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@vger.kernel.org # 4.15.x
Applied, with the following line changed to:
Cc: stable@vger.kernel.org # 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@lucaceresoli.net
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