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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id q9-20020a17090311c900b0017829f986a5sm6477104plh.133.2022.09.23.13.28.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 23 Sep 2022 13:28:25 -0700 (PDT) From: Kees Cook To: Vlastimil Babka Cc: Kees Cook , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Marco Elver , linux-mm@kvack.org, "Ruhl, Michael J" , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Greg Kroah-Hartman , Nick Desaulniers , Alex Elder , Josef Bacik , David Sterba , Sumit Semwal , =?UTF-8?q?Christian=20K=C3=B6nig?= , Jesse Brandeburg , Daniel Micay , Yonghong Song , Miguel Ojeda , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-fsdevel@vger.kernel.org, intel-wired-lan@lists.osuosl.org, dev@openvswitch.org, x86@kernel.org, llvm@lists.linux.dev, linux-hardening@vger.kernel.org Subject: [PATCH v2 01/16] slab: Remove __malloc attribute from realloc functions Date: Fri, 23 Sep 2022 13:28:07 -0700 Message-Id: <20220923202822.2667581-2-keescook@chromium.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220923202822.2667581-1-keescook@chromium.org> References: <20220923202822.2667581-1-keescook@chromium.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4158; h=from:subject; bh=MMNKX5wNJYq+FFEmxyLeG88Y0pnaYb/m5JRZI7mnarg=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBjLhbj8zMWKpgfJIfLMPzhNCTicodYe34AHw5xM3H6 j5Q5e5iJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCYy4W4wAKCRCJcvTf3G3AJkqXEA C0CZsQPuFBR2/YBQC6kBOKXs3AnUbDd1vBqtB/SiXvO/znjATFPdq/AAaSBC59HBiMKMePM5lvoiuf aYrT/n/J7UMzadTeGJDsCFyc95mxXFpunUjeXGaTgZojjSgAVg4DABiW54DaumW0lAWFAYegD26yeW JBuJYikNr/QTKW2lM4rlUyCE6YeklCEU+t6NysjAG5alyIx4W0dgH5pUSaAsO6hX65jz8XnK6X4gIg /ftbvkJQdCA8yp6HbKj3bRnJNwHhei3Ew8kR8tRkxr/QCstK0qco60yvO2mmfdDhJOTt8ljlhX+99P ki8iAJ2IUxqLrohWV0+vBNh/UwJAT/E2xl9J7vSz0a5lE1JDaJni0l7B9aWJ6wdTRIlb2RIw/25CU3 2jH0hGLqeXUGTIW8ZuajWL/FWv6nUhF3N+Zql34CZfjXaiVB/8urV6hGJYu0PjR4RhPJtooFtvcGnc NN4P/rvByw1L7/4EGJFqF8KQolNWMu558pdQ29AecI/zn4E9FW41pu2k0zXuekf9ZHdzPr//MRq0VK jji3tNn5ZbZXQWzbxXbbkECT6CK1qfq6Re4GlmJrjPbAnkWCC4gXdw7JW6JIg/Km6CtttHx519iZge eYs/03ai/ytBwKoKeQmOX9IHVAAm1pTNUYNBd0RtV+OAb1aVL8B7TsN5Okig== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org The __malloc attribute should not be applied to "realloc" functions, as the returned pointer may alias the storage of the prior pointer. Instead of splitting __malloc from __alloc_size, which would be a huge amount of churn, just create __realloc_size for the few cases where it is needed. Additionally removes the conditional test for __alloc_size__, which is always defined now. Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Cc: Andrew Morton Cc: Vlastimil Babka Cc: Roman Gushchin Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Marco Elver Cc: linux-mm@kvack.org Signed-off-by: Kees Cook --- include/linux/compiler_types.h | 13 +++++-------- include/linux/slab.h | 12 ++++++------ mm/slab_common.c | 4 ++-- 3 files changed, 13 insertions(+), 16 deletions(-) diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index 4f2a819fd60a..f141a6f6b9f6 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -271,15 +271,12 @@ struct ftrace_likely_data { /* * Any place that could be marked with the "alloc_size" attribute is also - * a place to be marked with the "malloc" attribute. Do this as part of the - * __alloc_size macro to avoid redundant attributes and to avoid missing a - * __malloc marking. + * a place to be marked with the "malloc" attribute, except those that may + * be performing a _reallocation_, as that may alias the existing pointer. + * For these, use __realloc_size(). */ -#ifdef __alloc_size__ -# define __alloc_size(x, ...) __alloc_size__(x, ## __VA_ARGS__) __malloc -#else -# define __alloc_size(x, ...) __malloc -#endif +#define __alloc_size(x, ...) __alloc_size__(x, ## __VA_ARGS__) __malloc +#define __realloc_size(x, ...) __alloc_size__(x, ## __VA_ARGS__) #ifndef asm_volatile_goto #define asm_volatile_goto(x...) asm goto(x) diff --git a/include/linux/slab.h b/include/linux/slab.h index 0fefdf528e0d..41bd036e7551 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -184,7 +184,7 @@ int kmem_cache_shrink(struct kmem_cache *s); /* * Common kmalloc functions provided by all allocators */ -void * __must_check krealloc(const void *objp, size_t new_size, gfp_t flags) __alloc_size(2); +void * __must_check krealloc(const void *objp, size_t new_size, gfp_t flags) __realloc_size(2); void kfree(const void *objp); void kfree_sensitive(const void *objp); size_t __ksize(const void *objp); @@ -647,10 +647,10 @@ static inline __alloc_size(1, 2) void *kmalloc_array(size_t n, size_t size, gfp_ * @new_size: new size of a single member of the array * @flags: the type of memory to allocate (see kmalloc) */ -static inline __alloc_size(2, 3) void * __must_check krealloc_array(void *p, - size_t new_n, - size_t new_size, - gfp_t flags) +static inline __realloc_size(2, 3) void * __must_check krealloc_array(void *p, + size_t new_n, + size_t new_size, + gfp_t flags) { size_t bytes; @@ -774,7 +774,7 @@ static inline __alloc_size(1, 2) void *kvcalloc(size_t n, size_t size, gfp_t fla } extern void *kvrealloc(const void *p, size_t oldsize, size_t newsize, gfp_t flags) - __alloc_size(3); + __realloc_size(3); extern void kvfree(const void *addr); extern void kvfree_sensitive(const void *addr, size_t len); diff --git a/mm/slab_common.c b/mm/slab_common.c index 17996649cfe3..457671ace7eb 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -1134,8 +1134,8 @@ module_init(slab_proc_init); #endif /* CONFIG_SLAB || CONFIG_SLUB_DEBUG */ -static __always_inline void *__do_krealloc(const void *p, size_t new_size, - gfp_t flags) +static __always_inline __realloc_size(2) void * +__do_krealloc(const void *p, size_t new_size, gfp_t flags) { void *ret; size_t ks; -- 2.34.1