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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id i8-20020a170902c94800b00178143a728esm2758861pla.275.2022.09.21.20.10.24 (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 , linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , "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 , Marco Elver , Miguel Ojeda , Jacob Shin , linux-kernel@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, linux-btrfs@vger.kernel.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 05/12] dma-buf: Proactively round up to kmalloc bucket size Date: Wed, 21 Sep 2022 20:10:06 -0700 Message-Id: <20220922031013.2150682-6-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 Content-Type: text/plain; charset=UTF-8 X-Developer-Signature: v=1; a=openpgp-sha256; l=1448; h=from:subject; bh=58mLiyNPt53YHcQiP0NJ/gcO5KVNHG9xKF/nxWP5lU4=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBjK9IT0VAPWCWir3uMps9kCdjSMILjRU6yciDG9uFs fWbeIjWJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCYyvSEwAKCRCJcvTf3G3AJuZ5EA CTJrl1LYI7CQAG4pCtipLkuzhhHVBFayO1cJ9nr4E0Jm4P1ZR+BSgD/HPdeicWCgV2fEGCG3A3qzTO bp/9wj/VPvNh93gqjrf2HSe113aZFNagRxlssfUYxwkKTY+LPLzDzin95QfiHah48Jg0HBw8zKWEmX dZTJH7KlwTcHEy9Bz5p3PA4qx+B3pkBrNQ0zdb4io0a7ErunaXVRCSpt2tZNukDe/wt1CXiR/32N+T 1euSAVbSYv0W0fFslnfEqztbrNKxL91NWnvy3XzftablM4/PXqSNUqv6xYBt7IY33WxxP+/g2Fn7HD 6QmdkXUhTr9armjFjNYZMQo0prwqkn0FJaXEIed35vePpH2uibYbE4OwOA2Dyo4lUtHPs/KAKQYEB3 6oCNer7mpHEc9oOoqN35lm+ZhZ9UmAPZl/X1Np9gol6eRnt/yo2BbllRVW8PfKLVzPclAS1ny/vZEN uVJmqmDUdiq2OpecYEKuqhvI07vawcYvhSB6Au1f9Ys6viXBeeurbiQKrvf0oP7kADVYUzN9YCua/x a6zit1PoOjCMh44PKnVGgBRCRhU0CfvSYrhoxA8P45Ye7BiKkBm0StH0S/n/9duZxNKqbCFgYNdviR h0OHIRRNJYqc0Tw95yUM7tJKCf1eAwytfKrF8F6YwYcUQ/V1S+/AOfGfUWHQ== 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 Instead of discovering the kmalloc bucket size _after_ allocation, round up proactively so the allocation is explicitly made for the full size, allowing the compiler to correctly reason about the resulting size of the buffer through the existing __alloc_size() hint. Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org Signed-off-by: Kees Cook --- drivers/dma-buf/dma-resv.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c index 205acb2c744d..a20f6db99b8f 100644 --- a/drivers/dma-buf/dma-resv.c +++ b/drivers/dma-buf/dma-resv.c @@ -98,12 +98,17 @@ static void dma_resv_list_set(struct dma_resv_list *list, static struct dma_resv_list *dma_resv_list_alloc(unsigned int max_fences) { struct dma_resv_list *list; + size_t size = struct_size(list, table, max_fences); - list = kmalloc(struct_size(list, table, max_fences), GFP_KERNEL); + /* Round up to the next kmalloc bucket size. */ + size = kmalloc_size_roundup(size); + + list = kmalloc(size, GFP_KERNEL); if (!list) return NULL; - list->max_fences = (ksize(list) - offsetof(typeof(*list), table)) / + /* Given the resulting bucket size, recalculated max_fences. */ + list->max_fences = (size - offsetof(typeof(*list), table)) / sizeof(*list->table); return list; -- 2.34.1