view sk-ed25519.c @ 1902:4a6725ac957c

Revert "Don't include sk keys at all in KEX list" This reverts git commit f972813ecdc7bb981d25b5a63638bd158f1c8e72. The sk algorithms need to remain in the sigalgs list so that they are included in the server-sig-algs ext-info message sent by the server. RFC8308 for server-sig-algs requires that all algorithms are listed (though OpenSSH client 8.4p1 tested doesn't require that)
author Matt Johnston <matt@ucc.asn.au>
date Thu, 24 Mar 2022 13:42:08 +0800
parents 35d504d59c05
children 333688ec53d0
line wrap: on
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#include "includes.h"

#if DROPBEAR_SK_ED25519

#include "dbutil.h"
#include "buffer.h"
#include "curve25519.h"
#include "ed25519.h"

int buf_sk_ed25519_verify(buffer *buf, const dropbear_ed25519_key *key, const buffer *data_buf, const char* app, unsigned int applen) {

	int ret = DROPBEAR_FAILURE;
	unsigned char *s;
	unsigned long slen;
	hash_state hs;
	unsigned char hash[SHA256_HASH_SIZE];
	buffer *sk_buffer = NULL;
	unsigned char flags;
	unsigned int counter;

	TRACE(("enter buf_sk_ed25519_verify"))
	dropbear_assert(key != NULL);

	slen = buf_getint(buf);
	if (slen != 64 || buf->len - buf->pos < slen) {
		TRACE(("leave buf_sk_ed25519_verify: bad size"))
		goto out;
	}
	s = buf_getptr(buf, slen);
	buf_incrpos(buf, slen);

	flags = buf_getbyte (buf);
	counter = buf_getint (buf);
	sk_buffer = buf_new (2*SHA256_HASH_SIZE+5);
	sha256_init (&hs);
	sha256_process (&hs, app, applen);
	sha256_done (&hs, hash);
	buf_putbytes (sk_buffer, hash, sizeof (hash));
	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, hash);
	buf_putbytes (sk_buffer, hash, sizeof (hash));

	if (dropbear_ed25519_verify(sk_buffer->data, sk_buffer->len,
				    s, slen, key->pub) == 0) {
		/* signature is valid */
		TRACE(("leave buf_sk_ed25519_verify: success!"))
		ret = DROPBEAR_SUCCESS;
	}

out:
	if (sk_buffer) {
		buf_free(sk_buffer);
	}
	TRACE(("leave buf_sk_ed25519_verify: ret %d", ret))
	return ret;
}

#endif /* DROPBEAR_SK_ED25519 */