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| author | Joerg Roedel <jroedel@suse.de> | 2015-11-04 13:53:26 +0100 |
|---|---|---|
| committer | Alex Williamson <alex.williamson@redhat.com> | 2015-11-04 09:27:39 -0700 |
| commit | e324fc82ea453fcbd3898ec7afb792f750c68979 (patch) | |
| tree | 914d7b4679b70b623a2784cc71e5a78f1e1acbf5 /drivers/vfio/vfio.c | |
| parent | 0990822c98661bd625033f0d523b5c33566657ef (diff) | |
| download | lwn-e324fc82ea453fcbd3898ec7afb792f750c68979.tar.gz lwn-e324fc82ea453fcbd3898ec7afb792f750c68979.zip | |
vfio: Fix bug in vfio_device_get_from_name()
The vfio_device_get_from_name() function might return a
non-NULL pointer, when called with a device name that is not
found in the list. This causes undefined behavior, in my
case calling an invalid function pointer later on:
kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
BUG: unable to handle kernel paging request at ffff8800cb3ddc08
[...]
Call Trace:
[<ffffffffa03bd733>] ? vfio_group_fops_unl_ioctl+0x253/0x410 [vfio]
[<ffffffff811efc4d>] do_vfs_ioctl+0x2cd/0x4c0
[<ffffffff811f9657>] ? __fget+0x77/0xb0
[<ffffffff811efeb9>] SyS_ioctl+0x79/0x90
[<ffffffff81001bb0>] ? syscall_return_slowpath+0x50/0x130
[<ffffffff8167f776>] entry_SYSCALL_64_fastpath+0x16/0x75
Fix the issue by returning NULL when there is no device with
the requested name in the list.
Cc: stable@vger.kernel.org # v4.2+
Fixes: 4bc94d5dc95d ("vfio: Fix lockdep issue")
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'drivers/vfio/vfio.c')
| -rw-r--r-- | drivers/vfio/vfio.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index 1c0f98c2f634..ab056f7af54d 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -711,11 +711,12 @@ EXPORT_SYMBOL_GPL(vfio_device_get_from_dev); static struct vfio_device *vfio_device_get_from_name(struct vfio_group *group, char *buf) { - struct vfio_device *device; + struct vfio_device *it, *device = NULL; mutex_lock(&group->device_lock); - list_for_each_entry(device, &group->device_list, group_next) { - if (!strcmp(dev_name(device->dev), buf)) { + list_for_each_entry(it, &group->device_list, group_next) { + if (!strcmp(dev_name(it->dev), buf)) { + device = it; vfio_device_get(device); break; } |