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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id u3-20020a17090341c300b0016d6963cb12sm2781495ple.304.2022.09.21.20.10.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 21 Sep 2022 20:10:26 -0700 (PDT) From: Kees Cook To: Vlastimil Babka Cc: Kees Cook , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Nick Desaulniers , Hao Luo , Marco Elver , linux-mm@kvack.org, "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Greg Kroah-Hartman , Alex Elder , Josef Bacik , David Sterba , Sumit Semwal , =?utf-8?q?Christian_K=C3=B6nig?= , Jesse Brandeburg , Daniel Micay , Yonghong Song , Miguel Ojeda , Jacob Shin , 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, linux-wireless@vger.kernel.org, llvm@lists.linux.dev, linux-hardening@vger.kernel.org Subject: [PATCH 11/12] slab: Remove __malloc attribute from realloc functions Date: Wed, 21 Sep 2022 20:10:12 -0700 Message-Id: <20220922031013.2150682-12-keescook@chromium.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220922031013.2150682-1-keescook@chromium.org> References: <20220922031013.2150682-1-keescook@chromium.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3544; h=from:subject; bh=oS2Iv+uVGC72Kt/ZsRdKSQv1v3zTVhJ3IWvWWRabp+g=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBjK9IUEKv90igkAnqqd37b6kR1bxxEz6G+6mdwmL8d hU8qttyJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCYyvSFAAKCRCJcvTf3G3AJqdIEA CK12iuKhH2Gb+F4wapUYpaSc373MS6rjJoFpsNm84+/ObvNHGEz2kq5kYHkOs7G3e8jhHlr4YXru45 YnbkR3SRCmUyJ7loADAzHlj0yCxkYniAAXvuZzfvc9luBT3TIsBLzOyoo8E8ylHkAK0aVycGXvAy+W PGkSD/jL+EQrHdUK+hra5t32/YXsbXr4NStVZ9IzHolQ9EI054AF8/LV77MBWpPIX5Ho1mGWzl1ijJ E9wFPHhl2hfKzU9eXD+N4EzOrlLceF+ztZPDuq2MdUfMxOdv5GAJKiW5FRq+IFpNkwIM9nhSPM5iQE YBr/ivEWQqdNFsPnRtgWssO370vtzYb+x61dFRrUn7/FKR7Om27TEYwAd6+P+FnDwRoMTV/BPuFe6C 7iiHIRbFsfrIUn/r4jYTZt4u6NtpaDA1FVV/Em1JDkKtSh3fWi4Ku18TGZQm81iMdScRZHubomFfI+ vxHjePLahrOHkSfaNZvuJLrLPDU7WsDADYD6e/53VTiL3yyHRtO0XH1DyMkIDUA2WPNZy6ISq70TQ5 eN54uMg3p8o5Bz9r112LSXwEkIA+2aRlSgWZDi0KwDLacLHhcuECUcvzHrANynElUzrtH5uoqtYyZh Y8ppyJSFYyPmpNrkQ/M6ZKVaeCwZCHu2ZcgtL5o8/NTiuMaB6SQl9nFcWJRg== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Precedence: bulk List-ID: X-Mailing-List: linux-media@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: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Cc: Andrew Morton Cc: Nick Desaulniers Cc: Hao Luo Cc: Marco Elver Cc: linux-mm@kvack.org Signed-off-by: Kees Cook --- include/linux/compiler_types.h | 13 +++++-------- include/linux/slab.h | 12 ++++++------ 2 files changed, 11 insertions(+), 14 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 4fc41e4ed4a2..ac3832b50dbb 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); @@ -661,10 +661,10 @@ 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; @@ -788,7 +788,7 @@ 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);