[PATCH 5.11 038/601] iio: sx9310: Fix access to variable DT array

Greg Kroah-Hartman
2021-05-12T16:53:09Z

From: Gwendal Grignou <gwendal@chromium.org>

commit 6f0078ae704d94b1a93e5f3d0a44cf3d8090fa91 upstream.

With the current code, we want to read 4 entries from DT array
"semtech,combined-sensors". If there are less, we silently fail as
of_property_read_u32_array() returns -EOVERFLOW.

First count the number of entries and if between 1 and 4, collect the
content of the array.

Fixes: 5b19ca2c78a0 ("iio: sx9310: Set various settings from DT")
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210326184603.251683-2-gwendal@chromium.org
Cc: <stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/iio/proximity/sx9310.c | 40 ++++++++++++++++++++++++++++------------
1 file changed, 28 insertions(+), 12 deletions(-)

--- a/drivers/iio/proximity/sx9310.c
+++ b/drivers/iio/proximity/sx9310.c
@@ -1221,17 +1221,17 @@ static int sx9310_init_compensation(stru
}

static const struct sx9310_reg_default *
-sx9310_get_default_reg(struct sx9310_data *data, int i,
+sx9310_get_default_reg(struct sx9310_data *data, int idx,
struct sx9310_reg_default *reg_def)
{
- int ret;
const struct device_node *np = data->client->dev.of_node;
- u32 combined[SX9310_NUM_CHANNELS] = { 4, 4, 4, 4 };
+ u32 combined[SX9310_NUM_CHANNELS];
+ u32 start = 0, raw = 0, pos = 0;
unsigned long comb_mask = 0;
+ int ret, i, count;
const char *res;
- u32 start = 0, raw = 0, pos = 0;

- memcpy(reg_def, &sx9310_default_regs[i], sizeof(*reg_def));
+ memcpy(reg_def, &sx9310_default_regs[idx], sizeof(*reg_def));
if (!np)
return reg_def;

@@ -1242,15 +1242,31 @@ sx9310_get_default_reg(struct sx9310_dat
reg_def->def |= SX9310_REG_PROX_CTRL2_SHIELDEN_GROUND;
}

- reg_def->def &= ~SX9310_REG_PROX_CTRL2_COMBMODE_MASK;
- of_property_read_u32_array(np, "semtech,combined-sensors",
- combined, ARRAY_SIZE(combined));
- for (i = 0; i < ARRAY_SIZE(combined); i++) {
- if (combined[i] <= SX9310_NUM_CHANNELS)
- comb_mask |= BIT(combined[i]);
+ count = of_property_count_elems_of_size(np, "semtech,combined-sensors",
+ sizeof(u32));
+ if (count > 0 && count <= ARRAY_SIZE(combined)) {
+ ret = of_property_read_u32_array(np, "semtech,combined-sensors",
+ combined, count);
+ if (ret)
+ break;
+ } else {
+ /*
+ * Either the property does not exist in the DT or the
+ * number of entries is incorrect.
+ */
+ break;
}
+ for (i = 0; i < count; i++) {
+ if (combined[i] >= SX9310_NUM_CHANNELS) {
+ /* Invalid sensor (invalid DT). */
+ break;
+ }
+ comb_mask |= BIT(combined[i]);
+ }
+ if (i < count)
+ break;

- comb_mask &= 0xf;
+ reg_def->def &= ~SX9310_REG_PROX_CTRL2_COMBMODE_MASK;
if (comb_mask == (BIT(3) | BIT(2) | BIT(1) | BIT(0)))
reg_def->def |= SX9310_REG_PROX_CTRL2_COMBMODE_CS0_CS1_CS2_CS3;
else if (comb_mask == (BIT(1) | BIT(2)))