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net/mpls: Implement handler for strict data checking on dumps

PATCH Applied David Ahern 2 participants 2 messages Oct 10, 2018 – Oct 11, 2018

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David Ahern

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#0 lore raw

PATCH 1/1 net/mpls: Implement handler for strict data checking on dumps

From: David Ahern <[email protected]>

Without CONFIG_INET enabled compiles fail with:

net/mpls/af_mpls.o: In function `mpls_dump_routes':
af_mpls.c:(.text+0xed0): undefined reference to `ip_valid_fib_dump_req'

The preference is for MPLS to use the same handler as ipv4 and ipv6 to allow consistency when doing a dump for AF_UNSPEC which walks all address families invoking the route dump handler. If INET is disabled then fallback to an MPLS version which can be tighter on the data checks.

Fixes e8ba330ac0c5 ("rtnetlink: Update fib dumps for strict data checking")
Reported-by Randy Dunlap <[email protected]>
Reported-by Arnd Bergmann <[email protected]>
Signed-off-by David Ahern <[email protected]>
---
 net/mpls/af_mpls.c | 36 +++++++++++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)
net/mpls/af_mpls.c +35 -1
index 7f891ffffc05..5fe274c47c41 100644
@@ -2031,6 +2031,40 @@ static int mpls_dump_route(struct sk_buff *skb, u32 portid, u32 seq, int event,
 	return -EMSGSIZE;
 }
 
+#if IS_ENABLED(CONFIG_INET)
+static int mpls_valid_fib_dump_req(const struct nlmsghdr *nlh,
+				   struct netlink_ext_ack *extack)
+{
+	return ip_valid_fib_dump_req(nlh, extack);
+}
+#else
+static int mpls_valid_fib_dump_req(const struct nlmsghdr *nlh,
+				   struct netlink_ext_ack *extack)
+{
+	struct rtmsg *rtm;
+
+	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
+		NL_SET_ERR_MSG_MOD(extack, "Invalid header for FIB dump request");
+		return -EINVAL;
+	}
+
+	rtm = nlmsg_data(nlh);
+	if (rtm->rtm_dst_len || rtm->rtm_src_len  || rtm->rtm_tos   ||
+	    rtm->rtm_table   || rtm->rtm_protocol || rtm->rtm_scope ||
+	    rtm->rtm_type    || rtm->rtm_flags) {
+		NL_SET_ERR_MSG_MOD(extack, "Invalid values in header for FIB dump request");
+		return -EINVAL;
+	}
+
+	if (nlmsg_attrlen(nlh, sizeof(*rtm))) {
+		NL_SET_ERR_MSG_MOD(extack, "Invalid data after header in FIB dump request");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+#endif
+
 static int mpls_dump_routes(struct sk_buff *skb, struct netlink_callback *cb)
 {
 	const struct nlmsghdr *nlh = cb->nlh;

@@ -2042,7 +2076,7 @@ static int mpls_dump_routes(struct sk_buff *skb, struct netlink_callback *cb)
 	ASSERT_RTNL();
 
 	if (cb->strict_check) {
-		int err = ip_valid_fib_dump_req(nlh, cb->extack);
+		int err = mpls_valid_fib_dump_req(nlh, cb->extack);
 
 		if (err < 0)
 			return err;
Signature · 1 line
2.11.0
maintainer Applied
#1 lore raw

From: David Ahern <[email protected]>
Date: Tue, 9 Oct 2018 11:10:43 -0700

Quoted 13 lines

From: David Ahern <[email protected]>

Without CONFIG_INET enabled compiles fail with:

net/mpls/af_mpls.o: In function `mpls_dump_routes':
af_mpls.c:(.text+0xed0): undefined reference to `ip_valid_fib_dump_req'

The preference is for MPLS to use the same handler as ipv4 and ipv6 to allow consistency when doing a dump for AF_UNSPEC which walks all address families invoking the route dump handler. If INET is disabled then fallback to an MPLS version which can be tighter on the data checks.

Quoted 4 lines
Fixes e8ba330ac0c5 ("rtnetlink: Update fib dumps for strict data checking")
Reported-by Randy Dunlap <[email protected]>
Reported-by Arnd Bergmann <[email protected]>
Signed-off-by David Ahern <[email protected]>

Applied.