1. 11 Mar, 2011 3 commits
  2. 10 Mar, 2011 36 commits
  3. 09 Mar, 2011 1 commit
    • Vasiliy Kulikov's avatar
      net: don't allow CAP_NET_ADMIN to load non-netdev kernel modules · 8909c9ad
      Vasiliy Kulikov authored
      Since a8f80e8f any process with
      CAP_NET_ADMIN may load any module from /lib/modules/.  This doesn't mean
      that CAP_NET_ADMIN is a superset of CAP_SYS_MODULE as modules are
      limited to /lib/modules/**.  However, CAP_NET_ADMIN capability shouldn't
      allow anybody load any module not related to networking.
      
      This patch restricts an ability of autoloading modules to netdev modules
      with explicit aliases.  This fixes CVE-2011-1019.
      
      Arnd Bergmann suggested to leave untouched the old pre-v2.6.32 behavior
      of loading netdev modules by name (without any prefix) for processes
      with CAP_SYS_MODULE to maintain the compatibility with network scripts
      that use autoloading netdev modules by aliases like "eth0", "wlan0".
      
      Currently there are only three users of the feature in the upstream
      kernel: ipip, ip_gre and sit.
      
          root@albatros:~# capsh --drop=$(seq -s, 0 11),$(seq -s, 13 34) --
          root@albatros:~# grep Cap /proc/$$/status
          CapInh:	0000000000000000
          CapPrm:	fffffff800001000
          CapEff:	fffffff800001000
          CapBnd:	fffffff800001000
          root@albatros:~# modprobe xfs
          FATAL: Error inserting xfs
          (/lib/modules/2.6.38-rc6-00001-g2bf4ca3/kernel/fs/xfs/xfs.ko): Operation not permitted
          root@albatros:~# lsmod | grep xfs
          root@albatros:~# ifconfig xfs
          xfs: error fetching interface information: Device not found
          root@albatros:~# lsmod | grep xfs
          root@albatros:~# lsmod | grep sit
          root@albatros:~# ifconfig sit
          sit: error fetching interface information: Device not found
          root@albatros:~# lsmod | grep sit
          root@albatros:~# ifconfig sit0
          sit0      Link encap:IPv6-in-IPv4
      	      NOARP  MTU:1480  Metric:1
      
          root@albatros:~# lsmod | grep sit
          sit                    10457  0
          tunnel4                 2957  1 sit
      
      For CAP_SYS_MODULE module loading is still relaxed:
      
          root@albatros:~# grep Cap /proc/$$/status
          CapInh:	0000000000000000
          CapPrm:	ffffffffffffffff
          CapEff:	ffffffffffffffff
          CapBnd:	ffffffffffffffff
          root@albatros:~# ifconfig xfs
          xfs: error fetching interface information: Device not found
          root@albatros:~# lsmod | grep xfs
          xfs                   745319  0
      
      Reference: https://lkml.org/lkml/2011/2/24/203Signed-off-by: default avatarVasiliy Kulikov <segoon@openwall.com>
      Signed-off-by: default avatarMichael Tokarev <mjt@tls.msk.ru>
      Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
      Acked-by: default avatarKees Cook <kees.cook@canonical.com>
      Signed-off-by: default avatarJames Morris <jmorris@namei.org>
      8909c9ad