git: ba169bddbc9d - stable/13 - ifconfig: Improve VLAN identifier parsing

The branch stable/13 has been updated by zlei:

URL: https://cgit.FreeBSD.org/src/commit/?id=ba169bddbc9da0dec833deb9cd274a68ec1bfd9c

commit ba169bddbc9da0dec833deb9cd274a68ec1bfd9c
Author:     Zhenlei Huang <zlei@FreeBSD.org>
AuthorDate: 2023-04-02 17:54:31 +0000
Commit:     Zhenlei Huang <zlei@FreeBSD.org>
CommitDate: 2023-04-10 04:15:05 +0000

    ifconfig: Improve VLAN identifier parsing
    
    VLAN identifier 0xFFF is reserved. It must not be configured or
    transmitted.
    
    Also validate during parsing to prevent potential integer overflow.
    
    Reviewed by:    #network, melifaro
    Fixes:          c7cffd65c5d85 Add support for stacked VLANs (IEEE 802.1ad, AKA Q-in-Q)
    MFC after:      1 week
    Differential Revision:  https://reviews.freebsd.org/D39282
    
    (cherry picked from commit 28b498e65ab40975ea12393498bacd6249b7204c)
---
 sbin/ifconfig/ifvlan.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/sbin/ifconfig/ifvlan.c b/sbin/ifconfig/ifvlan.c
index 8b7b6e9daf9a..40e1f697db7a 100644
--- a/sbin/ifconfig/ifvlan.c
+++ b/sbin/ifconfig/ifvlan.c
@@ -121,7 +121,7 @@ vlan_parse_ethervid(const char *name)
 {
 	char ifname[IFNAMSIZ];
 	char *cp;
-	int vid;
+	unsigned int vid;
 
 	strlcpy(ifname, name, IFNAMSIZ);
 	if ((cp = strrchr(ifname, '.')) == NULL)
@@ -134,9 +134,12 @@ vlan_parse_ethervid(const char *name)
 		errx(1, "invalid vlan tag");
 
 	vid = *cp++ - '0';
-	while ((*cp >= '0') && (*cp <= '9'))
+	while ((*cp >= '0') && (*cp <= '9')) {
 		vid = (vid * 10) + (*cp++ - '0');
-	if ((*cp != '\0') || (vid & ~0xFFF))
+		if (vid >= 0xFFF)
+			errx(1, "invalid vlan tag");
+	}
+	if (*cp != '\0')
 		errx(1, "invalid vlan tag");
 
 	/*