gdth: integer overflow in ioctl

gdth_ioctl_alloc() takes the size variable as an int. copy_from_user() takes the size variable as an unsigned long. gen.data_len and gen.sense_len are unsigned longs. On x86_64 longs are 64 bit and ints are 32 bit.

We could pass in a very large number and the allocation would truncate the size to 32 bits and allocate a small buffer. Then when we do the copy_from_user(), it would result in a memory corruption.

index b860d65..4cf7ffa 100644
@@ -4175,6 +4175,14 @@ static int ioc_general(void __user *arg, char *cmnd)
     ha = gdth_find_ha(gen.ionode);
     if (!ha)
         return -EFAULT;
+
+    if (gen.data_len > INT_MAX)
+        return -EINVAL;
+    if (gen.sense_len > INT_MAX)
+        return -EINVAL;
+    if (gen.data_len + gen.sense_len > INT_MAX)
+        return -EINVAL;
+
     if (gen.data_len + gen.sense_len != 0) {
         if (!(buf = gdth_ioctl_alloc(ha, gen.data_len + gen.sense_len,
                                      FALSE, &paddr)))

I never know if anyone gets my emails and so I has a small sad face on
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regards,
dan carpenter