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Security Fix(es):
- It was found that stacking a file system over procfs in the Linux kernel could
lead to a kernel stack overflow due to deep nesting, as demonstrated by mounting
ecryptfs over procfs and creating a recursion by mapping /proc/environ. An
unprivileged, local user could potentially use this flaw to escalate their
privileges on the system. (CVE-2016-1583, Important)
- It was reported that on s390x, the fork of a process with four page table
levels will cause memory corruption with a variety of symptoms. All processes
are created with three level page table and a limit of 4TB for the address
space. If the parent process has four page table levels with a limit of 8PB, the
function that duplicates the address space will try to copy memory areas outside
of the address space limit for the child process. (CVE-2016-2143, Moderate)
Bug Fix(es):
- Use of a multi-threaded workload with high memory mappings sometiems caused a
kernel panic, due to a race condition between the context switch and the
pagetable upgrade. This update fixes the switch_mm() by using the complete asce
parameter instead of the asce_bits parameter. As a result, the kernel no longer
panics in the described scenario. (BZ#1377472)
- When iptables created the Transmission Control Protocol (TCP) reset packet, a
kernel crash could occur due to uninitialized pointer to the TCP header within
the Socket Buffer (SKB). This update fixes the transport header pointer in TCP
reset for both IPv4 and IPv6, and the kernel no longer crashes in the described
situation.(BZ#1372266)
- Previously, when the Enhanced Error Handling (EEH) mechanism did not block the
PCI configuration space access and an error was detected, a kernel panic
occurred. This update fixes EEH to fix this problem. As a result, the kernel no
longer panics in the described scenario. (BZ#1379596)
- When the lockd service failed to start up completely, the notifier blocks were
in some cases registered on a notification chain multiple times, which caused
the occurrence of a circular list on the notification chain. Consequently, a
soft lock-up or a kernel oops occurred. With this update, the notifier blocks
are unregistered if lockd fails to start up completely, and the soft lock-ups or
the kernel oopses no longer occur under the described circumstances.
(BZ#1375637)
- When the Fibre Channel over Ethernet (FCoE) was configured, the FCoE
MaxFrameSize parameter was incorrectly restricted to 1452. With this update, the
NETIF_F_ALL_FCOE symbol
is no longer ignored, which fixes this bug. MaxFrameSize is now restricted to
2112, which is the correct value. (BZ#1381592)
- When the fnic driver was installed on Cisco UCS Blade Server, the discs were
under certain circumstances put into the offline state with the following error
message: "Medium access timeout failure. Offlining disk!". This update fixes
fnic to set the Small Computer System Interface (SCSI) status as DID_ABORT after
a successful abort operation. As a result, the discs are no longer put into the
offlined state in the described situation. (BZ#1382620)
Bugs fixed (https://bugzilla.redhat.com/):
1308908 - CVE-2016-2143 kernel: Fork of large process causes memory corruption
1344721 - CVE-2016-1583 kernel: Stack overflow via ecryptfs and /proc/$pid/environ
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