of: overlay: validate offset from property fixups

The smatch static checker marks the data in offset as untrusted,
leading it to warn:

  drivers/of/resolver.c:125 update_usages_of_a_phandle_reference()
  error: buffer underflow 'prop->value' 's32min-s32max'

Add check to verify that offset is within the property data.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Frank Rowand <frank.rowand@sony.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>
This commit is contained in:
Frank Rowand 2018-05-16 21:19:51 -07:00 committed by Rob Herring
parent 3b9cf7905f
commit 482137bf2a

View file

@ -122,6 +122,11 @@ static int update_usages_of_a_phandle_reference(struct device_node *overlay,
goto err_fail;
}
if (offset < 0 || offset + sizeof(__be32) > prop->length) {
err = -EINVAL;
goto err_fail;
}
*(__be32 *)(prop->value + offset) = cpu_to_be32(phandle);
}