RFR(xs): 8165936: Potential Heap buffer overflow when seaching timezone info files

[Thomas Stüfe]

Hi Roger,

thanks for the review! You are right, I will use dirent64 in offsetof.

Kind Regards, Thomas

On Tue, Sep 13, 2016 at 4:03 PM, Roger Riggs <Roger.Riggs at oracle.com> wrote:

> Hi Thomas,
>
> One minor point, it seems a bit asymmetric (@line 150) to cast to dirent64
> but use dirent in the offsetof calculation.
> Otherwise, looks fine.
>
> Roger
>
>
>
>
> On 9/13/2016 8:35 AM, Langer, Christoph wrote:
>
>> Hi Thomas,
>>
>> your change looks good. I'm also forwarding this to i18n-dev as issues in
>> TimeZone implementation are mostly handled there.
>>
>> One remark: Can you take the opportunity to also remove the blank between
>> the cast and malloc in line 150: "(struct dirent64 *) malloc..."?
>>
>> Unfortunately I'm no reviewer, so you still need an official review.
>>
>> Best regards
>> Christoph
>>
>> -----Original Message-----
>>> From: core-libs-dev [mailto:core-libs-dev-bounces at openjdk.java.net] On
>>> Behalf
>>> Of Thomas Stüfe
>>> Sent: Dienstag, 13. September 2016 12:54
>>> To: Java Core Libs <core-libs-dev at openjdk.java.net>
>>> Subject: RFR(xs): 8165936: Potential Heap buffer overflow when seaching
>>> timezone info files
>>>
>>> Dear all,
>>>
>>> please take a look at this small change:
>>>
>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8165936
>>> Webrev:
>>> http://cr.openjdk.java.net/~stuefe/webrevs/8165936-Potential
>>> -Heap-buffer-
>>> overflow-when-seaching-timezone-info-files/webrev.00/webrev/
>>>
>>> readdir_r is used to iterate over the content of a system directory, but
>>> the buffer passed to it is too small: Its size should include the size of
>>> the dirent structure itself (minus the d_name member).
>>>
>>> The fix also now checks the return code of pathconf(), and if pathconf()
>>> returns an error, falls back to the NAME_MAX compile time constant.
>>> Finally, it imposes a minimum size for the buffer, because on older
>>> System
>>> V systems NAME_MAX may be surprisingly small and readdir_r will not check
>>> the output buffer size. I think it is better to err on the safe side
>>> here.
>>>
>>> Kind Regards, Thomas
>>>
>>
>