usercopy: Mark kmalloc caches as usercopy caches

Mark the kmalloc slab caches as entirely whitelisted. These caches
are frequently used to fulfill kernel allocations that contain data
to be copied to/from userspace. Internal-only uses are also common,
but are scattered in the kernel. For now, mark all the kmalloc caches
as whitelisted.

This patch is modified from Brad Spengler/PaX Team's PAX_USERCOPY
whitelisting code in the last public patch of grsecurity/PaX based on my
understanding of the code. Changes or omissions from the original code are
mine and don't reflect the original grsecurity/PaX code.

Signed-off-by: David Windsor <dave@nullcore.net>
[kees: merged in moved kmalloc hunks, adjust commit log]
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Cc: linux-xfs@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Christoph Lameter <cl@linux.com>

diff --git a/mm/slab.c b/mm/slab.c
index b9b0df6..dd367fe 100644 (file)
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1291,7 +1291,8 @@ void __init kmem_cache_init(void)
         */
        kmalloc_caches[INDEX_NODE] = create_kmalloc_cache(
                                kmalloc_info[INDEX_NODE].name,
-                               kmalloc_size(INDEX_NODE), ARCH_KMALLOC_FLAGS);
+                               kmalloc_size(INDEX_NODE), ARCH_KMALLOC_FLAGS,
+                               0, kmalloc_size(INDEX_NODE));
        slab_state = PARTIAL_NODE;
        setup_kmalloc_cache_index_table();
 

diff --git a/mm/slab.h b/mm/slab.h
index 8f30307..1f013f7 100644 (file)
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -97,7 +97,8 @@ struct kmem_cache *kmalloc_slab(size_t, gfp_t);
 int __kmem_cache_create(struct kmem_cache *, slab_flags_t flags);
 
 extern struct kmem_cache *create_kmalloc_cache(const char *name, size_t size,
-                       slab_flags_t flags);
+                       slab_flags_t flags, size_t useroffset,
+                       size_t usersize);
 extern void create_boot_cache(struct kmem_cache *, const char *name,
                        size_t size, slab_flags_t flags, size_t useroffset,
                        size_t usersize);

diff --git a/mm/slab_common.c b/mm/slab_common.c
index a51f654..8ac2a63 100644 (file)
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -937,14 +937,15 @@ void __init create_boot_cache(struct kmem_cache *s, const char *name, size_t siz
 }
 
 struct kmem_cache *__init create_kmalloc_cache(const char *name, size_t size,
-                               slab_flags_t flags)
+                               slab_flags_t flags, size_t useroffset,
+                               size_t usersize)
 {
        struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
 
        if (!s)
                panic("Out of memory when creating slab %s\n", name);
 
-       create_boot_cache(s, name, size, flags, 0, size);
+       create_boot_cache(s, name, size, flags, useroffset, usersize);
        list_add(&s->list, &slab_caches);
        memcg_link_cache(s);
        s->refcount = 1;
@@ -1098,7 +1099,8 @@ void __init setup_kmalloc_cache_index_table(void)
 static void __init new_kmalloc_cache(int idx, slab_flags_t flags)
 {
        kmalloc_caches[idx] = create_kmalloc_cache(kmalloc_info[idx].name,
-                                       kmalloc_info[idx].size, flags);
+                                       kmalloc_info[idx].size, flags, 0,
+                                       kmalloc_info[idx].size);
 }
 
 /*
@@ -1139,7 +1141,7 @@ void __init create_kmalloc_caches(slab_flags_t flags)
 
                        BUG_ON(!n);
                        kmalloc_dma_caches[i] = create_kmalloc_cache(n,
-                               size, SLAB_CACHE_DMA | flags);
+                               size, SLAB_CACHE_DMA | flags, 0, 0);
                }
        }
 #endif