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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id o18-20020a17090ad25200b001fb1de10a4dsm280956pjw.33.2023.01.04.19.37.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 Jan 2023 19:37:54 -0800 (PST) From: Kees Cook To: Jens Axboe Cc: Kees Cook , Pavel Begunkov , "Gustavo A. R. Silva" , stable@vger.kernel.org, io-uring@vger.kernel.org, Dylan Yudaken , linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH] io_uring: Replace 0-length array with flexible array Date: Wed, 4 Jan 2023 19:37:48 -0800 Message-Id: <20230105033743.never.628-kees@kernel.org> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1795; h=from:subject:message-id; bh=r+TSIVb2BAWhTrGlFufqT3ga06iplRy8uL8xmu6l8Nc=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBjtkYLP77BW3IAXqPW/RhqrA24FMPNCSI45CQs2IEd fy5cqKeJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCY7ZGCwAKCRCJcvTf3G3AJqxND/ 4oGtR93uxHdilcizcL38yy4WDqC1zZkr1T3PXAepEgKMvcdsHqd9vzYPr2LgRHkCHsXo40ZPZR82Wz sUz0G6mP2tbZB85d990jEkkNQZE6Dc6OHj5I+dEsbm59Axce8iv0TpSEt8K8CZYg3VSuG/cQwyLKWa 4LLH3lIemP13XM3j4h035U+MPCF6jawWAw4chzz75/ulJIUSvDiS0ZxuAKPYZDTbbFsqkqMZzrAp6D azrxOyTr1c22SdkFTrF+0yqN4d245n9b8ueQlddoV5yPVaOQy1oDUXFlkgXJ2jvwNPa0phSgWastVe 6fjWF2k5OHzljQeBNtb8RqEf5Ud735dMTgPEU9o3lqQc8IkmGXyAsPi89wVk/eksoWrqcMP0s6XGcP hPrzB0Ixz2AW2bM2xyWPneebhaQlYnR3RO7xn83E8lbtKSTRRxcL0KhtD4Edoizki4soYMPUHFnvnG KC1035zSBZpj9w+SWeEGDgsSJlOria6hjC0f9gfypCRMvLRdVRRhy9amB+31qZ8a5fk9TtB4jbTjZY vqZu/+TYJuwU4zTLbR8YPtSipI4GKsxg7g/aN6FGlH7euKWsWi1JfGfraY+sAB6ZsrEqH/qCcAChe8 jmUNLNZCX8679hAFztKUsOc+IgPTku8pHV1XKvutWA5doN2Yq23jvjHDPujA== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org Zero-length arrays are deprecated[1]. Replace struct io_uring_buf_ring's "bufs" with a flexible array member. (How is the size of this array verified?) Detected with GCC 13, using -fstrict-flex-arrays=3: In function 'io_ring_buffer_select', inlined from 'io_buffer_select' at io_uring/kbuf.c:183:10: io_uring/kbuf.c:141:23: warning: array subscript 255 is outside the bounds of an interior zero-length array 'struct io_uring_buf[0]' [-Wzero-length-bounds] 141 | buf = &br->bufs[head]; | ^~~~~~~~~~~~~~~ In file included from include/linux/io_uring.h:7, from io_uring/kbuf.c:10: include/uapi/linux/io_uring.h: In function 'io_buffer_select': include/uapi/linux/io_uring.h:628:41: note: while referencing 'bufs' 628 | struct io_uring_buf bufs[0]; | ^~~~ [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays Fixes: c7fb19428d67 ("io_uring: add support for ring mapped supplied buffers") Cc: Jens Axboe Cc: Pavel Begunkov Cc: "Gustavo A. R. Silva" Cc: stable@vger.kernel.org Cc: io-uring@vger.kernel.org Signed-off-by: Kees Cook --- include/uapi/linux/io_uring.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 2780bce62faf..9d8861899cde 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -625,7 +625,7 @@ struct io_uring_buf_ring { __u16 resv3; __u16 tail; }; - struct io_uring_buf bufs[0]; + struct io_uring_buf bufs[]; }; };