[TRIVIAL] Re: setrlimit incorrectly allows hard limits to exceed soft limits

From: Rusty Trivial Russell (rusty@rustcorp.com.au)
Date: Thu Dec 05 2002 - 22:26:30 EST

From: Kingsley Cheung <kingsley@aurema.com>

  Oops, should be after the copy :-(
  

> In 2.4.19 (also 2.5.46) setrlimit code only ever makes a comparison to
> check the old soft limit with the new soft limit and the new hard
> limit with the old hard limit. There is never a check to ensure the
> new soft limit never exceeds the new hard limit.
>
> Just try "ulimit -H -m 10000" for memory limits that were not
> previously set. You end up with (hard limit = 10000) < (soft limit =
> unlimited).
>
> Fix is trivial.

--- trivial-2.5-bk/kernel/sys.c.orig 2002-12-06 13:56:43.000000000 +1100
+++ trivial-2.5-bk/kernel/sys.c 2002-12-06 13:56:43.000000000 +1100
@@ -1233,6 +1233,8 @@
                 return -EINVAL;
         if(copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
                 return -EFAULT;
+ if (new_rlim.rlim_cur > new_rlim.rlim_max)
+ return -EINVAL;
         old_rlim = current->rlim + resource;
         if (((new_rlim.rlim_cur > old_rlim->rlim_max) ||
              (new_rlim.rlim_max > old_rlim->rlim_max)) && 

-- 
  Don't blame me: the Monkey is driving
  File: Kingsley Cheung <kingsley@aurema.com>: Re: [PATCH] setrlimit incorrectly allows hard limits to exceed soft limits
-
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