vfio/pci: Fix integer overflows, bitmask check (CVE-2016-9083 CVE-2016-9084)

3 files changed, 102 insertions, 0 deletions

diff --git a/debian/changelog b/debian/changelog
index 6bab68293..f1125d32f 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -234,6 +234,8 @@ linux (4.8.11-1) UNRELEASED; urgency=medium
   * fs: Avoid premature clearing of capabilities (CVE-2015-1350)
     (Closes: #770492)
   * mpi: Fix NULL ptr dereference in mpi_powm() (CVE-2016-8650)
+  * vfio/pci: Fix integer overflows, bitmask check (CVE-2016-9083
+    CVE-2016-9084)
 
   [ Ben Hutchings ]
   * [arm64] Enable more drivers for X-Gene (Really closes: #840061):
diff --git a/debian/patches/bugfix/all/vfio-pci-Fix-integer-overflows-bitmask-check.patch b/debian/patches/bugfix/all/vfio-pci-Fix-integer-overflows-bitmask-check.patch
new file mode 100644
index 000000000..5bb21177a
--- /dev/null
+++ b/debian/patches/bugfix/all/vfio-pci-Fix-integer-overflows-bitmask-check.patch
@@ -0,0 +1,99 @@
+From: Vlad Tsyrklevich <vlad@tsyrklevich.net>
+Date: Wed, 12 Oct 2016 18:51:24 +0200
+Subject: vfio/pci: Fix integer overflows, bitmask check
+Origin: https://git.kernel.org/linus/05692d7005a364add85c6e25a6c4447ce08f913a
+
+The VFIO_DEVICE_SET_IRQS ioctl did not sufficiently sanitize
+user-supplied integers, potentially allowing memory corruption. This
+patch adds appropriate integer overflow checks, checks the range bounds
+for VFIO_IRQ_SET_DATA_NONE, and also verifies that only single element
+in the VFIO_IRQ_SET_DATA_TYPE_MASK bitmask is set.
+VFIO_IRQ_SET_ACTION_TYPE_MASK is already correctly checked later in
+vfio_pci_set_irqs_ioctl().
+
+Furthermore, a kzalloc is changed to a kcalloc because the use of a
+kzalloc with an integer multiplication allowed an integer overflow
+condition to be reached without this patch. kcalloc checks for overflow
+and should prevent a similar occurrence.
+
+Signed-off-by: Vlad Tsyrklevich <vlad@tsyrklevich.net>
+Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
+---
+ drivers/vfio/pci/vfio_pci.c       | 33 +++++++++++++++++++++------------
+ drivers/vfio/pci/vfio_pci_intrs.c |  2 +-
+ 2 files changed, 22 insertions(+), 13 deletions(-)
+
+diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
+index d624a52..031bc08 100644
+--- a/drivers/vfio/pci/vfio_pci.c
++++ b/drivers/vfio/pci/vfio_pci.c
+@@ -829,8 +829,9 @@ static long vfio_pci_ioctl(void *device_data,
+ 
+ 	} else if (cmd == VFIO_DEVICE_SET_IRQS) {
+ 		struct vfio_irq_set hdr;
++		size_t size;
+ 		u8 *data = NULL;
+-		int ret = 0;
++		int max, ret = 0;
+ 
+ 		minsz = offsetofend(struct vfio_irq_set, count);
+ 
+@@ -838,23 +839,31 @@ static long vfio_pci_ioctl(void *device_data,
+ 			return -EFAULT;
+ 
+ 		if (hdr.argsz < minsz || hdr.index >= VFIO_PCI_NUM_IRQS ||
++		    hdr.count >= (U32_MAX - hdr.start) ||
+ 		    hdr.flags & ~(VFIO_IRQ_SET_DATA_TYPE_MASK |
+ 				  VFIO_IRQ_SET_ACTION_TYPE_MASK))
+ 			return -EINVAL;
+ 
+-		if (!(hdr.flags & VFIO_IRQ_SET_DATA_NONE)) {
+-			size_t size;
+-			int max = vfio_pci_get_irq_count(vdev, hdr.index);
++		max = vfio_pci_get_irq_count(vdev, hdr.index);
++		if (hdr.start >= max || hdr.start + hdr.count > max)
++			return -EINVAL;
+ 
+-			if (hdr.flags & VFIO_IRQ_SET_DATA_BOOL)
+-				size = sizeof(uint8_t);
+-			else if (hdr.flags & VFIO_IRQ_SET_DATA_EVENTFD)
+-				size = sizeof(int32_t);
+-			else
+-				return -EINVAL;
++		switch (hdr.flags & VFIO_IRQ_SET_DATA_TYPE_MASK) {
++		case VFIO_IRQ_SET_DATA_NONE:
++			size = 0;
++			break;
++		case VFIO_IRQ_SET_DATA_BOOL:
++			size = sizeof(uint8_t);
++			break;
++		case VFIO_IRQ_SET_DATA_EVENTFD:
++			size = sizeof(int32_t);
++			break;
++		default:
++			return -EINVAL;
++		}
+ 
+-			if (hdr.argsz - minsz < hdr.count * size ||
+-			    hdr.start >= max || hdr.start + hdr.count > max)
++		if (size) {
++			if (hdr.argsz - minsz < hdr.count * size)
+ 				return -EINVAL;
+ 
+ 			data = memdup_user((void __user *)(arg + minsz),
+diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
+index c2e6089..1c46045 100644
+--- a/drivers/vfio/pci/vfio_pci_intrs.c
++++ b/drivers/vfio/pci/vfio_pci_intrs.c
+@@ -256,7 +256,7 @@ static int vfio_msi_enable(struct vfio_pci_device *vdev, int nvec, bool msix)
+ 	if (!is_irq_none(vdev))
+ 		return -EINVAL;
+ 
+-	vdev->ctx = kzalloc(nvec * sizeof(struct vfio_pci_irq_ctx), GFP_KERNEL);
++	vdev->ctx = kcalloc(nvec, sizeof(struct vfio_pci_irq_ctx), GFP_KERNEL);
+ 	if (!vdev->ctx)
+ 		return -ENOMEM;
+ 
+-- 
+2.1.4
+
diff --git a/debian/patches/series b/debian/patches/series
index f09c1db61..d09d09e7f 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -99,6 +99,7 @@ bugfix/all/fuse-Propagate-dentry-down-to-inode_change_ok.patch
 bugfix/all/fs-Give-dentry-to-inode_change_ok-instead-of-inode.patch
 bugfix/all/fs-Avoid-premature-clearing-of-capabilities.patch
 bugfix/all/mpi-Fix-NULL-ptr-dereference-in-mpi_powm-ver-3.patch
+bugfix/all/vfio-pci-Fix-integer-overflows-bitmask-check.patch
 
 # ABI maintenance