[swift-dev] Standard shared libraries with executable stack

[Sangjin Han]

Hi, Kim.

I have the WSL on Windows Preview.

Could you show the test source/command ?

-Han Sangjin

2016-06-14 21:10 GMT+09:00 Ryan Lovelett via swift-dev <swift-dev at swift.org>
:

> On Mon, Jun 13, 2016, at 11:33 PM, Dmitri Gribenko via swift-dev wrote:
> > On Sat, Jun 11, 2016 at 8:12 AM, 김종수 via swift-dev <swift-dev at swift.org>
> > wrote:
> > > I am testing Swift in "Windows Subsystem for Linux" which is a new
> feature
> > > of Windows 10 Anniversary Update scheduled in this year. WSL is Ubuntu
> LTS
> > > 14.04 compatible in user space.
> > >
> > > Swift runtime libraries such as libswiftCore.so are marked Executable
> Stack,
> > > which have no problem in Linux.
> > >
> > > dlopen()'ing swift runtime libraries causes mprotect() with
> PROT_GROWSDOWN,
> > > which is not documented but verified with strace.
> > >
> > > WSL has not implemented PROT_GROWSDOWN feature because of clean room
> > > development.
> > >
> > > Swift runtime libraries had not been marked Executable Stack before
> Febrary
> > > snapshot. And cmark and llvm/clang shared libraries are not marked too.
> > >
> > > ***My request is swift runtime libraries be not marked Executable
> Stack.***
> >
> > Hi,
> >
> > This could have been caused by our switch from the BFD linker to gold.
> > Could you try linking a hello world program using gold linker and
> > running it in WSL?
>
> I _think_ this problem existed before the switch from BFD to gold.
>
> I build and package a version of Swift for Linux. During the package
> processes makepkg [1] checks the installed binaries for common gotchas
> (I tried looking up exactly what is run but could not find it quickly).
>
> My point is that I've been seeing:
>
> swiftc W: ELF file ('usr/bin/swift-test') has executable stack.
> swiftc W: ELF file ('usr/bin/repl_swift') has executable stack.
> swiftc W: ELF file ('usr/bin/swift-build') has executable stack.
> swiftc W: ELF file ('usr/lib/swift/pm/libPackageDescription.so') has
> executable stack.
> swiftc W: ELF file ('usr/lib/swift/linux/libswiftGlibc.so') has
> executable stack.
> swiftc W: ELF file ('usr/lib/swift/linux/libXCTest.so') has executable
> stack.
> swiftc W: ELF file ('usr/lib/swift/linux/libswiftCore.so') has
> executable stack.
> swiftc W: ELF file ('usr/lib/swift/linux/libFoundation.so') has
> executable stack.
>
> Since at least the 20160208a release, but probably longer, I have been
> seeing the above errors. That predates the BFD to gold switch by at
> least a month. Though I do admit I don't remember the exact date that
> change landed.
>
> I have all the build logs dating back to February 22nd if that helps in
> anyway. Just food for thought.
>
> [1] https://www.archlinux.org/pacman/makepkg.8.html
>
> >
> > Are you sure that PROT_GROWSDOWN is the flag that enables executable
> > stack?  I thought that's what PROT_EXEC is for.  I'm not sure what
> > PROT_GROWSDOWN actually changes, if I were to speculate, I'd say it
> > could be a marker that means "this is a stack" or maybe even be just a
> > performance hint.
> >
> > Dmitri
> >
> > --
> > main(i,j){for(i=2;;i++){for(j=2;j<i;j++){if(!(i%j)){j=0;break;}}if
> > (j){printf("%d\n",i);}}} /*Dmitri Gribenko <gribozavr at gmail.com>*/
> > _______________________________________________
> > swift-dev mailing list
> > swift-dev at swift.org
> > https://lists.swift.org/mailman/listinfo/swift-dev
> _______________________________________________
> swift-dev mailing list
> swift-dev at swift.org
> https://lists.swift.org/mailman/listinfo/swift-dev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.swift.org/pipermail/swift-dev/attachments/20160615/93d33442/attachment.html>