decompress_bunzip2: fix rare decompression failure

The decompression code parses a huffman tree and counts the number of symbols for a given bit length. In rare cases, there may be >= 256 symbols with a given bit length, causing the unsigned char to overflow. This causes a decompression failure later when the code tries and fails to find the bit length for a given symbol. Since the maximum number of symbols is 258, use unsigned short instead. Link: https://lkml.kernel.org/r/20240717162016.1514077-1-ross.lagerwall@citrix.com Fixes: bc22c17 ("bzip2/lzma: library support for gzip, bzip2 and lzma decompression") Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com> Cc: Alain Knaff <alain@knaff.lu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: rosslagerwall

lib/decompress_bunzip2.c

@@ -232,7 +232,8 @@ static int INIT get_next_block(struct bunzip_data *bd)
  RUNB) */
 symCount = symTotal+2;
 for (j = 0; j < groupCount; j++) {
-unsigned char length[MAX_SYMBOLS], temp[MAX_HUFCODE_BITS+1];
+unsigned char length[MAX_SYMBOLS];
+unsigned short temp[MAX_HUFCODE_BITS+1];
 intminLen,maxLen, pp;
 /* Read Huffman code lengths for each symbol. They're
  stored in a way similar to mtf; record a starting