[v5,2/6] mm/slab: Plumb kmem_buckets into __do_kmalloc_node()

Message ID	20240619193357.1333772-2-kees@kernel.org (mailing list archive)
State	New
Headers	show Return-Path: <owner-linux-mm@kvack.org> From: Kees Cook <kees@kernel.org> To: Vlastimil Babka <vbabka@suse.cz> Cc: Kees Cook <kees@kernel.org>, "GONG, Ruiqi" <gongruiqi@huaweicloud.com>, Christoph Lameter <cl@linux.com>, Pekka Enberg <penberg@kernel.org>, David Rientjes <rientjes@google.com>, Joonsoo Kim <iamjoonsoo.kim@lge.com>, jvoisin <julien.voisin@dustri.org>, Andrew Morton <akpm@linux-foundation.org>, Roman Gushchin <roman.gushchin@linux.dev>, Hyeonggon Yoo <42.hyeyoo@gmail.com>, Xiu Jianfeng <xiujianfeng@huawei.com>, Suren Baghdasaryan <surenb@google.com>, Kent Overstreet <kent.overstreet@linux.dev>, Jann Horn <jannh@google.com>, Matteo Rizzo <matteorizzo@google.com>, Thomas Graf <tgraf@suug.ch>, Herbert Xu <herbert@gondor.apana.org.au>, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-hardening@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH v5 2/6] mm/slab: Plumb kmem_buckets into __do_kmalloc_node() Date: Wed, 19 Jun 2024 12:33:50 -0700 Message-Id: <20240619193357.1333772-2-kees@kernel.org> In-Reply-To: <20240619192131.do.115-kees@kernel.org> References: <20240619192131.do.115-kees@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org Precedence: bulk
Series	slab: Introduce dedicated bucket allocator \| expand [v5,0/6] slab: Introduce dedicated bucket allocator [v5,1/6] mm/slab: Introduce kmem_buckets typedef [v5,2/6] mm/slab: Plumb kmem_buckets into __do_kmalloc_node() [v5,3/6] mm/slab: Introduce kvmalloc_buckets_node() that can take kmem_buckets argument [v5,4/6] mm/slab: Introduce kmem_buckets_create() and family [v5,5/6] ipc, msg: Use dedicated slab buckets for alloc_msg() [v5,6/6] mm/util: Use dedicated slab buckets for memdup_user()

diff --git a/include/linux/slab.h b/include/linux/slab.h index 8a006fac57c6..708bde6039f0 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -570,6 +570,21 @@ void *kmem_cache_alloc_node_noprof(struct kmem_cache *s, gfp_t flags, int node) __assume_slab_alignment __malloc; #define kmem_cache_alloc_node(...) alloc_hooks(kmem_cache_alloc_node_noprof(__VA_ARGS__)) +/* + * These macros allow declaring a kmem_buckets * parameter alongside size, which + * can be compiled out with CONFIG_SLAB_BUCKETS=n so that a large number of call + * sites don't have to pass NULL. + */ +#ifdef CONFIG_SLAB_BUCKETS +#define DECL_BUCKET_PARAMS(_size, _b) size_t (_size), kmem_buckets *(_b) +#define PASS_BUCKET_PARAMS(_size, _b) (_size), (_b) +#define PASS_BUCKET_PARAM(_b) (_b) +#else +#define DECL_BUCKET_PARAMS(_size, _b) size_t (_size) +#define PASS_BUCKET_PARAMS(_size, _b) (_size) +#define PASS_BUCKET_PARAM(_b) NULL +#endif + /* * The following functions are not to be used directly and are intended only * for internal use from kmalloc() and kmalloc_node() @@ -579,7 +594,7 @@ void *kmem_cache_alloc_node_noprof(struct kmem_cache *s, gfp_t flags, void *__kmalloc_noprof(size_t size, gfp_t flags) __assume_kmalloc_alignment __alloc_size(1); -void *__kmalloc_node_noprof(size_t size, gfp_t flags, int node) +void *__kmalloc_node_noprof(DECL_BUCKET_PARAMS(size, b), gfp_t flags, int node) __assume_kmalloc_alignment __alloc_size(1); void *__kmalloc_cache_noprof(struct kmem_cache *s, gfp_t flags, size_t size) @@ -679,7 +694,7 @@ static __always_inline __alloc_size(1) void *kmalloc_node_noprof(size_t size, gf kmalloc_caches[kmalloc_type(flags, _RET_IP_)][index], flags, node, size); } - return __kmalloc_node_noprof(size, flags, node); + return __kmalloc_node_noprof(PASS_BUCKET_PARAMS(size, NULL), flags, node); } #define kmalloc_node(...) alloc_hooks(kmalloc_node_noprof(__VA_ARGS__)) @@ -730,8 +745,10 @@ static inline __realloc_size(2, 3) void * __must_check krealloc_array_noprof(voi */ #define kcalloc(n, size, flags) kmalloc_array(n, size, (flags) | __GFP_ZERO) -void *kmalloc_node_track_caller_noprof(size_t size, gfp_t flags, int node, - unsigned long caller) __alloc_size(1); +void *__kmalloc_node_track_caller_noprof(DECL_BUCKET_PARAMS(size, b), gfp_t flags, int node, + unsigned long caller) __alloc_size(1); +#define kmalloc_node_track_caller_noprof(size, flags, node, caller) \ + __kmalloc_node_track_caller_noprof(PASS_BUCKET_PARAMS(size, NULL), flags, node, caller) #define kmalloc_node_track_caller(...) \ alloc_hooks(kmalloc_node_track_caller_noprof(__VA_ARGS__, _RET_IP_)) @@ -757,7 +774,7 @@ static inline __alloc_size(1, 2) void *kmalloc_array_node_noprof(size_t n, size_ return NULL; if (__builtin_constant_p(n) && __builtin_constant_p(size)) return kmalloc_node_noprof(bytes, flags, node); - return __kmalloc_node_noprof(bytes, flags, node); + return __kmalloc_node_noprof(PASS_BUCKET_PARAMS(bytes, NULL), flags, node); } #define kmalloc_array_node(...) alloc_hooks(kmalloc_array_node_noprof(__VA_ARGS__)) diff --git a/mm/Kconfig b/mm/Kconfig index b4cb45255a54..20bb71e241c3 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -273,6 +273,22 @@ config SLAB_FREELIST_HARDENED sacrifices to harden the kernel slab allocator against common freelist exploit methods. +config SLAB_BUCKETS + bool "Support allocation from separate kmalloc buckets" + depends on !SLUB_TINY + help + Kernel heap attacks frequently depend on being able to create + specifically-sized allocations with user-controlled contents + that will be allocated into the same kmalloc bucket as a + target object. To avoid sharing these allocation buckets, + provide an explicitly separated set of buckets to be used for + user-controlled allocations. This may very slightly increase + memory fragmentation, though in practice it's only a handful + of extra pages since the bulk of user-controlled allocations + are relatively long-lived. + + If unsure, say Y. + config SLUB_STATS default n bool "Enable performance statistics" diff --git a/mm/slab.h b/mm/slab.h index b16e63191578..d5e8034af9d5 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -403,16 +403,18 @@ static inline unsigned int size_index_elem(unsigned int bytes) * KMALLOC_MAX_CACHE_SIZE and the caller must check that. */ static inline struct kmem_cache * -kmalloc_slab(size_t size, gfp_t flags, unsigned long caller) +kmalloc_slab(size_t size, kmem_buckets *b, gfp_t flags, unsigned long caller) { unsigned int index; + if (!b) + b = &kmalloc_caches[kmalloc_type(flags, caller)]; if (size <= 192) index = kmalloc_size_index[size_index_elem(size)]; else index = fls(size - 1); - return kmalloc_caches[kmalloc_type(flags, caller)][index]; + return (*b)[index]; } gfp_t kmalloc_fix_flags(gfp_t flags); diff --git a/mm/slab_common.c b/mm/slab_common.c index e0b1c109bed2..9b0f2ef951f1 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -702,7 +702,7 @@ size_t kmalloc_size_roundup(size_t size) * The flags don't matter since size_index is common to all. * Neither does the caller for just getting ->object_size. */ - return kmalloc_slab(size, GFP_KERNEL, 0)->object_size; + return kmalloc_slab(size, NULL, GFP_KERNEL, 0)->object_size; } /* Above the smaller buckets, size is a multiple of page size. */ diff --git a/mm/slub.c b/mm/slub.c index 3d19a0ee411f..80f0a51242d1 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -4117,7 +4117,7 @@ void *__kmalloc_large_node_noprof(size_t size, gfp_t flags, int node) EXPORT_SYMBOL(__kmalloc_large_node_noprof); static __always_inline -void *__do_kmalloc_node(size_t size, gfp_t flags, int node, +void *__do_kmalloc_node(size_t size, kmem_buckets *b, gfp_t flags, int node, unsigned long caller) { struct kmem_cache *s; @@ -4133,32 +4133,32 @@ void *__do_kmalloc_node(size_t size, gfp_t flags, int node, if (unlikely(!size)) return ZERO_SIZE_PTR; - s = kmalloc_slab(size, flags, caller); + s = kmalloc_slab(size, b, flags, caller); ret = slab_alloc_node(s, NULL, flags, node, caller, size); ret = kasan_kmalloc(s, ret, size, flags); trace_kmalloc(caller, ret, size, s->size, flags, node); return ret; } - -void *__kmalloc_node_noprof(size_t size, gfp_t flags, int node) +void *__kmalloc_node_noprof(DECL_BUCKET_PARAMS(size, b), gfp_t flags, int node) { - return __do_kmalloc_node(size, flags, node, _RET_IP_); + return __do_kmalloc_node(size, PASS_BUCKET_PARAM(b), flags, node, _RET_IP_); } EXPORT_SYMBOL(__kmalloc_node_noprof); void *__kmalloc_noprof(size_t size, gfp_t flags) { - return __do_kmalloc_node(size, flags, NUMA_NO_NODE, _RET_IP_); + return __do_kmalloc_node(size, NULL, flags, NUMA_NO_NODE, _RET_IP_); } EXPORT_SYMBOL(__kmalloc_noprof); -void *kmalloc_node_track_caller_noprof(size_t size, gfp_t flags, - int node, unsigned long caller) +void *__kmalloc_node_track_caller_noprof(DECL_BUCKET_PARAMS(size, b), gfp_t flags, + int node, unsigned long caller) { - return __do_kmalloc_node(size, flags, node, caller); + return __do_kmalloc_node(size, PASS_BUCKET_PARAM(b), flags, node, caller); + } -EXPORT_SYMBOL(kmalloc_node_track_caller_noprof); +EXPORT_SYMBOL(__kmalloc_node_track_caller_noprof); void *__kmalloc_cache_noprof(struct kmem_cache *s, gfp_t gfpflags, size_t size) {

[v5,2/6] mm/slab: Plumb kmem_buckets into __do_kmalloc_node()

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