linux-kernel - [PATCH] x86/fpu/xstate: Clear xstate header in copy_xstate_to_uabi

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

Message-ID: <875yy3wb8h.ffs@nanos.tec.linutronix.de>
Date:   Thu, 24 Jun 2021 17:09:18 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     Andy Lutomirski <luto@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Fenghua Yu <fenghua.yu@...el.com>,
        Tony Luck <tony.luck@...el.com>,
        Yu-cheng Yu <yu-cheng.yu@...el.com>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Borislav Petkov <bp@...e.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Chang Seok Bae <chang.seok.bae@...el.com>,
        Megha Dey <megha.dey@...ux.intel.com>,
        Oliver Sang <oliver.sang@...el.com>
Subject: [PATCH] x86/fpu/xstate: Clear xstate header in copy_xstate_to_uabi_buf() again

The change which made copy_xstate_to_uabi_buf() usable for
[x]fpregs_get() removed the zeroing of the header which means the
header, which is copied to user space later, contains except for the
xfeatures member random stack content.

Add the memset() back to zero it before usage.

Fixes: eb6f51723f03 ("x86/fpu: Make copy_xstate_to_kernel() usable for [x]fpregs_get()")
Reported-by: kernel test robot <oliver.sang@...el.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
Changelog summary: I'm a moron.
---
 arch/x86/kernel/fpu/xstate.c |    1 +
 1 file changed, 1 insertion(+)

--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -982,6 +982,7 @@ void copy_xstate_to_uabi_buf(struct memb
 	unsigned int zerofrom;
 	int i;
 
+	memset(&header, 0, sizeof(header));
 	header.xfeatures = xsave->header.xfeatures;
 
 	/* Mask out the feature bits depending on copy mode */