From 6c0c21adc742a255f0203ef76ef0ed6c8c3b0630 Mon Sep 17 00:00:00 2001 From: David Windsor Date: Sat, 10 Jun 2017 22:50:47 -0400 Subject: [PATCH] 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 [kees: merged in moved kmalloc hunks, adjust commit log] Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Cc: Andrew Morton Cc: linux-mm@kvack.org Cc: linux-xfs@vger.kernel.org Signed-off-by: Kees Cook Acked-by: Christoph Lameter --- mm/slab.c | 3 ++- mm/slab.h | 3 ++- mm/slab_common.c | 10 ++++++---- 3 files changed, 10 insertions(+), 6 deletions(-) diff --git a/mm/slab.c b/mm/slab.c index b9b0df620bb9..dd367fe17a4e 100644 --- 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 8f3030788e01..1f013f7795c6 100644 --- 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 a51f65408637..8ac2a6320a6c 100644 --- 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