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* [patch] decompress_bunzip2: off by one in get_next_block()
@ 2014-10-22  8:16 Dan Carpenter
  0 siblings, 0 replies; only message in thread
From: Dan Carpenter @ 2014-10-22  8:16 UTC (permalink / raw)
  To: Andrew Morton, Alain Knaff
  Cc: Yinghai Lu, linux-kernel, kernel-janitors, H. Peter Anvin

"origPtr" is used as an offset into the bd->dbuf[] array.  That array
is allocated in start_bunzip() and has "bd->dbufSize" number of elements
so the test here should be >= instead of >.

Later we check "origPtr" again before using it as an offset so I don't
know if this bug can be triggered in real life.

Fixes: bc22c17e12c1 ('bzip2/lzma: library support for gzip, bzip2 and lzma decompression')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

diff --git a/lib/decompress_bunzip2.c b/lib/decompress_bunzip2.c
index 8290e0b..6dd0335 100644
--- a/lib/decompress_bunzip2.c
+++ b/lib/decompress_bunzip2.c
@@ -184,7 +184,7 @@ static int INIT get_next_block(struct bunzip_data *bd)
 	if (get_bits(bd, 1))
 		return RETVAL_OBSOLETE_INPUT;
 	origPtr = get_bits(bd, 24);
-	if (origPtr > dbufSize)
+	if (origPtr >= dbufSize)
 		return RETVAL_DATA_ERROR;
 	/* mapping table: if some byte values are never used (encoding things
 	   like ascii text), the compression code removes the gaps to have fewer

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2014-10-22  8:16 [patch] decompress_bunzip2: off by one in get_next_block() Dan Carpenter

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