Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751564AbbL0KRN (ORCPT ); Sun, 27 Dec 2015 05:17:13 -0500 Received: from mail-pa0-f46.google.com ([209.85.220.46]:35985 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750884AbbL0KRL (ORCPT ); Sun, 27 Dec 2015 05:17:11 -0500 From: Nicolas Boichat To: Mark Brown Cc: Matthias Brugger , linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, glider@chromium.org, Leilk Liu Subject: [PATCH] spi: mediatek: Prevent overflows in FIFO transfers Date: Sun, 27 Dec 2015 18:17:06 +0800 Message-Id: <1451211426-20436-1-git-send-email-drinkcat@chromium.org> X-Mailer: git-send-email 2.6.0.rc2.230.g3dd15c0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2754 Lines: 86 In the case where transfer length is not a multiple of 4, KASAN reports 2 out-of-bounds memory accesses: - mtk_spi_interrupt: ioread32_rep writes past the end of trans->rx_buf. - mtk_spi_fifo_transfer: iowrite32_rep reads past the end of xfer->tx_buf. Fix this by using memcpy on the remainder of the bytes. Signed-off-by: Nicolas Boichat --- drivers/spi/spi-mt65xx.c | 28 ++++++++++++++++++---------- 1 file changed, 18 insertions(+), 10 deletions(-) diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c index 00a36da..8763eff 100644 --- a/drivers/spi/spi-mt65xx.c +++ b/drivers/spi/spi-mt65xx.c @@ -320,7 +320,8 @@ static int mtk_spi_fifo_transfer(struct spi_master *master, struct spi_device *spi, struct spi_transfer *xfer) { - int cnt; + int cnt, remainder; + u32 reg_val; struct mtk_spi *mdata = spi_master_get_devdata(master); mdata->cur_transfer = xfer; @@ -328,12 +329,16 @@ static int mtk_spi_fifo_transfer(struct spi_master *master, mtk_spi_prepare_transfer(master, xfer); mtk_spi_setup_packet(master); - if (xfer->len % 4) - cnt = xfer->len / 4 + 1; - else - cnt = xfer->len / 4; + cnt = xfer->len / 4; iowrite32_rep(mdata->base + SPI_TX_DATA_REG, xfer->tx_buf, cnt); + remainder = xfer->len % 4; + if (remainder > 0) { + reg_val = 0; + memcpy(®_val, xfer->tx_buf + (cnt * 4), remainder); + writel(reg_val, mdata->base + SPI_TX_DATA_REG); + } + mtk_spi_enable_transfer(master); return 1; @@ -415,7 +420,7 @@ static int mtk_spi_setup(struct spi_device *spi) static irqreturn_t mtk_spi_interrupt(int irq, void *dev_id) { - u32 cmd, reg_val, cnt; + u32 cmd, reg_val, cnt, remainder; struct spi_master *master = dev_id; struct mtk_spi *mdata = spi_master_get_devdata(master); struct spi_transfer *trans = mdata->cur_transfer; @@ -428,12 +433,15 @@ static irqreturn_t mtk_spi_interrupt(int irq, void *dev_id) if (!master->can_dma(master, master->cur_msg->spi, trans)) { if (trans->rx_buf) { - if (mdata->xfer_len % 4) - cnt = mdata->xfer_len / 4 + 1; - else - cnt = mdata->xfer_len / 4; + cnt = mdata->xfer_len / 4; ioread32_rep(mdata->base + SPI_RX_DATA_REG, trans->rx_buf, cnt); + remainder = mdata->xfer_len % 4; + if (remainder > 0) { + reg_val = readl(mdata->base + SPI_RX_DATA_REG); + memcpy(trans->rx_buf + (cnt * 4), + ®_val, remainder); + } } spi_finalize_current_transfer(master); return IRQ_HANDLED; -- 2.6.0.rc2.230.g3dd15c0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/