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| author | Kees Cook <keescook@chromium.org> | 2017-11-30 13:04:32 -0800 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2018-01-15 12:07:48 -0800 |
| commit | 2d891fbc3bb681ba1f826e7ee70dbe38ca7465fe (patch) | |
| tree | 1dac3dd3aac5a0fed8046b6f85bd944211260c70 /mm/slab.c | |
| parent | afcc90f8621e289cd082ba97900e76f01afe778c (diff) | |
| download | lwn-2d891fbc3bb681ba1f826e7ee70dbe38ca7465fe.tar.gz lwn-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.c')
| -rw-r--r-- | mm/slab.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/slab.c b/mm/slab.c index 1c02f6e94235..b9b0df620bb9 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -4426,7 +4426,8 @@ void __check_heap_object(const void *ptr, unsigned long n, struct page *page, * to be a temporary method to find any missing usercopy * whitelists. */ - if (offset <= cachep->object_size && + if (usercopy_fallback && + offset <= cachep->object_size && n <= cachep->object_size - offset) { usercopy_warn("SLAB object", cachep->name, to_user, offset, n); return; |