sha1.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * SHA-1 and HMAC-SHA1 library functions
  4 */
  5
  6#include <crypto/hmac.h>
  7#include <crypto/sha1.h>
  8#include <linux/bitops.h>
  9#include <linux/export.h>
 10#include <linux/kernel.h>
 11#include <linux/module.h>
 12#include <linux/string.h>
 13#include <linux/unaligned.h>
 14#include <linux/wordpart.h>
 15#include "fips.h"
 16
 17static const struct sha1_block_state sha1_iv = {
 18	.h = { SHA1_H0, SHA1_H1, SHA1_H2, SHA1_H3, SHA1_H4 },
 19};
 20
 21/*
 22 * If you have 32 registers or more, the compiler can (and should)
 23 * try to change the array[] accesses into registers. However, on
 24 * machines with less than ~25 registers, that won't really work,
 25 * and at least gcc will make an unholy mess of it.
 26 *
 27 * So to avoid that mess which just slows things down, we force
 28 * the stores to memory to actually happen (we might be better off
 29 * with a 'W(t)=(val);asm("":"+m" (W(t))' there instead, as
 30 * suggested by Artur Skawina - that will also make gcc unable to
 31 * try to do the silly "optimize away loads" part because it won't
 32 * see what the value will be).
 33 *
 34 * Ben Herrenschmidt reports that on PPC, the C version comes close
 35 * to the optimized asm with this (ie on PPC you don't want that
 36 * 'volatile', since there are lots of registers).
 37 *
 38 * On ARM we get the best code generation by forcing a full memory barrier
 39 * between each SHA_ROUND, otherwise gcc happily get wild with spilling and
 40 * the stack frame size simply explode and performance goes down the drain.
 41 */
 42
 43#ifdef CONFIG_X86
 44  #define setW(x, val) (*(volatile __u32 *)&W(x) = (val))
 45#elif defined(CONFIG_ARM)
 46  #define setW(x, val) do { W(x) = (val); __asm__("":::"memory"); } while (0)
 47#else
 48  #define setW(x, val) (W(x) = (val))
 49#endif
 50
 51/* This "rolls" over the 512-bit array */
 52#define W(x) (array[(x)&15])
 53
 54/*
 55 * Where do we get the source from? The first 16 iterations get it from
 56 * the input data, the next mix it from the 512-bit array.
 57 */
 58#define SHA_SRC(t) get_unaligned_be32((__u32 *)data + t)
 59#define SHA_MIX(t) rol32(W(t+13) ^ W(t+8) ^ W(t+2) ^ W(t), 1)
 60
 61#define SHA_ROUND(t, input, fn, constant, A, B, C, D, E) do { \
 62	__u32 TEMP = input(t); setW(t, TEMP); \
 63	E += TEMP + rol32(A,5) + (fn) + (constant); \
 64	B = ror32(B, 2); \
 65	TEMP = E; E = D; D = C; C = B; B = A; A = TEMP; } while (0)
 66
 67#define T_0_15(t, A, B, C, D, E)  SHA_ROUND(t, SHA_SRC, (((C^D)&B)^D) , 0x5a827999, A, B, C, D, E )
 68#define T_16_19(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (((C^D)&B)^D) , 0x5a827999, A, B, C, D, E )
 69#define T_20_39(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0x6ed9eba1, A, B, C, D, E )
 70#define T_40_59(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, ((B&C)+(D&(B^C))) , 0x8f1bbcdc, A, B, C, D, E )
 71#define T_60_79(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) ,  0xca62c1d6, A, B, C, D, E )
 72
 73/**
 74 * sha1_transform - single block SHA1 transform (deprecated)
 75 *
 76 * @digest: 160 bit digest to update
 77 * @data:   512 bits of data to hash
 78 * @array:  16 words of workspace (see note)
 79 *
 80 * This function executes SHA-1's internal compression function.  It updates the
 81 * 160-bit internal state (@digest) with a single 512-bit data block (@data).
 82 *
 83 * Don't use this function.  SHA-1 is no longer considered secure.  And even if
 84 * you do have to use SHA-1, this isn't the correct way to hash something with
 85 * SHA-1 as this doesn't handle padding and finalization.
 86 *
 87 * Note: If the hash is security sensitive, the caller should be sure
 88 * to clear the workspace. This is left to the caller to avoid
 89 * unnecessary clears between chained hashing operations.
 90 */
 91void sha1_transform(__u32 *digest, const char *data, __u32 *array)
 92{
 93	__u32 A, B, C, D, E;
 94	unsigned int i = 0;
 95
 96	A = digest[0];
 97	B = digest[1];
 98	C = digest[2];
 99	D = digest[3];
100	E = digest[4];
101
102	/* Round 1 - iterations 0-16 take their input from 'data' */
103	for (; i < 16; ++i)
104		T_0_15(i, A, B, C, D, E);
105
106	/* Round 1 - tail. Input from 512-bit mixing array */
107	for (; i < 20; ++i)
108		T_16_19(i, A, B, C, D, E);
109
110	/* Round 2 */
111	for (; i < 40; ++i)
112		T_20_39(i, A, B, C, D, E);
113
114	/* Round 3 */
115	for (; i < 60; ++i)
116		T_40_59(i, A, B, C, D, E);
117
118	/* Round 4 */
119	for (; i < 80; ++i)
120		T_60_79(i, A, B, C, D, E);
121
122	digest[0] += A;
123	digest[1] += B;
124	digest[2] += C;
125	digest[3] += D;
126	digest[4] += E;
127}
128EXPORT_SYMBOL(sha1_transform);
129
130/**
131 * sha1_init_raw - initialize the vectors for a SHA1 digest
132 * @buf: vector to initialize
133 */
134void sha1_init_raw(__u32 *buf)
135{
136	buf[0] = 0x67452301;
137	buf[1] = 0xefcdab89;
138	buf[2] = 0x98badcfe;
139	buf[3] = 0x10325476;
140	buf[4] = 0xc3d2e1f0;
141}
142EXPORT_SYMBOL(sha1_init_raw);
143
144static void __maybe_unused sha1_blocks_generic(struct sha1_block_state *state,
145					       const u8 *data, size_t nblocks)
146{
147	u32 workspace[SHA1_WORKSPACE_WORDS];
148
149	do {
150		sha1_transform(state->h, data, workspace);
151		data += SHA1_BLOCK_SIZE;
152	} while (--nblocks);
153
154	memzero_explicit(workspace, sizeof(workspace));
155}
156
157#ifdef CONFIG_CRYPTO_LIB_SHA1_ARCH
158#include "sha1.h" /* $(SRCARCH)/sha1.h */
159#else
160#define sha1_blocks sha1_blocks_generic
161#endif
162
163void sha1_init(struct sha1_ctx *ctx)
164{
165	ctx->state = sha1_iv;
166	ctx->bytecount = 0;
167}
168EXPORT_SYMBOL_GPL(sha1_init);
169
170void sha1_update(struct sha1_ctx *ctx, const u8 *data, size_t len)
171{
172	size_t partial = ctx->bytecount % SHA1_BLOCK_SIZE;
173
174	ctx->bytecount += len;
175
176	if (partial + len >= SHA1_BLOCK_SIZE) {
177		size_t nblocks;
178
179		if (partial) {
180			size_t l = SHA1_BLOCK_SIZE - partial;
181
182			memcpy(&ctx->buf[partial], data, l);
183			data += l;
184			len -= l;
185
186			sha1_blocks(&ctx->state, ctx->buf, 1);
187		}
188
189		nblocks = len / SHA1_BLOCK_SIZE;
190		len %= SHA1_BLOCK_SIZE;
191
192		if (nblocks) {
193			sha1_blocks(&ctx->state, data, nblocks);
194			data += nblocks * SHA1_BLOCK_SIZE;
195		}
196		partial = 0;
197	}
198	if (len)
199		memcpy(&ctx->buf[partial], data, len);
200}
201EXPORT_SYMBOL_GPL(sha1_update);
202
203static void __sha1_final(struct sha1_ctx *ctx, u8 out[SHA1_DIGEST_SIZE])
204{
205	u64 bitcount = ctx->bytecount << 3;
206	size_t partial = ctx->bytecount % SHA1_BLOCK_SIZE;
207
208	ctx->buf[partial++] = 0x80;
209	if (partial > SHA1_BLOCK_SIZE - 8) {
210		memset(&ctx->buf[partial], 0, SHA1_BLOCK_SIZE - partial);
211		sha1_blocks(&ctx->state, ctx->buf, 1);
212		partial = 0;
213	}
214	memset(&ctx->buf[partial], 0, SHA1_BLOCK_SIZE - 8 - partial);
215	*(__be64 *)&ctx->buf[SHA1_BLOCK_SIZE - 8] = cpu_to_be64(bitcount);
216	sha1_blocks(&ctx->state, ctx->buf, 1);
217
218	for (size_t i = 0; i < SHA1_DIGEST_SIZE; i += 4)
219		put_unaligned_be32(ctx->state.h[i / 4], out + i);
220}
221
222void sha1_final(struct sha1_ctx *ctx, u8 out[SHA1_DIGEST_SIZE])
223{
224	__sha1_final(ctx, out);
225	memzero_explicit(ctx, sizeof(*ctx));
226}
227EXPORT_SYMBOL_GPL(sha1_final);
228
229void sha1(const u8 *data, size_t len, u8 out[SHA1_DIGEST_SIZE])
230{
231	struct sha1_ctx ctx;
232
233	sha1_init(&ctx);
234	sha1_update(&ctx, data, len);
235	sha1_final(&ctx, out);
236}
237EXPORT_SYMBOL_GPL(sha1);
238
239static void __hmac_sha1_preparekey(struct sha1_block_state *istate,
240				   struct sha1_block_state *ostate,
241				   const u8 *raw_key, size_t raw_key_len)
242{
243	union {
244		u8 b[SHA1_BLOCK_SIZE];
245		unsigned long w[SHA1_BLOCK_SIZE / sizeof(unsigned long)];
246	} derived_key = { 0 };
247
248	if (unlikely(raw_key_len > SHA1_BLOCK_SIZE))
249		sha1(raw_key, raw_key_len, derived_key.b);
250	else
251		memcpy(derived_key.b, raw_key, raw_key_len);
252
253	for (size_t i = 0; i < ARRAY_SIZE(derived_key.w); i++)
254		derived_key.w[i] ^= REPEAT_BYTE(HMAC_IPAD_VALUE);
255	*istate = sha1_iv;
256	sha1_blocks(istate, derived_key.b, 1);
257
258	for (size_t i = 0; i < ARRAY_SIZE(derived_key.w); i++)
259		derived_key.w[i] ^= REPEAT_BYTE(HMAC_OPAD_VALUE ^
260						HMAC_IPAD_VALUE);
261	*ostate = sha1_iv;
262	sha1_blocks(ostate, derived_key.b, 1);
263
264	memzero_explicit(&derived_key, sizeof(derived_key));
265}
266
267void hmac_sha1_preparekey(struct hmac_sha1_key *key,
268			  const u8 *raw_key, size_t raw_key_len)
269{
270	__hmac_sha1_preparekey(&key->istate, &key->ostate,
271			       raw_key, raw_key_len);
272}
273EXPORT_SYMBOL_GPL(hmac_sha1_preparekey);
274
275void hmac_sha1_init(struct hmac_sha1_ctx *ctx, const struct hmac_sha1_key *key)
276{
277	ctx->sha_ctx.state = key->istate;
278	ctx->sha_ctx.bytecount = SHA1_BLOCK_SIZE;
279	ctx->ostate = key->ostate;
280}
281EXPORT_SYMBOL_GPL(hmac_sha1_init);
282
283void hmac_sha1_init_usingrawkey(struct hmac_sha1_ctx *ctx,
284				const u8 *raw_key, size_t raw_key_len)
285{
286	__hmac_sha1_preparekey(&ctx->sha_ctx.state, &ctx->ostate,
287			       raw_key, raw_key_len);
288	ctx->sha_ctx.bytecount = SHA1_BLOCK_SIZE;
289}
290EXPORT_SYMBOL_GPL(hmac_sha1_init_usingrawkey);
291
292void hmac_sha1_final(struct hmac_sha1_ctx *ctx, u8 out[SHA1_DIGEST_SIZE])
293{
294	/* Generate the padded input for the outer hash in ctx->sha_ctx.buf. */
295	__sha1_final(&ctx->sha_ctx, ctx->sha_ctx.buf);
296	memset(&ctx->sha_ctx.buf[SHA1_DIGEST_SIZE], 0,
297	       SHA1_BLOCK_SIZE - SHA1_DIGEST_SIZE);
298	ctx->sha_ctx.buf[SHA1_DIGEST_SIZE] = 0x80;
299	*(__be32 *)&ctx->sha_ctx.buf[SHA1_BLOCK_SIZE - 4] =
300		cpu_to_be32(8 * (SHA1_BLOCK_SIZE + SHA1_DIGEST_SIZE));
301
302	/* Compute the outer hash, which gives the HMAC value. */
303	sha1_blocks(&ctx->ostate, ctx->sha_ctx.buf, 1);
304	for (size_t i = 0; i < SHA1_DIGEST_SIZE; i += 4)
305		put_unaligned_be32(ctx->ostate.h[i / 4], out + i);
306
307	memzero_explicit(ctx, sizeof(*ctx));
308}
309EXPORT_SYMBOL_GPL(hmac_sha1_final);
310
311void hmac_sha1(const struct hmac_sha1_key *key,
312	       const u8 *data, size_t data_len, u8 out[SHA1_DIGEST_SIZE])
313{
314	struct hmac_sha1_ctx ctx;
315
316	hmac_sha1_init(&ctx, key);
317	hmac_sha1_update(&ctx, data, data_len);
318	hmac_sha1_final(&ctx, out);
319}
320EXPORT_SYMBOL_GPL(hmac_sha1);
321
322void hmac_sha1_usingrawkey(const u8 *raw_key, size_t raw_key_len,
323			   const u8 *data, size_t data_len,
324			   u8 out[SHA1_DIGEST_SIZE])
325{
326	struct hmac_sha1_ctx ctx;
327
328	hmac_sha1_init_usingrawkey(&ctx, raw_key, raw_key_len);
329	hmac_sha1_update(&ctx, data, data_len);
330	hmac_sha1_final(&ctx, out);
331}
332EXPORT_SYMBOL_GPL(hmac_sha1_usingrawkey);
333
334#if defined(sha1_mod_init_arch) || defined(CONFIG_CRYPTO_FIPS)
335static int __init sha1_mod_init(void)
336{
337#ifdef sha1_mod_init_arch
338	sha1_mod_init_arch();
339#endif
340	if (fips_enabled) {
341		/*
342		 * FIPS cryptographic algorithm self-test.  As per the FIPS
343		 * Implementation Guidance, testing HMAC-SHA1 satisfies the test
344		 * requirement for SHA-1 too.
345		 */
346		u8 mac[SHA1_DIGEST_SIZE];
347
348		hmac_sha1_usingrawkey(fips_test_key, sizeof(fips_test_key),
349				      fips_test_data, sizeof(fips_test_data),
350				      mac);
351		if (memcmp(fips_test_hmac_sha1_value, mac, sizeof(mac)) != 0)
352			panic("sha1: FIPS self-test failed\n");
353	}
354	return 0;
355}
356subsys_initcall(sha1_mod_init);
357
358static void __exit sha1_mod_exit(void)
359{
360}
361module_exit(sha1_mod_exit);
362#endif
363
364MODULE_DESCRIPTION("SHA-1 and HMAC-SHA1 library functions");
365MODULE_LICENSE("GPL");