From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Tue, 5 Nov 2013 05:55:18 +0000 (+1100)
Subject: drivers/block/paride/pg.c: underflow bug in pg_write()
X-Git-Tag: next-20131105~2^2~282
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=b250fd71d0f60860af88a8e35b96f85244e7dc58;p=karo-tx-linux.git

drivers/block/paride/pg.c: underflow bug in pg_write()

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 <dan.carpenter@oracle.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/drivers/block/paride/pg.c b/drivers/block/paride/pg.c
index 4a27b1de5fcb..2ce3dfd7e6b9 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;