linux-kernel - + espfix-code-cleanup.patch added to -mm tree

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <200607312226_MC3-1-C6A9-1757@compuserve.com>
Date:	Mon, 31 Jul 2006 22:24:47 -0400
From:	Chuck Ebbert <76306.1226@...puserve.com>
To:	"akpm@...l.org" <akpm@...l.org>
Cc:	zach@...are.com, rohitseth@...gle.com, JBeulich@...ell.com,
	ak@....de, stsp@...et.ru,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: + espfix-code-cleanup.patch added to -mm tree

In-Reply-To: <200607300016.k6U0GYu4023664@...ll0.pdx.osdl.net>

On Sat, 29 Jul 2006 17:16:34 -0700, Andrew Morton wrote:

>     espfix-code-cleanup.patch

After the fixup code does this:

       movl %esp, %eax         # pt_regs pointer
       movl %esp, %edx
       call patch_espfix_gdt
       pushl $__ESPFIX_SS
       CFI_ADJUST_CFA_OFFSET 4
       pushl %eax
       CFI_ADJUST_CFA_OFFSET 4
==>    lss (%esp), %esp
       CFI_ADJUST_CFA_OFFSET -8
       jmp restore_nocheck

we are on a ring0 32-bit stack that's not zero-based.  If an exception
occurs in that state, UNWIND_ESPFIX_STACK restores the proper kernel
SS and ESP but on return from the exception nothing restores the espfix
stack.  I guess this isn't a problem now because exceptions in kernel
mode are fatal but a kernel debugger might have problems here?

-- 
Chuck
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/