| 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
| ||
|
Message-Id: <1456413395-7679-2-git-send-email-boris.ostrovsky@oracle.com> Date: Thu, 25 Feb 2016 10:16:34 -0500 From: Boris Ostrovsky <boris.ostrovsky@...cle.com> To: konrad.wilk@...cle.com, david.vrabel@...rix.com Cc: xen-devel@...ts.xenproject.org, linux-kernel@...r.kernel.org, mcgrof@...nel.org, brgerst@...il.com, andrew.cooper3@...rix.com, Boris Ostrovsky <boris.ostrovsky@...cle.com>, stable@...r.kernel.org Subject: [PATCH v3 1/2] xen/x86: Zero out .bss for PV guests Baremetal kernels clear .bss early in the boot but Xen PV guests don't execute that code. They have been able to run without problems because Xen domain builder happens to give out zeroed pages. However, since this is not really guaranteed, .bss should be explicitly cleared. Signed-off-by: Boris Ostrovsky <boris.ostrovsky@...cle.com> Cc: stable@...r.kernel.org --- arch/x86/xen/xen-head.S | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S index b65f59a..11dbe49 100644 --- a/arch/x86/xen/xen-head.S +++ b/arch/x86/xen/xen-head.S @@ -38,6 +38,20 @@ __INIT ENTRY(startup_xen) cld + +#ifdef CONFIG_X86_32 +#define WSIZE_SHIFT 2 +#else +#define WSIZE_SHIFT 3 +#endif + /* Clear .bss */ + xor %eax,%eax + mov $__bss_start, %__ASM_REG(di) + mov $__bss_stop, %__ASM_REG(cx) + sub %__ASM_REG(di), %__ASM_REG(cx) + shr $WSIZE_SHIFT, %__ASM_REG(cx) + rep __ASM_SIZE(stos) + #ifdef CONFIG_X86_32 mov %esi,xen_start_info mov $init_thread_union+THREAD_SIZE,%esp -- 2.1.0
Powered by blists - more mailing lists