void
svl_crypto_ctx_free(svl_crypto_ctx *ctx)
{
if (!ctx)
return;
if (ctx->keyring_file && ctx->keyring_file != keyring)
keyring_free(ctx->keyring_file);
h_free(ctx);
}
int cmd_serval_sign(const char *sid_str,
const size_t sid_len,
const unsigned char *msg,
const size_t msg_len,
char *sig_str_buf,
const size_t sig_str_size,
const char *keyring_path,
const size_t keyring_len) {
int ret = 0;
unsigned char signed_msg[msg_len + SIGNATURE_BYTES];
keyring_file *_keyring = NULL;
unsigned char *key = NULL;
unsigned char packedSid[SID_SIZE] = {0};
CHECK(sig_str_size >= 2*SIGNATURE_BYTES + 1,"Signature buffer too small");
if (sid_str) {
CHECK_ERR(sid_len == 2*SID_SIZE && str_is_subscriber_id(sid_str) == 1,"Invalid SID");
stowSid(packedSid,0,sid_str);
}
if (keyring_path) {
CHECK_ERR(serval_init_keyring(sid_str ? packedSid : NULL,
sid_str ? SID_SIZE : 0,
keyring_path,
keyring_len,
&_keyring,
&key,
NULL), "Failed to initialize Serval keyring");
} else {
CHECK_ERR(serval_extract_sas(&key,NULL,keyring,packedSid),"Failed to fetch SAS key");
}
CHECK_ERR(serval_create_signature(key, msg, msg_len, signed_msg, SIGNATURE_BYTES + msg_len),"Failed to create signature");
strncpy(sig_str_buf,alloca_tohex(signed_msg + msg_len,SIGNATURE_BYTES),2*SIGNATURE_BYTES);
sig_str_buf[2*SIGNATURE_BYTES] = '\0';
ret = 1;
error:
if (_keyring) keyring_free(_keyring);
return ret;
}
int serval_sign(const char *sid,
const size_t sid_len,
const unsigned char *msg,
const size_t msg_len,
char *sig_buffer,
const size_t sig_size,
const char *keyringName,
const size_t keyring_len) {
keyring_identity *new_ident;
char keyringFile[1024];
assert(msg_len);
if (sid) assert(sid_len == 2*SID_SIZE);
if (keyringName == NULL || keyring_len == 0) {
FORM_SERVAL_INSTANCE_PATH(keyringFile, "serval.keyring"); // if no keyring specified, use default keyring
}
else { // otherwise, use specified keyring (NOTE: if keyring does not exist, it will be created)
strncpy(keyringFile,keyringName,keyring_len);
keyringFile[keyring_len] = '\0';
}
keyring = keyring_open(keyringFile);
keyring_enter_pin(keyring, KEYRING_PIN); // unlocks Serval keyring for using identities (also initializes global default identity my_subscriber)
if (!sid) {
//create new sid
int c;
for(c=0;c<keyring->context_count;c++) { // cycle through the keyring contexts until we find one with room for another identity
new_ident = keyring_create_identity(keyring,keyring->contexts[c], KEYRING_PIN); // create new Serval identity
if (new_ident)
break;
}
if (!new_ident) {
fprintf(stderr, "failed to create new SID\n");
return 1;
}
if (keyring_commit(keyring)) { // need to commit keyring or else new identity won't be saved (needs root permissions)
fprintf(stderr, "Failed to save new SID into keyring...make sure you are running as root!\n");
return 1;
}
sid = alloca_tohex_sid(new_ident->subscriber->sid); // convert SID from binary to hex
} else {
if (!str_is_subscriber_id(sid)) {
fprintf(stderr,"Invalid SID\n");
return 1;
}
}
unsigned char packedSid[SID_SIZE];
stowSid(packedSid,0,sid);
unsigned char *key=keyring_find_sas_private(keyring, packedSid, NULL); // get SAS key associated with our SID
if (!key)
return 1;
unsigned char hash[crypto_hash_sha512_BYTES];
unsigned long long sig_length = SIGNATURE_BYTES;
crypto_hash_sha512(hash, msg, msg_len); // create sha512 hash of message, which will then be signed
unsigned char signed_msg[msg_len + sig_length];
memcpy(signed_msg,msg,msg_len);
int ret = crypto_create_signature(key, hash, crypto_hash_sha512_BYTES, &signed_msg[msg_len], &sig_length); // create signature of message hash, append it to end of message
if (!ret) { //success
printf("%s\n", alloca_tohex(signed_msg + msg_len, sig_length));
printf("%s\n",sid);
if (sig_size > 0) {
if (sig_size >= 2*sig_length + 1) {
strncpy(sig_buffer,alloca_tohex(signed_msg + msg_len,sig_length),2*sig_length);
sig_buffer[2*sig_length] = '\0';
} else
fprintf(stderr,"Insufficient signature buffer size\n");
}
}
keyring_free(keyring);
return ret;
}
/*
Open keyring file, read BAM and create initial context using the
stored salt. */
keyring_file *keyring_open(char *file)
{
/* Allocate structure */
keyring_file *k=calloc(sizeof(keyring_file),1);
if (!k) {
WHY_perror("calloc");
return NULL;
}
/* Open keyring file read-write if we can, else use it read-only */
k->file=fopen(file,"r+");
if (!k->file) k->file=fopen(file,"r");
if (!k->file) k->file=fopen(file,"w+");
if (!k->file) {
WHY_perror("fopen");
WHYF("Could not open keyring file %s", file);
keyring_free(k);
return NULL;
}
if (fseeko(k->file,0,SEEK_END)) {
WHY_perror("fseeko");
WHYF("Could not seek to end of keyring file %s", file);
keyring_free(k);
return NULL;
}
k->file_size=ftello(k->file);
if (k->file_size<KEYRING_PAGE_SIZE) {
/* Uninitialised, so write 2KB of zeroes,
followed by 2KB of random bytes as salt. */
if (fseeko(k->file,0,SEEK_SET)) {
WHY_perror("fseeko");
WHYF("Could not seek to start of keyring file %s", file);
keyring_free(k);
return NULL;
}
unsigned char buffer[KEYRING_PAGE_SIZE];
bzero(&buffer[0],KEYRING_BAM_BYTES);
if (fwrite(&buffer[0],2048,1,k->file)!=1) {
WHY_perror("fwrite");
WHYF("Could not write empty bitmap in fresh keyring file %s", file);
keyring_free(k);
return NULL;
}
if (urandombytes(&buffer[0],KEYRING_PAGE_SIZE-KEYRING_BAM_BYTES)) {
WHYF("Could not get random keyring salt to put in fresh keyring file %s", file);
keyring_free(k);
return NULL;
}
if (fwrite(&buffer[0],KEYRING_PAGE_SIZE-KEYRING_BAM_BYTES,1,k->file) != 1) {
WHY_perror("fwrite");
WHYF("Could not write keyring salt in fresh keyring file %s", file);
keyring_free(k);
return NULL;
}
k->file_size=KEYRING_PAGE_SIZE;
}
/* Read BAMs for each slab in the file */
keyring_bam **b=&k->bam;
off_t offset=0;
while(offset<k->file_size) {
/* Read bitmap from slab.
Also, if offset is zero, read the salt */
if (fseeko(k->file,offset,SEEK_SET)) {
WHY_perror("fseeko");
WHYF("Could not seek to BAM in keyring file %s", file);
keyring_free(k);
return NULL;
}
*b=calloc(sizeof(keyring_bam),1);
if (!(*b)) {
WHY_perror("calloc");
WHYF("Could not allocate keyring_bam structure for key ring file %s", file);
keyring_free(k);
return NULL;
}
(*b)->file_offset=offset;
/* Read bitmap */
int r=fread(&(*b)->bitmap[0],KEYRING_BAM_BYTES,1,k->file);
if (r!=1) {
WHY_perror("fread");
WHYF("Could not read BAM from keyring file %s", file);
keyring_free(k);
return NULL;
}
/* Read salt if this is the first bitmap block.
We setup a context for this self-supplied key-ring salt.
(other keyring salts may be provided later on, resulting in
multiple contexts being loaded) */
if (!offset) {
k->contexts[0]=calloc(sizeof(keyring_context),1);
if (!k->contexts[0]) {
WHY_perror("calloc");
WHYF("Could not allocate keyring_context for keyring file %s", file);
keyring_free(k);
return NULL;
}
k->contexts[0]->KeyRingPin=strdup(""); /* Implied empty PIN if none provided */
k->contexts[0]->KeyRingSaltLen=KEYRING_PAGE_SIZE-KEYRING_BAM_BYTES;
k->contexts[0]->KeyRingSalt=malloc(k->contexts[0]->KeyRingSaltLen);
if (!k->contexts[0]->KeyRingSalt) {
WHY_perror("malloc");
WHYF("Could not allocate keyring_context->salt for keyring file %s", file);
keyring_free(k);
return NULL;
}
r=fread(&k->contexts[0]->KeyRingSalt[0],k->contexts[0]->KeyRingSaltLen,1,k->file);
if (r!=1) {
WHY_perror("fread");
WHYF("Could not read salt from keyring file %s", file);
keyring_free(k);
return NULL;
}
k->context_count=1;
}
/* Skip to next slab, and find next bam pointer. */
offset+=KEYRING_PAGE_SIZE*(KEYRING_BAM_BYTES<<3);
b=&(*b)->next;
}
return k;
}
