On 24 December 2013 02:37, Linus Torvalds <torva...@linux-foundation.org> wrote:
> Please cc the guilty parties when sending patches like this.
>
OK.
[Added Al Viro as well as this affects fs/binfmt_elf.c]
> Also, just out of interest, please describe how this bug affected
> things. Did we overflow the saved_auxv[] array, or what?
That is the risk, yes. AT_VECTOR_SIZE_BASE is supposed to be an upper
bound for the number of generic auxv entries, and this is currently
not the case. However, I am not aware of any actual problems that have
been caused, and powerpc is indeed the only arch that defines
ELF_HWCAP2 at the moment. But I spotted this when working on a series
that adds ELF_HWCAP2 to ARM, and other archs may follow in the future.
> Also, how
> does this change affect architectures that _don't_ have that
> ELF_HWCAP2 thing, ie everything but powerpc?
>
Some wasted space (two longs) in saved_auxv[] in mm_struct.
--
Ard.
> Acks, people?
>
> Linus
>
> On Mon, Dec 23, 2013 at 9:49 AM, Ard Biesheuvel
> <ard.biesheu...@linaro.org> wrote:
>> Commit 2171364d1a92 (powerpc: Add HWCAP2 aux entry) introduced a new
>> AT_ auxv entry type AT_HWCAP2 but failed to update AT_VECTOR_SIZE_BASE
>> accordingly.
>>
>> Signed-off-by: Ard Biesheuvel <ard.biesheu...@linaro.org>
>> Fixes: 2171364d1a92 (powerpc: Add HWCAP2 aux entry)
>> Cc: sta...@vger.kernel.org
>> ---
>>
>> include/linux/auxvec.h | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/include/linux/auxvec.h b/include/linux/auxvec.h
>> index 669fef5..3e0fbe4 100644
>> --- a/include/linux/auxvec.h
>> +++ b/include/linux/auxvec.h
>> @@ -3,6 +3,6 @@
>>
>> #include <uapi/linux/auxvec.h>
>>
>> -#define AT_VECTOR_SIZE_BASE 19 /* NEW_AUX_ENT entries in auxiliary table */
>> +#define AT_VECTOR_SIZE_BASE 20 /* NEW_AUX_ENT entries in auxiliary table */
>> /* number of "#define AT_.*" above, minus {AT_NULL, AT_IGNORE, AT_NOTELF}
>> */
>> #endif /* _LINUX_AUXVEC_H */
>> --
>> 1.8.3.2
>
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