On Mon, May 01, 2006 at 09:51:27AM -0400, Daniel Jacobowitz wrote:
> On Fri, Apr 28, 2006 at 09:49:56PM -0400, Jeff Dike wrote:
> > On Fri, Apr 28, 2006 at 10:28:46PM +0200, Blaisorblade wrote:
> > > bitmask = 0;
> > > set_bit(__NR_tee, bitmask);
> > > ptrace(PTRACE_SET_TRACEONLY, bitmask);
> >
> > Yup, I like this.
>
> I really recommend you not do this.
> Suppose the kernel knows about 32 more syscalls than userspace. It's
> going to read extra bits out of the bitmask that userspace didn't
> initialize!
The example above is a sketch, not a fully formed, compilable user. Every
proposed interface has had the mask length passed in - in the case
above in the data argument.
> Also, if you store the mask with the child process, it risks surprising
> existing tracers: attach, set mask, detach, then the next time someone
> attaches an old version of strace some syscalls will be "hidden".
Not if the mask only survives for the duration of a PTRACE_ATTACH, and
the mask is released on PTRACE_DETACH.
Jeff
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
