aspath_inflate() can be called with an empty ASPATH.

In this case ibuf_size(in) is 0 and the ibuf_open() fails because
right now 0 sized ibufs are not allowed. Add + 1 to the size calculation
as a workaround.
OK tb@

diff --git a/usr.sbin/bgpd/util.c b/usr.sbin/bgpd/util.c
index f3b08f9..eb9b610 100644 (file)
--- a/usr.sbin/bgpd/util.c
+++ b/usr.sbin/bgpd/util.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: util.c,v 1.80 2024/01/30 13:50:09 claudio Exp $ */
+/*     $OpenBSD: util.c,v 1.81 2024/02/02 16:14:51 claudio Exp $ */
 
 /*
  * Copyright (c) 2006 Claudio Jeker <claudio@openbsd.org>
@@ -547,8 +547,12 @@ aspath_inflate(struct ibuf *in)
        uint16_t         short_as;
        uint8_t          seg_type, seg_len;
 
-       /* allocate enough space for the worst case */
-       if ((out = ibuf_open(ibuf_size(in) * 2)) == NULL)
+       /*
+        * Allocate enough space for the worst case.
+        * XXX add 1 byte for the empty ASPATH case since we can't
+        * allocate an ibuf of 0 length.
+        */
+       if ((out = ibuf_open(ibuf_size(in) * 2 + 1)) == NULL)
                return (NULL);
 
        /* then copy the aspath */