On Thu, Jun 26, 2014 at 5:37 AM, David Drysdale <drysdale@xxxxxxxxxx> wrote: > On Mon, Jun 23, 2014 at 02:58:06PM -0700, Kees Cook wrote: >> In preparation for adding seccomp locking, move filter creation away >> from where it is checked and applied. This will allow for locking where >> no memory allocation is happening. The validation, filter attachment, >> and seccomp mode setting can all happen under the future locks. >> >> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> >> --- >> kernel/seccomp.c | 97 +++++++++++++++++++++++++++++++++++++----------------- >> 1 file changed, 67 insertions(+), 30 deletions(-) >> >> diff --git a/kernel/seccomp.c b/kernel/seccomp.c >> index afb916c7e890..edc8c79ed16d 100644 >> --- a/kernel/seccomp.c >> +++ b/kernel/seccomp.c >> @@ -515,6 +551,7 @@ static long seccomp_set_mode(unsigned long seccomp_mode, char __user *filter) >> current->seccomp.mode = seccomp_mode; >> set_thread_flag(TIF_SECCOMP); >> out: >> + seccomp_filter_free(prepared); >> return ret; >> } > > I think this needs to be inside #ifdef CONFIG_SECCOMP_FILTER to match > the definition of seccomp_filter_free: > > ../kernel/seccomp.c:554:2: error: implicit declaration of function ‘seccomp_filter_free’ [-Werror=implicit-function-declaration] Thanks for catching that! I've ended up rearranging the patch series so the prepare/attach split happens after I've split the set_mode functions now, so I've managed to avoid this condition now. :) -Kees -- Kees Cook Chrome OS Security
