From: mark.rutland@arm.com (Mark Rutland)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 3/3] arm64: dump: Add checking for writable and exectuable pages
Date: Fri, 30 Sep 2016 16:58:25 +0100 [thread overview]
Message-ID: <20160930155814.GA1729@remoulade> (raw)
In-Reply-To: <20160929213257.30505-4-labbott@redhat.com>
On Thu, Sep 29, 2016 at 02:32:57PM -0700, Laura Abbott wrote:
> @@ -219,6 +223,15 @@ static void note_page(struct pg_state *st, unsigned long addr, unsigned level,
> unsigned long delta;
>
> if (st->current_prot) {
> + if (st->check_wx &&
> + ((st->current_prot & PTE_RDONLY) != PTE_RDONLY) &&
> + ((st->current_prot & PTE_PXN) != PTE_PXN)) {
> + WARN_ONCE(1, "arm64/mm: Found insecure W+X mapping at address %p/%pS\n",
> + (void *)st->start_address,
> + (void *)st->start_address);
> + st->wx_pages += (addr - st->start_address) / PAGE_SIZE;
> + }
> +
Would it be worth verifying that all kernel mappings are UXN, too?
ARMv8 allows execute-only mappings, and a !UXN mapping could result in an info
leak (e.g. pointers in MOVZ+MOVK sequences), or potential asynchronous issues
(e.g. user instruction fetches accessing read-destructive device registers).
All kernel mappings *should* be UXN.
Thanks,
Mark.
next prev parent reply other threads:[~2016-09-30 15:58 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-29 21:32 [PATCH 0/3] WX Checking for arm64 Laura Abbott
2016-09-29 21:32 ` [PATCH 1/3] arm64: dump: Make ptdump debugfs a separate option Laura Abbott
2016-09-30 0:13 ` Mark Rutland
2016-09-30 0:31 ` Laura Abbott
2016-09-30 0:48 ` Mark Rutland
2016-09-30 1:11 ` Laura Abbott
2016-09-30 1:27 ` Mark Rutland
2016-09-29 21:32 ` [PATCH 2/3] arm64: dump: Make the page table dumping seq_file optional Laura Abbott
2016-09-30 0:36 ` Mark Rutland
2016-09-29 21:32 ` [PATCH 3/3] arm64: dump: Add checking for writable and exectuable pages Laura Abbott
2016-09-30 2:08 ` Mark Rutland
2016-09-30 15:58 ` Mark Rutland [this message]
2016-09-30 16:25 ` Kees Cook
2016-09-30 16:41 ` Mark Rutland
2016-09-30 17:16 ` Kees Cook
2016-09-30 1:29 ` [kernel-hardening] [PATCH 0/3] WX Checking for arm64 Kees Cook
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