dropbear/sk-ecdsa.c

64 lines
1.7 KiB
C

#include "includes.h"
#if DROPBEAR_SK_ECDSA
#include "dbutil.h"
#include "ecc.h"
#include "ecdsa.h"
#include "sk-ecdsa.h"
#include "ssh.h"
int buf_sk_ecdsa_verify(buffer *buf, const ecc_key *key, const buffer *data_buf,
const char* app, unsigned int applen,
unsigned char sk_flags_mask) {
hash_state hs;
unsigned char subhash[SHA256_HASH_SIZE];
buffer *sk_buffer = NULL, *sig_buffer = NULL;
unsigned char flags;
unsigned int counter;
int ret;
TRACE(("buf_sk_ecdsa_verify"))
/* from https://github.com/openssh/openssh-portable/blob/master/PROTOCOL.u2f */
/* ecdsa signature to verify (r, s) */
sig_buffer = buf_getbuf(buf);
flags = buf_getbyte (buf);
counter = buf_getint (buf);
/* create the message to be signed */
sk_buffer = buf_new (2*SHA256_HASH_SIZE+5);
sha256_init (&hs);
sha256_process (&hs, app, applen);
sha256_done (&hs, subhash);
buf_putbytes (sk_buffer, subhash, sizeof (subhash));
buf_putbyte (sk_buffer, flags);
buf_putint (sk_buffer, counter);
sha256_init (&hs);
sha256_process (&hs, data_buf->data, data_buf->len);
sha256_done (&hs, subhash);
buf_putbytes (sk_buffer, subhash, sizeof (subhash));
ret = buf_ecdsa_verify(sig_buffer, key, sk_buffer);
buf_free(sk_buffer);
buf_free(sig_buffer);
if (~flags & sk_flags_mask & SSH_SK_USER_PRESENCE_REQD) {
if (ret == DROPBEAR_SUCCESS) {
dropbear_log(LOG_WARNING, "Rejecting, user-presence not set");
}
ret = DROPBEAR_FAILURE;
}
if (~flags & sk_flags_mask & SSH_SK_USER_VERIFICATION_REQD) {
if (ret == DROPBEAR_SUCCESS) {
dropbear_log(LOG_WARNING, "Rejecting, user-verification not set");
}
ret = DROPBEAR_FAILURE;
}
TRACE(("leave buf_sk_ecdsa_verify, ret=%d", ret))
return ret;
}
#endif /* DROPBEAR_SK_ECDSA */