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From: Christoph Hellwig <hch@lst.de>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Dexuan Cui <decui@microsoft.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, Jessica Yu <jeyu@kernel.org>,
	x86@kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org,
	linux-mm@kvack.org
Subject: fix a hyperv W^X violation and remove vmalloc_exec
Date: Thu, 18 Jun 2020 08:43:04 +0200	[thread overview]
Message-ID: <20200618064307.32739-1-hch@lst.de> (raw)

Hi all,

Dexuan reported a W^X violation due to the fact that the hyper hypercall
page due switching it to be allocated using vmalloc_exec.  The problem
is that PAGE_KERNEL_EXEC as used by vmalloc_exec actually sets writable
permissions in the pte.  This series fixes the issue by switching to the
low-level __vmalloc_node_range interface that allows specifing more
detailed permissions instead.  It then also open codes the other two
callers and removes the somewhat confusing vmalloc_exec interface.

Peter noted that the hyper hypercall page allocation also has another
long standing issue in that it shouldn't use the full vmalloc but just
the module space.  This issue is so far theoretical as the allocation is
done early in the boot process.  I plan to fix it with another bigger
series for 5.9.

WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-hyperv@vger.kernel.org,
	Peter Zijlstra <peterz@infradead.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	x86@kernel.org, Dexuan Cui <decui@microsoft.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Jessica Yu <jeyu@kernel.org>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Will Deacon <will@kernel.org>,
	linux-arm-kernel@lists.infradead.org
Subject: fix a hyperv W^X violation and remove vmalloc_exec
Date: Thu, 18 Jun 2020 08:43:04 +0200	[thread overview]
Message-ID: <20200618064307.32739-1-hch@lst.de> (raw)

Hi all,

Dexuan reported a W^X violation due to the fact that the hyper hypercall
page due switching it to be allocated using vmalloc_exec.  The problem
is that PAGE_KERNEL_EXEC as used by vmalloc_exec actually sets writable
permissions in the pte.  This series fixes the issue by switching to the
low-level __vmalloc_node_range interface that allows specifing more
detailed permissions instead.  It then also open codes the other two
callers and removes the somewhat confusing vmalloc_exec interface.

Peter noted that the hyper hypercall page allocation also has another
long standing issue in that it shouldn't use the full vmalloc but just
the module space.  This issue is so far theoretical as the allocation is
done early in the boot process.  I plan to fix it with another bigger
series for 5.9.

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

             reply	other threads:[~2020-06-18  6:43 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-18  6:43 Christoph Hellwig [this message]
2020-06-18  6:43 ` fix a hyperv W^X violation and remove vmalloc_exec Christoph Hellwig
2020-06-18  6:43 ` [PATCH 1/3] x86/hyperv: allocate the hypercall page with only read and execute bits Christoph Hellwig
2020-06-18  6:43   ` Christoph Hellwig
2020-06-18 11:47   ` Wei Liu
2020-06-18 11:47     ` Wei Liu
2020-06-18  6:43 ` [PATCH 2/3] arm64: use PAGE_KERNEL_ROX directly in alloc_insn_page Christoph Hellwig
2020-06-18  6:43   ` Christoph Hellwig
2020-06-18  8:55   ` David Hildenbrand
2020-06-18  8:55     ` David Hildenbrand
2020-06-18 10:35     ` Peter Zijlstra
2020-06-18 10:35       ` Peter Zijlstra
2020-06-18 13:50       ` Christoph Hellwig
2020-06-18 13:50         ` Christoph Hellwig
2020-06-18  9:27   ` Peter Zijlstra
2020-06-18  9:27     ` Peter Zijlstra
2020-06-21  2:16   ` Andrew Morton
2020-06-23  9:05     ` Christoph Hellwig
2020-06-23  9:07       ` Will Deacon
2020-06-23  9:37         ` Peter Zijlstra
2020-06-23  9:57           ` Will Deacon
2020-06-27  7:34   ` Ard Biesheuvel
2020-06-27  7:34     ` Ard Biesheuvel
2020-06-27  7:34     ` Ard Biesheuvel
2020-06-27  7:56     ` Christoph Hellwig
2020-06-27  7:56       ` Christoph Hellwig
2020-06-27  7:57       ` Ard Biesheuvel
2020-06-27  7:57         ` Ard Biesheuvel
2020-06-27  7:57         ` Ard Biesheuvel
2020-06-18  6:43 ` [PATCH 3/3] mm: remove vmalloc_exec Christoph Hellwig
2020-06-18  6:43   ` Christoph Hellwig
2020-06-18  8:53   ` David Hildenbrand
2020-06-18  8:53     ` David Hildenbrand
2020-06-18  9:28 ` fix a hyperv W^X violation and " Peter Zijlstra
2020-06-18  9:28   ` Peter Zijlstra

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