[PATCH][Arm] gas: fix out of range conditional branch (PR/24991)

[Andreas Schwab]

On Sep 23 2019, Nick Clifton <nickc@redhat.com> wrote:

> Hi Tamar,
>
>   Being paranoid here....
>
>> +/* Perform range checks on positive and negative overflows by checking if the
>> +   VALUE given fits within the range of an BITS sized immediate.  */
>> +static bfd_boolean out_of_range_p (offsetT value, bfd_vma bits)
>> +{
>> +  return (value & ~((1 << bits)-1))
>> +         && ((value & ~((1 << bits)-1)) != ~((1 << bits)-1));
>> +}
>
> If bits is a large number then these shifts could overflow.  I would
> recommend adding a range check first.  Plus you should allow for the
> fact that sizeof (bits) and sizeof (value) could be small if the code
> is compiled for a 32-bit host...

The shifts should be performed in offsetT (or its unsigned equivalent),
not int.  bits can be int instead of bfd_vma.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
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