linux-kernel - RE: [PATCH] ARM: ioremap: Fix static vm area boundary checking.

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Date:	Thu, 15 May 2014 08:55:52 +0000
From:	"Li.Xiubo@...escale.com" <Li.Xiubo@...escale.com>
To:	Richard Lee <superlibj8301@...il.com>,
	"linux@....linux.org.uk" <linux@....linux.org.uk>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"arnd@...db.de" <arnd@...db.de>,
	"robherring2@...il.com" <robherring2@...il.com>
CC:	"lauraa@...eaurora.org" <lauraa@...eaurora.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH] ARM: ioremap: Fix static vm area boundary checking.

> Subject: [PATCH] ARM: ioremap: Fix static vm area boundary checking.
> 
> Static vm area boundary check:
> 
>       paddr1 --->|       |
>                  |       |
>                  |-------| <-\--- svm->vm->addr(is page aligned)
>       paddr2 --->|       |    |
>                  |     --| <--|-- svm->vm->phys_addr
>                  |       |    |
>       paddr3 --->|       |    |
>                  |       |    |
>                  |-------| <--|-- next page boundary
>                  |       |    |
>       paddr4 --->|       |    | <----- svm->vm->size(including guard page)
>                  |       |    |
>                  |       |    |
> max paddr_end -->|-------| <--|-- svm->vm's phys_addr_end
>                  | ///// |    |
>       paddr5 --->| guard |    |
>                  | page  |    |
>                  | ///// |    |
>                   -------  <-/--- svm->vm->addr + svm->vm_size
> 
> <1> If the paddr == paddr1, then continue;
> <2> If the paddr == paddr2~paddr4 and paddr_end > phys_addr_end,
>     then continue;
> <3> if the paddr >= paddr5 then continue;
> 
> Signed-off-by: Richard Lee <superlibj8301@...il.com>
> ---
>  arch/arm/mm/ioremap.c | 44 ++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 42 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c
> index be69333..2fa41f4 100644
> --- a/arch/arm/mm/ioremap.c
> +++ b/arch/arm/mm/ioremap.c
> @@ -47,16 +47,56 @@ static struct static_vm *find_static_vm_paddr(phys_addr_t
> paddr,
>  {
>  	struct static_vm *svm;
>  	struct vm_struct *vm;
> +	size_t offset;
> +
> +	/*
> +	 * Make sure the size the mapping size is page aligned.
> +	 */
> +	size = PAGE_ALIGN((paddr & ~PAGE_SIZE) + size);
> +	offset = paddr & ~PAGE_SIZE;
> 

Shouldn't it be PAGE_MASK ?

>  	list_for_each_entry(svm, &static_vmlist, list) {
> +		phys_addr_t paddr_end, phys_addr_end;
> +		size_t vmoff;
> +
>  		vm = &svm->vm;
>  		if (!(vm->flags & VM_ARM_STATIC_MAPPING))
>  			continue;
>  		if ((vm->flags & VM_ARM_MTYPE_MASK) != VM_ARM_MTYPE(mtype))
>  			continue;
> 
> -		if (vm->phys_addr > paddr ||
> -			paddr + size - 1 > vm->phys_addr + vm->size - 1)
> +		/* Static vm area boundary check:
> +		 *
> +		 *       paddr1 --->|       |
> +		 *                  |       |
> +		 *                  |-------| <-\--- svm->vm->addr(page aligned)
> +		 *       paddr2 --->|       |    |
> +		 *                  |     --| <--|-- svm->vm->phys_addr
> +		 *                  |       |    |
> +		 *       paddr3 --->|       |    |
> +		 *                  |       |    |
> +		 *                  |-------| <--|-- next page boundary
> +		 *                  |       |    |
> +		 *       paddr4 --->|       |    | <----- svm->vm->size,
> +		 *                  |       |    |         including guard page
> +		 *                  |       |    |
> +		 * max paddr_end -->|-------| <--|-- svm->vm's phys_addr_end
> +		 *                  | ///// |    |
> +		 *       paddr5 --->| guard |    |
> +		 *                  | page  |    |
> +		 *                  | ///// |    |
> +		 *                   -------  <-/-- svm->vm->addr + svm->vm_size
> +		 *
> +		 * <1> If paddr == paddr1, then continue;
> +		 * <2> If paddr == paddr2~paddr4 and paddr_end > phys_addr_end,
> +		 *     then continue;
> +		 * <3> if paddr >= paddr5 then continue;
> +		 */
> +		vmoff = vm->phys_addr & ~PAGE_SIZE;

And here.

Thanks,
BRs
Xiubo

> +		phys_addr_end = vm->phys_addr + vm->size - PAGE_SIZE - vmoff;
> +		paddr_end = paddr + size - offset;
> +		if (__phys_to_pfn(vm->phys_addr) > __phys_to_pfn(paddr) ||
> +			paddr_end - 1 > phys_addr_end - 1)
>  			continue;
> 
>  		return svm;
> --
> 1.8.4
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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