From c10fed329c1c104f375a75ed97ea3abef0786d62 Mon Sep 17 00:00:00 2001 From: Fei Shao Date: Thu, 21 Mar 2024 15:08:57 +0800 Subject: [PATCH] spi: spi-mt65xx: Fix NULL pointer access in interrupt handler [ Upstream commit a20ad45008a7c82f1184dc6dee280096009ece55 ] The TX buffer in spi_transfer can be a NULL pointer, so the interrupt handler may end up writing to the invalid memory and cause crashes. Add a check to trans->tx_buf before using it. Fixes: 1ce24864bff4 ("spi: mediatek: Only do dma for 4-byte aligned buffers") Signed-off-by: Fei Shao Reviewed-by: AngeloGioacchino Del Regno Link: https://msgid.link/r/20240321070942.1587146-2-fshao@chromium.org Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- drivers/spi/spi-mt65xx.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c index 49acba1dea1e..30aac6f093b2 100644 --- a/drivers/spi/spi-mt65xx.c +++ b/drivers/spi/spi-mt65xx.c @@ -659,17 +659,19 @@ static irqreturn_t mtk_spi_interrupt(int irq, void *dev_id) mdata->xfer_len = min(MTK_SPI_MAX_FIFO_SIZE, len); mtk_spi_setup_packet(master); - cnt = mdata->xfer_len / 4; - iowrite32_rep(mdata->base + SPI_TX_DATA_REG, - trans->tx_buf + mdata->num_xfered, cnt); + if (trans->tx_buf) { + cnt = mdata->xfer_len / 4; + iowrite32_rep(mdata->base + SPI_TX_DATA_REG, + trans->tx_buf + mdata->num_xfered, cnt); - remainder = mdata->xfer_len % 4; - if (remainder > 0) { - reg_val = 0; - memcpy(®_val, - trans->tx_buf + (cnt * 4) + mdata->num_xfered, - remainder); - writel(reg_val, mdata->base + SPI_TX_DATA_REG); + remainder = mdata->xfer_len % 4; + if (remainder > 0) { + reg_val = 0; + memcpy(®_val, + trans->tx_buf + (cnt * 4) + mdata->num_xfered, + remainder); + writel(reg_val, mdata->base + SPI_TX_DATA_REG); + } } mtk_spi_enable_transfer(master);