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 4.11-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-4.11 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 45292be0b3db0b7f8286683b376e2d9f949d11f9 Mon Sep 17 00:00:00 2001 From: Ian Abbott <abbotti@xxxxxxxxx> Date: Fri, 17 Feb 2017 11:09:08 +0000 Subject: staging: comedi: jr3_pci: fix possible null pointer dereference From: Ian Abbott <abbotti@xxxxxxxxx> 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. Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/staging/comedi/drivers/jr3_pci.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) --- a/drivers/staging/comedi/drivers/jr3_pci.c +++ b/drivers/staging/comedi/drivers/jr3_pci.c @@ -727,11 +727,12 @@ 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 abbotti@xxxxxxxxx are queue-4.11/staging-comedi-jr3_pci-fix-possible-null-pointer-dereference.patch queue-4.11/staging-comedi-jr3_pci-cope-with-jiffies-wraparound.patch