On Wed, Jul 07, 2010 at 10:31:37AM -0700, Linus Torvalds wrote: > On Wed, Jul 7, 2010 at 10:11 AM, Ulrich Drepper <drepper@xxxxxxxxxx> wrote: > > > > How does this work with old kernels which didn't initialize f_spare? > > Some of the compat layers (and older kernels) don't copy the f_spare > values, so user space should clear the field before doing the system > call, and you should be ok. > > There should be no actual _uninitialized_ values copied from the > kernel. IOW, either the kernel writes zero, or it doesn't write > anything at all. Anything else would be a security issue anyway (ie > kernel stack data leak). Afaik, no kernel does that. Sometime before 2.4.0 (I posted the exact release in the previous thread) the kernel initalized unused fields to 0xff. So if we want to support these kernels it is an issue. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
