fix(fetcher/checksum): panic when 0 < flen % (block_len * lanes) < bl…

…ock_len

rsync-fetcher/src/rsync/checksum.rs

@@ -138,14 +138,19 @@ fn checksum_payload_(
                 array_init::array_init(|_| vec![0u8; sum_head.block_len as usize + 4]);
 
             while block_remaining >= simd_impl.lanes() {
+                if file_remaining < sum_head.block_len as u64 * simd_impl.lanes() as u64 {
+                    // not enough data for simd
+                    break;
+                }
+
                 let mut datas: [&[u8]; md4_simd::simd::MAX_LANES] =
                     [&[]; md4_simd::simd::MAX_LANES];
                 for (idx, buf) in bufs[0..simd_impl.lanes()].iter_mut().enumerate() {
                     // let buf = &mut bufs[idx];
 
                     // Sqrt of usize must be in u32 range.
                     #[allow(clippy::cast_possible_truncation)]
-                    let n1 = min(sum_head.block_len as u64, file_remaining) as usize;
+                    let n1 = sum_head.block_len as usize;
 
                     file.read_exact(&mut buf[..n1]).expect("IO error");