parser_bison: fix length check for ifname in ifname_expr_alloc()

commit 122dce6b35205a3df419a5cae9acfd6e83e8725a upstream.

IFNAMSIZ is 16, and the allowed byte length of the name is one less than
that. Fix the length check and adjust a test for covering the longest
allowed interface name.

This is obviously a change in behavior, because previously interface
names with length 16 were accepted and were silently truncated along the
way. Now they are rejected as invalid.

Fixes: fa52bc225806 ("parser: reject zero-length interface names")
Signed-off-by: Thomas Haller <thaller@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/src/parser_bison.y b/src/parser_bison.y
index f1d85db33fb3238701a8d2e3ff050593b5a3f74b..c1e8cfe6de22aca5e07ded8531a37238d7a36a5c 100644 (file)
--- a/src/parser_bison.y
+++ b/src/parser_bison.y
@@ -15,6 +15,7 @@
 #include <stdio.h>
 #include <inttypes.h>
 #include <syslog.h>
+#include <net/if.h>
 #include <netinet/ip.h>
 #include <netinet/tcp.h>
 #include <netinet/if_ether.h>
@@ -157,7 +158,7 @@ static struct expr *ifname_expr_alloc(const struct location *location,
                return NULL;
        }
 
-       if (length > 16) {
+       if (length >= IFNAMSIZ) {
                xfree(name);
                erec_queue(error(location, "interface name too long"), queue);
                return NULL;

diff --git a/tests/shell/testcases/chains/0042chain_variable_0 b/tests/shell/testcases/chains/0042chain_variable_0
index 58535f76cc329a564485f24b763e2f91fd966230..5628e19cb85a7b60861eaf0fea67adadf25fd1c9 100755 (executable)
--- a/tests/shell/testcases/chains/0042chain_variable_0
+++ b/tests/shell/testcases/chains/0042chain_variable_0
@@ -16,6 +16,25 @@ $NFT -f - <<< $EXPECTED
 
 EXPECTED="define if_main = \"lo\"
 
+table netdev filter2 {
+       chain Main_Ingress2 {
+               type filter hook ingress devices = { \$if_main, d23456789012345x } priority -500; policy accept;
+       }
+}"
+
+rc=0
+$NFT -f - <<< $EXPECTED || rc=$?
+test "$rc" = 1
+cat <<EOF | $DIFF -u <($NFT list ruleset) -
+table netdev filter1 {
+       chain Main_Ingress1 {
+               type filter hook ingress device "lo" priority -500; policy accept;
+       }
+}
+EOF
+
+EXPECTED="define if_main = \"lo\"
+
 table netdev filter2 {
        chain Main_Ingress2 {
                type filter hook ingress devices = { \$if_main, dummy0 } priority -500; policy accept;