On Mon, Nov 26, 2018 at 05:35:07PM +0100, Luca Ceresoli wrote:
> imx274_read_reg() takes a u8 pointer ("reg") and casts it to pass it
> to regmap_read(), which takes an unsigned int pointer. This results in
> a corrupted stack and random crashes.
>
> Fixes: 0985dd306f72 ("media: imx274: V4l2 driver for Sony imx274 CMOS sensor")
> Cc: stable@xxxxxxxxxxxxxxx # 4.15.x
Applied, with the following line changed to:
Cc: stable@xxxxxxxxxxxxxxx # for 4.15 and up
FYI: if you add Cc: stable tag to the patch, it'll end up to the stable
trees; no need to explicitly add the stable@vger address to the recipients.
> Signed-off-by: Luca Ceresoli <luca@xxxxxxxxxxxxxxxx>
>
> ---
>
> Notes!
>
> I have no evidence of this bug showing up in the mainline driver. It
> appeared on a modified version where imx274_read_reg() is used,
> unmodified, in a different way than it does in mainline (passing a
> pointer to a single u8 instead of a pointer to an element of a u8
> array).
>
> Also the bug is only present in versions v4.15 (where the driver was
> added) to v4.19. The offending function is unused since commit
> ca017467c78b ("media: imx274: add helper to read multibyte
> registers"), merged in v4.20-rc1, thus master is not affected. I'm
> sending this bugfix patch anyway for easier integration in the stable
> branches. Later I plan to send a patch against master to entirely
> remove the function. Or somebody might want to use this function
> again, so better having a fixed version out anyway.
>
> I'm not 100% sure this qualifies this commit for stable trees.
> ---
> drivers/media/i2c/imx274.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/i2c/imx274.c b/drivers/media/i2c/imx274.c
> index e1b0395a657f..40c717f13eb8 100644
> --- a/drivers/media/i2c/imx274.c
> +++ b/drivers/media/i2c/imx274.c
> @@ -619,16 +619,19 @@ static int imx274_write_table(struct stimx274 *priv, const struct reg_8 table[])
>
> static inline int imx274_read_reg(struct stimx274 *priv, u16 addr, u8 *val)
> {
> + unsigned int uint_val;
> int err;
>
> - err = regmap_read(priv->regmap, addr, (unsigned int *)val);
> + err = regmap_read(priv->regmap, addr, &uint_val);
> if (err)
> dev_err(&priv->client->dev,
> "%s : i2c read failed, addr = %x\n", __func__, addr);
> else
> dev_dbg(&priv->client->dev,
> "%s : addr 0x%x, val=0x%x\n", __func__,
> - addr, *val);
> + addr, uint_val);
> +
> + *val = uint_val;
> return err;
> }
>
> --
> 2.17.1
>
--
Sakari Ailus
e-mail: sakari.ailus@xxxxxx
