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

#include "includes.h"
#include "dbutil.h"
#include "crypto_desc.h"
#include "ltc_prng.h"
#include "ecc.h"

#if DROPBEAR_LTC_PRNG
	int dropbear_ltc_prng = -1;
#endif


/* Register the compiled in ciphers.
 * This should be run before using any of the ciphers/hashes */
void crypto_init() {

	const struct ltc_cipher_descriptor *regciphers[] = {
#if DROPBEAR_AES
		&aes_desc,
#endif
#if DROPBEAR_BLOWFISH
		&blowfish_desc,
#endif
#if DROPBEAR_TWOFISH
		&twofish_desc,
#endif
#if DROPBEAR_3DES
		&des3_desc,
#endif
		NULL
	};

	const struct ltc_hash_descriptor *reghashes[] = {
		/* we need sha1 for hostkey stuff regardless */
		&sha1_desc,
#if DROPBEAR_MD5_HMAC
		&md5_desc,
#endif
#if DROPBEAR_SHA256
		&sha256_desc,
#endif
#if DROPBEAR_SHA384
		&sha384_desc,
#endif
#if DROPBEAR_SHA512
		&sha512_desc,
#endif
		NULL
	};	
	int i;
	
	for (i = 0; regciphers[i] != NULL; i++) {
		if (register_cipher(regciphers[i]) == -1) {
			dropbear_exit("Error registering crypto");
		}
	}

	for (i = 0; reghashes[i] != NULL; i++) {
		if (register_hash(reghashes[i]) == -1) {
			dropbear_exit("Error registering crypto");
		}
	}

#if DROPBEAR_LTC_PRNG
	dropbear_ltc_prng = register_prng(&dropbear_prng_desc);
	if (dropbear_ltc_prng == -1) {
		dropbear_exit("Error registering crypto");
	}
#endif

#if DROPBEAR_ECC
	ltc_mp = ltm_desc;
	dropbear_ecc_fill_dp();
#endif
}