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From:   Arnd Bergmann <arnd@kernel.org>
Date:   Tue, 27 Oct 2020 14:32:09 +0100
Message-ID: <CAK8P3a2nnnh81fUbrua5eG1km=2h0BzfiDGm-axYtkdoLGw60A@mail.gmail.com>
Subject: Re: [PATCH] firmware: xilinx: fix out-of-bounds access
To:     Michal Simek <michal.simek@xilinx.com>
Cc:     Rajan Vaja <rajanv@xilinx.com>, Rajan Vaja <rajan.vaja@xilinx.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Tejas Patel <tejas.patel@xilinx.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        git <git@xilinx.com>
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On Tue, Oct 27, 2020 at 10:53 AM Michal Simek <michal.simek@xilinx.com> wrote:
> On 26. 10. 20 16:54, Arnd Bergmann wrote:
> > From: Arnd Bergmann <arnd@arndb.de>
> >
> > The zynqmp_pm_set_suspend_mode() and zynqmp_pm_get_trustzone_version()
> > functions pass values as api_id into zynqmp_pm_invoke_fn
> > that are beyond PM_API_MAX, resulting in an out-of-bounds access:
> >
> > drivers/firmware/xilinx/zynqmp.c: In function 'zynqmp_pm_set_suspend_mode':
> > drivers/firmware/xilinx/zynqmp.c:150:24: warning: array subscript 2562 is above array bounds of 'u32[64]' {aka 'unsigned int[64]'} [-Warray-bounds]
> >   150 |  if (zynqmp_pm_features[api_id] != PM_FEATURE_UNCHECKED)
> >       |      ~~~~~~~~~~~~~~~~~~^~~~~~~~
> > drivers/firmware/xilinx/zynqmp.c:28:12: note: while referencing 'zynqmp_pm_features'
> >    28 | static u32 zynqmp_pm_features[PM_API_MAX];
> >       |            ^~~~~~~~~~~~~~~~~~
>
> Which CONFIG option/tool is reporting this issue?

This is with gcc-10. Commit 44720996e2d7 ("gcc-10: disable
'array-bounds' warning for
now") turned off this warning globally, but most of the reported warnings got
fixed in the meantime. I'm trying to take care of the rest so we can enabled it
again.

You should be able to reproduce the problem by removing the cc-disable-warning
line from the top-level Makefile.

        Arnd