1// SPDX-License-Identifier: GPL-2.0-or-later 2/* 3 * Cryptographic API. 4 * 5 * HMAC: Keyed-Hashing for Message Authentication (RFC2104). 6 * 7 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au> 8 * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au> 9 * 10 * The HMAC implementation is derived from USAGI. 11 * Copyright (c) 2002 Kazunori Miyazawa <miyazawa@linux-ipv6.org> / USAGI 12 */ 13 14#include <crypto/hmac.h> 15#include <crypto/internal/hash.h> 16#include <crypto/scatterwalk.h> 17#include <linux/err.h> 18#include <linux/fips.h> 19#include <linux/init.h> 20#include <linux/kernel.h> 21#include <linux/module.h> 22#include <linux/scatterlist.h> 23#include <linux/string.h> 24 25struct hmac_ctx { 26 struct crypto_shash *hash; 27}; 28 29static inline void *align_ptr(void *p, unsigned int align) 30{ 31 return (void *)ALIGN((unsigned long)p, align); 32} 33 34static inline struct hmac_ctx *hmac_ctx(struct crypto_shash *tfm) 35{ 36 return align_ptr(crypto_shash_ctx_aligned(tfm) + 37 crypto_shash_statesize(tfm) * 2, 38 crypto_tfm_ctx_alignment()); 39} 40 41static int hmac_setkey(struct crypto_shash *parent, 42 const u8 *inkey, unsigned int keylen) 43{ 44 int bs = crypto_shash_blocksize(parent); 45 int ds = crypto_shash_digestsize(parent); 46 int ss = crypto_shash_statesize(parent); 47 char *ipad = crypto_shash_ctx_aligned(parent); 48 char *opad = ipad + ss; 49 struct hmac_ctx *ctx = align_ptr(opad + ss, 50 crypto_tfm_ctx_alignment()); 51 struct crypto_shash *hash = ctx->hash; 52 SHASH_DESC_ON_STACK(shash, hash); 53 unsigned int i; 54 55 if (fips_enabled && (keylen < 112 / 8)) 56 return -EINVAL; 57 58 shash->tfm = hash; 59 60 if (keylen > bs) { 61 int err; 62 63 err = crypto_shash_digest(shash, inkey, keylen, ipad); 64 if (err) 65 return err; 66 67 keylen = ds; 68 } else 69 memcpy(ipad, inkey, keylen); 70 71 memset(ipad + keylen, 0, bs - keylen); 72 memcpy(opad, ipad, bs); 73 74 for (i = 0; i < bs; i++) { 75 ipad[i] ^= HMAC_IPAD_VALUE; 76 opad[i] ^= HMAC_OPAD_VALUE; 77 } 78 79 return crypto_shash_init(shash) ?: 80 crypto_shash_update(shash, ipad, bs) ?: 81 crypto_shash_export(shash, ipad) ?: 82 crypto_shash_init(shash) ?: 83 crypto_shash_update(shash, opad, bs) ?: 84 crypto_shash_export(shash, opad); 85} 86 87static int hmac_export(struct shash_desc *pdesc, void *out) 88{ 89 struct shash_desc *desc = shash_desc_ctx(pdesc); 90 91 return crypto_shash_export(desc, out); 92} 93 94static int hmac_import(struct shash_desc *pdesc, const void *in) 95{ 96 struct shash_desc *desc = shash_desc_ctx(pdesc); 97 struct hmac_ctx *ctx = hmac_ctx(pdesc->tfm); 98 99 desc->tfm = ctx->hash; 100 101 return crypto_shash_import(desc, in); 102} 103 104static int hmac_init(struct shash_desc *pdesc) 105{ 106 return hmac_import(pdesc, crypto_shash_ctx_aligned(pdesc->tfm)); 107} 108 109static int hmac_update(struct shash_desc *pdesc, 110 const u8 *data, unsigned int nbytes) 111{ 112 struct shash_desc *desc = shash_desc_ctx(pdesc); 113 114 return crypto_shash_update(desc, data, nbytes); 115} 116 117static int hmac_final(struct shash_desc *pdesc, u8 *out) 118{ 119 struct crypto_shash *parent = pdesc->tfm; 120 int ds = crypto_shash_digestsize(parent); 121 int ss = crypto_shash_statesize(parent); 122 char *opad = crypto_shash_ctx_aligned(parent) + ss; 123 struct shash_desc *desc = shash_desc_ctx(pdesc); 124 125 return crypto_shash_final(desc, out) ?: 126 crypto_shash_import(desc, opad) ?: 127 crypto_shash_finup(desc, out, ds, out); 128} 129 130static int hmac_finup(struct shash_desc *pdesc, const u8 *data, 131 unsigned int nbytes, u8 *out) 132{ 133 134 struct crypto_shash *parent = pdesc->tfm; 135 int ds = crypto_shash_digestsize(parent); 136 int ss = crypto_shash_statesize(parent); 137 char *opad = crypto_shash_ctx_aligned(parent) + ss; 138 struct shash_desc *desc = shash_desc_ctx(pdesc); 139 140 return crypto_shash_finup(desc, data, nbytes, out) ?: 141 crypto_shash_import(desc, opad) ?: 142 crypto_shash_finup(desc, out, ds, out); 143} 144 145static int hmac_init_tfm(struct crypto_shash *parent) 146{ 147 struct crypto_shash *hash; 148 struct shash_instance *inst = shash_alg_instance(parent); 149 struct crypto_shash_spawn *spawn = shash_instance_ctx(inst); 150 struct hmac_ctx *ctx = hmac_ctx(parent); 151 152 hash = crypto_spawn_shash(spawn); 153 if (IS_ERR(hash)) 154 return PTR_ERR(hash); 155 156 parent->descsize = sizeof(struct shash_desc) + 157 crypto_shash_descsize(hash); 158 159 ctx->hash = hash; 160 return 0; 161} 162 163static int hmac_clone_tfm(struct crypto_shash *dst, struct crypto_shash *src) 164{ 165 struct hmac_ctx *sctx = hmac_ctx(src); 166 struct hmac_ctx *dctx = hmac_ctx(dst); 167 struct crypto_shash *hash; 168 169 hash = crypto_clone_shash(sctx->hash); 170 if (IS_ERR(hash)) 171 return PTR_ERR(hash); 172 173 dctx->hash = hash; 174 return 0; 175} 176 177static void hmac_exit_tfm(struct crypto_shash *parent) 178{ 179 struct hmac_ctx *ctx = hmac_ctx(parent); 180 181 crypto_free_shash(ctx->hash); 182} 183 184static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb) 185{ 186 struct shash_instance *inst; 187 struct crypto_shash_spawn *spawn; 188 struct crypto_alg *alg; 189 struct shash_alg *salg; 190 u32 mask; 191 int err; 192 int ds; 193 int ss; 194 195 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH, &mask); 196 if (err) 197 return err; 198 199 inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL); 200 if (!inst) 201 return -ENOMEM; 202 spawn = shash_instance_ctx(inst); 203 204 err = crypto_grab_shash(spawn, shash_crypto_instance(inst), 205 crypto_attr_alg_name(tb[1]), 0, mask); 206 if (err) 207 goto err_free_inst; 208 salg = crypto_spawn_shash_alg(spawn); 209 alg = &salg->base; 210 211 /* The underlying hash algorithm must not require a key */ 212 err = -EINVAL; 213 if (crypto_shash_alg_needs_key(salg)) 214 goto err_free_inst; 215 216 ds = salg->digestsize; 217 ss = salg->statesize; 218 if (ds > alg->cra_blocksize || 219 ss < alg->cra_blocksize) 220 goto err_free_inst; 221 222 err = crypto_inst_setname(shash_crypto_instance(inst), tmpl->name, alg); 223 if (err) 224 goto err_free_inst; 225 226 inst->alg.base.cra_priority = alg->cra_priority; 227 inst->alg.base.cra_blocksize = alg->cra_blocksize; 228 inst->alg.base.cra_alignmask = alg->cra_alignmask; 229 230 ss = ALIGN(ss, alg->cra_alignmask + 1); 231 inst->alg.digestsize = ds; 232 inst->alg.statesize = ss; 233 234 inst->alg.base.cra_ctxsize = sizeof(struct hmac_ctx) + 235 ALIGN(ss * 2, crypto_tfm_ctx_alignment()); 236 237 inst->alg.init = hmac_init; 238 inst->alg.update = hmac_update; 239 inst->alg.final = hmac_final; 240 inst->alg.finup = hmac_finup; 241 inst->alg.export = hmac_export; 242 inst->alg.import = hmac_import; 243 inst->alg.setkey = hmac_setkey; 244 inst->alg.init_tfm = hmac_init_tfm; 245 inst->alg.clone_tfm = hmac_clone_tfm; 246 inst->alg.exit_tfm = hmac_exit_tfm; 247 248 inst->free = shash_free_singlespawn_instance; 249 250 err = shash_register_instance(tmpl, inst); 251 if (err) { 252err_free_inst: 253 shash_free_singlespawn_instance(inst); 254 } 255 return err; 256} 257 258static struct crypto_template hmac_tmpl = { 259 .name = "hmac", 260 .create = hmac_create, 261 .module = THIS_MODULE, 262}; 263 264static int __init hmac_module_init(void) 265{ 266 return crypto_register_template(&hmac_tmpl); 267} 268 269static void __exit hmac_module_exit(void) 270{ 271 crypto_unregister_template(&hmac_tmpl); 272} 273 274subsys_initcall(hmac_module_init); 275module_exit(hmac_module_exit); 276 277MODULE_LICENSE("GPL"); 278MODULE_DESCRIPTION("HMAC hash algorithm"); 279MODULE_ALIAS_CRYPTO("hmac"); 280