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authorLinus Torvalds <torvalds@linux-foundation.org>2016-08-08 14:48:14 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-08-08 14:48:14 -0700
commit1eccfa090eaea22558570054bbdc147817e1df5e (patch)
treea0adfdb87319abef88f575ee34314649193b7e92 /mm/slub.c
parent1bd4403d86a1c06cb6cc9ac87664a0c9d3413d51 (diff)
parented18adc1cdd00a5c55a20fbdaed4804660772281 (diff)
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Merge tag 'usercopy-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull usercopy protection from Kees Cook: "Tbhis implements HARDENED_USERCOPY verification of copy_to_user and copy_from_user bounds checking for most architectures on SLAB and SLUB" * tag 'usercopy-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: mm: SLUB hardened usercopy support mm: SLAB hardened usercopy support s390/uaccess: Enable hardened usercopy sparc/uaccess: Enable hardened usercopy powerpc/uaccess: Enable hardened usercopy ia64/uaccess: Enable hardened usercopy arm64/uaccess: Enable hardened usercopy ARM: uaccess: Enable hardened usercopy x86/uaccess: Enable hardened usercopy mm: Hardened usercopy mm: Implement stack frame object validation mm: Add is_migrate_cma_page
Diffstat (limited to 'mm/slub.c')
-rw-r--r--mm/slub.c40
1 files changed, 40 insertions, 0 deletions
diff --git a/mm/slub.c b/mm/slub.c
index 850737bdfbd8..cead06394e9e 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3764,6 +3764,46 @@ void *__kmalloc_node(size_t size, gfp_t flags, int node)
EXPORT_SYMBOL(__kmalloc_node);
#endif
+#ifdef CONFIG_HARDENED_USERCOPY
+/*
+ * Rejects objects that are incorrectly sized.
+ *
+ * Returns NULL if check passes, otherwise const char * to name of cache
+ * to indicate an error.
+ */
+const char *__check_heap_object(const void *ptr, unsigned long n,
+ struct page *page)
+{
+ struct kmem_cache *s;
+ unsigned long offset;
+ size_t object_size;
+
+ /* Find object and usable object size. */
+ s = page->slab_cache;
+ object_size = slab_ksize(s);
+
+ /* Reject impossible pointers. */
+ if (ptr < page_address(page))
+ return s->name;
+
+ /* Find offset within object. */
+ offset = (ptr - page_address(page)) % s->size;
+
+ /* Adjust for redzone and reject if within the redzone. */
+ if (kmem_cache_debug(s) && s->flags & SLAB_RED_ZONE) {
+ if (offset < s->red_left_pad)
+ return s->name;
+ offset -= s->red_left_pad;
+ }
+
+ /* Allow address range falling entirely within object size. */
+ if (offset <= object_size && n <= object_size - offset)
+ return NULL;
+
+ return s->name;
+}
+#endif /* CONFIG_HARDENED_USERCOPY */
+
static size_t __ksize(const void *object)
{
struct page *page;