From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Carpenter Date: Thu, 17 Oct 2013 16:44:19 +0000 Subject: [patch -resend] paride: underflow bug in pg_write() Message-Id: <20131017164418.GH11731@mwanda> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Tim Waugh , akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org The test here can underflow so we pass bogus lengths to the hardware. It's a static checker fix and I don't know the impact. Signed-off-by: Dan Carpenter --- I sent this originally Jul 31, 2013 but there was no response. diff --git a/drivers/block/paride/pg.c b/drivers/block/paride/pg.c index 4a27b1d..2ce3dfd 100644 --- a/drivers/block/paride/pg.c +++ b/drivers/block/paride/pg.c @@ -581,7 +581,7 @@ static ssize_t pg_write(struct file *filp, const char __user *buf, size_t count, if (hdr.magic != PG_MAGIC) return -EINVAL; - if (hdr.dlen > PG_MAX_DATA) + if (hdr.dlen < 0 || hdr.dlen > PG_MAX_DATA) return -EINVAL; if ((count - hs) > PG_MAX_DATA) return -EINVAL;