[PATCH] nvmem: core: Print error on wrong bits DT property

[Markus Schneider-Pargmann <msp@baylibre.com>]

The algorithms in nvmem core are built with the constraint that
bit_offset < 8. If bit_offset is greater the results are wrong. Print an
error if the devicetree 'bits' property is outside of the valid range
and abort parsing.

Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
---
 drivers/nvmem/core.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 980123fb4dde..a9832b5a608e 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -806,6 +806,11 @@ static int nvmem_add_cells_from_dt(struct nvmem_device *nvmem, struct device_nod
 		if (addr && len == (2 * sizeof(u32))) {
 			info.bit_offset = be32_to_cpup(addr++);
 			info.nbits = be32_to_cpup(addr);
+			if (info.bit_offset >= BITS_PER_BYTE || info.nbits < 1) {
+				dev_err(dev, "nvmem: invalid bits on %pOF\n", child);
+				of_node_put(child);
+				return -EINVAL;
+			}
 		}
 
 		info.np = of_node_get(child);
-- 
2.43.0