Synopsis: Important: kernel security and bug fix update
Advisory ID: SLSA-2014:0740-1
Issue Date: 2014-06-10
CVE Numbers: CVE-2014-1737
* 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.
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.
* A NULL pointer dereference flaw was found in the rds_ib_laddr_check()
function in the Linux kernel’s implementation of Reliable Datagram Sockets
(RDS). A local, unprivileged user could use this flaw to crash the system.
This update also fixes the following bugs:
* A bug in the futex system call could result in an overflow when passing
a very large positive timeout. As a consequence, the FUTEX_WAIT operation
did not work as intended and the system call was timing out immediately. A
backported patch fixes this bug by limiting very large positive timeouts
to the maximal supported value.
* A new Linux Security Module (LSM) functionality related to the setrlimit
hooks should produce a warning message when used by a third party module
that could not cope with it. However, due to a programming error, the
kernel could print this warning message when a process was setting rlimits
for a different process, or if rlimits were modified by another than the
main thread even though there was no incompatible third party module. This
update fixes the relevant code and ensures that the kernel handles this
warning message correctly.
* Previously, the kernel was unable to detect KVM on system boot if the
Hyper-V emulation was enabled. A patch has been applied to ensure that
both KVM and Hyper-V hypervisors are now correctly detected during system
* A function in the RPC code responsible for verifying whether cached
credentials match the current process did not perform the check correctly.
The code checked only whether the groups in the current process
credentials appear in the same order as in the cached credentials but did
not ensure that no other groups are present in the cached credentials. As
a consequence, when accessing files in NFS mounts, a process with the same
UID and GID as the original process but with a non-matching group list
could have been granted an unauthorized access to a file, or under certain
circumstances, the process could have been wrongly prevented from
accessing the file. The incorrect test condition has been fixed and the
problem can no longer occur.
* When being under heavy load, some Fibre Channel storage devices, such as
Hitachi and HP Open-V series, can send a logout (LOGO) message to the host
system. However, due to a bug in the lpfc driver, this could result in a
loss of active paths to the storage and the paths could not be recovered
without manual intervention. This update corrects the lpfc driver to
ensure automatic recovery of the lost paths to the storage in this
The system must be rebooted for this update to take effect.
– Scientific Linux Development Team