Patch "staging: comedi: jr3_pci: fix possible null pointer dereference" has been added to the 3.18-stable tree

This is a note to let you know that I've just added the patch titled

staging: comedi: jr3_pci: fix possible null pointer dereference

to the 3.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
staging-comedi-jr3_pci-fix-possible-null-pointer-dereference.patch
and it can be found in the queue-3.18 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Ian Abbott <[email protected]>
Date: Fri, 17 Feb 2017 11:09:08 +0000
Subject: staging: comedi: jr3_pci: fix possible null pointer dereference

From: Ian Abbott <[email protected]>

commit 45292be0b3db0b7f8286683b376e2d9f949d11f9 upstream.

For some reason, the driver does not consider allocation of the subdevice private data to be a fatal error when attaching the COMEDI device. It tests the subdevice private data pointer for validity at certain points, but omits some crucial tests. In particular, jr3_pci_auto_attach() calls jr3_pci_alloc_spriv() to allocate and initialize the subdevice private data, but the same function subsequently dereferences the pointer to access the next_time_min and next_time_max members without checking it first. The other missing test is in the timer expiry routine jr3_pci_poll_dev(), but it will crash before it gets that far.

Fix the bug by returning -ENOMEM from jr3_pci_auto_attach() as soon as one of the calls to jr3_pci_alloc_spriv() returns NULL. The COMEDI core will subsequently call jr3_pci_detach() to clean up.

---
 drivers/staging/comedi/drivers/jr3_pci.c |   11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

@@ -729,11 +729,12 @@ static int jr3_pci_auto_attach(struct co
 		s->insn_read	= jr3_pci_ai_insn_read;
 
 		spriv = jr3_pci_alloc_spriv(dev, s);
-		if (spriv) {
-			/* Channel specific range and maxdata */
-			s->range_table_list	= spriv->range_table_list;
-			s->maxdata_list		= spriv->maxdata_list;
-		}
+		if (!spriv)
+			return -ENOMEM;
+
+		/* Channel specific range and maxdata */
+		s->range_table_list	= spriv->range_table_list;
+		s->maxdata_list		= spriv->maxdata_list;
 	}
 
 	/*  Reset DSP card */

Patches currently in stable-queue which might be from [email protected] are

queue-3.18/staging-comedi-jr3_pci-fix-possible-null-pointer-dereference.patch queue-3.18/staging-comedi-jr3_pci-cope-with-jiffies-wraparound.patch