From 7296f62f0322d808362b21064deb34f20799c20d Mon Sep 17 00:00:00 2001 From: Nicholas Krause Date: Tue, 5 Jan 2016 14:32:54 -0500 Subject: [PATCH] megaraid: Fix possible NULL pointer deference in mraid_mm_ioctl This adds the needed check after the call to the function mraid_mm_alloc_kioc in order to make sure that this function has not returned NULL and therefore makes sure we do not deference a NULL pointer if one is returned by mraid_mm_alloc_kioc. Further more add needed comments explaining that this function call can return NULL if the list head is empty for the pointer passed in order to allow furture users to understand this required pointer check. Signed-off-by: Nicholas Krause Acked-by: Sumit Saxena Signed-off-by: Martin K. Petersen --- drivers/scsi/megaraid/megaraid_mm.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/scsi/megaraid/megaraid_mm.c b/drivers/scsi/megaraid/megaraid_mm.c index a70692779a16..4cf9ed96414f 100644 --- a/drivers/scsi/megaraid/megaraid_mm.c +++ b/drivers/scsi/megaraid/megaraid_mm.c @@ -179,8 +179,12 @@ mraid_mm_ioctl(struct file *filep, unsigned int cmd, unsigned long arg) /* * The following call will block till a kioc is available + * or return NULL if the list head is empty for the pointer + * of type mraid_mmapt passed to mraid_mm_alloc_kioc */ kioc = mraid_mm_alloc_kioc(adp); + if (!kioc) + return -ENXIO; /* * User sent the old mimd_t ioctl packet. Convert it to uioc_t. -- 2.20.1