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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id i62-20020a17090a3dc400b001facf455c91sm2649631pjc.21.2022.09.21.20.10.24 (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-fsdevel@vger.kernel.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_K=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-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.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 06/12] coredump: Proactively round up to kmalloc bucket size Date: Wed, 21 Sep 2022 20:10:07 -0700 Message-Id: <20220922031013.2150682-7-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=1167; h=from:subject; bh=pDNvsGLyQA8RpBfkkqJxHruRXSdA8gdZalovRqbX85w=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBjK9IT/n4E1MQAIRbO7TQnliesxT9vRRUjnB997VqU NfNmMx2JAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCYyvSEwAKCRCJcvTf3G3AJv1uD/ 0UeTRzC7PYbrNFpo0erBLhfyq0OXI7KWJPUznMmMf+cAop1hoIyAS6RCvOy3P43EFrYY2LvmcGU3Aj SICc7baXEFvYdMhDJ8d101AolLKruLzinzUGntwccPS2dZe2w/x8T733W5uMnEOoDIW14/zr4IUtRh Vlx7PoTaeYeaEQPZwbWSdxU7qtxeqxD9LsQu+HlBYfR1k5rQ/OwJUa0VLmxQS3VuLxNzcqUFIRrz3E N9wSWjXJ1fpBM5rUyeWWd8dLef4aKwvQUrxvsQ2VWqLB5t57NofX/QpwkS3ypabCJnUg2eUl37eba5 OV6vc8FtBSMSsXXhnZ0qRfqcqAOpIlqc5fvFIq+bl3f4xCiJNeEM7atqS3LN6ZEK9rF9EWiIyjfIU1 rFgqaXZ47QKcNt6D+tThDEVTDgBDzW+/xD6gFm/gAUYLMU55Xrc41oHohWX310hGuJ4uQfMnkpzfJD l7QDNBoaF6Eo/aHjjnO/L/2LHxrNen15gNgss8f3Pbl5cYUEIwKYQTUHz4t+WuflfhJ72ydBaVxPhi nvK5XI8oXLZUTCjvvJ0NvdCQbKmYhFiTddotTbfTvs9VyXcsa4oRA58e65OY4nlgV9+2HJHYaTy3u4 CX+OyRwkHX1tSGbw74SSBv0sSXX5LiEItWNDNN9XJyygxijXQxQ7uWbdLfNg== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 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-fsdevel@vger.kernel.org Signed-off-by: Kees Cook --- fs/coredump.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/coredump.c b/fs/coredump.c index 9f4aae202109..0894b2c35d98 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -68,7 +68,10 @@ struct core_name { static int expand_corename(struct core_name *cn, int size) { - char *corename = krealloc(cn->corename, size, GFP_KERNEL); + char *corename; + + size = kmalloc_size_roundup(size); + corename = krealloc(cn->corename, size, GFP_KERNEL); if (!corename) return -ENOMEM; @@ -76,7 +79,7 @@ static int expand_corename(struct core_name *cn, int size) if (size > core_name_size) /* racy but harmless */ core_name_size = size; - cn->size = ksize(corename); + cn->size = size; cn->corename = corename; return 0; }