Yama: handle 32-bit userspace prctl
authorKees Cook <keescook@chromium.org>
Mon, 27 Aug 2012 18:38:13 +0000 (11:38 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sun, 7 Oct 2012 15:39:34 +0000 (08:39 -0700)
commit762083a99afd67cc2661e3a7de97abd6ab657dce
treeac67ed44c23a870f7b4b1276f89a4acf7b5a9915
parent9c9cc09d08b083a38a341195597c6809113454c7
Yama: handle 32-bit userspace prctl

commit 2e4930eb7c8fb20a39dfb5f8a8f80402710dcea8 upstream.

When running a 64-bit kernel and receiving prctls from a 32-bit
userspace, the "-1" used as an unsigned long will end up being
misdetected. The kernel is looking for 0xffffffffffffffff instead of
0xffffffff. Since prctl lacks a distinct compat interface, Yama needs
to handle this translation itself. As such, support either value as
meaning PR_SET_PTRACER_ANY, to avoid breaking the ABI for 64-bit.

Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
security/yama/yama_lsm.c