1 /* 2 * Cryptographic API. 3 * 4 * MD5 Message Digest Algorithm (RFC1321). 5 * 6 * Derived from cryptoapi implementation, originally based on the 7 * public domain implementation written by Colin Plumb in 1993. 8 * 9 * Copyright (c) Cryptoapi developers. 10 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au> 11 * 12 * This program is free software; you can redistribute it and/or modify it 13 * under the terms of the GNU General Public License as published by the Free 14 * Software Foundation; either version 2 of the License, or (at your option) 15 * any later version. 16 * 17 */ 18 #include <crypto/internal/hash.h> 19 #include <crypto/md5.h> 20 #include <linux/init.h> 21 #include <linux/module.h> 22 #include <linux/string.h> 23 #include <linux/types.h> 24 #include <linux/cryptohash.h> 25 #include <asm/byteorder.h> 26 27 /* XXX: this stuff can be optimized */ 28 static inline void le32_to_cpu_array(u32 *buf, unsigned int words) 29 { 30 while (words--) { 31 __le32_to_cpus(buf); 32 buf++; 33 } 34 } 35 36 static inline void cpu_to_le32_array(u32 *buf, unsigned int words) 37 { 38 while (words--) { 39 __cpu_to_le32s(buf); 40 buf++; 41 } 42 } 43 44 static inline void md5_transform_helper(struct md5_state *ctx) 45 { 46 le32_to_cpu_array(ctx->block, sizeof(ctx->block) / sizeof(u32)); 47 md5_transform(ctx->hash, ctx->block); 48 } 49 50 static int md5_init(struct shash_desc *desc) 51 { 52 struct md5_state *mctx = shash_desc_ctx(desc); 53 54 mctx->hash[0] = MD5_H0; 55 mctx->hash[1] = MD5_H1; 56 mctx->hash[2] = MD5_H2; 57 mctx->hash[3] = MD5_H3; 58 mctx->byte_count = 0; 59 60 return 0; 61 } 62 63 static int md5_update(struct shash_desc *desc, const u8 *data, unsigned int len) 64 { 65 struct md5_state *mctx = shash_desc_ctx(desc); 66 const u32 avail = sizeof(mctx->block) - (mctx->byte_count & 0x3f); 67 68 mctx->byte_count += len; 69 70 if (avail > len) { 71 memcpy((char *)mctx->block + (sizeof(mctx->block) - avail), 72 data, len); 73 return 0; 74 } 75 76 memcpy((char *)mctx->block + (sizeof(mctx->block) - avail), 77 data, avail); 78 79 md5_transform_helper(mctx); 80 data += avail; 81 len -= avail; 82 83 while (len >= sizeof(mctx->block)) { 84 memcpy(mctx->block, data, sizeof(mctx->block)); 85 md5_transform_helper(mctx); 86 data += sizeof(mctx->block); 87 len -= sizeof(mctx->block); 88 } 89 90 memcpy(mctx->block, data, len); 91 92 return 0; 93 } 94 95 static int md5_final(struct shash_desc *desc, u8 *out) 96 { 97 struct md5_state *mctx = shash_desc_ctx(desc); 98 const unsigned int offset = mctx->byte_count & 0x3f; 99 char *p = (char *)mctx->block + offset; 100 int padding = 56 - (offset + 1); 101 102 *p++ = 0x80; 103 if (padding < 0) { 104 memset(p, 0x00, padding + sizeof (u64)); 105 md5_transform_helper(mctx); 106 p = (char *)mctx->block; 107 padding = 56; 108 } 109 110 memset(p, 0, padding); 111 mctx->block[14] = mctx->byte_count << 3; 112 mctx->block[15] = mctx->byte_count >> 29; 113 le32_to_cpu_array(mctx->block, (sizeof(mctx->block) - 114 sizeof(u64)) / sizeof(u32)); 115 md5_transform(mctx->hash, mctx->block); 116 cpu_to_le32_array(mctx->hash, sizeof(mctx->hash) / sizeof(u32)); 117 memcpy(out, mctx->hash, sizeof(mctx->hash)); 118 memset(mctx, 0, sizeof(*mctx)); 119 120 return 0; 121 } 122 123 static int md5_export(struct shash_desc *desc, void *out) 124 { 125 struct md5_state *ctx = shash_desc_ctx(desc); 126 127 memcpy(out, ctx, sizeof(*ctx)); 128 return 0; 129 } 130 131 static int md5_import(struct shash_desc *desc, const void *in) 132 { 133 struct md5_state *ctx = shash_desc_ctx(desc); 134 135 memcpy(ctx, in, sizeof(*ctx)); 136 return 0; 137 } 138 139 static struct shash_alg alg = { 140 .digestsize = MD5_DIGEST_SIZE, 141 .init = md5_init, 142 .update = md5_update, 143 .final = md5_final, 144 .export = md5_export, 145 .import = md5_import, 146 .descsize = sizeof(struct md5_state), 147 .statesize = sizeof(struct md5_state), 148 .base = { 149 .cra_name = "md5", 150 .cra_flags = CRYPTO_ALG_TYPE_SHASH, 151 .cra_blocksize = MD5_HMAC_BLOCK_SIZE, 152 .cra_module = THIS_MODULE, 153 } 154 }; 155 156 static int __init md5_mod_init(void) 157 { 158 return crypto_register_shash(&alg); 159 } 160 161 static void __exit md5_mod_fini(void) 162 { 163 crypto_unregister_shash(&alg); 164 } 165 166 module_init(md5_mod_init); 167 module_exit(md5_mod_fini); 168 169 MODULE_LICENSE("GPL"); 170 MODULE_DESCRIPTION("MD5 Message Digest Algorithm"); 171 MODULE_ALIAS_CRYPTO("md5"); 172