libsec: sha256 support for thumbprint files, use it in ssh as well

initThumbprints() now takes an application tag argument
so x509 and ssh can coexist.

the thumbprint entries can now hold both sha1 and sha256
hashes. okThumbprint() now takes a len argument for the
hash length used.

the new function okCertificate() hashes the certificate
with both and checks for any matches.

on failure, okCertificate() returns 0 and sets error string.

we also check for include loops now in thumbfiles, limiting
the number of includes to 8.

1 files changed, 12 insertions, 45 deletions

diff --git a/sys/src/cmd/ssh.c b/sys/src/cmd/ssh.c
index a635dd546..e4e1f3e89 100644
--- a/sys/src/cmd/ssh.c
+++ b/sys/src/cmd/ssh.c
@@ -4,7 +4,6 @@
 #include <libsec.h>
 #include <auth.h>
 #include <authsrv.h>
-#include <bio.h>
 
 enum {
 	MSG_DISCONNECT = 1,
@@ -84,7 +83,6 @@ char *user, *service, *status, *host, *cmd;
 
 Oneway recv, send;
 void dispatch(void);
-int checkthumb(char*, uchar*);
 
 void
 shutdown(void)
@@ -580,22 +578,25 @@ Next1:	switch(recvpkt()){
 	ds = hashstr(ys, 32, ds);
 
 	if(thumb[0] == 0){
+		Thumbprint *ok;
+
 		sha2_256(ks, nks, h, nil);
-		i = snprint(thumb, sizeof(thumb), "%.*[", sizeof(h), h);
+		i = enc64(thumb, sizeof(thumb), h, sizeof(h));
 		while(i > 0 && thumb[i-1] == '=')
-			thumb[--i] = '\0';
+			i--;
+		thumb[i] = '\0';
+
 		if(debug)
 			fprint(2, "host fingerprint: %s\n", thumb);
-		switch(checkthumb(thumbfile, h)){
-		case 0:
-			werrstr("host unknown");
-		default:
+
+		ok = initThumbprints(thumbfile, nil, "ssh");
+		if(ok == nil || !okThumbprint(h, sizeof(h), ok)){
+			if(ok != nil) werrstr("unknown host");
 			fprint(2, "%s: %r, to add after verification:\n", argv0);
-			fprint(2, "\techo 'ssh sha256=%s # %s' >> %q\n", thumb, host, thumbfile);
+			fprint(2, "\techo 'ssh sha256=%s server=%s' >> %q\n", thumb, host, thumbfile);
 			sysfatal("checking hostkey failed: %r");
-		case 1:
-			break;
 		}
+		freeThumbprints(ok);
 	}
 
 	if((pub = ssh2rsapub(ks, nks)) == nil)
@@ -1074,39 +1075,6 @@ rawon(void)
 	}
 }
 
-int
-checkthumb(char *file, uchar hash[SHA2_256dlen])
-{
-	uchar sum[SHA2_256dlen];
-	char *line, *field[50];
-	Biobuf *bin;
-
-	if((bin = Bopen(file, OREAD)) == nil)
-		return -1;
-	for(; (line = Brdstr(bin, '\n', 1)) != nil; free(line)){
-		if(tokenize(line, field, nelem(field)) < 2)
-			continue;
-		if(strcmp(field[0], "ssh") != 0 || strncmp(field[1], "sha256=", 7) != 0)
-			continue;
-		field[1] += 7;
-		if(dec64(sum, SHA2_256dlen, field[1], strlen(field[1])) != SHA2_256dlen){
-			werrstr("malformed ssh entry in %s: %s", file, field[1]);
-			goto err;
-		}
-		if(memcmp(sum, hash, SHA2_256dlen) == 0){
-			free(line);
-			Bterm(bin);
-			return 1;
-		}
-	}
-	Bterm(bin);
-	return 0;
-err:
-	free(line);
-	Bterm(bin);
-	return -1;
-}
-
 void
 usage(void)
 {
@@ -1124,7 +1092,6 @@ main(int argc, char *argv[])
 	quotefmtinstall();
 	fmtinstall('B', mpfmt);
 	fmtinstall('H', encodefmt);
-	fmtinstall('[', encodefmt);
 
 	s = getenv("TERM");
 	raw = s != nil && strcmp(s, "dumb") != 0;