1 | // SPDX-License-Identifier: GPL-2.0 OR MIT |
2 | /* |
3 | * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. |
4 | */ |
5 | |
6 | #include <crypto/algapi.h> |
7 | #include <crypto/internal/hash.h> |
8 | #include <crypto/internal/poly1305.h> |
9 | #include <crypto/internal/simd.h> |
10 | #include <linux/crypto.h> |
11 | #include <linux/jump_label.h> |
12 | #include <linux/kernel.h> |
13 | #include <linux/module.h> |
14 | #include <linux/sizes.h> |
15 | #include <asm/intel-family.h> |
16 | #include <asm/simd.h> |
17 | |
18 | asmlinkage void poly1305_init_x86_64(void *ctx, |
19 | const u8 key[POLY1305_BLOCK_SIZE]); |
20 | asmlinkage void poly1305_blocks_x86_64(void *ctx, const u8 *inp, |
21 | const size_t len, const u32 padbit); |
22 | asmlinkage void poly1305_emit_x86_64(void *ctx, u8 mac[POLY1305_DIGEST_SIZE], |
23 | const u32 nonce[4]); |
24 | asmlinkage void poly1305_emit_avx(void *ctx, u8 mac[POLY1305_DIGEST_SIZE], |
25 | const u32 nonce[4]); |
26 | asmlinkage void poly1305_blocks_avx(void *ctx, const u8 *inp, const size_t len, |
27 | const u32 padbit); |
28 | asmlinkage void poly1305_blocks_avx2(void *ctx, const u8 *inp, const size_t len, |
29 | const u32 padbit); |
30 | asmlinkage void poly1305_blocks_avx512(void *ctx, const u8 *inp, |
31 | const size_t len, const u32 padbit); |
32 | |
33 | static __ro_after_init DEFINE_STATIC_KEY_FALSE(poly1305_use_avx); |
34 | static __ro_after_init DEFINE_STATIC_KEY_FALSE(poly1305_use_avx2); |
35 | static __ro_after_init DEFINE_STATIC_KEY_FALSE(poly1305_use_avx512); |
36 | |
37 | struct poly1305_arch_internal { |
38 | union { |
39 | struct { |
40 | u32 h[5]; |
41 | u32 is_base2_26; |
42 | }; |
43 | u64 hs[3]; |
44 | }; |
45 | u64 r[2]; |
46 | u64 pad; |
47 | struct { u32 r2, r1, r4, r3; } rn[9]; |
48 | }; |
49 | |
50 | /* The AVX code uses base 2^26, while the scalar code uses base 2^64. If we hit |
51 | * the unfortunate situation of using AVX and then having to go back to scalar |
52 | * -- because the user is silly and has called the update function from two |
53 | * separate contexts -- then we need to convert back to the original base before |
54 | * proceeding. It is possible to reason that the initial reduction below is |
55 | * sufficient given the implementation invariants. However, for an avoidance of |
56 | * doubt and because this is not performance critical, we do the full reduction |
57 | * anyway. Z3 proof of below function: https://xn--4db.cc/ltPtHCKN/py |
58 | */ |
59 | static void convert_to_base2_64(void *ctx) |
60 | { |
61 | struct poly1305_arch_internal *state = ctx; |
62 | u32 cy; |
63 | |
64 | if (!state->is_base2_26) |
65 | return; |
66 | |
67 | cy = state->h[0] >> 26; state->h[0] &= 0x3ffffff; state->h[1] += cy; |
68 | cy = state->h[1] >> 26; state->h[1] &= 0x3ffffff; state->h[2] += cy; |
69 | cy = state->h[2] >> 26; state->h[2] &= 0x3ffffff; state->h[3] += cy; |
70 | cy = state->h[3] >> 26; state->h[3] &= 0x3ffffff; state->h[4] += cy; |
71 | state->hs[0] = ((u64)state->h[2] << 52) | ((u64)state->h[1] << 26) | state->h[0]; |
72 | state->hs[1] = ((u64)state->h[4] << 40) | ((u64)state->h[3] << 14) | (state->h[2] >> 12); |
73 | state->hs[2] = state->h[4] >> 24; |
74 | #define ULT(a, b) ((a ^ ((a ^ b) | ((a - b) ^ b))) >> (sizeof(a) * 8 - 1)) |
75 | cy = (state->hs[2] >> 2) + (state->hs[2] & ~3ULL); |
76 | state->hs[2] &= 3; |
77 | state->hs[0] += cy; |
78 | state->hs[1] += (cy = ULT(state->hs[0], cy)); |
79 | state->hs[2] += ULT(state->hs[1], cy); |
80 | #undef ULT |
81 | state->is_base2_26 = 0; |
82 | } |
83 | |
84 | static void poly1305_simd_init(void *ctx, const u8 key[POLY1305_BLOCK_SIZE]) |
85 | { |
86 | poly1305_init_x86_64(ctx, key); |
87 | } |
88 | |
89 | static void poly1305_simd_blocks(void *ctx, const u8 *inp, size_t len, |
90 | const u32 padbit) |
91 | { |
92 | struct poly1305_arch_internal *state = ctx; |
93 | |
94 | /* SIMD disables preemption, so relax after processing each page. */ |
95 | BUILD_BUG_ON(SZ_4K < POLY1305_BLOCK_SIZE || |
96 | SZ_4K % POLY1305_BLOCK_SIZE); |
97 | |
98 | if (!static_branch_likely(&poly1305_use_avx) || |
99 | (len < (POLY1305_BLOCK_SIZE * 18) && !state->is_base2_26) || |
100 | !crypto_simd_usable()) { |
101 | convert_to_base2_64(ctx); |
102 | poly1305_blocks_x86_64(ctx, inp, len, padbit); |
103 | return; |
104 | } |
105 | |
106 | do { |
107 | const size_t bytes = min_t(size_t, len, SZ_4K); |
108 | |
109 | kernel_fpu_begin(); |
110 | if (IS_ENABLED(CONFIG_AS_AVX512) && static_branch_likely(&poly1305_use_avx512)) |
111 | poly1305_blocks_avx512(ctx, inp, len: bytes, padbit); |
112 | else if (static_branch_likely(&poly1305_use_avx2)) |
113 | poly1305_blocks_avx2(ctx, inp, len: bytes, padbit); |
114 | else |
115 | poly1305_blocks_avx(ctx, inp, len: bytes, padbit); |
116 | kernel_fpu_end(); |
117 | |
118 | len -= bytes; |
119 | inp += bytes; |
120 | } while (len); |
121 | } |
122 | |
123 | static void poly1305_simd_emit(void *ctx, u8 mac[POLY1305_DIGEST_SIZE], |
124 | const u32 nonce[4]) |
125 | { |
126 | if (!static_branch_likely(&poly1305_use_avx)) |
127 | poly1305_emit_x86_64(ctx, mac, nonce); |
128 | else |
129 | poly1305_emit_avx(ctx, mac, nonce); |
130 | } |
131 | |
132 | void poly1305_init_arch(struct poly1305_desc_ctx *dctx, const u8 key[POLY1305_KEY_SIZE]) |
133 | { |
134 | poly1305_simd_init(ctx: &dctx->h, key); |
135 | dctx->s[0] = get_unaligned_le32(p: &key[16]); |
136 | dctx->s[1] = get_unaligned_le32(p: &key[20]); |
137 | dctx->s[2] = get_unaligned_le32(p: &key[24]); |
138 | dctx->s[3] = get_unaligned_le32(p: &key[28]); |
139 | dctx->buflen = 0; |
140 | dctx->sset = true; |
141 | } |
142 | EXPORT_SYMBOL(poly1305_init_arch); |
143 | |
144 | static unsigned int crypto_poly1305_setdctxkey(struct poly1305_desc_ctx *dctx, |
145 | const u8 *inp, unsigned int len) |
146 | { |
147 | unsigned int acc = 0; |
148 | if (unlikely(!dctx->sset)) { |
149 | if (!dctx->rset && len >= POLY1305_BLOCK_SIZE) { |
150 | poly1305_simd_init(ctx: &dctx->h, key: inp); |
151 | inp += POLY1305_BLOCK_SIZE; |
152 | len -= POLY1305_BLOCK_SIZE; |
153 | acc += POLY1305_BLOCK_SIZE; |
154 | dctx->rset = 1; |
155 | } |
156 | if (len >= POLY1305_BLOCK_SIZE) { |
157 | dctx->s[0] = get_unaligned_le32(p: &inp[0]); |
158 | dctx->s[1] = get_unaligned_le32(p: &inp[4]); |
159 | dctx->s[2] = get_unaligned_le32(p: &inp[8]); |
160 | dctx->s[3] = get_unaligned_le32(p: &inp[12]); |
161 | acc += POLY1305_BLOCK_SIZE; |
162 | dctx->sset = true; |
163 | } |
164 | } |
165 | return acc; |
166 | } |
167 | |
168 | void poly1305_update_arch(struct poly1305_desc_ctx *dctx, const u8 *src, |
169 | unsigned int srclen) |
170 | { |
171 | unsigned int bytes, used; |
172 | |
173 | if (unlikely(dctx->buflen)) { |
174 | bytes = min(srclen, POLY1305_BLOCK_SIZE - dctx->buflen); |
175 | memcpy(dctx->buf + dctx->buflen, src, bytes); |
176 | src += bytes; |
177 | srclen -= bytes; |
178 | dctx->buflen += bytes; |
179 | |
180 | if (dctx->buflen == POLY1305_BLOCK_SIZE) { |
181 | if (likely(!crypto_poly1305_setdctxkey(dctx, dctx->buf, POLY1305_BLOCK_SIZE))) |
182 | poly1305_simd_blocks(ctx: &dctx->h, inp: dctx->buf, POLY1305_BLOCK_SIZE, padbit: 1); |
183 | dctx->buflen = 0; |
184 | } |
185 | } |
186 | |
187 | if (likely(srclen >= POLY1305_BLOCK_SIZE)) { |
188 | bytes = round_down(srclen, POLY1305_BLOCK_SIZE); |
189 | srclen -= bytes; |
190 | used = crypto_poly1305_setdctxkey(dctx, inp: src, len: bytes); |
191 | if (likely(bytes - used)) |
192 | poly1305_simd_blocks(ctx: &dctx->h, inp: src + used, len: bytes - used, padbit: 1); |
193 | src += bytes; |
194 | } |
195 | |
196 | if (unlikely(srclen)) { |
197 | dctx->buflen = srclen; |
198 | memcpy(dctx->buf, src, srclen); |
199 | } |
200 | } |
201 | EXPORT_SYMBOL(poly1305_update_arch); |
202 | |
203 | void poly1305_final_arch(struct poly1305_desc_ctx *dctx, u8 *dst) |
204 | { |
205 | if (unlikely(dctx->buflen)) { |
206 | dctx->buf[dctx->buflen++] = 1; |
207 | memset(dctx->buf + dctx->buflen, 0, |
208 | POLY1305_BLOCK_SIZE - dctx->buflen); |
209 | poly1305_simd_blocks(ctx: &dctx->h, inp: dctx->buf, POLY1305_BLOCK_SIZE, padbit: 0); |
210 | } |
211 | |
212 | poly1305_simd_emit(ctx: &dctx->h, mac: dst, nonce: dctx->s); |
213 | memzero_explicit(s: dctx, count: sizeof(*dctx)); |
214 | } |
215 | EXPORT_SYMBOL(poly1305_final_arch); |
216 | |
217 | static int crypto_poly1305_init(struct shash_desc *desc) |
218 | { |
219 | struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc); |
220 | |
221 | *dctx = (struct poly1305_desc_ctx){}; |
222 | return 0; |
223 | } |
224 | |
225 | static int crypto_poly1305_update(struct shash_desc *desc, |
226 | const u8 *src, unsigned int srclen) |
227 | { |
228 | struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc); |
229 | |
230 | poly1305_update_arch(dctx, src, srclen); |
231 | return 0; |
232 | } |
233 | |
234 | static int crypto_poly1305_final(struct shash_desc *desc, u8 *dst) |
235 | { |
236 | struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc); |
237 | |
238 | if (unlikely(!dctx->sset)) |
239 | return -ENOKEY; |
240 | |
241 | poly1305_final_arch(dctx, dst); |
242 | return 0; |
243 | } |
244 | |
245 | static struct shash_alg alg = { |
246 | .digestsize = POLY1305_DIGEST_SIZE, |
247 | .init = crypto_poly1305_init, |
248 | .update = crypto_poly1305_update, |
249 | .final = crypto_poly1305_final, |
250 | .descsize = sizeof(struct poly1305_desc_ctx), |
251 | .base = { |
252 | .cra_name = "poly1305" , |
253 | .cra_driver_name = "poly1305-simd" , |
254 | .cra_priority = 300, |
255 | .cra_blocksize = POLY1305_BLOCK_SIZE, |
256 | .cra_module = THIS_MODULE, |
257 | }, |
258 | }; |
259 | |
260 | static int __init poly1305_simd_mod_init(void) |
261 | { |
262 | if (boot_cpu_has(X86_FEATURE_AVX) && |
263 | cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL)) |
264 | static_branch_enable(&poly1305_use_avx); |
265 | if (boot_cpu_has(X86_FEATURE_AVX) && boot_cpu_has(X86_FEATURE_AVX2) && |
266 | cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL)) |
267 | static_branch_enable(&poly1305_use_avx2); |
268 | if (IS_ENABLED(CONFIG_AS_AVX512) && boot_cpu_has(X86_FEATURE_AVX) && |
269 | boot_cpu_has(X86_FEATURE_AVX2) && boot_cpu_has(X86_FEATURE_AVX512F) && |
270 | cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM | XFEATURE_MASK_AVX512, NULL) && |
271 | /* Skylake downclocks unacceptably much when using zmm, but later generations are fast. */ |
272 | boot_cpu_data.x86_model != INTEL_FAM6_SKYLAKE_X) |
273 | static_branch_enable(&poly1305_use_avx512); |
274 | return IS_REACHABLE(CONFIG_CRYPTO_HASH) ? crypto_register_shash(alg: &alg) : 0; |
275 | } |
276 | |
277 | static void __exit poly1305_simd_mod_exit(void) |
278 | { |
279 | if (IS_REACHABLE(CONFIG_CRYPTO_HASH)) |
280 | crypto_unregister_shash(alg: &alg); |
281 | } |
282 | |
283 | module_init(poly1305_simd_mod_init); |
284 | module_exit(poly1305_simd_mod_exit); |
285 | |
286 | MODULE_LICENSE("GPL" ); |
287 | MODULE_AUTHOR("Jason A. Donenfeld <Jason@zx2c4.com>" ); |
288 | MODULE_DESCRIPTION("Poly1305 authenticator" ); |
289 | MODULE_ALIAS_CRYPTO("poly1305" ); |
290 | MODULE_ALIAS_CRYPTO("poly1305-simd" ); |
291 | |