[PATCH 1/2] Staging: bcm: Fix an invalid dereference to a zero length kmalloc in IOCTL_BCM_BULK_WRM

[Kevin McKinney]

Variable IoBuffer.InputLength is chosen from userspace,
and can therefore be zero. If so, then we will get a kernel
Oops. To resolve this issue, this patch checks to confirm
IoBuffer.InputLength is not equal to zero before invoking
the kmalloc call.

Signed-off-by: Kevin McKinney <klmckinney1 at gmail.com>
---
 drivers/staging/bcm/Bcmchar.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/drivers/staging/bcm/Bcmchar.c b/drivers/staging/bcm/Bcmchar.c
index fa4a854..47d6818 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 == 0)
+			return -EINVAL;
+
 		pvBuffer = kmalloc(IoBuffer.InputLength, GFP_KERNEL);
 		if (!pvBuffer)
 			return -ENOMEM;
-- 
1.7.4.1