libsec: add X509reqtoRSApub() function and return subject alt names in X509to*pub() name buffer

We need a way to parse a rsa certificate request and return the public
key and subject names. The new function X509reqtoRSApub() works the
same way as X509toRSApub() but on a certificate request.

We also need to support certificates that are valid for multiple domain
names (as tlshand does not support certificate selection). For this
reason, a comma separated list is returned as the certificate subject,
making it symmetric to X509rsareq() handling.

A little helper is provided with this change (auth/x5092pub) that takes
a certificate (or a certificate request when -r flag is provided) and
outputs the RSA public key in plan 9 format appended with the subject
attribute.

2 files changed, 64 insertions, 0 deletions

diff --git a/sys/src/cmd/auth/mkfile b/sys/src/cmd/auth/mkfile
index 833e257be..bf5dbff2d 100644
--- a/sys/src/cmd/auth/mkfile
+++ b/sys/src/cmd/auth/mkfile
@@ -35,6 +35,7 @@ TARG=\
 	userpasswd\
 	warning\
 	wrkey\
+	x5092pub\
 
 DIRS=\
 	factotum\
diff --git a/sys/src/cmd/auth/x5092pub.c b/sys/src/cmd/auth/x5092pub.c
new file mode 100644
index 000000000..2b9ef2067
--- /dev/null
+++ b/sys/src/cmd/auth/x5092pub.c
@@ -0,0 +1,63 @@
+#include <u.h>
+#include <libc.h>
+#include <bio.h>
+#include <auth.h>
+#include <mp.h>
+#include <libsec.h>
+
+int fd;
+int req = 0;
+char subject[1024];
+
+void
+usage(void)
+{
+	fprint(2, "usage: aux/x5092pub [-r] [file]\n");
+	exits("usage");
+}
+
+void
+main(int argc, char **argv)
+{
+	int tot, n;
+	uchar *buf;
+	RSApub *pub;
+
+	quotefmtinstall();
+	fmtinstall('B', mpfmt);
+	fmtinstall('H', encodefmt);
+
+	ARGBEGIN{
+	case 'r':
+		req = 1;
+		break;
+	default:
+		usage();
+	}ARGEND
+
+	fd = 0;
+	if(argc == 1)
+		fd = open(argv[0], OREAD);
+	else if(argc != 0)
+		usage();
+	buf = nil;
+	tot = 0;
+	for(;;){
+		buf = realloc(buf, tot+8192);
+		if(buf == nil)
+			sysfatal("realloc: %r");
+		if((n = read(fd, buf+tot, 8192)) < 0)
+			sysfatal("read: %r");
+		if(n == 0)
+			break;
+		tot += n;
+	}
+	if(req)
+		pub = X509reqtoRSApub(buf, tot, subject, sizeof(subject));
+	else
+		pub = X509toRSApub(buf, tot, subject, sizeof(subject));
+	if(pub == nil)
+		sysfatal("X509toRSApub: %r");
+	print("key proto=rsa size=%d ek=%B n=%B subject=%q \n", mpsignif(pub->n), pub->ek, pub->n, subject);
+	exits(nil);
+}