It was found that reporting emulation failures to user space could lead to either a local (CVE-2014-7842) or a L2->L1 (CVE-2010-5313) denial of service. In the case of a local denial of service, an attacker must have access to the MMIO area or be able to access an I/O port. Please note that on certain systems, HPET is mapped to userspace as part of vdso (vvar) and thus an unprivileged user may generate MMIO transactions (and enter the emulator) this way.
Florian Weimer of the Red Hat Product Security Team discovere that the mnlnlmsgportidok() function in libmnl 1.0.3 and earlier did not correctly validate the origin of a Netlink message, allowing local attackers to spoof Netlink messages, with context-dependent consequences.
An SCTP server doing ASCONF will panic on malformed INIT ping-of-death in the form of:
------------ INIT[PARAM: SETPRIMARYIP] ------------>
A remote attacker could use this flaw to crash the system by sending a maliciously prepared SCTP packet in order to trigger a NULL pointer dereference on the server.
Upstream patch:
https://git.kernel.org/cgit/linux/kernel/git/davem/net.git/commit/?id=e40607cbe270a9e8360907cb1e62ddf0736e4864
Acknowledgements:
This issue was discovered by Liu Wei of Red Hat.
It was found that Linux kernel's sctp stack is prone to remotely triggerable memory pressure issue caused by excessive queueing.
A remote attacker could use this flaw to cause denial-of-service conditions on the system.
Upstream commmit:
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=26b87c7881006311828bb0ab271a551a62dcceb4
Last updated 24 July 2024
Common Vulnerabilities and Exposures assigned an identifier CVE-2014-9090 to the following vulnerability:
Name: CVE-2014-9090 URL: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-9090 Assigned: 20141126 Reference: http://www.openwall.com/lists/oss-security/2014/11/26/5 Reference: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=6f442be2fb22be02cafa606f1769fa1e6f894441 Reference: https://github.com/torvalds/linux/commit/6f442be2fb22be02cafa606f1769fa1e6f894441
The dodoublefault function in arch/x86/kernel/traps.c in the Linux kernel through 3.17.4 does not properly handle faults associated with the Stack Segment (SS) segment register when espfix64 is involved, which allows local users to cause a denial of service (panic) via a modifyldt system call, as demonstrated by sigreturn32 in the linux-clock-tests test suite.
arch/x86/kvm/vmx.c in the KVM subsystem in the Linux kernel before 3.12 does not have an exit handler for the INVEPT instruction, which allows guest OS users to cause a denial of service (guest OS crash) via a crafted application.
arch/x86/kernel/tls.c in the Thread Local Storage (TLS) implementation in the Linux kernel through 3.18.1 allows local users to bypass the espfix protection mechanism, and consequently makes it easier for local users to bypass the ASLR protection mechanism, via a crafted application that makes a setthreadarea system call and later reads a 16-bit value.
Last updated 24 July 2024
ISSUE DESCRIPTION =================
Xen PCI backend driver does not perform proper sanity checks on the device's state.
Which in turn allows the generic MSI code (called by Xen PCI backend) to be called incorrectly leading to hitting BUG conditions or causing NULL pointer exceptions in the MSI code.
To exploit this the guest can craft specific sequence of XENPCIOP operations which will trigger this.
Furthermore the frontend can also craft an continous stream of XENPCIOPenablemsi which will trigger an continous stream of WARN() messages triggered by the MSI code leading to the logging in the initial domain to exhaust disk space.
Lastly there is also missing check to verify whether the device has memory decoding enabled set at the start of the day leading the initial domain "accesses to the respective MMIO or I/O port ranges would - - on PCI Express devices - [which can] lead to Unsupported Request responses. The treatment of such errors is platform specific." (from XSA-120). Note that if XSA-120 'addendum' patch has been applied this particular sub-issue is not exploitable.
IMPACT ======
Malicious guest administrators can cause denial of service. If driver domains are not in use, the impact is a host crash.
Only x86 systems are vulnerable. ARM systems are not vulnerable.
VULNERABLE SYSTEMS ==================
This bug affects systems using Linux as the driver domain, including non-disaggregated systems using Linux as dom0.
Linux versions v3.1 and onwards are vulnerable due to supporting PCI pass-through backend driver.
PV and HVM guests which have been granted access to physical PCI devices (PCI passthrough') can take advantage of this vulnerability.
Furthermore, the vulnerability is only applicable when the passed-through PCI devices are MSI-capable or MSI-X. (Most modern devices are).
MITIGATION ==========
Not using PCI passthrough for PV and HVM guests. Note that for HVM guests QEMU is used for PCI passthrough - however the toolstack sets up also the 'PV' PCI which the guest can utilize if it chooses to do so.
External References:
http://xenbits.xen.org/xsa/advisory-157.html
Acknowledgements:
Red Hat would like to thank the Xen project for reporting this issue.
Last updated 24 July 2024
Last updated 24 July 2024
Last updated 24 July 2024
journalunmapbuffer()'s zapbuffer: code clears a lot of buffer head state ala discardbuffer(), but does not touch Delay or Unwritten as discardbuffer() does.
This can be problematic in some areas of the ext4 code which assume that if they have found a buffer marked unwritten or delay, then it's a live one. They do not check whether a buffer is mapped, so jbd2's partial teardown can be problematic if they assume that this buffer head is still valid.
(Mounting without a journal also avoids the bug, because with no journal we go to unmapbuffer(), which does the right thing).
An unprivileged local user could use this flaw to crash the system.
A flaw was found in the way Linux kernel's XFS filesystem implementation handled links with pathname larger than MAXPATHLEN. When CONFIGXFSDEBUG configuration option was not enabled when compiling Linux kernel, an attacker able to mount malicious XFS image could use this flaw to crash the system, or potentially, elevate his privileges on that system.
Proposed upstream patch: http://oss.sgi.com/archives/xfs/2011-10/msg00345.html
Datalen paremeter of sockallocsendpskb() function is not validated before setting frags of allocated skb, which can lead to heap overflow.
On Red Hat Enterprise Linux 5 a user having access to TUN/TAP virtual device could use this flaw to crash the system or to potentially escalate their privileges. The resulting CVSS score is 6.2.
On Red Hat Enterprise Linux 6 a privileged guest user could use this flaw to crash the host or to potentially escalate their privileges on the host. The resulting CVSS score is 7.4.
Buffer overflow in virt/kvm/irqcomm.c in the KVM subsystem in the Linux kernel before 3.2.24 allows local users to cause a denial of service (crash) and possibly execute arbitrary code via vectors related to Message Signaled Interrupts (MSI), irq routing entries, and an incorrect check by the setuproutingentry function before invoking the kvmsetirq function.
Last updated 24 July 2024
Last updated 24 July 2024
Last updated 24 July 2024
Last updated 24 July 2024
Florian Weimer of the Red Hat Product Security Team discovered that hypervkvpd would exit when it processed a spoofed Netlink packet that had been sent from an untrusted local user, in the following code:
len = recvfrom(fd, kvprecvbuffer, sizeof(kvprecvbuffer), 0, addrp, &addrl);
if (len < 0 || addr.nlpid) { syslog(LOGERR, "recvfrom failed; pid:%u error:%d %s", addr.nlpid, errno, strerror(errno)); close(fd); return -1; }
Acknowledgements:
This issue was discovered by Florian Weimer of the Red Hat Product Security Team.
Last updated 24 July 2024
Last updated 24 July 2024
Last updated 24 July 2024
Last updated 24 July 2024
Last updated 24 July 2024
Last updated 24 July 2024
Last updated 24 July 2024
Last updated 24 July 2024