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>

1 files changed, 19 insertions, 0 deletions

diff --git a/tests/shell/testcases/chains/0042chain_variable_0 b/tests/shell/testcases/chains/0042chain_variable_0
index 58535f76..5628e19c 100755
--- a/tests/shell/testcases/chains/0042chain_variable_0
+++ b/tests/shell/testcases/chains/0042chain_variable_0
@@ -18,6 +18,25 @@ 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;
 	}
 }"