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Diffstat (limited to 'ks_mmap.c')
| -rw-r--r-- | ks_mmap.c | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/ks_mmap.c b/ks_mmap.c new file mode 100644 index 0000000..5eb2a13 --- /dev/null +++ b/ks_mmap.c @@ -0,0 +1,179 @@ +/* + * ks_mmap.c + * --------- + * Keystore implementation over POSIX mmap(). + * + * Authors: Rob Austein + * Copyright (c) 2015, NORDUnet A/S All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: + * - Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * + * - Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * - Neither the name of the NORDUnet nor the names of its contributors may + * be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS + * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED + * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A + * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED + * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include <unistd.h> +#include <fcntl.h> +#include <sys/mman.h> +#include <string.h> +#include <sys/errno.h> +#include <unistd.h> + +#include "hal.h" +#include "hal_internal.h" + +#ifndef HAL_KS_MMAP_FILE +#define HAL_KS_MMAP_FILE ".cryptech_hal_keystore" +#endif + +#ifndef MAP_FILE +#define MAP_FILE 0 +#endif + +/* + * Storing the KEK in with the keys it's protecting is a bad idea, but we have no better + * place to put it (real protection requires dedicated hardware, which we don't have here). + */ + +#define KEKBUF_LEN (bitsToBytes(256)) + +static hal_ks_keydb_t *db; +static uint8_t *kekbuf; + +const hal_ks_keydb_t *hal_ks_get_keydb(void) +{ + if (db != NULL) + return db; + + const char * const env = getenv("CRYPTECH_KEYSTORE"); + const char * const home = getenv("HOME"); + const char * const base = HAL_KS_MMAP_FILE; + const long pagemask = sysconf(_SC_PAGESIZE) - 1; + const size_t len = (sizeof(hal_ks_keydb_t) + KEKBUF_LEN + pagemask) & ~pagemask; + + char fn_[strlen(base) + (home == NULL ? 0 : strlen(home)) + 2]; + const char *fn = fn_; + int fd; + + if (pagemask < 0) + return NULL; + + if (env != NULL) + fn = env; + else if (home == NULL) + fn = base; + else + strcat(strcat(strcpy(fn_, home), "/"), base); + + if ((fd = open(fn, O_RDWR | O_CREAT | O_EXCL, 0600)) >= 0) { + uint8_t zeros[len]; + memset(zeros, 0, sizeof(zeros)); + (void) write(fd, zeros, sizeof(zeros)); + } + else if (errno == EEXIST) { + fd = open(fn, O_RDWR | O_CREAT, 0600); + } + + if (fd >= 0 && (db = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_FILE | MAP_SHARED, fd, 0)) != NULL) + kekbuf = (uint8_t *) (db + 1); + + (void) close(fd); + + return db; +} + +hal_error_t hal_ks_set_keydb(const hal_ks_key_t * const key, + const int loc) +{ + if (key == NULL || loc < 0 || loc >= sizeof(db->keys)/sizeof(*db->keys) || key->in_use) + return HAL_ERROR_BAD_ARGUMENTS; + + db->keys[loc] = *key; + db->keys[loc].in_use = 1; + return HAL_OK; +} + +hal_error_t hal_ks_del_keydb(const int loc) +{ + if (loc < 0 || loc >= sizeof(db->keys)/sizeof(*db->keys)) + return HAL_ERROR_BAD_ARGUMENTS; + + db->keys[loc].in_use = 0; + memset(&db->keys[loc], 0, sizeof(db->keys[loc])); + return HAL_OK; +} + +hal_error_t hal_ks_set_pin(const hal_user_t user, + const hal_ks_pin_t * const pin) +{ + if (pin == NULL) + return HAL_ERROR_BAD_ARGUMENTS; + + hal_ks_pin_t *p = NULL; + + switch (user) { + case HAL_USER_WHEEL: p = &db->wheel_pin; break; + case HAL_USER_SO: p = &db->so_pin; break; + case HAL_USER_NORMAL: p = &db->user_pin; break; + default: return HAL_ERROR_BAD_ARGUMENTS; + } + + *p = *pin; + return HAL_OK; +} + +hal_error_t hal_ks_get_kek(uint8_t *kek, + size_t *kek_len, + const size_t kek_max) +{ + if (kek == NULL || kek_len == NULL || kek_max < bitsToBytes(128)) + return HAL_ERROR_BAD_ARGUMENTS; + + if (kekbuf == NULL) + return HAL_ERROR_IMPOSSIBLE; + + hal_error_t err; + + const size_t len = ((kek_max < bitsToBytes(192)) ? bitsToBytes(128) : + (kek_max < bitsToBytes(256)) ? bitsToBytes(192) : + bitsToBytes(256)); + + uint8_t t = 0; + + for (int i = 0; i < KEKBUF_LEN; i++) + t |= kekbuf[i]; + + if (t == 0 && (err = hal_rpc_get_random(kekbuf, sizeof(KEKBUF_LEN))) != HAL_OK) + return err; + + memcpy(kek, kekbuf, len); + *kek_len = len; + return HAL_OK; +} + +/* + * Local variables: + * indent-tabs-mode: nil + * End: + */ |