Re: [PATCH] spi: spidev: Fix user-space memory access.

From: dsneddon
Date: Fri Jun 20 2014 - 16:40:49 EST


I just noticed this patch breaks when CONFIG_COMPAT isn't defined. Please
ignore this patch for now.

> When the spidev module tries to access the user space memory passed in via
> an IOCTL the compat_ptr function should be called to ensure
> compatibility between kernel space and user space.
>
> Signed-off-by: Dan Sneddon <dsneddon@xxxxxxxxxxxxxx>
> ---
> drivers/spi/spidev.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
> index e3bc23b..3a45158 100644
> --- a/drivers/spi/spidev.c
> +++ b/drivers/spi/spidev.c
> @@ -252,14 +252,16 @@ static int spidev_message(struct spidev_data
> *spidev,
> if (u_tmp->rx_buf) {
> k_tmp->rx_buf = buf;
> if (!access_ok(VERIFY_WRITE, (u8 __user *)
> - (uintptr_t) u_tmp->rx_buf,
> + (uintptr_t)compat_ptr( +
> u_tmp->rx_buf),
> u_tmp->len))
> goto done;
> }
> if (u_tmp->tx_buf) {
> k_tmp->tx_buf = buf;
> if (copy_from_user(buf, (const u8 __user *)
> - (uintptr_t) u_tmp->tx_buf,
> + (uintptr_t)compat_ptr( +
> u_tmp->tx_buf),
> u_tmp->len))
> goto done;
> }
> @@ -294,8 +296,8 @@ static int spidev_message(struct spidev_data *spidev,
> for (n = n_xfers, u_tmp = u_xfers; n; n--, u_tmp++) {
> if (u_tmp->rx_buf) {
> if (__copy_to_user((u8 __user *)
> - (uintptr_t) u_tmp->rx_buf, buf, -
> u_tmp->len)) {
> +
> (uintptr_t)compat_ptr(u_tmp->rx_buf),
> + buf, u_tmp->len)) {
> status = -EFAULT;
> goto done;
> }
> --
> 1.8.4
>
>
>
>
>
>
> ---
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> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> hosted by The Linux Foundation
>
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--
---
sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

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