coredump: make core dump functionality optional

Adds an expert Kconfig option, CONFIG_COREDUMP, which allows disabling of
core dump.  This saves approximately 2.6k in the compiled kernel, and
complements CONFIG_ELF_CORE, which now depends on it.

CONFIG_COREDUMP also disables coredump-related sysctls, except for
suid_dumpable and related functions, which are necessary for ptrace.

[akpm@linux-foundation.org: fix binfmt_aout.c build]
Signed-off-by: Alex Kelly <alex.page.kelly@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/fs/Kconfig.binfmt b/fs/Kconfig.binfmt
index 022574202749..0efd1524b977 100644
--- a/fs/Kconfig.binfmt
+++ b/fs/Kconfig.binfmt
@@ -164,3 +164,11 @@ config BINFMT_MISC
           You may say M here for module support and later load the module when
           you have use for it; the module is called binfmt_misc. If you
           don't know what to answer at this point, say Y.
+
+config COREDUMP
+        bool "Enable core dump support" if EXPERT
+        default y
+        help
+          This option enables support for performing core dumps. You almost
+          certainly want to say Y here. Not necessary on systems that never
+          need debugging or only ever run flawless code.