shared-bindings: Check that I2C and SPI reads and writes are given a buffer of at least 1. (adafruit#370)

tannewt · dhalbert · commit bd7abcda970e · 2017-10-25T17:28:23.000-04:00
Fixes adafruit#358
diff --git a/shared-bindings/busio/I2C.c b/shared-bindings/busio/I2C.c
@@ -201,6 +201,10 @@ STATIC mp_obj_t busio_i2c_readfrom_into(size_t n_args, const mp_obj_t *pos_args,
     int32_t start = args[ARG_start].u_int;
     uint32_t length = bufinfo.len;
     normalize_buffer_bounds(&start, args[ARG_end].u_int, &length);
+    if (length == 0) {
+        mp_raise_ValueError("Buffer must be at least length 1");
+    }
+
     uint8_t status = common_hal_busio_i2c_read(self, args[ARG_address].u_int, ((uint8_t*)bufinfo.buf) + start, length);
     if (status != 0) {
         mp_raise_OSError(status);
@@ -250,6 +254,10 @@ STATIC mp_obj_t busio_i2c_writeto(size_t n_args, const mp_obj_t *pos_args, mp_ma
     uint32_t length = bufinfo.len;
     normalize_buffer_bounds(&start, args[ARG_end].u_int, &length);
 
+    if (length == 0) {
+        mp_raise_ValueError("Buffer must be at least length 1");
+    }
+
     // do the transfer
     uint8_t status = common_hal_busio_i2c_write(self, args[ARG_address].u_int,
         ((uint8_t*) bufinfo.buf) + start, length, args[ARG_stop].u_bool);
diff --git a/shared-bindings/busio/SPI.c b/shared-bindings/busio/SPI.c
@@ -231,6 +231,10 @@ STATIC mp_obj_t busio_spi_write(size_t n_args, const mp_obj_t *pos_args, mp_map_
     uint32_t length = bufinfo.len;
     normalize_buffer_bounds(&start, args[ARG_end].u_int, &length);
 
+    if (length == 0) {
+        mp_raise_ValueError("Buffer must be at least length 1");
+    }
+
     bool ok = common_hal_busio_spi_write(self, ((uint8_t*)bufinfo.buf) + start, length);
     if (!ok) {
         mp_raise_OSError(MP_EIO);
@@ -269,6 +273,10 @@ STATIC mp_obj_t busio_spi_readinto(size_t n_args, const mp_obj_t *pos_args, mp_m
     uint32_t length = bufinfo.len;
     normalize_buffer_bounds(&start, args[ARG_end].u_int, &length);
 
+    if (length == 0) {
+        mp_raise_ValueError("Buffer must be at least length 1");
+    }
+
     bool ok = common_hal_busio_spi_read(self, ((uint8_t*)bufinfo.buf) + start, length, args[ARG_write_value].u_int);
     if (!ok) {
         mp_raise_OSError(MP_EIO);
