Re: named + capset = EPERM [Was: 2.6.24-rc3-mm2]

[Casey Schaufler <casey@schaufler-ca.com>]

--- Jiri Slaby <jirislaby@gmail.com> wrote:

> On 11/28/2007 12:41 PM, Andrew Morton wrote:
> >
>
ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.24-rc3/2.6.24-rc3-mm2/
> [...]
> > +capabilities-introduce-per-process-capability-bounding-set.patch
> 
> A regression against -mm1. This patch breaks bind (9.5.0-18.a7.fc8):
> capset(0x19980330, 0,
>
{CAP_DAC_READ_SEARCH|CAP_SETGID|CAP_SETUID|CAP_NET_BIND_SERVICE|CAP_SYS_CHROOT|CAP_SYS_RESOURCE,
>
CAP_DAC_READ_SEARCH|CAP_SETGID|CAP_SETUID|CAP_NET_BIND_SERVICE|CAP_SYS_CHROOT|CAP_SYS_RESOURCE,
> 0}) = -1 EPERM (Operation not permitted)
> 
> $ grep SEC .config
> CONFIG_SECCOMP=y
> # CONFIG_NETWORK_SECMARK is not set
> CONFIG_RPCSEC_GSS_KRB5=m
> # CONFIG_RPCSEC_GSS_SPKM3 is not set
> # CONFIG_SECURITY is not set
> # CONFIG_SECURITY_FILE_CAPABILITIES is not set
> 
> probably this hunk?:
> @@ -133,6 +119,12 @@ int cap_capset_check (struct task_struct
>                 /* incapable of using this inheritable set */
>                 return -EPERM;
>         }
> +       if (!!cap_issubset(*inheritable,
> +                          cap_combine(target->cap_inheritable,
> +                                      current->cap_bset))) {
> +               /* no new pI capabilities outside bounding set */
> +               return -EPERM;
> +       }
> 
>         /* verify restrictions on target's new Permitted set */
>         if (!cap_issubset (*permitted,

I can see that the value for CAP_LAST_CAP is not right in
include/linux/capability.h, but I don't know if that is the
only problem. I should have a patch (unless someone beats me to it)
later today.


Casey Schaufler
casey@schaufler-ca.com