1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* Public-key operation keyctls 3 * 4 * Copyright (C) 2016 Red Hat, Inc. All Rights Reserved. 5 * Written by David Howells (dhowells@redhat.com) 6 */ 7 8 #include <linux/slab.h> 9 #include <linux/err.h> 10 #include <linux/key.h> 11 #include <linux/keyctl.h> 12 #include <linux/parser.h> 13 #include <linux/uaccess.h> 14 #include <keys/user-type.h> 15 #include "internal.h" 16 17 static void keyctl_pkey_params_free(struct kernel_pkey_params *params) 18 { 19 kfree(params->info); 20 key_put(params->key); 21 } 22 23 enum { 24 Opt_err, 25 Opt_enc, /* "enc=<encoding>" eg. "enc=oaep" */ 26 Opt_hash, /* "hash=<digest-name>" eg. "hash=sha1" */ 27 }; 28 29 static const match_table_t param_keys = { 30 { Opt_enc, "enc=%s" }, 31 { Opt_hash, "hash=%s" }, 32 { Opt_err, NULL } 33 }; 34 35 /* 36 * Parse the information string which consists of key=val pairs. 37 */ 38 static int keyctl_pkey_params_parse(struct kernel_pkey_params *params) 39 { 40 unsigned long token_mask = 0; 41 substring_t args[MAX_OPT_ARGS]; 42 char *c = params->info, *p, *q; 43 int token; 44 45 while ((p = strsep(&c, " \t"))) { 46 if (*p == '\0' || *p == ' ' || *p == '\t') 47 continue; 48 token = match_token(p, param_keys, args); 49 if (token == Opt_err) 50 return -EINVAL; 51 if (__test_and_set_bit(token, &token_mask)) 52 return -EINVAL; 53 q = args[0].from; 54 if (!q[0]) 55 return -EINVAL; 56 57 switch (token) { 58 case Opt_enc: 59 params->encoding = q; 60 break; 61 62 case Opt_hash: 63 params->hash_algo = q; 64 break; 65 66 default: 67 return -EINVAL; 68 } 69 } 70 71 return 0; 72 } 73 74 /* 75 * Interpret parameters. Callers must always call the free function 76 * on params, even if an error is returned. 77 */ 78 static int keyctl_pkey_params_get(key_serial_t id, 79 const char __user *_info, 80 struct kernel_pkey_params *params) 81 { 82 key_ref_t key_ref; 83 void *p; 84 int ret; 85 86 memset(params, 0, sizeof(*params)); 87 params->encoding = "raw"; 88 89 p = strndup_user(_info, PAGE_SIZE); 90 if (IS_ERR(p)) 91 return PTR_ERR(p); 92 params->info = p; 93 94 ret = keyctl_pkey_params_parse(params); 95 if (ret < 0) 96 return ret; 97 98 key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH); 99 if (IS_ERR(key_ref)) 100 return PTR_ERR(key_ref); 101 params->key = key_ref_to_ptr(key_ref); 102 103 if (!params->key->type->asym_query) 104 return -EOPNOTSUPP; 105 106 return 0; 107 } 108 109 /* 110 * Get parameters from userspace. Callers must always call the free function 111 * on params, even if an error is returned. 112 */ 113 static int keyctl_pkey_params_get_2(const struct keyctl_pkey_params __user *_params, 114 const char __user *_info, 115 int op, 116 struct kernel_pkey_params *params) 117 { 118 struct keyctl_pkey_params uparams; 119 struct kernel_pkey_query info; 120 int ret; 121 122 memset(params, 0, sizeof(*params)); 123 params->encoding = "raw"; 124 125 if (copy_from_user(&uparams, _params, sizeof(uparams)) != 0) 126 return -EFAULT; 127 128 ret = keyctl_pkey_params_get(uparams.key_id, _info, params); 129 if (ret < 0) 130 return ret; 131 132 ret = params->key->type->asym_query(params, &info); 133 if (ret < 0) 134 return ret; 135 136 switch (op) { 137 case KEYCTL_PKEY_ENCRYPT: 138 if (uparams.in_len > info.max_dec_size || 139 uparams.out_len > info.max_enc_size) 140 return -EINVAL; 141 break; 142 case KEYCTL_PKEY_DECRYPT: 143 if (uparams.in_len > info.max_enc_size || 144 uparams.out_len > info.max_dec_size) 145 return -EINVAL; 146 break; 147 case KEYCTL_PKEY_SIGN: 148 if (uparams.in_len > info.max_data_size || 149 uparams.out_len > info.max_sig_size) 150 return -EINVAL; 151 break; 152 case KEYCTL_PKEY_VERIFY: 153 if (uparams.in_len > info.max_data_size || 154 uparams.in2_len > info.max_sig_size) 155 return -EINVAL; 156 break; 157 default: 158 BUG(); 159 } 160 161 params->in_len = uparams.in_len; 162 params->out_len = uparams.out_len; /* Note: same as in2_len */ 163 return 0; 164 } 165 166 /* 167 * Query information about an asymmetric key. 168 */ 169 long keyctl_pkey_query(key_serial_t id, 170 const char __user *_info, 171 struct keyctl_pkey_query __user *_res) 172 { 173 struct kernel_pkey_params params; 174 struct kernel_pkey_query res; 175 long ret; 176 177 ret = keyctl_pkey_params_get(id, _info, ¶ms); 178 if (ret < 0) 179 goto error; 180 181 ret = params.key->type->asym_query(¶ms, &res); 182 if (ret < 0) 183 goto error; 184 185 ret = -EFAULT; 186 if (copy_to_user(_res, &res, sizeof(res)) == 0 && 187 clear_user(_res->__spare, sizeof(_res->__spare)) == 0) 188 ret = 0; 189 190 error: 191 keyctl_pkey_params_free(¶ms); 192 return ret; 193 } 194 195 /* 196 * Encrypt/decrypt/sign 197 * 198 * Encrypt data, decrypt data or sign data using a public key. 199 * 200 * _info is a string of supplementary information in key=val format. For 201 * instance, it might contain: 202 * 203 * "enc=pkcs1 hash=sha256" 204 * 205 * where enc= specifies the encoding and hash= selects the OID to go in that 206 * particular encoding if required. If enc= isn't supplied, it's assumed that 207 * the caller is supplying raw values. 208 * 209 * If successful, the amount of data written into the output buffer is 210 * returned. 211 */ 212 long keyctl_pkey_e_d_s(int op, 213 const struct keyctl_pkey_params __user *_params, 214 const char __user *_info, 215 const void __user *_in, 216 void __user *_out) 217 { 218 struct kernel_pkey_params params; 219 void *in, *out; 220 long ret; 221 222 ret = keyctl_pkey_params_get_2(_params, _info, op, ¶ms); 223 if (ret < 0) 224 goto error_params; 225 226 ret = -EOPNOTSUPP; 227 if (!params.key->type->asym_eds_op) 228 goto error_params; 229 230 switch (op) { 231 case KEYCTL_PKEY_ENCRYPT: 232 params.op = kernel_pkey_encrypt; 233 break; 234 case KEYCTL_PKEY_DECRYPT: 235 params.op = kernel_pkey_decrypt; 236 break; 237 case KEYCTL_PKEY_SIGN: 238 params.op = kernel_pkey_sign; 239 break; 240 default: 241 BUG(); 242 } 243 244 in = memdup_user(_in, params.in_len); 245 if (IS_ERR(in)) { 246 ret = PTR_ERR(in); 247 goto error_params; 248 } 249 250 ret = -ENOMEM; 251 out = kmalloc(params.out_len, GFP_KERNEL); 252 if (!out) 253 goto error_in; 254 255 ret = params.key->type->asym_eds_op(¶ms, in, out); 256 if (ret < 0) 257 goto error_out; 258 259 if (copy_to_user(_out, out, ret) != 0) 260 ret = -EFAULT; 261 262 error_out: 263 kfree(out); 264 error_in: 265 kfree(in); 266 error_params: 267 keyctl_pkey_params_free(¶ms); 268 return ret; 269 } 270 271 /* 272 * Verify a signature. 273 * 274 * Verify a public key signature using the given key, or if not given, search 275 * for a matching key. 276 * 277 * _info is a string of supplementary information in key=val format. For 278 * instance, it might contain: 279 * 280 * "enc=pkcs1 hash=sha256" 281 * 282 * where enc= specifies the signature blob encoding and hash= selects the OID 283 * to go in that particular encoding. If enc= isn't supplied, it's assumed 284 * that the caller is supplying raw values. 285 * 286 * If successful, 0 is returned. 287 */ 288 long keyctl_pkey_verify(const struct keyctl_pkey_params __user *_params, 289 const char __user *_info, 290 const void __user *_in, 291 const void __user *_in2) 292 { 293 struct kernel_pkey_params params; 294 void *in, *in2; 295 long ret; 296 297 ret = keyctl_pkey_params_get_2(_params, _info, KEYCTL_PKEY_VERIFY, 298 ¶ms); 299 if (ret < 0) 300 goto error_params; 301 302 ret = -EOPNOTSUPP; 303 if (!params.key->type->asym_verify_signature) 304 goto error_params; 305 306 in = memdup_user(_in, params.in_len); 307 if (IS_ERR(in)) { 308 ret = PTR_ERR(in); 309 goto error_params; 310 } 311 312 in2 = memdup_user(_in2, params.in2_len); 313 if (IS_ERR(in2)) { 314 ret = PTR_ERR(in2); 315 goto error_in; 316 } 317 318 params.op = kernel_pkey_verify; 319 ret = params.key->type->asym_verify_signature(¶ms, in, in2); 320 321 kfree(in2); 322 error_in: 323 kfree(in); 324 error_params: 325 keyctl_pkey_params_free(¶ms); 326 return ret; 327 } 328