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[2001:8b0:1d0::2]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-42132471e01sm10905625e9.13.2024.05.31.05.46.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 31 May 2024 05:46:29 -0700 (PDT) From: Peter Maydell To: qemu-arm@nongnu.org, qemu-devel@nongnu.org Cc: Alistair Francis , "Edgar E. Iglesias" , Alexandra Diupina Subject: [PATCH] hw/dma/xlnx_dpdma: Read descriptor into buffer, not into pointer-to-buffer Date: Fri, 31 May 2024 13:46:28 +0100 Message-Id: <20240531124628.476938-1-peter.maydell@linaro.org> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Received-SPF: pass client-ip=2a00:1450:4864:20::32e; envelope-from=peter.maydell@linaro.org; helo=mail-wm1-x32e.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org In fdf029762f501 we factored out the handling of reading and writing DMA descriptors from guest memory. Unfortunately we accidentally made the descriptor-read read the descriptor into the address of the buffer rather than into the buffer, because we didn't notice we needed to update the arguments to the dma_memory_read() call. Before the refactoring, "&desc" is the address of a local struct DPDMADescriptor variable in xlnx_dpdma_start_operation(), which is the correct target for the guest-memory-read. But after the refactoring 'desc' is the "DPDMADescriptor *desc" argument to the new function, and so it is already an address. This bug is an overrun of a stack variable, since a pointer is at most 8 bytes long and we try to read 64 bytes, as well as being incorrect behaviour. Pass 'desc' rather than '&desc' as the dma_memory_read() argument to fix this. (The same bug is not present in xlnx_dpdma_write_descriptor(), because there we are writing the descriptor from a local struct variable "DPDMADescriptor tmp_desc" and so passing &tmp_desc to dma_memory_write() is correct.) Spotted by Coverity: CID 1546649 Fixes: fdf029762f50101 ("xlnx_dpdma: fix descriptor endianness bug") Signed-off-by: Peter Maydell Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Edgar E. Iglesias --- hw/dma/xlnx_dpdma.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/dma/xlnx_dpdma.c b/hw/dma/xlnx_dpdma.c index dde4aeca401..a685bd28bb8 100644 --- a/hw/dma/xlnx_dpdma.c +++ b/hw/dma/xlnx_dpdma.c @@ -619,7 +619,7 @@ static MemTxResult xlnx_dpdma_read_descriptor(XlnxDPDMAState *s, DPDMADescriptor *desc) { MemTxResult res = dma_memory_read(&address_space_memory, desc_addr, - &desc, sizeof(DPDMADescriptor), + desc, sizeof(DPDMADescriptor), MEMTXATTRS_UNSPECIFIED); if (res) { return res;