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 case KEYCTL_PKEY_DECRYPT: 139 if (uparams.in_len > info.max_enc_size || 140 uparams.out_len > info.max_dec_size) 141 return -EINVAL; 142 break; 143 case KEYCTL_PKEY_SIGN: 144 case KEYCTL_PKEY_VERIFY: 145 if (uparams.in_len > info.max_sig_size || 146 uparams.out_len > info.max_data_size) 147 return -EINVAL; 148 break; 149 default: 150 BUG(); 151 } 152 153 params->in_len = uparams.in_len; 154 params->out_len = uparams.out_len; 155 return 0; 156 } 157 158 /* 159 * Query information about an asymmetric key. 160 */ 161 long keyctl_pkey_query(key_serial_t id, 162 const char __user *_info, 163 struct keyctl_pkey_query __user *_res) 164 { 165 struct kernel_pkey_params params; 166 struct kernel_pkey_query res; 167 long ret; 168 169 memset(¶ms, 0, sizeof(params)); 170 171 ret = keyctl_pkey_params_get(id, _info, ¶ms); 172 if (ret < 0) 173 goto error; 174 175 ret = params.key->type->asym_query(¶ms, &res); 176 if (ret < 0) 177 goto error; 178 179 ret = -EFAULT; 180 if (copy_to_user(_res, &res, sizeof(res)) == 0 && 181 clear_user(_res->__spare, sizeof(_res->__spare)) == 0) 182 ret = 0; 183 184 error: 185 keyctl_pkey_params_free(¶ms); 186 return ret; 187 } 188 189 /* 190 * Encrypt/decrypt/sign 191 * 192 * Encrypt data, decrypt data or sign data using a public key. 193 * 194 * _info is a string of supplementary information in key=val format. For 195 * instance, it might contain: 196 * 197 * "enc=pkcs1 hash=sha256" 198 * 199 * where enc= specifies the encoding and hash= selects the OID to go in that 200 * particular encoding if required. If enc= isn't supplied, it's assumed that 201 * the caller is supplying raw values. 202 * 203 * If successful, the amount of data written into the output buffer is 204 * returned. 205 */ 206 long keyctl_pkey_e_d_s(int op, 207 const struct keyctl_pkey_params __user *_params, 208 const char __user *_info, 209 const void __user *_in, 210 void __user *_out) 211 { 212 struct kernel_pkey_params params; 213 void *in, *out; 214 long ret; 215 216 ret = keyctl_pkey_params_get_2(_params, _info, op, ¶ms); 217 if (ret < 0) 218 goto error_params; 219 220 ret = -EOPNOTSUPP; 221 if (!params.key->type->asym_eds_op) 222 goto error_params; 223 224 switch (op) { 225 case KEYCTL_PKEY_ENCRYPT: 226 params.op = kernel_pkey_encrypt; 227 break; 228 case KEYCTL_PKEY_DECRYPT: 229 params.op = kernel_pkey_decrypt; 230 break; 231 case KEYCTL_PKEY_SIGN: 232 params.op = kernel_pkey_sign; 233 break; 234 default: 235 BUG(); 236 } 237 238 in = memdup_user(_in, params.in_len); 239 if (IS_ERR(in)) { 240 ret = PTR_ERR(in); 241 goto error_params; 242 } 243 244 ret = -ENOMEM; 245 out = kmalloc(params.out_len, GFP_KERNEL); 246 if (!out) 247 goto error_in; 248 249 ret = params.key->type->asym_eds_op(¶ms, in, out); 250 if (ret < 0) 251 goto error_out; 252 253 if (copy_to_user(_out, out, ret) != 0) 254 ret = -EFAULT; 255 256 error_out: 257 kfree(out); 258 error_in: 259 kfree(in); 260 error_params: 261 keyctl_pkey_params_free(¶ms); 262 return ret; 263 } 264 265 /* 266 * Verify a signature. 267 * 268 * Verify a public key signature using the given key, or if not given, search 269 * for a matching key. 270 * 271 * _info is a string of supplementary information in key=val format. For 272 * instance, it might contain: 273 * 274 * "enc=pkcs1 hash=sha256" 275 * 276 * where enc= specifies the signature blob encoding and hash= selects the OID 277 * to go in that particular encoding. If enc= isn't supplied, it's assumed 278 * that the caller is supplying raw values. 279 * 280 * If successful, 0 is returned. 281 */ 282 long keyctl_pkey_verify(const struct keyctl_pkey_params __user *_params, 283 const char __user *_info, 284 const void __user *_in, 285 const void __user *_in2) 286 { 287 struct kernel_pkey_params params; 288 void *in, *in2; 289 long ret; 290 291 ret = keyctl_pkey_params_get_2(_params, _info, KEYCTL_PKEY_VERIFY, 292 ¶ms); 293 if (ret < 0) 294 goto error_params; 295 296 ret = -EOPNOTSUPP; 297 if (!params.key->type->asym_verify_signature) 298 goto error_params; 299 300 in = memdup_user(_in, params.in_len); 301 if (IS_ERR(in)) { 302 ret = PTR_ERR(in); 303 goto error_params; 304 } 305 306 in2 = memdup_user(_in2, params.in2_len); 307 if (IS_ERR(in2)) { 308 ret = PTR_ERR(in2); 309 goto error_in; 310 } 311 312 params.op = kernel_pkey_verify; 313 ret = params.key->type->asym_verify_signature(¶ms, in, in2); 314 315 kfree(in2); 316 error_in: 317 kfree(in); 318 error_params: 319 keyctl_pkey_params_free(¶ms); 320 return ret; 321 } 322