Yama: add PR_SET_PTRACER_ANY

For a process to entirely disable Yama ptrace restrictions, it can use
the special PR_SET_PTRACER_ANY pid to indicate that any otherwise allowed
process may ptrace it. This is stronger than calling PR_SET_PTRACER with
pid "1" because it includes processes in external pid namespaces. This is
currently needed by the Chrome renderer, since its crash handler (Breakpad)
runs external to the renderer's pid namespace.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/prctl.h b/include/linux/prctl.h
index 4d0e5bc5458c..a0413ac3abe8 100644
--- a/include/linux/prctl.h
+++ b/include/linux/prctl.h
@@ -119,5 +119,6 @@
  * A value of 0 mean "no process".
  */
 #define PR_SET_PTRACER 0x59616d61
+# define PR_SET_PTRACER_ANY ((unsigned long)-1)
 
 #endif /* _LINUX_PRCTL_H */