[PATCH] setrlimit incorrectly allows hard limits to exceed soft limits

[PATCH] setrlimit incorrectly allows hard limits to exceed soft limits

[Kingsley Cheung]

Hi,

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.

--- sys.c       Sat Aug  3 10:39:46 2002
+++ edited.sys.c        Mon Nov 11 14:49:19 2002
@@ -1118,6 +1118,8 @@
 
        if (resource >= RLIM_NLIMITS)
                return -EINVAL;
+       if (new_rlim.rlim_cur > new_rlim.rlim_max)
+               return -EINVAL;
        if(copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
                return -EFAULT;
        old_rlim = current->rlim + resource;

--
			Kingsley

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

[Kingsley Cheung]

Oops, should be after the copy :-(

--- sys.c       Sat Aug  3 10:39:46 2002
+++ edited.sys.c        Mon Nov 11 15:56:51 2002
@@ -1120,6 +1120,8 @@
                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)) &&


On Mon, Nov 11, 2002 at 03:10:05PM +1100, Kingsley Cheung wrote:
> Hi,
> 
> 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.
> 
> --- sys.c       Sat Aug  3 10:39:46 2002
> +++ edited.sys.c        Mon Nov 11 14:49:19 2002
> @@ -1118,6 +1118,8 @@
>  
>         if (resource >= RLIM_NLIMITS)
>                 return -EINVAL;
> +       if (new_rlim.rlim_cur > new_rlim.rlim_max)
> +               return -EINVAL;
>         if(copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
>                 return -EFAULT;
>         old_rlim = current->rlim + resource;
> 

-- 
		Kingsley