Dave Hansen [dave@xxxxxxxxxxxxxxxxxx] wrote:
| On Sun, 2009-11-01 at 12:45 -0800, Sukadev Bhattiprolu wrote:
| > +int sys_clone_with_pids(struct pt_regs *regs)
| > +{
| ...
| > + rc = copy_from_user(&kcs, ucs, sizeof(kcs));
| > + if (rc)
| > + return -EFAULT;
| > +
| > + /*
| > + * TODO: If size of clone_args is not what the kernel expects, it
| > + * could be that kernel is newer and has an extended structure.
| > + * When that happens, this check needs to be smarter (and we
| > + * need an additional copy_from_user()). For now, assume exact
| > + * match.
| > + */
| > + if (kcs.clone_args_size != sizeof(kcs))
| > + return -EINVAL;
| > +
| > + /*
| > + * To avoid future compatibility issues, ensure unused fields are 0.
| > + */
| > + if (kcs.reserved1 || kcs.clone_flags_high)
| > + return -EINVAL;
|
| Suka, is there a reason we don't have these bits in some
| arch-independent code? I would have thought the stuff in the
| process_32.c code would be just as thin a wrapper as possible to unwrap
| the pt_regs and call into generic code.
Yes, it can be in arch independent code: but couple of minor inconvinences:
- currently the arch independent code does not know about the
'clone_args' structure. This helps keep this patchset smaller.
It could know about it in the future (when more flags are added).
- and we need to check these *before* unwrapping the values from
pt_regs.
Well, you are right. Will define 'check_clone_with_pids_params()' in
kernel/fork.c and call it here before unwrapping the params.
Suka
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