RFR(xs): (jdk10) 8173828: realpath is unsafe

[Dmitry Samersoff]

Thomas,

> thank you for the review. These are good points, I addressed them all:

os_posix.cpp:

  1110: it's better to write as outbuf == NULL

os_solaris.cpp:

  2037: return value of realpath is not checked. Could you fix it as well?

-Dmitry


On 2017-03-14 14:19, Thomas Stüfe wrote:
> Hi Dmitry,
> 
> thank you for the review. These are good points, I addressed them all:
> 
> New
> webrev: http://cr.openjdk.java.net/~stuefe/webrevs/8173828-realpath-is-unsafe/jdk10-webrev.01/webrev/
> Delta to
> last: http://cr.openjdk.java.net/~stuefe/webrevs/8173828-realpath-is-unsafe/jdk10-webrev.00-to-01/webrev/
> 
> Thanks, Thomas
> 
> On Tue, Mar 14, 2017 at 10:00 AM, Dmitry Samersoff
> <dmitry.samersoff at oracle.com <mailto:dmitry.samersoff at oracle.com>> wrote:
> 
>     Thomas,
> 
>     os_posix.cpp:
> 
>     1121: It might be better to return ENAMETOOLONG
> 
>     1131: It might be better to check for
>           filename != NULL && outbuf != NULL before any call to realpath
>           and return EINVAL for product and assert it for debug build.
> 
>     1134: What is the goal of this assert? Do you see this problem?
> 
>     1135: If realpath overwrites outbuf, strlen might have unpredictable
>           effect.
> 
>           So it might be better to set last byte of outbuf to 0 before
>           call to realpath and check that it is still zero after call
> 
>     -Dmitry
> 
>     On 2017-03-14 10:11, Thomas Stüfe wrote:
>     > Hi all,
>     >
>     > may I have reviews for this smallish fix.
>     >
>     > Issue: https://bugs.openjdk.java.net/browse/JDK-8173828
>     <https://bugs.openjdk.java.net/browse/JDK-8173828>
>     > Webrev:
>     >
>     http://cr.openjdk.java.net/~stuefe/webrevs/8173828-realpath-is-unsafe/jdk10-webrev.00/
>     <http://cr.openjdk.java.net/~stuefe/webrevs/8173828-realpath-is-unsafe/jdk10-webrev.00/>
>     >
>     > In short, realpath(3) is unsafe the way it is traditionally used
>     (with a
>     > user buffer provided). It is safe if used in the new POSIX.1-2008
>     compliant
>     > way. To wrap this behavior, I added a new os::Posix::realpath()
>     function
>     > which takes a buffer and a buffer size (like a sane API would but the
>     > ancient realpath() did not) and moved safe buffer handling into
>     this API.
>     >
>     > Kind Regards, Thomas
>     >
> 
> 
>     --
>     Dmitry Samersoff
>     Oracle Java development team, Saint Petersburg, Russia
>     * I would love to change the world, but they won't give me the sources.
> 
> 


-- 
Dmitry Samersoff
Oracle Java development team, Saint Petersburg, Russia
* I would love to change the world, but they won't give me the sources.