From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kees Cook Date: Tue, 9 Jan 2018 12:55:35 -0800 Message-Id: <1515531365-37423-7-git-send-email-keescook@chromium.org> In-Reply-To: <1515531365-37423-1-git-send-email-keescook@chromium.org> References: <1515531365-37423-1-git-send-email-keescook@chromium.org> Subject: [kernel-hardening] [PATCH 06/36] usercopy: Mark kmalloc caches as usercopy caches To: linux-kernel@vger.kernel.org Cc: Kees Cook , David Windsor , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , linux-mm@kvack.org, linux-xfs@vger.kernel.org, Linus Torvalds , Alexander Viro , Andy Lutomirski , Christoph Hellwig , "David S. Miller" , Laura Abbott , Mark Rutland , "Martin K. Petersen" , Paolo Bonzini , Christian Borntraeger , Christoffer Dall , Dave Kleikamp , Jan Kara , Luis de Bethencourt , Marc Zyngier , Rik van Riel , Matthew Garrett , linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, netdev@vger.kernel.org, kernel-hardening@lists.openwall.com List-ID: From: David Windsor 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: Christoph Lameter 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 --- 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 d9939828f8e4..6488066e718a 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 fc3e66bdce75..6c9e945907b6 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -929,14 +929,15 @@ 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; @@ -1090,7 +1091,8 @@ 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); } /* @@ -1131,7 +1133,7 @@ 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 -- 2.7.4