diff options
| author | Nicolas Boichat <drinkcat@chromium.org> | 2015-12-27 10:17:06 (GMT) |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2015-12-30 17:26:40 (GMT) |
| commit | de327e4966cdbad2b7053c84a6f591fbdc54f7cb (patch) | |
| tree | 4d84876c8a528509fa6c9fa412a401934f80f56d /drivers/spi | |
| parent | 8005c49d9aea74d382f474ce11afbbc7d7130bec (diff) | |
| download | linux-de327e4966cdbad2b7053c84a6f591fbdc54f7cb.tar.xz | |
spi: mediatek: Prevent overflows in FIFO transfers
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 <drinkcat@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/spi-mt65xx.c | 28 |
1 files changed, 18 insertions, 10 deletions
diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c index 563954a..375d412 100644 --- a/drivers/spi/spi-mt65xx.c +++ b/drivers/spi/spi-mt65xx.c @@ -323,7 +323,8 @@ 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; @@ -331,12 +332,16 @@ 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; @@ -418,7 +423,7 @@ 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; @@ -431,12 +436,15 @@ 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; |