fix some gcc warnings (#73) * tweak string size fix gcc8 warnings ``` svr-agentfwd.c: In function 'bindagent': svr-agentfwd.c:254:53: warning: '%s' directive output may be truncated writing up to 107 bytes into a region of size between 0 and 107 [-Wformat-truncation=] snprintf(addr.sun_path, sizeof(addr.sun_path), "%s/%s", path, sockfile); ^~ ~~~~~~~~ svr-agentfwd.c:254:2: note: 'snprintf' output between 2 and 216 bytes into a destination of size 108 snprintf(addr.sun_path, sizeof(addr.sun_path), "%s/%s", path, sockfile); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ``` * cleanup signed/unsigned comparison fix gcc8 warnings ``` scp.c: In function 'do_local_cmd': scp.c:132:17: warning: comparison of integer expressions of different signedness: 'u_int' {aka 'unsigned int'} and 'int' [-Wsign-compare] for (i = 0; i < a->num; i++) ^ scpmisc.c: In function 'addargs': scpmisc.c:161:25: warning: comparison of integer expressions of different signedness: 'int' and 'u_int' {aka 'unsigned int'} [-Wsign-compare] } else if (args->num+2 >= nalloc) ^~ scpmisc.c: In function 'replacearg': scpmisc.c:183:12: warning: comparison of integer expressions of different signedness: 'u_int' {aka 'unsigned int'} and 'int' [-Wsign-compare] if (which >= args->num) ^~ scpmisc.c: In function 'freeargs': scpmisc.c:196:17: warning: comparison of integer expressions of different signedness: 'u_int' {aka 'unsigned int'} and 'int' [-Wsign-compare] for (i = 0; i < args->num; i++) ^ ``` see https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/misc.h.diff?r1=1.16&r2=1.17

#ifndef DROPBEAR_ECDSA_H_
#define DROPBEAR_ECDSA_H_

#include "includes.h"
#include "buffer.h"
#include "signkey.h"

#if DROPBEAR_ECDSA

/* prefer 256 or 384 since those are SHOULD for
   draft-ietf-curdle-ssh-kex-sha2.txt */
#if DROPBEAR_ECC_256
#define ECDSA_DEFAULT_SIZE 256
#elif DROPBEAR_ECC_384
#define ECDSA_DEFAULT_SIZE 384
#elif DROPBEAR_ECC_521
#define ECDSA_DEFAULT_SIZE 521
#else
#error ECDSA cannot be enabled without enabling at least one size (256, 384, 521)
#endif

ecc_key *gen_ecdsa_priv_key(unsigned int bit_size);
ecc_key *buf_get_ecdsa_pub_key(buffer* buf);
ecc_key *buf_get_ecdsa_priv_key(buffer *buf);
void buf_put_ecdsa_pub_key(buffer *buf, ecc_key *key);
void buf_put_ecdsa_priv_key(buffer *buf, ecc_key *key);
enum signkey_type ecdsa_signkey_type(const ecc_key * key);

void buf_put_ecdsa_sign(buffer *buf, const ecc_key *key, const buffer *data_buf);
int buf_ecdsa_verify(buffer *buf, const ecc_key *key, const buffer *data_buf);
/* Returns 1 on success */
int signkey_is_ecdsa(enum signkey_type type);

#endif

#endif /* DROPBEAR_ECDSA_H_ */