From: Ondrej Zajicek (work) <santiago@crfreenet.org>
Date: Mon, 28 Dec 2020 14:23:28 +0000 (+0100)
Subject: Filter: Fix return on top-level
X-Git-Tag: v2.0.8~31
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=9e2635505a08e3453eef487360e49b4b70987ceb;p=thirdparty%2Fbird.git

Filter: Fix return on top-level

Broken detection of top-level case caused crash when return was called
from top-of-stack position. It should behave as reject/accept.

Thanks to Damian Zaremba for the bugreport.
---

diff --git a/filter/f-inst.c b/filter/f-inst.c
index 58717d558..b6bc81f7b 100644
--- a/filter/f-inst.c
+++ b/filter/f-inst.c
@@ -922,18 +922,17 @@
     uint retpos = fstk->vcnt;
 
     /* Drop every sub-block including ourselves */
-    while ((fstk->ecnt-- > 0) && !(fstk->estk[fstk->ecnt].emask & FE_RETURN))
-      ;
+    do fstk->ecnt--;
+    while ((fstk->ecnt > 0) && !(fstk->estk[fstk->ecnt].emask & FE_RETURN));
 
     /* Now we are at the caller frame; if no such, try to convert to accept/reject. */
     if (!fstk->ecnt)
+    {
       if (fstk->vstk[retpos].type == T_BOOL)
-	if (fstk->vstk[retpos].val.i)
-	  return F_ACCEPT;
-	else
-	  return F_REJECT;
+	return (fstk->vstk[retpos].val.i) ? F_ACCEPT :  F_REJECT;
       else
 	runtime("Can't return non-bool from non-function");
+    }
 
     /* Set the value stack position, overwriting the former implicit void */
     fstk->vcnt = fstk->estk[fstk->ecnt].ventry - 1;