A flaw was found in the way the Linux kernel's floppy driver handled user space provided data in certain error code paths while processing FDRAWCMD IOCTL commands. A local user with write access to /dev/fdX could use this flaw to free (using the kfree() function) arbitrary kernel memory. (CVE-2014-1737, Important) It was found that the Linux kernel's floppy driver leaked internal kernel memory addresses to user space during the processing of the FDRAWCMD IOCTL command. A local user with write access to /dev/fdX could use this flaw to obtain information about the kernel heap arrangement. (CVE-2014-1738, Low) Note: A local user with write access to /dev/fdX could use these two flaws (CVE-2014-1737 in combination with CVE-2014-1738) to escalate their privileges on the system.

Last updated 24 July 2024

Last updated 24 July 2024

arch/x86/kvm/x86.c in the Linux kernel before 2.6.36.2 does not initialize certain structure members, which allows local users to obtain potentially sensitive information from kernel stack memory via read operations on the /dev/kvm device.

Description of problem: There is a problem with the ioctl subsystem for drm, though it is most explicitly exposed by the intel GEM driver. Under driver-defined ioctls, drm does not sanitize the ioctl command, allowing the caller to specify how much memory should be kmalloc'd and copied back to the caller, regardless of what the driver ioctl actually does (it doesn't even need to succeed).

drivers/gpu/drm/drmdrv.c

long drmioctl(struct file filp, unsigned int cmd, unsigned long arg) ... unsigned int nr = DRMIOCTLNR(cmd); ... if ((nr >= DRMCOMMANDBASE) && (nr < DRMCOMMANDEND) && (nr < DRMCOMMANDBASE + dev->driver->numioctls)) ioctl = &dev->driver->ioctls[nr - DRMCOMMANDBASE]; ... if (cmd & (IOCIN | IOCOUT)) { if (IOCSIZE(cmd) <= sizeof(stackkdata)) { kdata = stackkdata; } else { kdata = kmalloc(IOCSIZE(cmd), GFPKERNEL); ... } } ... retcode = func(dev, kdata, filepriv); ... if (cmd & IOCOUT) { if (copytouser((void user )arg, kdata, IOCSIZE(cmd)) != 0) retcode = -EFAULT; }

"cmd" is caller-controlled, and can do whatever it likes for IOCSIZE(cmd), IOCIN and IOCOUT, resulting in leakage of previously freed kernel heap memory contents up to 16K in size.