James Petterson writes:

I've found a possible bug in libbb/interface.c, in function
if_readlist_proc(). This function calls get_name(), and passes
as an argument 'name', a buffer of 16 bytes (IFNAMSIZ).  The
function get_name(), however, may use more than 16 bytes,
when it is searching for aliases. Even if you don't have an
alias interface, you can run into trouble if the interface
has received more than 99999999 bytes, in which case the
space between the interface name and the rx stats
disappears, as in the /proc/net/dev example below:
 wan0.200:264573315  462080    ...
In this case get_name() correctly identifies the interface name
as "wan0.200", but to do that it uses 18 bytes of the 'name'
buffer, which could lead to an unpredictable error.

A simple solution would be to increase the size of the buffer:

1 files changed, 2 insertions, 2 deletions

diff --git a/libbb/interface.c b/libbb/interface.c
index 46c3ba9..47358fe 100644
--- a/libbb/interface.c
+++ b/libbb/interface.c
@@ -15,7 +15,7 @@
  *              that either displays or sets the characteristics of
  *              one or more of the system's networking interfaces.
  *
- * Version:     $Id: interface.c,v 1.17 2003/07/22 08:56:46 andersen Exp $
+ * Version:     $Id: interface.c,v 1.18 2003/07/28 06:35:32 andersen Exp $
  *
  * Author:      Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
  *              and others.  Copyright 1993 MicroWalt Corporation
@@ -1134,7 +1134,7 @@ static int if_readlist_proc(char *target)
 
 	err = 0;
 	while (fgets(buf, sizeof buf, fh)) {
-		char *s, name[IFNAMSIZ];
+		char *s, name[128];
 
 		s = get_name(name, buf);
 		ife = add_interface(name);