asix-sigma: Avoid use of variable length arrays

[libsigrok.git] / src / hardware / asix-sigma / asix-sigma.c

diff --git a/src/hardware/asix-sigma/asix-sigma.c b/src/hardware/asix-sigma/asix-sigma.c
index 957b1d1ac7c7a2098a979be701006fdf392dd80f..6e7f1fd716d52c04fd8c816348cb3088d2629e97 100644 (file)
--- a/src/hardware/asix-sigma/asix-sigma.c
+++ b/src/hardware/asix-sigma/asix-sigma.c
@@ -130,13 +130,23 @@ static int sigma_write(void *buf, size_t size, struct dev_context *devc)
        return ret;
 }
 
+/*
+ * NOTE: We chose the buffer size to be large enough to hold any write to the
+ * device. We still print a message just in case.
+ */
 static int sigma_write_register(uint8_t reg, uint8_t *data, size_t len,
                                struct dev_context *devc)
 {
        size_t i;
-       uint8_t buf[len + 2];
+       uint8_t buf[80];
        int idx = 0;
 
+       if ((len + 2) > sizeof(buf)) {
+               sr_err("Attempted to write %zu bytes, but buffer is too small.",
+                      len + 2);
+               return SR_ERR_BUG;
+       }
+
        buf[idx++] = REG_ADDR_LOW | (reg & 0xf);
        buf[idx++] = REG_ADDR_HIGH | (reg >> 4);