Integer Overflow or Wraparound

Summary

The snappy-java is a fast compressor/decompressor for Java. Due to unchecked multiplications, an integer overflow may occur in versions prior to 1.1.10.1, causing a fatal error. The function "shuffle(int[] input)" in the file "BitShuffle.java" receives an array of integers and applies a bit shuffle on it. It does so by multiplying the length by 4 and passing it to the natively compiled "shuffle" function. Since the length is not tested, the multiplication by four can cause an integer overflow and become a smaller value than the true size, or even zero or negative. In the case of a negative value, a "java.lang.NegativeArraySizeException" exception will raise, which can crash the program. In a case of a value that is zero or too small, the code that afterward references the shuffled array will assume a bigger size of the array, which might cause exceptions such as "java.lang.ArrayIndexOutOfBoundsException". The same issue exists also when using the "shuffle" functions that receive a double, float, long, and short, each using a different multiplier that may cause the same issue.