From 58c939e2991b4610f5712a97ad9ee99af0aa1541 Mon Sep 17 00:00:00 2001
From: David Gwynne <dlg@cvs.openbsd.org>
Date: Mon, 17 Jul 2017 06:32:54 +0000
Subject: add support for binary sysctl payloads by handling them as hex
 strings.

this was part of a demo showing how to implement the kernel side of
sysctl(3) for setting Semantically Opaque Interface Identifier key
material, but it seems to be the most straightforward path toward
integrating soiikey handling and rc.

ok florian@ sthen@ naddy@ tb@
---
 sbin/sysctl/sysctl.c | 107 +++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 100 insertions(+), 7 deletions(-)

(limited to 'sbin')

diff --git a/sbin/sysctl/sysctl.c b/sbin/sysctl/sysctl.c
index 94f78c0d673..39588ee6516 100644
--- a/sbin/sysctl/sysctl.c
+++ b/sbin/sysctl/sysctl.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sysctl.c,v 1.226 2017/04/25 17:33:16 tb Exp $	*/
+/*	$OpenBSD: sysctl.c,v 1.227 2017/07/17 06:32:53 dlg Exp $	*/
 /*	$NetBSD: sysctl.c,v 1.9 1995/09/30 07:12:50 thorpej Exp $	*/
 
 /*
@@ -182,6 +182,8 @@ int	Aflag, aflag, nflag, qflag;
 /* prototypes */
 void debuginit(void);
 void listall(char *, struct list *);
+int parse_hex_char(char);
+ssize_t parse_hex_string(unsigned char *, size_t, const char *);
 void parse(char *, int);
 void parse_baddynamic(int *, size_t, char *, void **, size_t *, int, int);
 void usage(void);
@@ -286,6 +288,53 @@ listall(char *prefix, struct list *lp)
 	}
 }
 
+int
+parse_hex_char(char ch)
+{
+	if (ch >= '0' && ch <= '9')
+		return (ch - '0');
+
+	ch = tolower(ch);
+	if (ch >= 'a' && ch <= 'f')
+		return (ch - 'a' + 10);
+
+	return (-1);
+}
+
+ssize_t
+parse_hex_string(unsigned char *dst, size_t dstlen, const char *src)
+{
+	ssize_t len = 0;
+	int digit;
+
+	while (len < dstlen) {
+		if (*src == '\0')
+			return (len);
+
+		digit = parse_hex_char(*src++);
+		if (digit == -1)
+			return (-1);
+		dst[len] = digit << 4;
+
+		digit = parse_hex_char(*src++);
+		if (digit == -1)
+			return (-1);
+		
+		dst[len] |= digit;
+		len++;
+	}
+
+	while (*src != '\0') {
+		if (parse_hex_char(*src++) == -1 ||
+		    parse_hex_char(*src++) == -1)
+			return (-1);
+
+		len++;
+	}
+
+	return (len);
+}
+
 /*
  * Parse a name into a MIB entry.
  * Lookup and print out the MIB entry if it exists.
@@ -302,6 +351,7 @@ parse(char *string, int flags)
 	struct list *lp;
 	int mib[CTL_MAXNAME];
 	char *cp, *bufp, buf[SYSCTL_BUFSIZ];
+	unsigned char hex[SYSCTL_BUFSIZ];
 
 	(void)strlcpy(buf, string, sizeof(buf));
 	bufp = buf;
@@ -566,6 +616,11 @@ parse(char *string, int flags)
 			len = sysctl_inet6(string, &bufp, mib, flags, &type);
 			if (len < 0)
 				return;
+#ifdef IPV6CTL_SOIIKEY
+			if (mib[2] == IPPROTO_IPV6 &&
+			    mib[3] == IPV6CTL_SOIIKEY)
+				special |= HEX;
+#endif
 
 			if ((mib[2] == IPPROTO_IPV6 && mib[3] == IPV6CTL_MRTMFC) ||
 			    (mib[2] == IPPROTO_IPV6 && mib[3] == IPV6CTL_MRTMIF) ||
@@ -717,6 +772,27 @@ parse(char *string, int flags)
 			newval = &quadval;
 			newsize = sizeof(quadval);
 			break;
+		case CTLTYPE_STRING:
+			if (special & HEX) {
+				ssize_t len;
+
+				len = parse_hex_string(hex, sizeof(hex),
+				    newval);
+				if (len == -1) {
+					warnx("%s: hex string %s: invalid",
+					    string, newval);
+					return;
+				}
+				if (len > sizeof(hex)) {
+					warnx("%s: hex string %s: too long",
+					    string, newval);
+					return;
+				}
+
+				newval = hex;
+				newsize = len;
+			}
+			break;
 		}
 	}
 	size = (special & SMALLBUF) ? 512 : SYSCTL_BUFSIZ;
@@ -936,13 +1012,30 @@ parse(char *string, int flags)
 		if (newval == NULL) {
 			if (!nflag)
 				(void)printf("%s%s", string, equ);
-			(void)puts(buf);
-		} else {
-			if (!qflag) {
-				if (!nflag)
-					(void)printf("%s: %s -> ", string, buf);
-				(void)puts((char *)newval);
+			if (special & HEX) {
+				size_t i;
+				for (i = 0; i < size; i++) {
+					(void)printf("%02x",
+					    (unsigned char)buf[i]);
+				}
+				(void)printf("\n");
+			} else
+				(void)puts(buf);
+		} else if (!qflag) {
+			if (!nflag) {
+				(void)printf("%s: ", string);
+				if (special & HEX) {
+					size_t i;
+					for (i = 0; i < size; i++) {
+						(void)printf("%02x",
+						    (unsigned char)buf[i]);
+					}
+				} else
+					(void)printf("%s", cp);
+
+				(void)printf(" -> ");
 			}
+			(void)puts(cp);
 		}
 		return;
 
-- 
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