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authorNicolas Boichat <drinkcat@chromium.org>2015-12-27 18:17:06 +0800
committerMark Brown <broonie@kernel.org>2015-12-30 17:26:40 +0000
commitde327e4966cdbad2b7053c84a6f591fbdc54f7cb (patch)
tree4d84876c8a528509fa6c9fa412a401934f80f56d /drivers/spi
parent8005c49d9aea74d382f474ce11afbbc7d7130bec (diff)
downloadlinux-de327e4966cdbad2b7053c84a6f591fbdc54f7cb.tar.bz2
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.c28
1 files changed, 18 insertions, 10 deletions
diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c
index 563954a61424..375d412dbf05 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(&reg_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),
+ &reg_val, remainder);
+ }
}
spi_finalize_current_transfer(master);
return IRQ_HANDLED;