kernel-hardening - Re: [PATCH v1] kdump, vmcoreinfo: report memory sections virtual addresses

server OS

Date: Fri, 19 Aug 2016 10:41:46 +0800
From: Baoquan He <bhe@...hat.com>
To: Thomas Garnier <thgarnie@...gle.com>
Cc: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
        "H . Peter Anvin" <hpa@...or.com>,
        Eric Biederman <ebiederm@...ssion.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Xunlei Pang <xlpang@...hat.com>,
        HATAYAMA Daisuke <d.hatayama@...fujitsu.com>, keescook@...omium.org,
        kernel-hardening@...ts.openwall.com, surovegin@...gle.com,
        x86@...nel.org, kexec@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1] kdump, vmcoreinfo: report memory sections virtual
 addresses

This makes sense. Makedumpfile need this to parse memory sections.

Ack.

Acked-by: Baoquan He <bhe@...hat.com>

On 08/18/16 at 07:47am, Thomas Garnier wrote:
> KASLR memory randomization can randomize the base of the physical memory
> mapping (PAGE_OFFSET), vmalloc (VMALLOC_START) and vmemmap
> (VMEMMAP_START). Adding these variables on VMCOREINFO so tools can
> easily identify the base of each memory section.
> 
> Signed-off-by: Thomas Garnier <thgarnie@...gle.com>
> ---
> Based on next-20160817
> ---
>  arch/x86/kernel/machine_kexec_64.c | 3 +++
>  include/linux/kexec.h              | 6 ++++++
>  2 files changed, 9 insertions(+)
> 
> diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
> index fc3389f..b1f15a2 100644
> --- a/arch/x86/kernel/machine_kexec_64.c
> +++ b/arch/x86/kernel/machine_kexec_64.c
> @@ -338,6 +338,9 @@ void arch_crash_save_vmcoreinfo(void)
>  	vmcoreinfo_append_str("KERNELOFFSET=%lx\n",
>  			      kaslr_offset());
>  	VMCOREINFO_PHYS_BASE(phys_base);
> +	VMCOREINFO_PAGE_OFFSET(PAGE_OFFSET);
> +	VMCOREINFO_VMALLOC_START(VMALLOC_START);
> +	VMCOREINFO_VMEMMAP_START(VMEMMAP_START);
>  }
>  
>  /* arch-dependent functionality related to kexec file-based syscall */
> diff --git a/include/linux/kexec.h b/include/linux/kexec.h
> index d3ae429..cd3874c 100644
> --- a/include/linux/kexec.h
> +++ b/include/linux/kexec.h
> @@ -261,6 +261,12 @@ phys_addr_t paddr_vmcoreinfo_note(void);
>  	vmcoreinfo_append_str("CONFIG_%s=y\n", #name)
>  #define VMCOREINFO_PHYS_BASE(value) \
>  	vmcoreinfo_append_str("PHYS_BASE=%lx\n", (unsigned long)value)

Could it be better to define only one MACRO like VMCOREINFO_
> +#define VMCOREINFO_PAGE_OFFSET(value) \
> +	vmcoreinfo_append_str("PAGE_OFFSET=%lx\n", (unsigned long)value)
> +#define VMCOREINFO_VMALLOC_START(value) \
> +	vmcoreinfo_append_str("VMALLOC_START=%lx\n", (unsigned long)value)
> +#define VMCOREINFO_VMEMMAP_START(value) \
> +	vmcoreinfo_append_str("VMEMMAP_START=%lx\n", (unsigned long)value)
>  
>  extern struct kimage *kexec_image;
>  extern struct kimage *kexec_crash_image;
> -- 
> 2.8.0.rc3.226.g39d4020
> 
> 
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