1 // SPDX-License-Identifier: GPL-2.0 2 3 #include <linux/ceph/ceph_debug.h> 4 5 #include <linux/err.h> 6 #include <linux/scatterlist.h> 7 #include <linux/sched.h> 8 #include <linux/slab.h> 9 #include <crypto/aes.h> 10 #include <crypto/skcipher.h> 11 #include <linux/key-type.h> 12 #include <linux/sched/mm.h> 13 14 #include <keys/ceph-type.h> 15 #include <keys/user-type.h> 16 #include <linux/ceph/decode.h> 17 #include "crypto.h" 18 19 /* 20 * Set ->key and ->tfm. The rest of the key should be filled in before 21 * this function is called. 22 */ 23 static int set_secret(struct ceph_crypto_key *key, void *buf) 24 { 25 unsigned int noio_flag; 26 int ret; 27 28 key->key = NULL; 29 key->tfm = NULL; 30 31 switch (key->type) { 32 case CEPH_CRYPTO_NONE: 33 return 0; /* nothing to do */ 34 case CEPH_CRYPTO_AES: 35 break; 36 default: 37 return -ENOTSUPP; 38 } 39 40 if (!key->len) 41 return -EINVAL; 42 43 key->key = kmemdup(buf, key->len, GFP_NOIO); 44 if (!key->key) { 45 ret = -ENOMEM; 46 goto fail; 47 } 48 49 /* crypto_alloc_sync_skcipher() allocates with GFP_KERNEL */ 50 noio_flag = memalloc_noio_save(); 51 key->tfm = crypto_alloc_sync_skcipher("cbc(aes)", 0, 0); 52 memalloc_noio_restore(noio_flag); 53 if (IS_ERR(key->tfm)) { 54 ret = PTR_ERR(key->tfm); 55 key->tfm = NULL; 56 goto fail; 57 } 58 59 ret = crypto_sync_skcipher_setkey(key->tfm, key->key, key->len); 60 if (ret) 61 goto fail; 62 63 return 0; 64 65 fail: 66 ceph_crypto_key_destroy(key); 67 return ret; 68 } 69 70 int ceph_crypto_key_clone(struct ceph_crypto_key *dst, 71 const struct ceph_crypto_key *src) 72 { 73 memcpy(dst, src, sizeof(struct ceph_crypto_key)); 74 return set_secret(dst, src->key); 75 } 76 77 int ceph_crypto_key_encode(struct ceph_crypto_key *key, void **p, void *end) 78 { 79 if (*p + sizeof(u16) + sizeof(key->created) + 80 sizeof(u16) + key->len > end) 81 return -ERANGE; 82 ceph_encode_16(p, key->type); 83 ceph_encode_copy(p, &key->created, sizeof(key->created)); 84 ceph_encode_16(p, key->len); 85 ceph_encode_copy(p, key->key, key->len); 86 return 0; 87 } 88 89 int ceph_crypto_key_decode(struct ceph_crypto_key *key, void **p, void *end) 90 { 91 int ret; 92 93 ceph_decode_need(p, end, 2*sizeof(u16) + sizeof(key->created), bad); 94 key->type = ceph_decode_16(p); 95 ceph_decode_copy(p, &key->created, sizeof(key->created)); 96 key->len = ceph_decode_16(p); 97 ceph_decode_need(p, end, key->len, bad); 98 ret = set_secret(key, *p); 99 memzero_explicit(*p, key->len); 100 *p += key->len; 101 return ret; 102 103 bad: 104 dout("failed to decode crypto key\n"); 105 return -EINVAL; 106 } 107 108 int ceph_crypto_key_unarmor(struct ceph_crypto_key *key, const char *inkey) 109 { 110 int inlen = strlen(inkey); 111 int blen = inlen * 3 / 4; 112 void *buf, *p; 113 int ret; 114 115 dout("crypto_key_unarmor %s\n", inkey); 116 buf = kmalloc(blen, GFP_NOFS); 117 if (!buf) 118 return -ENOMEM; 119 blen = ceph_unarmor(buf, inkey, inkey+inlen); 120 if (blen < 0) { 121 kfree(buf); 122 return blen; 123 } 124 125 p = buf; 126 ret = ceph_crypto_key_decode(key, &p, p + blen); 127 kfree(buf); 128 if (ret) 129 return ret; 130 dout("crypto_key_unarmor key %p type %d len %d\n", key, 131 key->type, key->len); 132 return 0; 133 } 134 135 void ceph_crypto_key_destroy(struct ceph_crypto_key *key) 136 { 137 if (key) { 138 kfree_sensitive(key->key); 139 key->key = NULL; 140 if (key->tfm) { 141 crypto_free_sync_skcipher(key->tfm); 142 key->tfm = NULL; 143 } 144 } 145 } 146 147 static const u8 *aes_iv = (u8 *)CEPH_AES_IV; 148 149 /* 150 * Should be used for buffers allocated with kvmalloc(). 151 * Currently these are encrypt out-buffer (ceph_buffer) and decrypt 152 * in-buffer (msg front). 153 * 154 * Dispose of @sgt with teardown_sgtable(). 155 * 156 * @prealloc_sg is to avoid memory allocation inside sg_alloc_table() 157 * in cases where a single sg is sufficient. No attempt to reduce the 158 * number of sgs by squeezing physically contiguous pages together is 159 * made though, for simplicity. 160 */ 161 static int setup_sgtable(struct sg_table *sgt, struct scatterlist *prealloc_sg, 162 const void *buf, unsigned int buf_len) 163 { 164 struct scatterlist *sg; 165 const bool is_vmalloc = is_vmalloc_addr(buf); 166 unsigned int off = offset_in_page(buf); 167 unsigned int chunk_cnt = 1; 168 unsigned int chunk_len = PAGE_ALIGN(off + buf_len); 169 int i; 170 int ret; 171 172 if (buf_len == 0) { 173 memset(sgt, 0, sizeof(*sgt)); 174 return -EINVAL; 175 } 176 177 if (is_vmalloc) { 178 chunk_cnt = chunk_len >> PAGE_SHIFT; 179 chunk_len = PAGE_SIZE; 180 } 181 182 if (chunk_cnt > 1) { 183 ret = sg_alloc_table(sgt, chunk_cnt, GFP_NOFS); 184 if (ret) 185 return ret; 186 } else { 187 WARN_ON(chunk_cnt != 1); 188 sg_init_table(prealloc_sg, 1); 189 sgt->sgl = prealloc_sg; 190 sgt->nents = sgt->orig_nents = 1; 191 } 192 193 for_each_sg(sgt->sgl, sg, sgt->orig_nents, i) { 194 struct page *page; 195 unsigned int len = min(chunk_len - off, buf_len); 196 197 if (is_vmalloc) 198 page = vmalloc_to_page(buf); 199 else 200 page = virt_to_page(buf); 201 202 sg_set_page(sg, page, len, off); 203 204 off = 0; 205 buf += len; 206 buf_len -= len; 207 } 208 WARN_ON(buf_len != 0); 209 210 return 0; 211 } 212 213 static void teardown_sgtable(struct sg_table *sgt) 214 { 215 if (sgt->orig_nents > 1) 216 sg_free_table(sgt); 217 } 218 219 static int ceph_aes_crypt(const struct ceph_crypto_key *key, bool encrypt, 220 void *buf, int buf_len, int in_len, int *pout_len) 221 { 222 SYNC_SKCIPHER_REQUEST_ON_STACK(req, key->tfm); 223 struct sg_table sgt; 224 struct scatterlist prealloc_sg; 225 char iv[AES_BLOCK_SIZE] __aligned(8); 226 int pad_byte = AES_BLOCK_SIZE - (in_len & (AES_BLOCK_SIZE - 1)); 227 int crypt_len = encrypt ? in_len + pad_byte : in_len; 228 int ret; 229 230 WARN_ON(crypt_len > buf_len); 231 if (encrypt) 232 memset(buf + in_len, pad_byte, pad_byte); 233 ret = setup_sgtable(&sgt, &prealloc_sg, buf, crypt_len); 234 if (ret) 235 return ret; 236 237 memcpy(iv, aes_iv, AES_BLOCK_SIZE); 238 skcipher_request_set_sync_tfm(req, key->tfm); 239 skcipher_request_set_callback(req, 0, NULL, NULL); 240 skcipher_request_set_crypt(req, sgt.sgl, sgt.sgl, crypt_len, iv); 241 242 /* 243 print_hex_dump(KERN_ERR, "key: ", DUMP_PREFIX_NONE, 16, 1, 244 key->key, key->len, 1); 245 print_hex_dump(KERN_ERR, " in: ", DUMP_PREFIX_NONE, 16, 1, 246 buf, crypt_len, 1); 247 */ 248 if (encrypt) 249 ret = crypto_skcipher_encrypt(req); 250 else 251 ret = crypto_skcipher_decrypt(req); 252 skcipher_request_zero(req); 253 if (ret) { 254 pr_err("%s %scrypt failed: %d\n", __func__, 255 encrypt ? "en" : "de", ret); 256 goto out_sgt; 257 } 258 /* 259 print_hex_dump(KERN_ERR, "out: ", DUMP_PREFIX_NONE, 16, 1, 260 buf, crypt_len, 1); 261 */ 262 263 if (encrypt) { 264 *pout_len = crypt_len; 265 } else { 266 pad_byte = *(char *)(buf + in_len - 1); 267 if (pad_byte > 0 && pad_byte <= AES_BLOCK_SIZE && 268 in_len >= pad_byte) { 269 *pout_len = in_len - pad_byte; 270 } else { 271 pr_err("%s got bad padding %d on in_len %d\n", 272 __func__, pad_byte, in_len); 273 ret = -EPERM; 274 goto out_sgt; 275 } 276 } 277 278 out_sgt: 279 teardown_sgtable(&sgt); 280 return ret; 281 } 282 283 int ceph_crypt(const struct ceph_crypto_key *key, bool encrypt, 284 void *buf, int buf_len, int in_len, int *pout_len) 285 { 286 switch (key->type) { 287 case CEPH_CRYPTO_NONE: 288 *pout_len = in_len; 289 return 0; 290 case CEPH_CRYPTO_AES: 291 return ceph_aes_crypt(key, encrypt, buf, buf_len, in_len, 292 pout_len); 293 default: 294 return -ENOTSUPP; 295 } 296 } 297 298 static int ceph_key_preparse(struct key_preparsed_payload *prep) 299 { 300 struct ceph_crypto_key *ckey; 301 size_t datalen = prep->datalen; 302 int ret; 303 void *p; 304 305 ret = -EINVAL; 306 if (datalen <= 0 || datalen > 32767 || !prep->data) 307 goto err; 308 309 ret = -ENOMEM; 310 ckey = kmalloc(sizeof(*ckey), GFP_KERNEL); 311 if (!ckey) 312 goto err; 313 314 /* TODO ceph_crypto_key_decode should really take const input */ 315 p = (void *)prep->data; 316 ret = ceph_crypto_key_decode(ckey, &p, (char*)prep->data+datalen); 317 if (ret < 0) 318 goto err_ckey; 319 320 prep->payload.data[0] = ckey; 321 prep->quotalen = datalen; 322 return 0; 323 324 err_ckey: 325 kfree(ckey); 326 err: 327 return ret; 328 } 329 330 static void ceph_key_free_preparse(struct key_preparsed_payload *prep) 331 { 332 struct ceph_crypto_key *ckey = prep->payload.data[0]; 333 ceph_crypto_key_destroy(ckey); 334 kfree(ckey); 335 } 336 337 static void ceph_key_destroy(struct key *key) 338 { 339 struct ceph_crypto_key *ckey = key->payload.data[0]; 340 341 ceph_crypto_key_destroy(ckey); 342 kfree(ckey); 343 } 344 345 struct key_type key_type_ceph = { 346 .name = "ceph", 347 .preparse = ceph_key_preparse, 348 .free_preparse = ceph_key_free_preparse, 349 .instantiate = generic_key_instantiate, 350 .destroy = ceph_key_destroy, 351 }; 352 353 int __init ceph_crypto_init(void) 354 { 355 return register_key_type(&key_type_ceph); 356 } 357 358 void ceph_crypto_shutdown(void) 359 { 360 unregister_key_type(&key_type_ceph); 361 } 362