confid: Remove more unsafe from generate

umskt/src/confid/black_box.rs

@@ -1,8 +1,4 @@
-use std::{
+use std::mem::{size_of, swap};
-    ffi::c_void,
-    mem::{size_of, swap},
-    ptr,
-};
 
 #[derive(Copy, Clone)]
 #[repr(C)]
@@ -961,21 +957,12 @@ pub unsafe fn generate(installation_id_str: &[u8], confirmation_id: &mut [u8]) -
         return 5_i32;
     }
     let mut keybuf: [u8; 16] = [0; 16];
-    let mut hardware_id = parsed.hardware_id;
+    keybuf[..8].copy_from_slice(&parsed.hardware_id.to_le_bytes()[..8]);
-    ptr::copy_nonoverlapping(
+    let product_id_mixed: u64 = (product_id_1 as u64) << 41_i32
-        &mut hardware_id as *mut u64 as *const c_void,
-        keybuf.as_mut_ptr() as *mut c_void,
-        8,
-    );
-    let mut product_id_mixed: u64 = (product_id_1 as u64) << 41_i32
         | (product_id_2 as u64) << 58_i32
         | (product_id_3 as u64) << 17_i32
         | product_id_4 as u64;
-    ptr::copy_nonoverlapping(
+    keybuf[8..16].copy_from_slice(&product_id_mixed.to_le_bytes()[..8]);
-        &mut product_id_mixed as *mut u64 as *const c_void,
-        keybuf.as_mut_ptr().offset(8) as *mut c_void,
-        8,
-    );
     let mut d_0: TDivisor = TDivisor {
         u: [0; 2],
         v: [0; 2],
@@ -1108,31 +1095,29 @@ pub unsafe fn generate(installation_id_str: &[u8], confirmation_id: &mut [u8]) -
         decimal[34_usize.wrapping_sub(i)] = c4 as u8;
         i = i.wrapping_add(1);
     }
-    let mut q: *mut u8 = confirmation_id.as_mut_ptr();
+    let q = confirmation_id;
-    i = 0_i32 as usize;
+    let mut i: usize = 0;
+    let mut q_i = 0;
     while i < 7 {
         if i != 0 {
-            let fresh2 = q;
+            q[q_i] = b'-';
-            q = q.offset(1);
+            q_i += 1;
-            *fresh2 = '-' as u8;
         }
-        let p_0: *mut u8 = decimal.as_mut_ptr().add(i.wrapping_mul(5));
+        let p_0: &mut [u8] = &mut decimal[i.wrapping_mul(5)..];
-        *q.offset(0_i32 as isize) = (*p_0.offset(0_i32 as isize) as i32 + '0' as i32) as u8;
+        q[q_i] = (p_0[0] as i32 + '0' as i32) as u8;
-        *q.offset(1_i32 as isize) = (*p_0.offset(1_i32 as isize) as i32 + '0' as i32) as u8;
+        q[q_i + 1] = (p_0[1] as i32 + '0' as i32) as u8;
-        *q.offset(2_i32 as isize) = (*p_0.offset(2_i32 as isize) as i32 + '0' as i32) as u8;
+        q[q_i + 2] = (p_0[2] as i32 + '0' as i32) as u8;
-        *q.offset(3_i32 as isize) = (*p_0.offset(3_i32 as isize) as i32 + '0' as i32) as u8;
+        q[q_i + 3] = (p_0[3] as i32 + '0' as i32) as u8;
-        *q.offset(4_i32 as isize) = (*p_0.offset(4_i32 as isize) as i32 + '0' as i32) as u8;
+        q[q_i + 4] = (p_0[4] as i32 + '0' as i32) as u8;
-        *q.offset(5_i32 as isize) = ((*p_0.offset(0_i32 as isize) as i32
+        q[q_i + 5] = ((p_0[0] as i32
-            + *p_0.offset(1_i32 as isize) as i32 * 2_i32
+            + p_0[1] as i32 * 2_i32
-            + *p_0.offset(2_i32 as isize) as i32
+            + p_0[2] as i32
-            + *p_0.offset(3_i32 as isize) as i32 * 2_i32
+            + p_0[3] as i32 * 2_i32
-            + *p_0.offset(4_i32 as isize) as i32)
+            + p_0[4] as i32)
             % 7_i32
             + '0' as i32) as u8;
-        q = q.offset(6_i32 as isize);
+        q_i = q_i.wrapping_add(6);
         i = i.wrapping_add(1);
     }
-    let fresh3 = q.offset(1);
-    *fresh3 = 0_i32 as u8;
     0_i32
 }

umskt/src/confid/mod.rs

@@ -26,7 +26,7 @@ pub fn generate(installation_id: &str) -> Result<String, ConfirmationIdError> {
         return Err(ConfirmationIdError::TooLarge);
     }
     let inst_id = installation_id.as_bytes();
-    let mut conf_id = [0u8; 49];
+    let mut conf_id = [0u8; 48];
     let result = unsafe { black_box::generate(inst_id, &mut conf_id) };
     match result {
         0 => {}
@@ -38,7 +38,7 @@ pub fn generate(installation_id: &str) -> Result<String, ConfirmationIdError> {
         6 => return Err(ConfirmationIdError::Unlucky),
         _ => panic!("Unknown error code: {}", result),
     }
-    Ok(String::from_utf8_lossy(&conf_id[..48]).into())
+    Ok(String::from_utf8_lossy(&conf_id).into())
 }
 
 #[cfg(test)]