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Message-ID: <20170307142140.GB3514@leverpostej>
Date: Tue, 7 Mar 2017 14:21:40 +0000
From: Mark Rutland <mark.rutland@....com>
To: Ard Biesheuvel <ard.biesheuvel@...aro.org>
Cc: linux-arm-kernel@...ts.infradead.org,
kernel-hardening@...ts.openwall.com, catalin.marinas@....com,
will.deacon@....com, labbott@...oraproject.org,
kvmarm@...ts.cs.columbia.edu, marc.zyngier@....com,
keescook@...omium.org, andre.przywara@....com, james.morse@....com,
suzuki.poulose@....com
Subject: Re: [PATCH v4 5/6] arm64: mmu: apply strict permissions to
.init.text and .init.data
On Sat, Mar 04, 2017 at 02:30:47PM +0000, Ard Biesheuvel wrote:
> diff --git a/arch/arm64/include/asm/sections.h b/arch/arm64/include/asm/sections.h
> index 4e7e7067afdb..22582819b2e5 100644
> --- a/arch/arm64/include/asm/sections.h
> +++ b/arch/arm64/include/asm/sections.h
> @@ -24,7 +24,8 @@ extern char __hibernate_exit_text_start[], __hibernate_exit_text_end[];
> extern char __hyp_idmap_text_start[], __hyp_idmap_text_end[];
> extern char __hyp_text_start[], __hyp_text_end[];
> extern char __idmap_text_start[], __idmap_text_end[];
> +extern char __initdata_begin[], __initdata_end[];
> +extern char __inittext_begin[], __inittext_end[];
> extern char __irqentry_text_start[], __irqentry_text_end[];
> extern char __mmuoff_data_start[], __mmuoff_data_end[];
> -
> #endif /* __ASM_SECTIONS_H */
Unintended whitespace change?
Please restore the line above the endif.
> diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
> index b8deffa9e1bf..2c93d259046c 100644
> --- a/arch/arm64/kernel/vmlinux.lds.S
> +++ b/arch/arm64/kernel/vmlinux.lds.S
> @@ -143,12 +143,27 @@ SECTIONS
>
> . = ALIGN(SEGMENT_ALIGN);
> __init_begin = .;
> + __inittext_begin = .;
>
> INIT_TEXT_SECTION(8)
> .exit.text : {
> ARM_EXIT_KEEP(EXIT_TEXT)
> }
>
> + . = ALIGN(4);
> + .altinstructions : {
> + __alt_instructions = .;
> + *(.altinstructions)
> + __alt_instructions_end = .;
> + }
> + .altinstr_replacement : {
> + *(.altinstr_replacement)
> + }
> +
> + . = ALIGN(PAGE_SIZE);
Arguably this should be SEGMENT_ALIGN for consitency, but given this is
just .init* this should be fine.
> + __inittext_end = .;
> + __initdata_begin = .;
> +
> .init.data : {
> INIT_DATA
> INIT_SETUP(16)
[...]
> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
> index edd982f88714..0612573ef869 100644
> --- a/arch/arm64/mm/mmu.c
> +++ b/arch/arm64/mm/mmu.c
> @@ -459,14 +459,18 @@ early_param("rodata", parse_rodata);
> */
> static void __init map_kernel(pgd_t *pgd)
> {
> - static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_init, vmlinux_data;
> + static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_inittext,
> + vmlinux_initdata, vmlinux_data;
>
> pgprot_t text_prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;
>
> map_kernel_segment(pgd, _text, _etext, text_prot, &vmlinux_text);
> - map_kernel_segment(pgd, __start_rodata, __init_begin, PAGE_KERNEL, &vmlinux_rodata);
> - map_kernel_segment(pgd, __init_begin, __init_end, PAGE_KERNEL_EXEC,
> - &vmlinux_init);
> + map_kernel_segment(pgd, __start_rodata, __inittext_begin, PAGE_KERNEL,
> + &vmlinux_rodata);
> + map_kernel_segment(pgd, __inittext_begin, __inittext_end, text_prot,
> + &vmlinux_inittext);
> + map_kernel_segment(pgd, __initdata_begin, __initdata_end, PAGE_KERNEL,
> + &vmlinux_initdata);
> map_kernel_segment(pgd, _data, _end, PAGE_KERNEL, &vmlinux_data);
This all look fine, given text_prot is used for the init text.
With the whitespace restored:
Reviewed-by: Mark Rutland <mark.rutland@....com>
Mark.
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