awk: fix segfault on for loop syntax error

Parsing "for()" segfaults as awk fails to find loop iteration expressions.

Signed-off-by: Brian Foley <bpfoley@google.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 4 insertions, 1 deletions

diff --git a/editors/awk.c b/editors/awk.c
index d0269b9f4..685e8bed8 100644
--- a/editors/awk.c
+++ b/editors/awk.c
@@ -1514,7 +1514,7 @@ static void chain_group(void)
                         next_token(TC_SEQSTART);
                         n2 = parse_expr(TC_SEMICOL | TC_SEQTERM);
                         if (t_tclass & TC_SEQTERM) {    /* for-in */
-                                if ((n2->info & OPCLSMASK) != OC_IN)
+                                if (!n2 || (n2->info & OPCLSMASK) != OC_IN)
                                         syntax_error(EMSG_UNEXP_TOKEN);
                                 n = chain_node(OC_WALKINIT | VV);
                                 n->l.n = n2->l.n;
diff --git a/testsuite/awk.tests b/testsuite/awk.tests
index adab4ae1e..82937bc10 100755
--- a/testsuite/awk.tests
+++ b/testsuite/awk.tests
@@ -316,6 +316,9 @@ testing "awk continue" \
         "" \
         'BEGIN { if (1) continue; else a = 1 }'
 
+testing "awk handles invalid for loop" \
+    "awk '{ for() }' 2>&1" "awk: cmd. line:1: Unexpected token\n" "" ""
+
 # testing "description" "command" "result" "infile" "stdin"
 
 exit $FAILCOUNT