CVS commit: src/sbin/ifconfig

["Kamil Rytarowski" <kamil%netbsd.org@localhost>]

Module Name:    src
Committed By:   kamil
Date:           Mon Jun 11 17:45:51 UTC 2018

Modified Files:
        src/sbin/ifconfig: af_inet.c

Log Message:
Correct Undefined Behavior in ifconfig(8)

Unportable left shift reported with MKSANITIZER=yes USE_SANITIZER=undefined:

# ifconfig
alc0: flags=0x8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        ec_capabilities=3<VLAN_MTU,VLAN_HWTAGGING>
        ec_enabled=0
        address: xx:xx:xx:xx:xx:xx
/public/src.git/sbin/ifconfig/af_inet.c:102:34: runtime error: left shift of 16777215 by 8 places cannot be represented in type 'int'
        inet 192.168.0.38/24 broadcast 192.168.0.255 flags 0x0
        inet6 xxxx::xxxx:xxxx:xxxx:xxx%alc0/64 flags 0x0 scopeid 0x1
lo0: flags=0x8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 33624
        inet 127.0.0.1/8 flags 0x0
        inet6 ::1/128 flags 0x20<NODAD>
        inet6 fe80::1%lo0/64 flags 0x0 scopeid 0x2

Change shifting left 1 to shifting 1U. This corrects the issue.

        if (cidr < 32) {                /* more than 1 bit in mask */
                /* check for non-contig netmask */
                if ((mask ^ (((1 << cidr) - 1) << (32 - cidr))) != 0) // <- here
                        return -1;      /* noncontig, no pfxlen */
        }

Solution suggested by <uwe>

Sponsored by <The NetBSD Foundation>


To generate a diff of this commit:
cvs rdiff -u -r1.24 -r1.25 src/sbin/ifconfig/af_inet.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.