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43830468b6
SHA-1 can be written in fewer than 100 lines of code. Just add a basic SHA-1 implementation so that there's no need to use an external library or try to pull in the kernel's SHA-1 implementation. The kernel's SHA-1 implementation is not really intended to be pulled into userspace programs in the way that it was proposed to do so for perf (https://lore.kernel.org/r/20250521225307.743726-3-yuzhuo@google.com/), and it's also likely to undergo some refactoring in the future. There's no need to tie userspace tools to it. Include a test for sha1() in the util test suite. Signed-off-by: Eric Biggers <ebiggers@kernel.org> Reviewed-by: Ian Rogers <irogers@google.com> Link: https://lore.kernel.org/r/20250625202311.23244-3-ebiggers@kernel.org Signed-off-by: Namhyung Kim <namhyung@kernel.org>
97 lines
2.9 KiB
C
97 lines
2.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* SHA-1 message digest algorithm
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*
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* Copyright 2025 Google LLC
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*/
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#include <linux/bitops.h>
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#include <linux/kernel.h>
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#include <linux/unaligned.h>
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#include <string.h>
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#include "sha1.h"
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#define SHA1_BLOCK_SIZE 64
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static const u32 sha1_K[4] = { 0x5A827999, 0x6ED9EBA1, 0x8F1BBCDC, 0xCA62C1D6 };
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#define SHA1_ROUND(i, a, b, c, d, e) \
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do { \
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if ((i) >= 16) \
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w[i] = rol32(w[(i) - 16] ^ w[(i) - 14] ^ w[(i) - 8] ^ \
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w[(i) - 3], \
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1); \
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e += w[i] + rol32(a, 5) + sha1_K[(i) / 20]; \
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if ((i) < 20) \
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e += (b & (c ^ d)) ^ d; \
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else if ((i) < 40 || (i) >= 60) \
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e += b ^ c ^ d; \
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else \
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e += (c & d) ^ (b & (c ^ d)); \
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b = rol32(b, 30); \
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/* The new (a, b, c, d, e) is the old (e, a, b, c, d). */ \
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} while (0)
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#define SHA1_5ROUNDS(i) \
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do { \
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SHA1_ROUND((i) + 0, a, b, c, d, e); \
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SHA1_ROUND((i) + 1, e, a, b, c, d); \
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SHA1_ROUND((i) + 2, d, e, a, b, c); \
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SHA1_ROUND((i) + 3, c, d, e, a, b); \
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SHA1_ROUND((i) + 4, b, c, d, e, a); \
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} while (0)
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#define SHA1_20ROUNDS(i) \
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do { \
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SHA1_5ROUNDS((i) + 0); \
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SHA1_5ROUNDS((i) + 5); \
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SHA1_5ROUNDS((i) + 10); \
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SHA1_5ROUNDS((i) + 15); \
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} while (0)
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static void sha1_blocks(u32 h[5], const u8 *data, size_t nblocks)
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{
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while (nblocks--) {
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u32 a = h[0];
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u32 b = h[1];
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u32 c = h[2];
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u32 d = h[3];
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u32 e = h[4];
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u32 w[80];
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for (int i = 0; i < 16; i++)
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w[i] = get_unaligned_be32(&data[i * 4]);
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SHA1_20ROUNDS(0);
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SHA1_20ROUNDS(20);
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SHA1_20ROUNDS(40);
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SHA1_20ROUNDS(60);
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h[0] += a;
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h[1] += b;
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h[2] += c;
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h[3] += d;
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h[4] += e;
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data += SHA1_BLOCK_SIZE;
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}
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}
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/* Calculate the SHA-1 message digest of the given data. */
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void sha1(const void *data, size_t len, u8 out[SHA1_DIGEST_SIZE])
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{
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u32 h[5] = { 0x67452301, 0xEFCDAB89, 0x98BADCFE, 0x10325476,
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0xC3D2E1F0 };
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u8 final_data[2 * SHA1_BLOCK_SIZE] = { 0 };
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size_t final_len = len % SHA1_BLOCK_SIZE;
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sha1_blocks(h, data, len / SHA1_BLOCK_SIZE);
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memcpy(final_data, data + len - final_len, final_len);
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final_data[final_len] = 0x80;
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final_len = round_up(final_len + 9, SHA1_BLOCK_SIZE);
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put_unaligned_be64((u64)len * 8, &final_data[final_len - 8]);
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sha1_blocks(h, final_data, final_len / SHA1_BLOCK_SIZE);
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for (int i = 0; i < 5; i++)
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put_unaligned_be32(h[i], &out[i * 4]);
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}
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