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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>
This commit is contained in:
David Windsor 2017-06-10 22:50:47 -04:00 committed by Kees Cook
parent 2d891fbc3b
commit 6c0c21adc7
3 changed files with 10 additions and 6 deletions
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3
mm/slab.c
View File

@ -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();

3
mm/slab.h
View File

@ -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);

10
mm/slab_common.c
View File

@ -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