1 /* $OpenBSD: uvm_swap_encrypt.c,v 1.19 2014/11/18 02:37:31 tedu Exp $ */ 2 3 /* 4 * Copyright 1999 Niels Provos <provos@citi.umich.edu> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by Niels Provos. 18 * 4. The name of the author may not be used to endorse or promote products 19 * derived from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 #include <sys/param.h> 34 #include <sys/systm.h> 35 #include <sys/kernel.h> 36 #include <sys/malloc.h> 37 #include <sys/sysctl.h> 38 #include <sys/time.h> 39 #include <sys/conf.h> 40 #include <crypto/rijndael.h> 41 42 #include <uvm/uvm.h> 43 44 struct swap_key *kcur = NULL; 45 rijndael_ctx swap_ctxt; 46 47 int uvm_doswapencrypt = 1; 48 u_int uvm_swpkeyscreated = 0; 49 u_int uvm_swpkeysdeleted = 0; 50 51 int swap_encrypt_initialized = 0; 52 53 int 54 swap_encrypt_ctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, 55 void *newp, size_t newlen, struct proc *p) 56 { 57 /* all sysctl names at this level are terminal */ 58 if (namelen != 1) 59 return (ENOTDIR); /* overloaded */ 60 61 switch (name[0]) { 62 case SWPENC_ENABLE: { 63 int doencrypt = uvm_doswapencrypt; 64 int result; 65 66 result = sysctl_int(oldp, oldlenp, newp, newlen, &doencrypt); 67 if (result) 68 return result; 69 70 /* 71 * Swap Encryption has been turned on, we need to 72 * initialize state for swap devices that have been 73 * added. 74 */ 75 if (doencrypt) 76 uvm_swap_initcrypt_all(); 77 uvm_doswapencrypt = doencrypt; 78 return (0); 79 } 80 case SWPENC_CREATED: 81 return (sysctl_rdint(oldp, oldlenp, newp, uvm_swpkeyscreated)); 82 case SWPENC_DELETED: 83 return (sysctl_rdint(oldp, oldlenp, newp, uvm_swpkeysdeleted)); 84 default: 85 return (EOPNOTSUPP); 86 } 87 /* NOTREACHED */ 88 } 89 90 void 91 swap_key_delete(struct swap_key *key) 92 { 93 /* Make sure that this key gets removed if we just used it */ 94 swap_key_cleanup(key); 95 96 explicit_bzero(key, sizeof(*key)); 97 uvm_swpkeysdeleted++; 98 } 99 100 /* 101 * Encrypt the data before it goes to swap, the size should be 64-bit 102 * aligned. 103 */ 104 105 void 106 swap_encrypt(struct swap_key *key, caddr_t src, caddr_t dst, u_int64_t block, 107 size_t count) 108 { 109 u_int32_t *dsrc = (u_int32_t *)src; 110 u_int32_t *ddst = (u_int32_t *)dst; 111 u_int32_t iv[4]; 112 u_int32_t iv1, iv2, iv3, iv4; 113 114 if (!swap_encrypt_initialized) 115 swap_encrypt_initialized = 1; 116 117 swap_key_prepare(key, 1); 118 119 count /= sizeof(u_int32_t); 120 121 iv[0] = block >> 32; iv[1] = block; iv[2] = ~iv[0]; iv[3] = ~iv[1]; 122 rijndael_encrypt(&swap_ctxt, (u_char *)iv, (u_char *)iv); 123 iv1 = iv[0]; iv2 = iv[1]; iv3 = iv[2]; iv4 = iv[3]; 124 125 for (; count > 0; count -= 4) { 126 ddst[0] = dsrc[0] ^ iv1; 127 ddst[1] = dsrc[1] ^ iv2; 128 ddst[2] = dsrc[2] ^ iv3; 129 ddst[3] = dsrc[3] ^ iv4; 130 /* 131 * Do not worry about endianess, it only needs to decrypt 132 * on this machine. 133 */ 134 rijndael_encrypt(&swap_ctxt, (u_char *)ddst, (u_char *)ddst); 135 iv1 = ddst[0]; 136 iv2 = ddst[1]; 137 iv3 = ddst[2]; 138 iv4 = ddst[3]; 139 140 dsrc += 4; 141 ddst += 4; 142 } 143 } 144 145 /* 146 * Decrypt the data after we retrieved it from swap, the size should be 64-bit 147 * aligned. 148 */ 149 150 void 151 swap_decrypt(struct swap_key *key, caddr_t src, caddr_t dst, u_int64_t block, 152 size_t count) 153 { 154 u_int32_t *dsrc = (u_int32_t *)src; 155 u_int32_t *ddst = (u_int32_t *)dst; 156 u_int32_t iv[4]; 157 u_int32_t iv1, iv2, iv3, iv4, niv1, niv2, niv3, niv4; 158 159 if (!swap_encrypt_initialized) 160 panic("swap_decrypt: key not initialized"); 161 162 swap_key_prepare(key, 0); 163 164 count /= sizeof(u_int32_t); 165 166 iv[0] = block >> 32; iv[1] = block; iv[2] = ~iv[0]; iv[3] = ~iv[1]; 167 rijndael_encrypt(&swap_ctxt, (u_char *)iv, (u_char *)iv); 168 iv1 = iv[0]; iv2 = iv[1]; iv3 = iv[2]; iv4 = iv[3]; 169 170 for (; count > 0; count -= 4) { 171 ddst[0] = niv1 = dsrc[0]; 172 ddst[1] = niv2 = dsrc[1]; 173 ddst[2] = niv3 = dsrc[2]; 174 ddst[3] = niv4 = dsrc[3]; 175 rijndael_decrypt(&swap_ctxt, (u_char *)ddst, (u_char *)ddst); 176 ddst[0] ^= iv1; 177 ddst[1] ^= iv2; 178 ddst[2] ^= iv3; 179 ddst[3] ^= iv4; 180 181 iv1 = niv1; 182 iv2 = niv2; 183 iv3 = niv3; 184 iv4 = niv4; 185 186 dsrc += 4; 187 ddst += 4; 188 } 189 } 190 191 void 192 swap_key_prepare(struct swap_key *key, int encrypt) 193 { 194 /* 195 * Check if we have prepared for this key already, 196 * if we only have the encryption schedule, we have 197 * to recompute and get the decryption schedule also. 198 */ 199 if (kcur == key && (encrypt || !swap_ctxt.enc_only)) 200 return; 201 202 if (encrypt) 203 rijndael_set_key_enc_only(&swap_ctxt, (u_char *)key->key, 204 sizeof(key->key) * 8); 205 else 206 rijndael_set_key(&swap_ctxt, (u_char *)key->key, 207 sizeof(key->key) * 8); 208 209 kcur = key; 210 } 211 212 /* 213 * Make sure that a specific key is no longer available. 214 */ 215 216 void 217 swap_key_cleanup(struct swap_key *key) 218 { 219 /* Check if we have a key */ 220 if (kcur == NULL || kcur != key) 221 return; 222 223 /* Zero out the subkeys */ 224 explicit_bzero(&swap_ctxt, sizeof(swap_ctxt)); 225 226 kcur = NULL; 227 } 228