Bug 337520

Summary:	net-misc/selfdhcp _FORTIFY_SOURCE indicates presence of overflow
Product:	Gentoo Linux	Reporter:	Diego Elio Pettenò (RETIRED) <flameeyes>
Component:	Current packages	Assignee:	No maintainer - Look at https://wiki.gentoo.org/wiki/Project:Proxy_Maintainers if you want to take care of it <maintainer-needed>
Status:	RESOLVED FIXED
Severity:	major	CC:	hardened, signals
Priority:	High	Keywords:	Inclusion, PATCH
Version:	unspecified
Hardware:	All
OS:	Linux
Whiteboard:
Package list:		Runtime testing required:	---
Bug Depends on:
Bug Blocks:	259417
Attachments:	Build log Patch to fix buffer overflow ebuild to apply the patch Fixed patch to provide enough space for the \0

Description Diego Elio Pettenò (RETIRED) gentoo-dev

2010-09-15 17:23:11 UTC

You're receiving this bug because the package in Summary has produced _FORTIFY_SOURCE related warnings indicating the presence of a sure overflow in a static buffer.

Even though this is not always an indication of a security problem it might even be. So please check this out ASAP.

By the way, _FORTIFY_SOURCE is disabled when you disable optimisation, so don't try finding out the cause using -O0.

Thanks,
Your friendly neighborhood tinderboxer

Comment 1 Diego Elio Pettenò (RETIRED) gentoo-dev

2010-09-15 17:23:25 UTC

Created attachment 247488 [details]
Build log

Comment 2 Kevin McCarthy (RETIRED) gentoo-dev

2011-01-29 14:08:48 UTC

Created attachment 260990 [details, diff]
Patch to fix buffer overflow

Comment 3 Kevin McCarthy (RETIRED) gentoo-dev

2011-01-29 14:09:13 UTC

Created attachment 260991 [details]
ebuild to apply the patch

Comment 4 Diego Elio Pettenò (RETIRED) gentoo-dev

2011-01-29 16:52:00 UTC

Hi Kevin, your patch here has still a problem: strncpy() doesn't ensure a final '\0' with the size provided, so it should be sizeof(dest)-1 rather than simply sizeof(dest). It takes away the warning because it won't hit the limit but it won't take care of terminating it properly, so further errors could creep afterwards. The interface you were expecting is strlcpy() which is not available in GLIBC.

Comment 5 Kevin McCarthy (RETIRED) gentoo-dev

2011-01-29 17:00:28 UTC

Created attachment 261017 [details, diff]
Fixed patch to provide enough space for the \0

Nice catch... I should've known better, but it's been a while since I've done any heavy C development. Anyway, I've uploaded a corrected patch.

Comment 6 Pacho Ramos gentoo-dev

2012-03-03 15:44:43 UTC

+*selfdhcp-0.2a-r1 (03 Mar 2012)
+
+  03 Mar 2012; Pacho Ramos <pacho@gentoo.org>
+  +files/selfdhcp-0.2a-buffer-overflow.patch, +selfdhcp-0.2a-r1.ebuild,
+  -selfdhcp-0.2a.ebuild:
+  Fix overflow, bug #337520 by flameeyes and fix by Kevin McCarthy.
+