ((a & b) ^ (a & c) ^ (b & c));
+}
+
+static inline void
+update_w(uint32_t *w, int i, const uint8_t *buffer)
+{
+    int j;
+    for (j = 0; j < 16; j++) {
+        if (i < 16){
+            w[j] =
+                ((uint32_t)buffer[0] << 24) |
+                ((uint32_t)buffer[1] << 16) |
+                ((uint32_t)buffer[2] <<  8) |
+                ((uint32_t)buffer[3]);
+            buffer += 4;
+        }else {
+            uint32_t a = w[(j + 1) & 15];
+            uint32_t b = w[(j + 14) & 15];
+            uint32_t s0 = (rotr(a,  7) ^ rotr(a, 18) ^ (a >>  3));
+            uint32_t s1 = (rotr(b, 17) ^ rotr(b, 19) ^ (b >> 10));
+            w[j] += w[(j + 9) & 15] + s0 + s1;
+        }
+    }
+}
+
+static void
+sha256_block(struct sha256 *sha)
+{
+    uint32_t *state = sha->state;
+
+    static const uint32_t k[8 * 8] = {
+        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,
+    };
+
+    uint32_t a = state[0];
+    uint32_t b = state[1];
+    uint32_t c = state[2];
+    uint32_t d = state[3];
+    uint32_t e = state[4];
+    uint32_t f = state[5];
+    uint32_t g = state[6];
+    uint32_t h = state[7];
+
+    uint32_t w[16];
+
+    int i, j;
+    for (i = 0; i < 64; i += 16) {
+        update_w(w, i, sha->buffer);
+
+        for (j = 0; j < 16; j += 4) {
+            uint32_t temp;
+            temp = h + step1(e, f, g) + k[i + j + 0] + w[j + 0];
+            h = temp + d;
+            d = temp + step2(a, b, c);
+            temp = g + step1(h, e, f) + k[i + j + 1] + w[j + 1];
+            g = temp + c;
+            c = temp + step2(d, a, b);
+            temp = f + step1(g, h, e) + k[i + j + 2] + w[j + 2];
+            f = temp + b;
+            b = temp + step2(c, d, a);
+            temp = e + step1(f, g, h) + k[i + j + 3] + w[j + 3];
+            e = temp + a;
+            a = temp + step2(b, c, d);
+        }
+    }
+
+    state[0] += a;
+    state[1] += b;
+    state[2] += c;
+    state[3] += d;
+    state[4] += e;
+    state[5] += f;
+    state[6] += g;
+    state[7] += h;
+}
+
+void
+sha256_init(struct sha256 *sha)
+{
+    sha->state[0] = 0x6a09e667;
+    sha->state[1] = 0xbb67ae85;
+    sha->state[2] = 0x3c6ef372;
+    sha->state[3] = 0xa54ff53a;
+    sha->state[4] = 0x510e527f;
+    sha->state[5] = 0x9b05688c;
+    sha->state[6] = 0x1f83d9ab;
+    sha->state[7] = 0x5be0cd19;
+    sha->n_bits = 0;
+    sha->buffer_counter = 0;
+}
+
+void
+sha256_append_byte(struct sha256 *sha, uint8_t byte)
+{
+    sha->buffer[sha->buffer_counter++] = byte;
+    sha->n_bits += 8;
+
+    if (sha->buffer_counter == 64) {
+        sha->buffer_counter = 0;
+        sha256_block(sha);
+    }
+}
+
+void
+sha256_append(struct sha256 *sha, const void *src, size_t n_bytes)
+{
+    const uint8_t *bytes = (const uint8_t*)src;
+    size_t i;
+
+    for (i = 0; i < n_bytes; i++) {
+        sha256_append_byte(sha, bytes[i]);
+    }
+}
+
+void
+sha256_finalize(struct sha256 *sha)
+{
+    int i;
+    uint64_t n_bits = sha->n_bits;
+
+    sha256_append_byte(sha, 0x80);
+
+    while (sha->buffer_counter != 56) {
+        sha256_append_byte(sha, 0);
+    }
+
+    for (i = 7; i >= 0; i--) {
+        uint8_t byte = (n_bits >> 8 * i) & 0xff;
+        sha256_append_byte(sha, byte);
+    }
+}
+
+void
+sha256_finalize_hex(struct sha256 *sha, char *dst_hex65)
+{
+    int i, j;
+    sha256_finalize(sha);
+
+    for (i = 0; i < 8; i++) {
+        for (j = 7; j >= 0; j--) {
+            uint8_t nibble = (sha->state[i] >> j * 4) & 0xf;
+            *dst_hex65++ = "0123456789abcdef"[nibble];
+        }
+    }
+
+    *dst_hex65 = '\0';
+}
+
+void
+sha256_finalize_bytes(struct sha256 *sha, void *dst_bytes32)
+{
+    uint8_t *ptr = (uint8_t*)dst_bytes32;
+    int i, j;
+    sha256_finalize(sha);
+
+    for (i = 0; i < 8; i++) {
+        for (j = 3; j >= 0; j--) {
+            *ptr++ = (sha->state[i] >> j * 8) & 0xff;
+        }
+    }
+}
+
+void
+sha256_hex(const void *src, size_t n_bytes, char *dst_hex65)
+{
+    struct sha256 sha;
+
+    sha256_init(&sha);
+    sha256_append(&sha, src, n_bytes);
+    sha256_finalize_hex(&sha, dst_hex65);
+}
+
+void sha256_bytes(const void *src, size_t n_bytes, void *dst_bytes32){
+    struct sha256 sha;
+
+    sha256_init(&sha);
+    sha256_append(&sha, src, n_bytes);
+    sha256_finalize_bytes(&sha, dst_bytes32);
+}