sha256.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * SHA-224, SHA-256, HMAC-SHA224, and HMAC-SHA256 library functions
  4 *
  5 * Copyright (c) Jean-Luc Cooke <jlcooke@certainkey.com>
  6 * Copyright (c) Andrew McDonald <andrew@mcdonald.org.uk>
  7 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
  8 * Copyright (c) 2014 Red Hat Inc.
  9 * Copyright 2025 Google LLC
 10 */
 11
 12#include <crypto/hmac.h>
 13#include <crypto/sha2.h>
 14#include <linux/export.h>
 15#include <linux/kernel.h>
 16#include <linux/module.h>
 17#include <linux/string.h>
 18#include <linux/unaligned.h>
 19#include <linux/wordpart.h>
 20#include "fips.h"
 21
 22static const struct sha256_block_state sha224_iv = {
 23	.h = {
 24		SHA224_H0, SHA224_H1, SHA224_H2, SHA224_H3,
 25		SHA224_H4, SHA224_H5, SHA224_H6, SHA224_H7,
 26	},
 27};
 28
 29static const struct sha256_ctx initial_sha256_ctx = {
 30	.ctx = {
 31		.state = {
 32			.h = {
 33				SHA256_H0, SHA256_H1, SHA256_H2, SHA256_H3,
 34				SHA256_H4, SHA256_H5, SHA256_H6, SHA256_H7,
 35			},
 36		},
 37		.bytecount = 0,
 38	},
 39};
 40
 41#define sha256_iv (initial_sha256_ctx.ctx.state)
 42
 43static const u32 sha256_K[64] = {
 44	0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1,
 45	0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
 46	0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786,
 47	0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
 48	0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147,
 49	0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
 50	0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b,
 51	0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
 52	0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a,
 53	0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
 54	0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2,
 55};
 56
 57#define Ch(x, y, z) ((z) ^ ((x) & ((y) ^ (z))))
 58#define Maj(x, y, z) (((x) & (y)) | ((z) & ((x) | (y))))
 59#define e0(x) (ror32((x), 2) ^ ror32((x), 13) ^ ror32((x), 22))
 60#define e1(x) (ror32((x), 6) ^ ror32((x), 11) ^ ror32((x), 25))
 61#define s0(x) (ror32((x), 7) ^ ror32((x), 18) ^ ((x) >> 3))
 62#define s1(x) (ror32((x), 17) ^ ror32((x), 19) ^ ((x) >> 10))
 63
 64static inline void LOAD_OP(int I, u32 *W, const u8 *input)
 65{
 66	W[I] = get_unaligned_be32((__u32 *)input + I);
 67}
 68
 69static inline void BLEND_OP(int I, u32 *W)
 70{
 71	W[I] = s1(W[I - 2]) + W[I - 7] + s0(W[I - 15]) + W[I - 16];
 72}
 73
 74#define SHA256_ROUND(i, a, b, c, d, e, f, g, h)                    \
 75	do {                                                       \
 76		u32 t1, t2;                                        \
 77		t1 = h + e1(e) + Ch(e, f, g) + sha256_K[i] + W[i]; \
 78		t2 = e0(a) + Maj(a, b, c);                         \
 79		d += t1;                                           \
 80		h = t1 + t2;                                       \
 81	} while (0)
 82
 83static void sha256_block_generic(struct sha256_block_state *state,
 84				 const u8 *input, u32 W[64])
 85{
 86	u32 a, b, c, d, e, f, g, h;
 87	int i;
 88
 89	/* load the input */
 90	for (i = 0; i < 16; i += 8) {
 91		LOAD_OP(i + 0, W, input);
 92		LOAD_OP(i + 1, W, input);
 93		LOAD_OP(i + 2, W, input);
 94		LOAD_OP(i + 3, W, input);
 95		LOAD_OP(i + 4, W, input);
 96		LOAD_OP(i + 5, W, input);
 97		LOAD_OP(i + 6, W, input);
 98		LOAD_OP(i + 7, W, input);
 99	}
100
101	/* now blend */
102	for (i = 16; i < 64; i += 8) {
103		BLEND_OP(i + 0, W);
104		BLEND_OP(i + 1, W);
105		BLEND_OP(i + 2, W);
106		BLEND_OP(i + 3, W);
107		BLEND_OP(i + 4, W);
108		BLEND_OP(i + 5, W);
109		BLEND_OP(i + 6, W);
110		BLEND_OP(i + 7, W);
111	}
112
113	/* load the state into our registers */
114	a = state->h[0];
115	b = state->h[1];
116	c = state->h[2];
117	d = state->h[3];
118	e = state->h[4];
119	f = state->h[5];
120	g = state->h[6];
121	h = state->h[7];
122
123	/* now iterate */
124	for (i = 0; i < 64; i += 8) {
125		SHA256_ROUND(i + 0, a, b, c, d, e, f, g, h);
126		SHA256_ROUND(i + 1, h, a, b, c, d, e, f, g);
127		SHA256_ROUND(i + 2, g, h, a, b, c, d, e, f);
128		SHA256_ROUND(i + 3, f, g, h, a, b, c, d, e);
129		SHA256_ROUND(i + 4, e, f, g, h, a, b, c, d);
130		SHA256_ROUND(i + 5, d, e, f, g, h, a, b, c);
131		SHA256_ROUND(i + 6, c, d, e, f, g, h, a, b);
132		SHA256_ROUND(i + 7, b, c, d, e, f, g, h, a);
133	}
134
135	state->h[0] += a;
136	state->h[1] += b;
137	state->h[2] += c;
138	state->h[3] += d;
139	state->h[4] += e;
140	state->h[5] += f;
141	state->h[6] += g;
142	state->h[7] += h;
143}
144
145static void __maybe_unused
146sha256_blocks_generic(struct sha256_block_state *state,
147		      const u8 *data, size_t nblocks)
148{
149	u32 W[64];
150
151	do {
152		sha256_block_generic(state, data, W);
153		data += SHA256_BLOCK_SIZE;
154	} while (--nblocks);
155
156	memzero_explicit(W, sizeof(W));
157}
158
159#if defined(CONFIG_CRYPTO_LIB_SHA256_ARCH) && !defined(__DISABLE_EXPORTS)
160#include "sha256.h" /* $(SRCARCH)/sha256.h */
161#else
162#define sha256_blocks sha256_blocks_generic
163#endif
164
165static void __sha256_init(struct __sha256_ctx *ctx,
166			  const struct sha256_block_state *iv,
167			  u64 initial_bytecount)
168{
169	ctx->state = *iv;
170	ctx->bytecount = initial_bytecount;
171}
172
173void sha224_init(struct sha224_ctx *ctx)
174{
175	__sha256_init(&ctx->ctx, &sha224_iv, 0);
176}
177EXPORT_SYMBOL_GPL(sha224_init);
178
179void sha256_init(struct sha256_ctx *ctx)
180{
181	__sha256_init(&ctx->ctx, &sha256_iv, 0);
182}
183EXPORT_SYMBOL_GPL(sha256_init);
184
185void __sha256_update(struct __sha256_ctx *ctx, const u8 *data, size_t len)
186{
187	size_t partial = ctx->bytecount % SHA256_BLOCK_SIZE;
188
189	ctx->bytecount += len;
190
191	if (partial + len >= SHA256_BLOCK_SIZE) {
192		size_t nblocks;
193
194		if (partial) {
195			size_t l = SHA256_BLOCK_SIZE - partial;
196
197			memcpy(&ctx->buf[partial], data, l);
198			data += l;
199			len -= l;
200
201			sha256_blocks(&ctx->state, ctx->buf, 1);
202		}
203
204		nblocks = len / SHA256_BLOCK_SIZE;
205		len %= SHA256_BLOCK_SIZE;
206
207		if (nblocks) {
208			sha256_blocks(&ctx->state, data, nblocks);
209			data += nblocks * SHA256_BLOCK_SIZE;
210		}
211		partial = 0;
212	}
213	if (len)
214		memcpy(&ctx->buf[partial], data, len);
215}
216EXPORT_SYMBOL(__sha256_update);
217
218static void __sha256_final(struct __sha256_ctx *ctx,
219			   u8 *out, size_t digest_size)
220{
221	u64 bitcount = ctx->bytecount << 3;
222	size_t partial = ctx->bytecount % SHA256_BLOCK_SIZE;
223
224	ctx->buf[partial++] = 0x80;
225	if (partial > SHA256_BLOCK_SIZE - 8) {
226		memset(&ctx->buf[partial], 0, SHA256_BLOCK_SIZE - partial);
227		sha256_blocks(&ctx->state, ctx->buf, 1);
228		partial = 0;
229	}
230	memset(&ctx->buf[partial], 0, SHA256_BLOCK_SIZE - 8 - partial);
231	*(__be64 *)&ctx->buf[SHA256_BLOCK_SIZE - 8] = cpu_to_be64(bitcount);
232	sha256_blocks(&ctx->state, ctx->buf, 1);
233
234	for (size_t i = 0; i < digest_size; i += 4)
235		put_unaligned_be32(ctx->state.h[i / 4], out + i);
236}
237
238void sha224_final(struct sha224_ctx *ctx, u8 out[SHA224_DIGEST_SIZE])
239{
240	__sha256_final(&ctx->ctx, out, SHA224_DIGEST_SIZE);
241	memzero_explicit(ctx, sizeof(*ctx));
242}
243EXPORT_SYMBOL(sha224_final);
244
245void sha256_final(struct sha256_ctx *ctx, u8 out[SHA256_DIGEST_SIZE])
246{
247	__sha256_final(&ctx->ctx, out, SHA256_DIGEST_SIZE);
248	memzero_explicit(ctx, sizeof(*ctx));
249}
250EXPORT_SYMBOL(sha256_final);
251
252void sha224(const u8 *data, size_t len, u8 out[SHA224_DIGEST_SIZE])
253{
254	struct sha224_ctx ctx;
255
256	sha224_init(&ctx);
257	sha224_update(&ctx, data, len);
258	sha224_final(&ctx, out);
259}
260EXPORT_SYMBOL(sha224);
261
262void sha256(const u8 *data, size_t len, u8 out[SHA256_DIGEST_SIZE])
263{
264	struct sha256_ctx ctx;
265
266	sha256_init(&ctx);
267	sha256_update(&ctx, data, len);
268	sha256_final(&ctx, out);
269}
270EXPORT_SYMBOL(sha256);
271
272/*
273 * Pre-boot environments (as indicated by __DISABLE_EXPORTS being defined) just
274 * need the generic SHA-256 code.  Omit all other features from them.
275 */
276#ifndef __DISABLE_EXPORTS
277
278#ifndef sha256_finup_2x_arch
279static bool sha256_finup_2x_arch(const struct __sha256_ctx *ctx,
280				 const u8 *data1, const u8 *data2, size_t len,
281				 u8 out1[SHA256_DIGEST_SIZE],
282				 u8 out2[SHA256_DIGEST_SIZE])
283{
284	return false;
285}
286static bool sha256_finup_2x_is_optimized_arch(void)
287{
288	return false;
289}
290#endif
291
292/* Sequential fallback implementation of sha256_finup_2x() */
293static noinline_for_stack void sha256_finup_2x_sequential(
294	const struct __sha256_ctx *ctx, const u8 *data1, const u8 *data2,
295	size_t len, u8 out1[SHA256_DIGEST_SIZE], u8 out2[SHA256_DIGEST_SIZE])
296{
297	struct __sha256_ctx mut_ctx;
298
299	mut_ctx = *ctx;
300	__sha256_update(&mut_ctx, data1, len);
301	__sha256_final(&mut_ctx, out1, SHA256_DIGEST_SIZE);
302
303	mut_ctx = *ctx;
304	__sha256_update(&mut_ctx, data2, len);
305	__sha256_final(&mut_ctx, out2, SHA256_DIGEST_SIZE);
306}
307
308void sha256_finup_2x(const struct sha256_ctx *ctx, const u8 *data1,
309		     const u8 *data2, size_t len, u8 out1[SHA256_DIGEST_SIZE],
310		     u8 out2[SHA256_DIGEST_SIZE])
311{
312	if (ctx == NULL)
313		ctx = &initial_sha256_ctx;
314
315	if (likely(sha256_finup_2x_arch(&ctx->ctx, data1, data2, len, out1,
316					out2)))
317		return;
318	sha256_finup_2x_sequential(&ctx->ctx, data1, data2, len, out1, out2);
319}
320EXPORT_SYMBOL_GPL(sha256_finup_2x);
321
322bool sha256_finup_2x_is_optimized(void)
323{
324	return sha256_finup_2x_is_optimized_arch();
325}
326EXPORT_SYMBOL_GPL(sha256_finup_2x_is_optimized);
327
328static void __hmac_sha256_preparekey(struct sha256_block_state *istate,
329				     struct sha256_block_state *ostate,
330				     const u8 *raw_key, size_t raw_key_len,
331				     const struct sha256_block_state *iv)
332{
333	union {
334		u8 b[SHA256_BLOCK_SIZE];
335		unsigned long w[SHA256_BLOCK_SIZE / sizeof(unsigned long)];
336	} derived_key = { 0 };
337
338	if (unlikely(raw_key_len > SHA256_BLOCK_SIZE)) {
339		if (iv == &sha224_iv)
340			sha224(raw_key, raw_key_len, derived_key.b);
341		else
342			sha256(raw_key, raw_key_len, derived_key.b);
343	} else {
344		memcpy(derived_key.b, raw_key, raw_key_len);
345	}
346
347	for (size_t i = 0; i < ARRAY_SIZE(derived_key.w); i++)
348		derived_key.w[i] ^= REPEAT_BYTE(HMAC_IPAD_VALUE);
349	*istate = *iv;
350	sha256_blocks(istate, derived_key.b, 1);
351
352	for (size_t i = 0; i < ARRAY_SIZE(derived_key.w); i++)
353		derived_key.w[i] ^= REPEAT_BYTE(HMAC_OPAD_VALUE ^
354						HMAC_IPAD_VALUE);
355	*ostate = *iv;
356	sha256_blocks(ostate, derived_key.b, 1);
357
358	memzero_explicit(&derived_key, sizeof(derived_key));
359}
360
361void hmac_sha224_preparekey(struct hmac_sha224_key *key,
362			    const u8 *raw_key, size_t raw_key_len)
363{
364	__hmac_sha256_preparekey(&key->key.istate, &key->key.ostate,
365				 raw_key, raw_key_len, &sha224_iv);
366}
367EXPORT_SYMBOL_GPL(hmac_sha224_preparekey);
368
369void hmac_sha256_preparekey(struct hmac_sha256_key *key,
370			    const u8 *raw_key, size_t raw_key_len)
371{
372	__hmac_sha256_preparekey(&key->key.istate, &key->key.ostate,
373				 raw_key, raw_key_len, &sha256_iv);
374}
375EXPORT_SYMBOL_GPL(hmac_sha256_preparekey);
376
377void __hmac_sha256_init(struct __hmac_sha256_ctx *ctx,
378			const struct __hmac_sha256_key *key)
379{
380	__sha256_init(&ctx->sha_ctx, &key->istate, SHA256_BLOCK_SIZE);
381	ctx->ostate = key->ostate;
382}
383EXPORT_SYMBOL_GPL(__hmac_sha256_init);
384
385void hmac_sha224_init_usingrawkey(struct hmac_sha224_ctx *ctx,
386				  const u8 *raw_key, size_t raw_key_len)
387{
388	__hmac_sha256_preparekey(&ctx->ctx.sha_ctx.state, &ctx->ctx.ostate,
389				 raw_key, raw_key_len, &sha224_iv);
390	ctx->ctx.sha_ctx.bytecount = SHA256_BLOCK_SIZE;
391}
392EXPORT_SYMBOL_GPL(hmac_sha224_init_usingrawkey);
393
394void hmac_sha256_init_usingrawkey(struct hmac_sha256_ctx *ctx,
395				  const u8 *raw_key, size_t raw_key_len)
396{
397	__hmac_sha256_preparekey(&ctx->ctx.sha_ctx.state, &ctx->ctx.ostate,
398				 raw_key, raw_key_len, &sha256_iv);
399	ctx->ctx.sha_ctx.bytecount = SHA256_BLOCK_SIZE;
400}
401EXPORT_SYMBOL_GPL(hmac_sha256_init_usingrawkey);
402
403static void __hmac_sha256_final(struct __hmac_sha256_ctx *ctx,
404				u8 *out, size_t digest_size)
405{
406	/* Generate the padded input for the outer hash in ctx->sha_ctx.buf. */
407	__sha256_final(&ctx->sha_ctx, ctx->sha_ctx.buf, digest_size);
408	memset(&ctx->sha_ctx.buf[digest_size], 0,
409	       SHA256_BLOCK_SIZE - digest_size);
410	ctx->sha_ctx.buf[digest_size] = 0x80;
411	*(__be32 *)&ctx->sha_ctx.buf[SHA256_BLOCK_SIZE - 4] =
412		cpu_to_be32(8 * (SHA256_BLOCK_SIZE + digest_size));
413
414	/* Compute the outer hash, which gives the HMAC value. */
415	sha256_blocks(&ctx->ostate, ctx->sha_ctx.buf, 1);
416	for (size_t i = 0; i < digest_size; i += 4)
417		put_unaligned_be32(ctx->ostate.h[i / 4], out + i);
418
419	memzero_explicit(ctx, sizeof(*ctx));
420}
421
422void hmac_sha224_final(struct hmac_sha224_ctx *ctx,
423		       u8 out[SHA224_DIGEST_SIZE])
424{
425	__hmac_sha256_final(&ctx->ctx, out, SHA224_DIGEST_SIZE);
426}
427EXPORT_SYMBOL_GPL(hmac_sha224_final);
428
429void hmac_sha256_final(struct hmac_sha256_ctx *ctx,
430		       u8 out[SHA256_DIGEST_SIZE])
431{
432	__hmac_sha256_final(&ctx->ctx, out, SHA256_DIGEST_SIZE);
433}
434EXPORT_SYMBOL_GPL(hmac_sha256_final);
435
436void hmac_sha224(const struct hmac_sha224_key *key,
437		 const u8 *data, size_t data_len, u8 out[SHA224_DIGEST_SIZE])
438{
439	struct hmac_sha224_ctx ctx;
440
441	hmac_sha224_init(&ctx, key);
442	hmac_sha224_update(&ctx, data, data_len);
443	hmac_sha224_final(&ctx, out);
444}
445EXPORT_SYMBOL_GPL(hmac_sha224);
446
447void hmac_sha256(const struct hmac_sha256_key *key,
448		 const u8 *data, size_t data_len, u8 out[SHA256_DIGEST_SIZE])
449{
450	struct hmac_sha256_ctx ctx;
451
452	hmac_sha256_init(&ctx, key);
453	hmac_sha256_update(&ctx, data, data_len);
454	hmac_sha256_final(&ctx, out);
455}
456EXPORT_SYMBOL_GPL(hmac_sha256);
457
458void hmac_sha224_usingrawkey(const u8 *raw_key, size_t raw_key_len,
459			     const u8 *data, size_t data_len,
460			     u8 out[SHA224_DIGEST_SIZE])
461{
462	struct hmac_sha224_ctx ctx;
463
464	hmac_sha224_init_usingrawkey(&ctx, raw_key, raw_key_len);
465	hmac_sha224_update(&ctx, data, data_len);
466	hmac_sha224_final(&ctx, out);
467}
468EXPORT_SYMBOL_GPL(hmac_sha224_usingrawkey);
469
470void hmac_sha256_usingrawkey(const u8 *raw_key, size_t raw_key_len,
471			     const u8 *data, size_t data_len,
472			     u8 out[SHA256_DIGEST_SIZE])
473{
474	struct hmac_sha256_ctx ctx;
475
476	hmac_sha256_init_usingrawkey(&ctx, raw_key, raw_key_len);
477	hmac_sha256_update(&ctx, data, data_len);
478	hmac_sha256_final(&ctx, out);
479}
480EXPORT_SYMBOL_GPL(hmac_sha256_usingrawkey);
481
482#if defined(sha256_mod_init_arch) || defined(CONFIG_CRYPTO_FIPS)
483static int __init sha256_mod_init(void)
484{
485#ifdef sha256_mod_init_arch
486	sha256_mod_init_arch();
487#endif
488	if (fips_enabled) {
489		/*
490		 * FIPS cryptographic algorithm self-test.  As per the FIPS
491		 * Implementation Guidance, testing HMAC-SHA256 satisfies the
492		 * test requirement for SHA-224, SHA-256, and HMAC-SHA224 too.
493		 */
494		u8 mac[SHA256_DIGEST_SIZE];
495
496		hmac_sha256_usingrawkey(fips_test_key, sizeof(fips_test_key),
497					fips_test_data, sizeof(fips_test_data),
498					mac);
499		if (memcmp(fips_test_hmac_sha256_value, mac, sizeof(mac)) != 0)
500			panic("sha256: FIPS self-test failed\n");
501	}
502	return 0;
503}
504subsys_initcall(sha256_mod_init);
505
506static void __exit sha256_mod_exit(void)
507{
508}
509module_exit(sha256_mod_exit);
510#endif
511
512#endif /* !__DISABLE_EXPORTS */
513
514MODULE_DESCRIPTION("SHA-224, SHA-256, HMAC-SHA224, and HMAC-SHA256 library functions");
515MODULE_LICENSE("GPL");