Re: remaining flexible-array conversions

From: Kees Cook <keescook@chromium.org>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Nathan Chancellor <natechancellor@gmail.com>,
	"Gustavo A. R. Silva" <gustavo@embeddedor.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Greg KH <gregkh@linuxfoundation.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-rdma@vger.kernel.org, clang-built-linux@googlegroups.com
Subject: Re: remaining flexible-array conversions
Date: Fri, 24 Apr 2020 08:24:30 -0700	[thread overview]
Message-ID: <202004240824.F042AFFBF@keescook> (raw)
In-Reply-To: <20200424121553.GE26002@ziepe.ca>

On Fri, Apr 24, 2020 at 09:15:53AM -0300, Jason Gunthorpe wrote:
> On Thu, Apr 23, 2020 at 08:47:04PM -0700, Nathan Chancellor wrote:
> > Hi Gustavo,
> > 
> > On Wed, Apr 22, 2020 at 01:26:02PM -0500, Gustavo A. R. Silva wrote:
> > > Hi Linus,
> > > 
> > > Just wanted to ask you if you would agree on pulling the remaining
> > > flexible-array conversions all at once, after they bake for a couple
> > > of weeks in linux-next[1]
> > > 
> > > This is not a disruptive change and there are no code generation
> > > differences. So, I think it would make better use of everyone's time
> > > if you pull this treewide patch[2] from my tree (after sending you a
> > > proper pull-request, of course) sometime in the next couple of weeks.
> > > 
> > > Notice that the treewide patch I mention here has been successfully
> > > built (on top of v5.7-rc1) for multiple architectures (arm, arm64,
> > > sparc, powerpc, ia64, s390, i386, nios2, c6x, xtensa, openrisc, mips,
> > > parisc, x86_64, riscv, sh, sparc64) and 82 different configurations
> > > with the help of the 0-day CI guys[3].
> > > 
> > > What do you think?
> > > 
> > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=d496496793ff69c4a6b1262a0001eb5cd0a56544
> > > [2] https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git/commit/?h=for-next/kspp&id=d783301058f3d3605f9ad34f0192692ef572d663
> > > [3] https://github.com/GustavoARSilva/linux-hardening/blob/master/cii/kernel-ci/kspp-fam0-20200420.md
> > > 
> > > Thanks
> > 
> > That patch in -next appears to introduce some warnings with clang when
> > CONFIG_UAPI_HEADER_TEST is enabled (allyesconfig/allmodconfig exposed it
> > for us with KernelCI [1]):
> 
> Indeed, I've tried these conversions before and run into problems like
> this, and more. Particularly in userspace these structs also get
> embedded in other structs and the warnings explode.
> 
> Please drop changes to ib_user_verbs.h from your series

We might need to make the UAPI changes separately (or not at all).

-- 
Kees Cook