From 0a80ca190a39943029719facf7edb990def7ae62 Mon Sep 17 00:00:00 2001
From: Damien Miller <djm@mindrot.org>
Date: Sat, 27 Feb 2010 07:55:05 +1100
Subject:  - OpenBSD CVS Sync    - djm@cvs.openbsd.org 2010/02/26 20:29:54     
 [PROTOCOL PROTOCOL.agent PROTOCOL.certkeys addrmatch.c auth-options.c]     
 [auth-options.h auth.h auth2-pubkey.c authfd.c dns.c dns.h hostfile.c]     
 [hostfile.h kex.h kexdhs.c kexgexs.c key.c key.h match.h monitor.c]     
 [myproposal.h servconf.c servconf.h ssh-add.c ssh-agent.c ssh-dss.c]     
 [ssh-keygen.1 ssh-keygen.c ssh-rsa.c ssh.1 ssh.c ssh2.h sshconnect.c]     
 [sshconnect2.c sshd.8 sshd.c sshd_config.5]      Add support for certificate
 key types for users and hosts.

     OpenSSH certificate key types are not X.509 certificates, but a much
     simpler format that encodes a public key, identity information and
     some validity constraints and signs it with a CA key. CA keys are
     regular SSH keys. This certificate style avoids the attack surface
     of X.509 certificates and is very easy to deploy.

     Certified host keys allow automatic acceptance of new host keys
     when a CA certificate is marked as sh/known_hosts.
     see VERIFYING HOST KEYS in ssh(1) for details.

     Certified user keys allow authentication of users when the signing
     CA key is marked as trusted in authorized_keys. See "AUTHORIZED_KEYS
     FILE FORMAT" in sshd(8) for details.

     Certificates are minted using ssh-keygen(1), documentation is in
     the "CERTIFICATES" section of that manpage.

     Documentation on the format of certificates is in the file
     PROTOCOL.certkeys

     feedback and ok markus@
---
 addrmatch.c | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 77 insertions(+), 1 deletion(-)

(limited to 'addrmatch.c')

diff --git a/addrmatch.c b/addrmatch.c
index d39885b7..5b6773cc 100644
--- a/addrmatch.c
+++ b/addrmatch.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: addrmatch.c,v 1.4 2008/12/10 03:55:20 stevesk Exp $ */
+/*	$OpenBSD: addrmatch.c,v 1.5 2010/02/26 20:29:54 djm Exp $ */
 
 /*
  * Copyright (c) 2004-2008 Damien Miller <djm@mindrot.org>
@@ -126,6 +126,8 @@ addr_netmask(int af, u_int l, struct xaddr *n)
 	switch (af) {
 	case AF_INET:
 		n->af = AF_INET;
+		if (l == 0)
+			return 0;
 		n->v4.s_addr = htonl((0xffffffff << (32 - l)) & 0xffffffff);
 		return 0;
 	case AF_INET6:
@@ -422,3 +424,77 @@ addr_match_list(const char *addr, const char *_list)
 
 	return ret;
 }
+
+/*
+ * Match "addr" against list CIDR list "_list". Lexical wildcards and
+ * negation are not supported. If "addr" == NULL, will verify structure
+ * of "_list".
+ *
+ * Returns 1 on match found (never returned when addr == NULL).
+ * Returns 0 on if no match found, or no errors found when addr == NULL.
+ * Returns -1 on error
+ */
+int
+addr_match_cidr_list(const char *addr, const char *_list)
+{
+	char *list, *cp, *o;
+	struct xaddr try_addr, match_addr;
+	u_int masklen;
+	int ret = 0, r;
+
+	if (addr != NULL && addr_pton(addr, &try_addr) != 0) {
+		debug2("%s: couldn't parse address %.100s", __func__, addr);
+		return 0;
+	}
+	if ((o = list = strdup(_list)) == NULL)
+		return -1;
+	while ((cp = strsep(&list, ",")) != NULL) {
+		if (*cp == '\0') {
+			error("%s: empty entry in list \"%.100s\"",
+			    __func__, o);
+			ret = -1;
+			break;
+		}
+
+		/*
+		 * NB. This function is called in pre-auth with untrusted data,
+		 * so be extra paranoid about junk reaching getaddrino (via
+		 * addr_pton_cidr).
+		 */
+
+		/* Stop junk from reaching getaddrinfo. +3 is for masklen */
+		if (strlen(cp) > INET6_ADDRSTRLEN + 3) {
+			error("%s: list entry \"%.100s\" too long",
+			    __func__, cp);
+			ret = -1;
+			break;
+		}
+#define VALID_CIDR_CHARS "0123456789abcdefABCDEF.:/"
+		if (strspn(cp, VALID_CIDR_CHARS) != strlen(cp)) {
+			error("%s: list entry \"%.100s\" contains invalid "
+			    "characters", __func__, cp);
+			ret = -1;
+		}
+
+		/* Prefer CIDR address matching */
+		r = addr_pton_cidr(cp, &match_addr, &masklen);
+		if (r == -1) {
+			error("Invalid network entry \"%.100s\"", cp);
+			ret = -1;
+			break;
+		} else if (r == -2) {
+			error("Inconsistent mask length for "
+			    "network \"%.100s\"", cp);
+			ret = -1;
+			break;
+		} else if (r == 0 && addr != NULL) {
+			if (addr_netmatch(&try_addr, &match_addr,
+			    masklen) == 0)
+				ret = 1;
+			continue;
+		}
+	}
+	xfree(o);
+
+	return ret;
+}
-- 
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