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, bytes, padbit); 112 else if (static_branch_likely(&poly1305_use_avx2)) 113 poly1305_blocks_avx2(ctx, inp, bytes, padbit); 114 else 115 poly1305_blocks_avx(ctx, inp, 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(&dctx->h, key); 135 dctx->s[0] = get_unaligned_le32(&key[16]); 136 dctx->s[1] = get_unaligned_le32(&key[20]); 137 dctx->s[2] = get_unaligned_le32(&key[24]); 138 dctx->s[3] = get_unaligned_le32(&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(&dctx->h, 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(&inp[0]); 158 dctx->s[1] = get_unaligned_le32(&inp[4]); 159 dctx->s[2] = get_unaligned_le32(&inp[8]); 160 dctx->s[3] = get_unaligned_le32(&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(&dctx->h, dctx->buf, POLY1305_BLOCK_SIZE, 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, src, bytes); 191 if (likely(bytes - used)) 192 poly1305_simd_blocks(&dctx->h, src + used, bytes - used, 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(&dctx->h, dctx->buf, POLY1305_BLOCK_SIZE, 0); 210 } 211 212 poly1305_simd_emit(&dctx->h, dst, dctx->s); 213 memzero_explicit(dctx, 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) : 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); 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