/* SPDX-License-Identifier: LicenseRef-alg-sha1-public-domain */

/*
SHA-1 in C
By Steve Reid <sreid@sea-to-sky.net>
100% Public Domain

-----------------
Modified 7/98
By James H. Brown <jbrown@burgoyne.com>
Still 100% Public Domain

Corrected a problem which generated improper hash values on 16 bit machines
Routine SHA1Update changed from
  void SHA1Update(SHA1_CTX* context, unsigned char* data, unsigned int len)
to
  void SHA1Update(SHA1_CTX* context, unsigned char* data, unsigned long len)

The 'len' parameter was declared an int which works fine on 32 bit machines.
However, on 16 bit machines an int is too small for the shifts being done
against
it.  This caused the hash function to generate incorrect values if len was
greater than 8191 (8K - 1) due to the 'len << 3' on line 3 of SHA1Update().

Since the file IO in main() reads 16K at a time, any file 8K or larger would
be guaranteed to generate the wrong hash (e.g. Test Vector #3,
a million "a"s).

I also changed the declaration of variables i & j in SHA1Update to
unsigned long from unsigned int for the same reason.

These changes should make no difference to any 32 bit implementations since
an int and a long are the same size in those environments.

--
I also corrected a few compiler warnings generated by Borland C.
1. Added #include <process.h> for exit() prototype
2. Removed unused variable 'j' in SHA1Final
3. Changed exit(0) to return(0) at end of main.

ALL changes I made can be located by searching for comments containing 'JHB'
-----------------
Modified 8/98
By Steve Reid <sreid@sea-to-sky.net>
Still 100% public domain

1- Removed #include <process.h> and used return() instead of exit()
2- Fixed overwriting of finalcount in SHA1Final() (discovered by Chris Hall)
3- Changed email address from steve@edmweb.com to sreid@sea-to-sky.net

-----------------
Modified 4/01
By Saul Kravitz <Saul.Kravitz@celera.com>
Still 100% PD
Modified to run on Compaq Alpha hardware.

-----------------
Modified 07/2002
By Ralph Giles <giles@ghostscript.com>
Still 100% public domain
modified for use with stdint types, autoconf
code cleanup, removed attribution comments
switched SHA1Final() argument order for consistency
use SHA1_ prefix for public api
move public api to sha1.h

-----------------
Modified 10/2017
By Björn Esser <besser82@fedoraproject.org>
Still 100% public domain
modified for use with libxcrypt

Modified 09/2024
By anonymix007 <48598263+anonymix007@users.noreply.github.com>
Still 100% public domain
modified for use with systemd
*/

#include "memory-util-fundamental.h"
#include "sha1.h"

#define SHA1_DIGEST_SIZE 20

#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))

/* blk0() and blk() perform the initial expand. */
/* I got the idea of expanding during the round function from SSLeay */
/* FIXME: can we do this in an endian-proof way? */
#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
#        define blk0(i) block.l[i]
#else
#        define blk0(i) (block.l[i] = (rol(block.l[i], 24) & 0xFF00FF00) | (rol(block.l[i], 8) & 0x00FF00FF))
#endif
#define blk(i)                                                                                    \
        (block.l[i & 15] = rol(                                                                   \
                         block.l[(i + 13) & 15] ^ block.l[(i + 8) & 15] ^ block.l[(i + 2) & 15] ^ \
                                         block.l[i & 15],                                         \
                         1))

/* (R0+R1), R2, R3, R4 are the different operations used in SHA1 */
#define R0(v, w, x, y, z, i)                                         \
        z += ((w & (x ^ y)) ^ y) + blk0(i) + 0x5A827999 + rol(v, 5); \
        w = rol(w, 30);
#define R1(v, w, x, y, z, i)                                        \
        z += ((w & (x ^ y)) ^ y) + blk(i) + 0x5A827999 + rol(v, 5); \
        w = rol(w, 30);
#define R2(v, w, x, y, z, i)                                \
        z += (w ^ x ^ y) + blk(i) + 0x6ED9EBA1 + rol(v, 5); \
        w = rol(w, 30);
#define R3(v, w, x, y, z, i)                                              \
        z += (((w | x) & y) | (w & x)) + blk(i) + 0x8F1BBCDC + rol(v, 5); \
        w = rol(w, 30);
#define R4(v, w, x, y, z, i)                                \
        z += (w ^ x ^ y) + blk(i) + 0xCA62C1D6 + rol(v, 5); \
        w = rol(w, 30);

/* Hash a single 512-bit block. This is the core of the algorithm. */
static void sha1_do_transform(uint32_t state[5], const uint8_t buffer[64]) {
        uint32_t a, b, c, d, e;
        typedef union {
                uint8_t c[64];
                uint32_t l[16];
        } CHAR64LONG16;
        CHAR64LONG16 block;

        memcpy(&block, buffer, 64);

        /* Copy context->state[] to working vars */
        a = state[0];
        b = state[1];
        c = state[2];
        d = state[3];
        e = state[4];

        /* 4 rounds of 20 operations each. Loop unrolled. */
        R0(a, b, c, d, e, 0);
        R0(e, a, b, c, d, 1);
        R0(d, e, a, b, c, 2);
        R0(c, d, e, a, b, 3);
        R0(b, c, d, e, a, 4);
        R0(a, b, c, d, e, 5);
        R0(e, a, b, c, d, 6);
        R0(d, e, a, b, c, 7);
        R0(c, d, e, a, b, 8);
        R0(b, c, d, e, a, 9);
        R0(a, b, c, d, e, 10);
        R0(e, a, b, c, d, 11);
        R0(d, e, a, b, c, 12);
        R0(c, d, e, a, b, 13);
        R0(b, c, d, e, a, 14);
        R0(a, b, c, d, e, 15);
        R1(e, a, b, c, d, 16);
        R1(d, e, a, b, c, 17);
        R1(c, d, e, a, b, 18);
        R1(b, c, d, e, a, 19);
        R2(a, b, c, d, e, 20);
        R2(e, a, b, c, d, 21);
        R2(d, e, a, b, c, 22);
        R2(c, d, e, a, b, 23);
        R2(b, c, d, e, a, 24);
        R2(a, b, c, d, e, 25);
        R2(e, a, b, c, d, 26);
        R2(d, e, a, b, c, 27);
        R2(c, d, e, a, b, 28);
        R2(b, c, d, e, a, 29);
        R2(a, b, c, d, e, 30);
        R2(e, a, b, c, d, 31);
        R2(d, e, a, b, c, 32);
        R2(c, d, e, a, b, 33);
        R2(b, c, d, e, a, 34);
        R2(a, b, c, d, e, 35);
        R2(e, a, b, c, d, 36);
        R2(d, e, a, b, c, 37);
        R2(c, d, e, a, b, 38);
        R2(b, c, d, e, a, 39);
        R3(a, b, c, d, e, 40);
        R3(e, a, b, c, d, 41);
        R3(d, e, a, b, c, 42);
        R3(c, d, e, a, b, 43);
        R3(b, c, d, e, a, 44);
        R3(a, b, c, d, e, 45);
        R3(e, a, b, c, d, 46);
        R3(d, e, a, b, c, 47);
        R3(c, d, e, a, b, 48);
        R3(b, c, d, e, a, 49);
        R3(a, b, c, d, e, 50);
        R3(e, a, b, c, d, 51);
        R3(d, e, a, b, c, 52);
        R3(c, d, e, a, b, 53);
        R3(b, c, d, e, a, 54);
        R3(a, b, c, d, e, 55);
        R3(e, a, b, c, d, 56);
        R3(d, e, a, b, c, 57);
        R3(c, d, e, a, b, 58);
        R3(b, c, d, e, a, 59);
        R4(a, b, c, d, e, 60);
        R4(e, a, b, c, d, 61);
        R4(d, e, a, b, c, 62);
        R4(c, d, e, a, b, 63);
        R4(b, c, d, e, a, 64);
        R4(a, b, c, d, e, 65);
        R4(e, a, b, c, d, 66);
        R4(d, e, a, b, c, 67);
        R4(c, d, e, a, b, 68);
        R4(b, c, d, e, a, 69);
        R4(a, b, c, d, e, 70);
        R4(e, a, b, c, d, 71);
        R4(d, e, a, b, c, 72);
        R4(c, d, e, a, b, 73);
        R4(b, c, d, e, a, 74);
        R4(a, b, c, d, e, 75);
        R4(e, a, b, c, d, 76);
        R4(d, e, a, b, c, 77);
        R4(c, d, e, a, b, 78);
        R4(b, c, d, e, a, 79);

        /* Add the working vars back into context.state[] */
        state[0] += a;
        state[1] += b;
        state[2] += c;
        state[3] += d;
        state[4] += e;

        /* Wipe variables */
        a = b = c = d = e = 0;
}

/* SHA1Init - Initialize new context */
void sha1_init_ctx(struct sha1_ctx *ctx) {
        /* SHA1 initialization constants */
        ctx->state[0] = 0x67452301;
        ctx->state[1] = 0xEFCDAB89;
        ctx->state[2] = 0x98BADCFE;
        ctx->state[3] = 0x10325476;
        ctx->state[4] = 0xC3D2E1F0;
        ctx->count[0] = ctx->count[1] = 0;
}

/* Run your data through this. */
void sha1_process_bytes(const void *buffer, size_t size, struct sha1_ctx *ctx) {
        size_t i, j;

        j = (ctx->count[0] >> 3) & 63;
        if ((ctx->count[0] += (uint32_t) size << 3) < ((uint32_t) size << 3))
                ctx->count[1]++;
        ctx->count[1] += (uint32_t) (size >> 29);
        if ((j + size) > 63) {
                memcpy(&ctx->buffer[j], buffer, (i = 64 - j));
                sha1_do_transform(ctx->state, ctx->buffer);
                DISABLE_WARNING_STRINGOP_OVERREAD;
                for (; i + 63 < size; i += 64)
                        sha1_do_transform(ctx->state, (const uint8_t *) buffer + i);
                REENABLE_WARNING;
                j = 0;
        } else
                i = 0;
        memcpy(&ctx->buffer[j], (const uint8_t *) buffer + i, size - i);
}

/* Add padding and return the message digest. */
void *sha1_finish_ctx(struct sha1_ctx *ctx, uint8_t result[static SHA1_DIGEST_SIZE]) {
        uint32_t i;
        uint8_t finalcount[8];

        for (i = 0; i < 8; i++) {
                finalcount[i] = (unsigned char) ((ctx->count[(i >= 4 ? 0 : 1)] >> ((3 - (i & 3)) * 8)) &
                                                 255); /* Endian independent */
        }
        sha1_process_bytes((const uint8_t *) "\200", 1, ctx);
        while ((ctx->count[0] & 504) != 448)
                sha1_process_bytes((const uint8_t *) "\0", 1, ctx);
        sha1_process_bytes(finalcount, 8, ctx); /* Should cause a sha1_do_transform() */
        for (i = 0; i < SHA1_DIGEST_SIZE; i++) {
                result[i] = (uint8_t) ((ctx->state[i >> 2] >> ((3 - (i & 3)) * 8)) & 255);
        }

        /* Wipe variables */
        i = 0;
        memzero(ctx, sizeof(struct sha1_ctx));
        memzero(finalcount, 8); /* SWR */

        return result;
}
