Messages in this thread | | | Date | Wed, 24 Nov 2010 19:05:35 +0800 | From | Américo Wang <> | Subject | Re: [PATCH v2] fs: select: fix information leak to userspace |
| |
On Wed, Nov 24, 2010 at 10:44:50AM +0000, Pádraig Brady wrote: >On 23/11/10 18:02, Andreas Dilger wrote: >> On 2010-11-23, at 07:45, walter harms wrote: >>> Maybe we can convince the gcc people to make 0 padding default. That will not solve the problems for other compilers but when they claim "works like gcc" we can press then to support this also. I can imagine that this will close some other subtle leaks also. >> >> It makes the most sense to tackle this at the GCC level, since the added overhead of doing memset(0) on the whole struct may be non-trivial for commonly-used and/or large structures. Since GCC is already explicitly zeroing the _used_ fields in the struct, it can much more easily determine whether there is padding in the structure, and zero those few bytes as needed. > >Zero padding structs is part of C90. Details here: >http://www.pixelbeat.org/programming/gcc/auto_init.html
Nope.
> >gcc doesn't zero pad when _all_ elements are specified. >
That is what gcc does, not what C standard specifies. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |