setrlimit() nit

[David Stevens]

The setrlimit() system call doesn't enforce rlim_cur <= rlim_max. This can
lead
to some unexpected results. For example, if you call setrlimit() with
RLIMIT_CPU with a hard limit of 60 secs, and a soft limit of "unlimited",
nothing will ever happen-- the hard limit is ignored, because it's never
checked if the soft limit hasn't been exceeded first (see kernel/timer.c).
     BSD had the same flaw-- always annoyed me. Simple fix (below). Diffs
are for 2.4.8.

                              +-DLS

--- linux/kernel/sys.c   Thu Jul 26 13:43:33 2001
+++ linux.NEW/kernel/sys.c    Thu Aug 16 00:20:14 2001
@@ -1119,6 +1119,8 @@
          return -EINVAL;
     if(copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
          return -EFAULT;
+    if (new_rlim.rlim_cur > new_rlim.rlim_max)
+         new_rlim.rlim_cur = new_rlim.rlim_max;
     old_rlim = current->rlim + resource;
     if (((new_rlim.rlim_cur > old_rlim->rlim_max) ||
          (new_rlim.rlim_max > old_rlim->rlim_max)) &&