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Date:      Wed, 27 May 2020 21:41:01 -0500
From:      Justin Hibbits <chmeeedalf@gmail.com>
To:        Brandon Bergren <bdragon@FreeBSD.org>
Cc:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   Re: svn commit: r361568 - head/sys/powerpc/aim
Message-ID:  <20200527214101.59293529@titan.knownspace>
In-Reply-To: <202005280049.04S0n3jS096937@repo.freebsd.org>
References:  <202005280049.04S0n3jS096937@repo.freebsd.org>

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On Thu, 28 May 2020 00:49:03 +0000 (UTC)
Brandon Bergren <bdragon@FreeBSD.org> wrote:

> Author: bdragon
> Date: Thu May 28 00:49:02 2020
> New Revision: 361568
> URL: https://svnweb.freebsd.org/changeset/base/361568
> 
> Log:
>   [PowerPC] Fix radix crash when passing -1 from userspace
>   
>   Found by running libc tests with radix enabled.
>   
>   Detect unsigned integer wrapping with a postcondition.
>   
>   Note: Radix MMU is not enabled by default yet.
>   
>   Sponsored by:	Tag1 Consulting, Inc.
> 
> Modified:
>   head/sys/powerpc/aim/mmu_radix.c
> 
> Modified: head/sys/powerpc/aim/mmu_radix.c
> ==============================================================================
> --- head/sys/powerpc/aim/mmu_radix.c	Wed May 27 23:20:35
> 2020	(r361567) +++ head/sys/powerpc/aim/mmu_radix.c	Thu
> May 28 00:49:02 2020	(r361568) @@ -6000,7 +6000,8 @@
> mmu_radix_kremove(vm_offset_t va) int mmu_radix_map_user_ptr(pmap_t
> pm, volatile const void *uaddr, void **kaddr, size_t ulen, size_t
> *klen) {
> -	if ((uintptr_t)uaddr + ulen >= VM_MAXUSER_ADDRESS)
> +	if ((uintptr_t)uaddr + ulen >= VM_MAXUSER_ADDRESS ||
> +	    (uintptr_t)uaddr + ulen < (uintptr_t)uaddr)
>  		return (EFAULT);
>  
>  	*kaddr = (void *)(uintptr_t)uaddr;

Wouldn't

    if ((uintptr_t)uaddr >= VM_MAXUSER_ADDRESS ||
        (uintptr_t)uaddr + ulen >= VM_MAXUSER_ADDRESS)

be more appropriate?

- Justin



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