1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * MD5 and HMAC-MD5 library functions 4 * 5 * md5_block() is derived from cryptoapi implementation, originally based on the 6 * public domain implementation written by Colin Plumb in 1993. 7 * 8 * Copyright (c) Cryptoapi developers. 9 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au> 10 * Copyright 2025 Google LLC 11 */ 12 13 #include <crypto/hmac.h> 14 #include <crypto/md5.h> 15 #include <linux/export.h> 16 #include <linux/kernel.h> 17 #include <linux/module.h> 18 #include <linux/string.h> 19 #include <linux/wordpart.h> 20 21 static const struct md5_block_state md5_iv = { 22 .h = { MD5_H0, MD5_H1, MD5_H2, MD5_H3 }, 23 }; 24 25 #define F1(x, y, z) (z ^ (x & (y ^ z))) 26 #define F2(x, y, z) F1(z, x, y) 27 #define F3(x, y, z) (x ^ y ^ z) 28 #define F4(x, y, z) (y ^ (x | ~z)) 29 30 #define MD5STEP(f, w, x, y, z, in, s) \ 31 (w += f(x, y, z) + in, w = rol32(w, s) + x) 32 33 static void md5_block(struct md5_block_state *state, 34 const u8 data[MD5_BLOCK_SIZE]) 35 { 36 u32 in[MD5_BLOCK_WORDS]; 37 u32 a, b, c, d; 38 39 memcpy(in, data, MD5_BLOCK_SIZE); 40 le32_to_cpu_array(in, ARRAY_SIZE(in)); 41 42 a = state->h[0]; 43 b = state->h[1]; 44 c = state->h[2]; 45 d = state->h[3]; 46 47 MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7); 48 MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12); 49 MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17); 50 MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22); 51 MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7); 52 MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12); 53 MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17); 54 MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22); 55 MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7); 56 MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12); 57 MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17); 58 MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22); 59 MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7); 60 MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12); 61 MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17); 62 MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22); 63 64 MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5); 65 MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9); 66 MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14); 67 MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20); 68 MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5); 69 MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9); 70 MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14); 71 MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20); 72 MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5); 73 MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9); 74 MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14); 75 MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20); 76 MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5); 77 MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9); 78 MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14); 79 MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20); 80 81 MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4); 82 MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11); 83 MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16); 84 MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23); 85 MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4); 86 MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11); 87 MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16); 88 MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23); 89 MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4); 90 MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11); 91 MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16); 92 MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23); 93 MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4); 94 MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11); 95 MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16); 96 MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23); 97 98 MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6); 99 MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10); 100 MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15); 101 MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21); 102 MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6); 103 MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10); 104 MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15); 105 MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21); 106 MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6); 107 MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10); 108 MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15); 109 MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21); 110 MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6); 111 MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10); 112 MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15); 113 MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21); 114 115 state->h[0] += a; 116 state->h[1] += b; 117 state->h[2] += c; 118 state->h[3] += d; 119 } 120 121 static void md5_blocks(struct md5_block_state *state, 122 const u8 *data, size_t nblocks) 123 { 124 do { 125 md5_block(state, data); 126 data += MD5_BLOCK_SIZE; 127 } while (--nblocks); 128 } 129 130 void md5_init(struct md5_ctx *ctx) 131 { 132 ctx->state = md5_iv; 133 ctx->bytecount = 0; 134 } 135 EXPORT_SYMBOL_GPL(md5_init); 136 137 void md5_update(struct md5_ctx *ctx, const u8 *data, size_t len) 138 { 139 size_t partial = ctx->bytecount % MD5_BLOCK_SIZE; 140 141 ctx->bytecount += len; 142 143 if (partial + len >= MD5_BLOCK_SIZE) { 144 size_t nblocks; 145 146 if (partial) { 147 size_t l = MD5_BLOCK_SIZE - partial; 148 149 memcpy(&ctx->buf[partial], data, l); 150 data += l; 151 len -= l; 152 153 md5_blocks(&ctx->state, ctx->buf, 1); 154 } 155 156 nblocks = len / MD5_BLOCK_SIZE; 157 len %= MD5_BLOCK_SIZE; 158 159 if (nblocks) { 160 md5_blocks(&ctx->state, data, nblocks); 161 data += nblocks * MD5_BLOCK_SIZE; 162 } 163 partial = 0; 164 } 165 if (len) 166 memcpy(&ctx->buf[partial], data, len); 167 } 168 EXPORT_SYMBOL_GPL(md5_update); 169 170 static void __md5_final(struct md5_ctx *ctx, u8 out[MD5_DIGEST_SIZE]) 171 { 172 u64 bitcount = ctx->bytecount << 3; 173 size_t partial = ctx->bytecount % MD5_BLOCK_SIZE; 174 175 ctx->buf[partial++] = 0x80; 176 if (partial > MD5_BLOCK_SIZE - 8) { 177 memset(&ctx->buf[partial], 0, MD5_BLOCK_SIZE - partial); 178 md5_blocks(&ctx->state, ctx->buf, 1); 179 partial = 0; 180 } 181 memset(&ctx->buf[partial], 0, MD5_BLOCK_SIZE - 8 - partial); 182 *(__le64 *)&ctx->buf[MD5_BLOCK_SIZE - 8] = cpu_to_le64(bitcount); 183 md5_blocks(&ctx->state, ctx->buf, 1); 184 185 cpu_to_le32_array(ctx->state.h, ARRAY_SIZE(ctx->state.h)); 186 memcpy(out, ctx->state.h, MD5_DIGEST_SIZE); 187 } 188 189 void md5_final(struct md5_ctx *ctx, u8 out[MD5_DIGEST_SIZE]) 190 { 191 __md5_final(ctx, out); 192 memzero_explicit(ctx, sizeof(*ctx)); 193 } 194 EXPORT_SYMBOL_GPL(md5_final); 195 196 void md5(const u8 *data, size_t len, u8 out[MD5_DIGEST_SIZE]) 197 { 198 struct md5_ctx ctx; 199 200 md5_init(&ctx); 201 md5_update(&ctx, data, len); 202 md5_final(&ctx, out); 203 } 204 EXPORT_SYMBOL_GPL(md5); 205 206 static void __hmac_md5_preparekey(struct md5_block_state *istate, 207 struct md5_block_state *ostate, 208 const u8 *raw_key, size_t raw_key_len) 209 { 210 union { 211 u8 b[MD5_BLOCK_SIZE]; 212 unsigned long w[MD5_BLOCK_SIZE / sizeof(unsigned long)]; 213 } derived_key = { 0 }; 214 215 if (unlikely(raw_key_len > MD5_BLOCK_SIZE)) 216 md5(raw_key, raw_key_len, derived_key.b); 217 else 218 memcpy(derived_key.b, raw_key, raw_key_len); 219 220 for (size_t i = 0; i < ARRAY_SIZE(derived_key.w); i++) 221 derived_key.w[i] ^= REPEAT_BYTE(HMAC_IPAD_VALUE); 222 *istate = md5_iv; 223 md5_blocks(istate, derived_key.b, 1); 224 225 for (size_t i = 0; i < ARRAY_SIZE(derived_key.w); i++) 226 derived_key.w[i] ^= REPEAT_BYTE(HMAC_OPAD_VALUE ^ 227 HMAC_IPAD_VALUE); 228 *ostate = md5_iv; 229 md5_blocks(ostate, derived_key.b, 1); 230 231 memzero_explicit(&derived_key, sizeof(derived_key)); 232 } 233 234 void hmac_md5_preparekey(struct hmac_md5_key *key, 235 const u8 *raw_key, size_t raw_key_len) 236 { 237 __hmac_md5_preparekey(&key->istate, &key->ostate, raw_key, raw_key_len); 238 } 239 EXPORT_SYMBOL_GPL(hmac_md5_preparekey); 240 241 void hmac_md5_init(struct hmac_md5_ctx *ctx, const struct hmac_md5_key *key) 242 { 243 ctx->hash_ctx.state = key->istate; 244 ctx->hash_ctx.bytecount = MD5_BLOCK_SIZE; 245 ctx->ostate = key->ostate; 246 } 247 EXPORT_SYMBOL_GPL(hmac_md5_init); 248 249 void hmac_md5_init_usingrawkey(struct hmac_md5_ctx *ctx, 250 const u8 *raw_key, size_t raw_key_len) 251 { 252 __hmac_md5_preparekey(&ctx->hash_ctx.state, &ctx->ostate, 253 raw_key, raw_key_len); 254 ctx->hash_ctx.bytecount = MD5_BLOCK_SIZE; 255 } 256 EXPORT_SYMBOL_GPL(hmac_md5_init_usingrawkey); 257 258 void hmac_md5_final(struct hmac_md5_ctx *ctx, u8 out[MD5_DIGEST_SIZE]) 259 { 260 /* Generate the padded input for the outer hash in ctx->hash_ctx.buf. */ 261 __md5_final(&ctx->hash_ctx, ctx->hash_ctx.buf); 262 memset(&ctx->hash_ctx.buf[MD5_DIGEST_SIZE], 0, 263 MD5_BLOCK_SIZE - MD5_DIGEST_SIZE); 264 ctx->hash_ctx.buf[MD5_DIGEST_SIZE] = 0x80; 265 *(__le64 *)&ctx->hash_ctx.buf[MD5_BLOCK_SIZE - 8] = 266 cpu_to_le64(8 * (MD5_BLOCK_SIZE + MD5_DIGEST_SIZE)); 267 268 /* Compute the outer hash, which gives the HMAC value. */ 269 md5_blocks(&ctx->ostate, ctx->hash_ctx.buf, 1); 270 cpu_to_le32_array(ctx->ostate.h, ARRAY_SIZE(ctx->ostate.h)); 271 memcpy(out, ctx->ostate.h, MD5_DIGEST_SIZE); 272 273 hmac_md5_zeroize_ctx(ctx); 274 } 275 EXPORT_SYMBOL_GPL(hmac_md5_final); 276 277 void hmac_md5(const struct hmac_md5_key *key, 278 const u8 *data, size_t data_len, u8 out[MD5_DIGEST_SIZE]) 279 { 280 struct hmac_md5_ctx ctx; 281 282 hmac_md5_init(&ctx, key); 283 hmac_md5_update(&ctx, data, data_len); 284 hmac_md5_final(&ctx, out); 285 } 286 EXPORT_SYMBOL_GPL(hmac_md5); 287 288 void hmac_md5_usingrawkey(const u8 *raw_key, size_t raw_key_len, 289 const u8 *data, size_t data_len, 290 u8 out[MD5_DIGEST_SIZE]) 291 { 292 struct hmac_md5_ctx ctx; 293 294 hmac_md5_init_usingrawkey(&ctx, raw_key, raw_key_len); 295 hmac_md5_update(&ctx, data, data_len); 296 hmac_md5_final(&ctx, out); 297 } 298 EXPORT_SYMBOL_GPL(hmac_md5_usingrawkey); 299 300 MODULE_DESCRIPTION("MD5 and HMAC-MD5 library functions"); 301 MODULE_LICENSE("GPL"); 302