From: Kevin McKinney <klmckinney1@gmail.com>
Date: Sat, 17 Dec 2011 16:53:37 +0000 (-0500)
Subject: Staging: bcm: Fix an invalid dereference to a kmalloc in IOCTL_BCM_BULK_WRM
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=221fd753dd002222b595f8af0e289fff0c9cf5a8;p=linux-beck.git

Staging: bcm: Fix an invalid dereference to a kmalloc in IOCTL_BCM_BULK_WRM

Variable IoBuffer.InputLength is chosen from userspace,
and can therefore be less than the intended size. In this
case,the memory from the kmalloc call is eventually cast
to a PBULKWRM_BUFFER. If the IoBuffer.InputLength does not
meet the minimum size of PBULKWRM_BUFFER, then we will get
a kernel Oops. To resolve this issue, this patch verifies
IoBuffer.InputLength meets the minimum size before invoking
the kmalloc call.

Signed-off-by: Kevin McKinney <klmckinney1@gmail.com>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/drivers/staging/bcm/Bcmchar.c b/drivers/staging/bcm/Bcmchar.c
index fa4a854ba054..179707b5e7c7 100644
--- a/drivers/staging/bcm/Bcmchar.c
+++ b/drivers/staging/bcm/Bcmchar.c
@@ -1137,7 +1137,9 @@ cntrlEnd:
 		if (copy_from_user(&IoBuffer, argp, sizeof(IOCTL_BUFFER)))
 			return -EFAULT;
 
-		/* FIXME: restrict length */
+		if (IoBuffer.InputLength < sizeof(ULONG) * 2)
+			return -EINVAL;
+
 		pvBuffer = kmalloc(IoBuffer.InputLength, GFP_KERNEL);
 		if (!pvBuffer)
 			return -ENOMEM;