Files
pcp/libpcp/vault.c
2013-10-28 22:50:05 +01:00

398 lines
9.4 KiB
C

#include "vault.h"
vault_t *pcpvault_init(char *filename) {
vault_t *vault = pcpvault_new(filename, 0);
if(vault != NULL) {
if(vault->isnew == 1) {
if(pcpvault_create(vault) != 0) {
pcpvault_close(vault);
return NULL;
}
}
else {
if(pcpvault_fetchall(vault) != 0) {
errno = 0; // weird, something sets it to ENOENT and it's not me
pcpvault_close(vault);
return NULL;
}
}
}
return vault;
}
vault_t *pcpvault_new(char *filename, int is_tmp) {
vault_t *vault = ucmalloc(sizeof(vault_t));
FILE *fd;
struct stat stat_buf;
if(is_tmp) {
filename = ucmalloc(1024);
uint32_t a,b;
while (1) {
a = arc4random();
b = arc4random();
snprintf(filename, 1024, "%s/.pcpvault-%08x%08x", getenv("HOME"), a, b);
if (stat (filename, &stat_buf) != 0)
break;
}
unlink(filename);
vault->size = 0;
vault->modified = 0;
vault->mode = 0;
}
else {
if (stat (filename, &stat_buf) == 0) {
vault->size = stat_buf.st_size;
vault->modified = stat_buf.st_mtime;
vault->mode = stat_buf.st_mode;
}
else {
vault->size = 0;
vault->modified = 0;
vault->mode = 0;
}
}
if(vault->size == 0) {
vault->isnew = 1;
mode_t old_mask = umask (S_IWGRP | S_IWOTH | S_IRGRP | S_IROTH);
if((fd = fopen(filename, "wb+")) == NULL) {
fatal("Could not create vault file %s", filename);
umask (old_mask);
goto errn;
}
umask (old_mask);
}
else {
if((fd = fopen(filename, "rb+")) == NULL) {
fatal("Could not open vault file %s", filename);
goto errn;
}
}
vault->fd = fd;
vault->filename = filename;
vault->unsafed = 0;
return vault;
errn:
free(vault);
return NULL;
}
int pcpvault_create(vault_t *vault) {
vault_header_t *header = ucmalloc(sizeof(vault_header_t));
header->fileid = PCP_VAULT_ID;
header->version = PCP_VAULT_VERSION;
vault->version = header->version;
memcpy(vault->checksum, header->checksum, 32);
vh2be(header);
fseek(vault->fd, 0, SEEK_SET);
fwrite(header, sizeof(vault_header_t), 1, vault->fd);
if(ferror(vault->fd) != 0) {
fatal("Failed to write fileheader to vault %s!\n", vault->filename);
return 1;
}
vault->unsafed = 0;
return 0;
}
int pcpvault_additem(vault_t *vault, void *item, size_t itemsize, uint8_t type, uint8_t do_hash) {
vault_item_header_t *header = ucmalloc(sizeof(vault_item_header_t));
header->type = type;
header->size = itemsize;
crypto_hash_sha256((unsigned char*)header->checksum, item, itemsize);
ih2be(header);
void *saveitem = ucmalloc(itemsize);
memcpy(saveitem, item, itemsize);
if(type == PCP_KEY_TYPE_PUBLIC)
pubkey2be((pcp_pubkey_t *)saveitem);
else
key2be((pcp_key_t *)saveitem);
fwrite(header, sizeof(vault_item_header_t), 1, vault->fd);
fwrite(saveitem, itemsize, 1, vault->fd);
bzero(saveitem, itemsize);
free(saveitem);
if(do_hash == 1) {
// we don't re-hash if it's a full update
if(type == PCP_KEY_TYPE_PUBLIC) {
pcp_pubkey_t *p = (pcp_pubkey_t *)item;
HASH_ADD_STR( pcppubkey_hash, id, p );
}
else {
pcp_key_t *s = (pcp_key_t *)item;
HASH_ADD_STR( pcpkey_hash, id, s );
}
pcpvault_update_checksum(vault);
}
if(ferror(vault->fd) != 0) {
fatal("Failed to add an item to vault %s!\n", vault->filename);
return 1;
}
vault->unsafed = 0;
return 0;
}
int pcpvault_writeall(vault_t *vault) {
vault_t *tmp = pcpvault_new(NULL, 1); // FIXME
if(tmp != NULL) {
if(pcpvault_create(tmp) == 0) {
pcp_key_t *k, *kt = NULL;
HASH_ITER(hh, pcpkey_hash, k, kt) {
if(pcpvault_additem(tmp, (void *)k, sizeof(pcp_key_t), PCP_KEY_TYPE_SECRET, 0) != 0)
goto errwa;
}
pcp_pubkey_t *p, *pt = NULL;
HASH_ITER(hh, pcppubkey_hash, p, pt) {
if(pcpvault_additem(tmp, (void *)p, sizeof(pcp_pubkey_t), PCP_KEY_TYPE_PUBLIC, 0) != 0)
goto errwa;
}
pcpvault_update_checksum(tmp);
pcpvault_copy(tmp, vault);
}
}
errwa:
if(tmp != NULL) {
pcpvault_unlink(tmp);
free(tmp);
}
return 1;
}
void pcpvault_update_checksum(vault_t *vault) {
unsigned char *checksum = pcpvault_create_checksum(vault);
vault_header_t *header = ucmalloc(sizeof(vault_header_t));
header->fileid = PCP_VAULT_ID;
header->version = PCP_VAULT_VERSION;
memcpy(header->checksum, checksum, 32);
memcpy(vault->checksum, checksum, 32);
vh2be(header);
fseek(vault->fd, 0, SEEK_SET);
fwrite(header, sizeof(vault_header_t), 1, vault->fd);
fseek(vault->fd, 0, SEEK_END);
}
unsigned char *pcpvault_create_checksum(vault_t *vault) {
size_t skeysize = sizeof(pcp_key_t) - sizeof(UT_hash_handle);
size_t pkeysize = sizeof(pcp_pubkey_t) - sizeof(UT_hash_handle);
int numskeys = HASH_COUNT(pcpkey_hash);
int numpkeys = HASH_COUNT(pcppubkey_hash);
size_t datasize = (skeysize * numskeys) + (pkeysize * numpkeys);
unsigned char *data = ucmalloc(datasize);
unsigned char *checksum = ucmalloc(32);
size_t datapos = 0;
pcp_key_t *k, *kt = NULL;
HASH_ITER(hh, pcpkey_hash, k, kt) {
key2be(k);
memcpy(&data[datapos], k, skeysize);
key2native(k);
datapos += skeysize;
}
pcp_pubkey_t *p, *pt = NULL;
HASH_ITER(hh, pcppubkey_hash, p, pt) {
pubkey2be(p);
memcpy(&data[datapos], p, pkeysize);
pubkey2native(p);
datapos += pkeysize;
}
crypto_hash_sha256(checksum, data, datasize);
bzero(data, datasize);
free(data);
return checksum;
}
void pcpvault_copy(vault_t *tmp, vault_t *vault) {
// fetch tmp content
fseek(tmp->fd, 0, SEEK_END);
int tmpsize = ftell(tmp->fd);
fseek(tmp->fd, 0, SEEK_SET);
unsigned char *in = ucmalloc(tmpsize);
fread(in, tmpsize, 1, tmp->fd);
// and put it into the old file
vault->fd = freopen(vault->filename, "wb+", vault->fd);
fwrite(in, tmpsize, 1, vault->fd);
}
void pcpvault_unlink(vault_t *tmp) {
int i, tmpsize;
unsigned char *r;
fseek(tmp->fd, 0, SEEK_END);
tmpsize = ftell(tmp->fd);
r = ucmalloc(tmpsize);
for (i=0; i<16; ++i) {
fseek(tmp->fd, 0, SEEK_SET);
arc4random_buf(r, tmpsize);
fwrite(r, tmpsize, 1, tmp->fd);
}
fclose(tmp->fd);
unlink(tmp->filename);
free(r);
}
int pcpvault_close(vault_t *vault) {
if(vault != NULL) {
if(vault->fd) {
if(vault->unsafed == 1) {
pcpvault_writeall(vault);
}
fclose(vault->fd);
}
free(vault);
vault = NULL;
}
return 0;
}
vault_header_t * vh2be(vault_header_t *h) {
h->version = htobe32(h->version);
return h;
}
vault_header_t * vh2native(vault_header_t *h) {
h->version = be32toh(h->version);
return h;
}
vault_item_header_t * ih2be(vault_item_header_t *h) {
h->version = htobe32(h->version);
h->size = htobe32(h->size);
return h;
}
vault_item_header_t * ih2native(vault_item_header_t *h) {
h->version = be32toh(h->version);
h->size = be32toh(h->size);
return h;
}
int pcpvault_fetchall(vault_t *vault) {
fseek(vault->fd, 0, SEEK_SET);
vault_header_t *header = ucmalloc(sizeof(vault_header_t));
vault_item_header_t *item = ucmalloc(sizeof(vault_item_header_t));
fread(header, sizeof(vault_header_t), 1, vault->fd);
vh2native(header);
if(header->fileid == PCP_VAULT_ID && header->version == PCP_VAULT_VERSION) {
// loop over the file and slurp everything in
pcpkey_hash = NULL;
pcppubkey_hash = NULL;
int readpos = 0;
pcp_key_t *key;
pcp_pubkey_t *pubkey;
int bytesleft = 0;
int ksize = sizeof(pcp_pubkey_t); // smallest possbile item
vault->version = header->version;
memcpy(vault->checksum, header->checksum, 32);
for(;;) {
readpos = ftell(vault->fd);
if(vault->size - readpos >= sizeof(vault_item_header_t)) {
// an item header follows
fread(item, sizeof(vault_item_header_t), 1, vault->fd);
ih2native(item);
if(item->size > 0) {
// item is valid
readpos = ftell(vault->fd);
bytesleft = vault->size - readpos;
if(bytesleft >= ksize) {
// a key follows
if(item->type == PCP_KEY_TYPE_MAINSECRET ||
item->type == PCP_KEY_TYPE_SECRET) {
// read a secret key
key = ucmalloc(sizeof(pcp_key_t));
fread(key, sizeof(pcp_key_t), 1, vault->fd);
key2native(key);
//pcp_dumpkey(key);
HASH_ADD_STR( pcpkey_hash, id, key );
}
else if(item->type == PCP_KEY_TYPE_PUBLIC) {
// read a public key
pubkey = ucmalloc(sizeof(pcp_pubkey_t));
fread(pubkey, sizeof(pcp_pubkey_t), 1, vault->fd);
pubkey2native(pubkey);
HASH_ADD_STR( pcppubkey_hash, id, pubkey );
}
else {
fatal("Failed to read vault - invalid key type: %02X! at %d\n", item->type, readpos);
goto err;
}
}
else {
fatal("Failed to read vault - that's no pcp key at %d!\n", readpos);
goto err;
}
}
else {
fatal("Failed to read vault - invalid key item header size at %d!\n",
readpos);
goto err;
}
}
else {
// no more items
break;
}
}
}
else {
fatal("Unexpected vault file format!\n");
goto err;
}
unsigned char *checksum = NULL;
checksum = pcpvault_create_checksum(vault);
if(HASH_COUNT(pcpkey_hash) + HASH_COUNT(pcppubkey_hash) > 0) {
// only validate the checksum if there are keys
if(memcmp(checksum, vault->checksum, 32) != 0) {
fatal("Error: the checksum of the key vault doesn't match its contents!\n");
goto err;
}
}
free(checksum);
free(item);
free(header);
return 0;
err:
free(item);
free(header);
pcp_cleanhashes();
return -1;
}