use libc base64 code instead of libcrypt for ifconfig wg key handling

[David Gwynne]

libc has undocumented base64 encoding and decoding funtionality. this
cuts ifconfig over to using it instead of the code in libcrypto.

whether the libc functionality should be "blessed" and documented is a
separate issue.

ok?

Index: Makefile
===================================================================
RCS file: /cvs/src/sbin/ifconfig/Makefile,v
retrieving revision 1.16
diff -u -p -r1.16 Makefile
--- Makefile    21 Jun 2020 12:20:06 -0000      1.16
+++ Makefile    21 Jun 2020 23:15:34 -0000
@@ -4,7 +4,7 @@ PROG=   ifconfig
 SRCS=  ifconfig.c brconfig.c sff.c
 MAN=   ifconfig.8
 
-LDADD= -lutil -lm -lcrypto
+LDADD= -lutil -lm
 DPADD= ${LIBUTIL}
 
 .include <bsd.prog.mk>
Index: ifconfig.c
===================================================================
RCS file: /cvs/src/sbin/ifconfig/ifconfig.c,v
retrieving revision 1.422
diff -u -p -r1.422 ifconfig.c
--- ifconfig.c  21 Jun 2020 12:20:06 -0000      1.422
+++ ifconfig.c  21 Jun 2020 23:15:35 -0000
@@ -5673,14 +5673,12 @@ setifpriority(const char *id, int param)
  * space.
  */
 #define WG_BASE64_KEY_LEN (4 * ((WG_KEY_LEN + 2) / 3))
-#define WG_TMP_KEY_LEN (WG_BASE64_KEY_LEN / 4 * 3)
 #define WG_LOAD_KEY(dst, src, fn_name) do {                            \
-       uint8_t _tmp[WG_TMP_KEY_LEN];                                   \
+       uint8_t _tmp[WG_KEY_LEN]; int _r;                               \
        if (strlen(src) != WG_BASE64_KEY_LEN)                           \
                errx(1, fn_name " (key): invalid length");              \
-       if (EVP_DecodeBlock(_tmp, src,                                  \
-           WG_BASE64_KEY_LEN) != WG_TMP_KEY_LEN)                       \
-               errx(1, fn_name " (key): invalid base64");              \
+       if ((_r = b64_pton(src, _tmp, sizeof(_tmp))) != sizeof(_tmp))           
\
+               errx(1, fn_name " (key): invalid base64 %d/%zu", _r, 
sizeof(_tmp));             \
        memcpy(dst, _tmp, WG_KEY_LEN);                                  \
 } while (0)
 
@@ -5899,13 +5897,15 @@ wg_status(void)
        if (wg_interface->i_flags & WG_INTERFACE_HAS_RTABLE)
                printf("\twgrtable %d\n", wg_interface->i_rtable);
        if (wg_interface->i_flags & WG_INTERFACE_HAS_PUBLIC) {
-               EVP_EncodeBlock(key, wg_interface->i_public, WG_KEY_LEN);
+               b64_ntop(wg_interface->i_public, WG_KEY_LEN,
+                   key, sizeof(key));
                printf("\twgpubkey %s\n", key);
        }
 
        wg_peer = &wg_interface->i_peers[0];
        for (i = 0; i < wg_interface->i_peers_count; i++) {
-               EVP_EncodeBlock(key, wg_peer->p_public, WG_KEY_LEN);
+               b64_ntop(wg_peer->p_public, WG_KEY_LEN,
+                   key, sizeof(key));
                printf("\twgpeer %s\n", key);
 
                if (wg_peer->p_flags & WG_PEER_HAS_PSK)