| Message ID | 20211013181658.1020262-6-samitolvanen@google.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | x86: Add support for Clang CFI | expand |
On Wed, Oct 13, 2021 at 11:16:48AM -0700, Sami Tolvanen wrote: > If allocate_probes fails, func_remove replaces the old function > with a pointer to tp_stub_func, which is called using a mismatching > function pointer that will always trip indirect call checks with > CONFIG_CFI_CLANG. Use DEFINE_CFI_IMMEDATE_RETURN_STUB to define > tp_stub_func to allow it to pass CFI checking. > > Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org>
On Wed, 13 Oct 2021 11:16:48 -0700 Sami Tolvanen <samitolvanen@google.com> wrote: > If allocate_probes fails, func_remove replaces the old function > with a pointer to tp_stub_func, which is called using a mismatching > function pointer that will always trip indirect call checks with > CONFIG_CFI_CLANG. Use DEFINE_CFI_IMMEDATE_RETURN_STUB to define > tp_stub_func to allow it to pass CFI checking. > > Signed-off-by: Sami Tolvanen <samitolvanen@google.com> > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > Tested-by: Nick Desaulniers <ndesaulniers@google.com> > Tested-by: Sedat Dilek <sedat.dilek@gmail.com> > --- > kernel/tracepoint.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c > index 64ea283f2f86..8a0d463c8507 100644 > --- a/kernel/tracepoint.c > +++ b/kernel/tracepoint.c > @@ -9,6 +9,7 @@ > #include <linux/list.h> > #include <linux/rcupdate.h> > #include <linux/tracepoint.h> > +#include <linux/cfi.h> > #include <linux/err.h> > #include <linux/slab.h> > #include <linux/sched/signal.h> > @@ -99,10 +100,7 @@ struct tp_probes { > }; > > /* Called in removal of a func but failed to allocate a new tp_funcs */ > -static void tp_stub_func(void) > -{ > - return; > -} > +static DEFINE_CFI_IMMEDIATE_RETURN_STUB(tp_stub_func); Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> -- Steve > > static inline void *allocate_probes(int count) > {
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index 64ea283f2f86..8a0d463c8507 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -9,6 +9,7 @@ #include <linux/list.h> #include <linux/rcupdate.h> #include <linux/tracepoint.h> +#include <linux/cfi.h> #include <linux/err.h> #include <linux/slab.h> #include <linux/sched/signal.h> @@ -99,10 +100,7 @@ struct tp_probes { }; /* Called in removal of a func but failed to allocate a new tp_funcs */ -static void tp_stub_func(void) -{ - return; -} +static DEFINE_CFI_IMMEDIATE_RETURN_STUB(tp_stub_func); static inline void *allocate_probes(int count) {