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authorKees Cook <keescook@chromium.org>2017-11-30 22:04:32 +0100
committerKees Cook <keescook@chromium.org>2018-01-15 21:07:48 +0100
commit2d891fbc3bb681ba1f826e7ee70dbe38ca7465fe (patch)
tree1dac3dd3aac5a0fed8046b6f85bd944211260c70 /mm/slab_common.c
parentusercopy: WARN() on slab cache usercopy region violations (diff)
downloadlinux-2d891fbc3bb681ba1f826e7ee70dbe38ca7465fe.tar.xz
linux-2d891fbc3bb681ba1f826e7ee70dbe38ca7465fe.zip
usercopy: Allow strict enforcement of whitelists
This introduces CONFIG_HARDENED_USERCOPY_FALLBACK to control the behavior of hardened usercopy whitelist violations. By default, whitelist violations will continue to WARN() so that any bad or missing usercopy whitelists can be discovered without being too disruptive. If this config is disabled at build time or a system is booted with "slab_common.usercopy_fallback=0", usercopy whitelists will BUG() instead of WARN(). This is useful for admins that want to use usercopy whitelists immediately. Suggested-by: Matthew Garrett <mjg59@google.com> Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'mm/slab_common.c')
-rw-r--r--mm/slab_common.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/mm/slab_common.c b/mm/slab_common.c
index fc3e66bdce75..a51f65408637 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -31,6 +31,14 @@ LIST_HEAD(slab_caches);
DEFINE_MUTEX(slab_mutex);
struct kmem_cache *kmem_cache;
+#ifdef CONFIG_HARDENED_USERCOPY
+bool usercopy_fallback __ro_after_init =
+ IS_ENABLED(CONFIG_HARDENED_USERCOPY_FALLBACK);
+module_param(usercopy_fallback, bool, 0400);
+MODULE_PARM_DESC(usercopy_fallback,
+ "WARN instead of reject usercopy whitelist violations");
+#endif
+
static LIST_HEAD(slab_caches_to_rcu_destroy);
static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work);
static DECLARE_WORK(slab_caches_to_rcu_destroy_work,