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Date:   Thu, 6 Feb 2020 04:38:52 -0800
From:   Kees Cook <keescook@chromium.org>
To:     Kristen Carlson Accardi <kristen@linux.intel.com>
Cc:     tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com,
        arjan@linux.intel.com, rick.p.edgecombe@intel.com, x86@kernel.org,
        linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com
Subject: Re: [RFC PATCH 01/11] modpost: Support >64K sections
Message-ID: <202002060438.C2C977F8@keescook>
References: <20200205223950.1212394-1-kristen@linux.intel.com>
 <20200205223950.1212394-2-kristen@linux.intel.com>
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On Wed, Feb 05, 2020 at 02:39:40PM -0800, Kristen Carlson Accardi wrote:
> According to the ELF specification, if the value of st_shndx
> contains SH_XINDEX, the actual section header index is too
> large to fit in the st_shndx field and you should use the
> value out of the SHT_SYMTAB_SHNDX section instead. This table
> was already being parsed and saved into symtab_shndx_start, however
> it was not being used, causing segfaults when the number of
> sections is greater than 64K. Check the st_shndx field for
> SHN_XINDEX prior to using.
> 
> Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>

Looking at "readelf" output continues to make me laugh. :)

Reviewed-by: Kees Cook <keescook@chromium.org>

-Kees

-- 
Kees Cook