Hi, while "ifconfig -A" now accepts CIDR notation, it does not reject prefix length values outside of [0,32]. Also, with a prefix length of 0, undefined begavior is invoked, and at least on x86_64 a wrong netmask is computed.
I think the attached patch fixes this. If it is OK, I can commit the changes. What do you think? Br, Erik
>From d4d56a3d36be612d22a9a2146e53698c967ec5e9 Mon Sep 17 00:00:00 2001 From: Erik Auerswald <auers...@unix-ag.uni-kl.de> Date: Tue, 23 Apr 2024 22:28:19 +0200 Subject: [PATCH] ifconfig: prefix length handling fixes for -A With option -A, ifconfig accepted too small and too large prefix length values. Depending on the given prefix length value, this could result in undefined behavior. Using a valid prefix length of 0 also resulted in undefined behavior and a wrong result on at least the x86_64 architecture. * NEWS: Mention ifconfig fixes. * ifconfig/options.c (parse_opt): Reject too small and too large prefix length values for IPv4 addresses. Avoid undefined behavior with a prefix length of 0. * tests/ifconfig.sh: Test rejection of invalid prefix length value examples. --- NEWS | 3 +++ ifconfig/options.c | 4 ++-- tests/ifconfig.sh | 11 +++++++++++ 3 files changed, 16 insertions(+), 2 deletions(-) diff --git a/NEWS b/NEWS index 535fccb8..bb3f5f1d 100644 --- a/NEWS +++ b/NEWS @@ -10,6 +10,9 @@ Thanks to Rui Chen and Caleb Xu, see Thanks to Collin Funk: https://lists.gnu.org/archive/html/bug-inetutils/2024-03/msg00000.html +** ifconfig: With -A, reject invalid prefix length specifications, and +correctly handle a prefix length of 0. + * Noteworthy changes in release 2.5 (2023-12-29) [stable] ** ftpd, rcp, rlogin, rsh, rshd, uucpd diff --git a/ifconfig/options.c b/ifconfig/options.c index e4a56369..d22a349d 100644 --- a/ifconfig/options.c +++ b/ifconfig/options.c @@ -535,10 +535,10 @@ parse_opt (int key, char *arg, struct argp_state *state) *netlen++ = 0; n = strtol (netlen, &end, 10); - if (end == netlen) + if (end == netlen || n < 0 || n > 32) error (EXIT_FAILURE, 0, "Wrong netmask length %s", netlen); - addr.s_addr = htonl (INADDR_BROADCAST << (32 - n)); + addr.s_addr = n ? htonl (INADDR_BROADCAST << (32 - n)) : INADDR_ANY; str = strdup (inet_ntoa (addr)); parse_opt_set_netmask (ifp, str); } diff --git a/tests/ifconfig.sh b/tests/ifconfig.sh index 048f1ff5..bed7f043 100755 --- a/tests/ifconfig.sh +++ b/tests/ifconfig.sh @@ -142,6 +142,17 @@ else EOT fi +# Check that unusable prefix length values are rejected when using -A +# +for preflen in p 33 -1; +do + $IFCONFIG -i $LO -A 192.0.2.1/$preflen 2>&1 | \ + $GREP 'Wrong netmask length' >/dev/null 2>&1 || + { errno=1; + echo >&2 "Failed to reject invalid prefix length '$preflen'." + } +done + test $errno -ne 0 || $silence echo "Successful testing". exit $errno -- 2.25.1
