ISSUE DESCRIPTION =================

Guests are currently permitted to modify all of the (writable) bits in the PCI command register of devices passed through to them. This in particular allows them to disable memory and I/O decoding on the device unless the device is an SR-IOV virtual function, in which case subsequent accesses to the respective MMIO or I/O port ranges would - - on PCI Express devices - lead to Unsupported Request responses. The treatmeant of such errors is platform specific.

IMPACT ======

In the event that the platform surfaces aforementioned UR responses as Non-Maskable Interrupts, and either the OS is configured to treat NMIs as fatal or (e.g. via ACPI's APEI) the platform tells the OS to treat these errors as fatal, the host would crash, leading to a Denial of Service.

VULNERABLE SYSTEMS ==================

Xen versions 3.3 and onwards are vulnerable due to supporting PCI pass-through. Upstream Linux versions 3.1 and onwards are vulnerable due to supporting PCI backend functionality. Other Linux versions as well as other OS versions may be vulnerable too.

Any domain which is given access to a non-SR-IOV virtual function PCI Express device can take advantage of this vulnerability.

MITIGATION ==========

This issue can be avoided by not assigning PCI Express devices other than SR-IOV virtual functions to untrusted guests.

RESOLUTION ==========

Applying the attached patch resolves this issue for upstream Linux.

xsa120.patch Linux 3.19

$ sha256sum xsa120.patch 5167215293d4a8a05f090fca5b20eb5878213a0158a0e7a12c245553db81a855 xsa120.patch

USN-4142-1 fixed a vulnerability in e2fsprogs. This update provides the corresponding update for Ubuntu 12.04 ESM and Ubuntu 14.04 ESM. Original advisory details: It was discovered that e2fsprogs incorrectly handled certain ext4 partitions. An attacker could possibly use this issue to execute arbitrary code.

It was discovered that e2fsprogs incorrectly handled certain ext4 partitions. An attacker could possibly use this issue to execute arbitrary code.

It was discovered that Cyrus SASL incorrectly handled certain LDAP packets. An attacker could possibly use this issue to execute arbitrary code or cause a denial of service.

USN-4360-1 fixed a vulnerability in json-c. The security fix introduced a memory leak that was reverted in USN-4360-2 and USN-4360-3. This update provides the correct fix update for CVE-2020-12762. Original advisory details: It was discovered that json-c incorrectly handled certain JSON files. An attacker could possibly use this issue to execute arbitrary code.

It was discovered that json-c incorrectly handled certain JSON files. An attacker could possibly use this issue to execute arbitrary code.

USN-3770-1 fixed a vulnerability in Little CMS. This update provides the corresponding update for Ubuntu 12.04 ESM. Original advisory details: Pedro Ribeiro discoreved that Little CMS incorrectly handled certain files. An attacker could possibly use this issue to cause a denial of service. (CVE-2013-4276) Ibrahim El-Sayed discovered that Little CMS incorrectly handled certain files. An attacker could possibly use this issue to cause a denial of service. (CVE-2016-10165) Quang Nguyen discovered that Little CMS incorrectly handled certain files. An attacker could possibly use this issue to execute arbitrary code. (CVE-2018-16435)

Josef Gajdusek discovered that the LibVNCServer client library incorrectly handled certain FrameBufferUpdate messages. If a user were tricked into connecting to a malicious server, an attacker could use this issue to cause a denial of service, or possibly execute arbitrary code. (CVE-2016-9941, CVE-2016-9942)

USN-3739-1 fixed a vulnerability in libxml2. This update provides the corresponding update for Ubuntu 12.04. Original advisory details: Matias Brutti discovered that libxml2 incorrectly handled certain XML files. An attacker could possibly use this issue to expose sensitive information. (CVE-2016-9318) It was discovered that libxml2 incorrectly handled certain files. An attacker could possibly use this issue to cause a denial of service. (CVE-2018-14404)

It was discovered that the PHP Fileinfo component incorrectly handled certain magic files. An attacker could use this issue to cause PHP to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 16.04 LTS. (CVE-2015-8865) Hans Jerry Illikainen discovered that the PHP Zip extension incorrectly handled certain malformed Zip archives. A remote attacker could use this issue to cause PHP to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 16.04 LTS. (CVE-2016-3078) It was discovered that PHP incorrectly handled invalid indexes in the SplDoublyLinkedList class. An attacker could use this issue to cause PHP to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 16.04 LTS. (CVE-2016-3132) It was discovered that the PHP rawurlencode() function incorrectly handled large strings. A remote attacker could use this issue to cause PHP to crash, resulting in a denial of service. This issue only affected Ubuntu 16.04 LTS. (CVE-2016-4070) It was discovered that the PHP phpsnmperror() function incorrectly handled string formatting. A remote attacker could use this issue to cause PHP to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 16.04 LTS. (CVE-2016-4071) It was discovered that the PHP phar extension incorrectly handled certain filenames in archives. A remote attacker could use this issue to cause PHP to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 16.04 LTS. (CVE-2016-4072) It was discovered that the PHP mbstrcut() function incorrectly handled string formatting. A remote attacker could use this issue to cause PHP to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 16.04 LTS. (CVE-2016-4073) It was discovered that the PHP phar extension incorrectly handled certain archive files. A remote attacker could use this issue to cause PHP to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 12.04 LTS, Ubuntu 14.04 LTS and Ubuntu 15.10. (CVE-2016-4342, CVE-2016-4343) It was discovered that the PHP bcpowmod() function incorrectly handled memory. A remote attacker could use this issue to cause PHP to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2016-4537, CVE-2016-4538) It was discovered that the PHP XML parser incorrectly handled certain malformed XML data. A remote attacker could possibly use this issue to cause PHP to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2016-4539) It was discovered that certain PHP grapheme functions incorrectly handled negative offsets. A remote attacker could possibly use this issue to cause PHP to crash, resulting in a denial of service. (CVE-2016-4540, CVE-2016-4541) It was discovered that PHP incorrectly handled certain malformed EXIF tags. A remote attacker could possibly use this issue to cause PHP to crash, resulting in a denial of service. (CVE-2016-4542, CVE-2016-4543, CVE-2016-4544)

Karthikeyan Bhargavan discovered that NSS incorrectly handled state transitions for the TLS state machine. If a remote attacker were able to perform a machine-in-the-middle attack, this flaw could be exploited to skip the ServerKeyExchange message and remove the forward-secrecy property. (CVE-2015-2721) Watson Ladd discovered that NSS incorrectly handled Elliptical Curve Cryptography (ECC) multiplication. A remote attacker could possibly use this issue to spoof ECDSA signatures. (CVE-2015-2730) As a security improvement, this update modifies NSS behaviour to reject DH key sizes below 768 bits, preventing a possible downgrade attack. This update also refreshes the NSS package to version 3.19.2 which includes the latest CA certificate bundle.

USN-3347-1 fixed a vulnerability in Libgcrypt. This update provides the corresponding update for Ubuntu 12.04 ESM. Original advisory details: Daniel J. Bernstein, Joachim Breitner, Daniel Genkin, Leon Groot Bruinderink, Nadia Heninger, Tanja Lange, Christine van Vredendaal, and Yuval Yarom discovered that Libgcrypt was susceptible to an attack via side channels. A local attacker could use this attack to recover RSA private keys. (CVE-2017-7526)

USN-3733-1 fixed a vulnerability in GnuPG. This update provides the corresponding update for Ubuntu 12.04 ESM. Original advisory details: Daniel J. Bernstein, Joachim Breitner, Daniel Genkin, Leon Groot Bruinderink, Nadia Heninger, Tanja Lange, Christine van Vredendaal, and Yuval Yarom discovered that GnuPG is vulnerable to a cache side-channel attack. A local attacker could use this attack to recover RSA private keys.

Atte Kettunen discovered an out-of-bounds read when handling certain Content Security Policy (CSP) directives in some circumstances. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit this to cause a denial of service via application crash. (CVE-2016-2827) Christoph Diehl, Christian Holler, Gary Kwong, Nathan Froyd, Honza Bambas, Seth Fowler, Michael Smith, Andrew McCreight, Dan Minor, Byron Campen, Jon Coppeard, Steve Fink, Tyson Smith, and Carsten Book discovered multiple memory safety issues in Firefox. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit these to cause a denial of service via application crash, or execute arbitrary code. (CVE-2016-5256, CVE-2016-5257) Atte Kettunen discovered a heap buffer overflow during text conversion with some unicode characters. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit this to cause a denial of service via application crash, or execute arbitrary code. (CVE-2016-5270) Abhishek Arya discovered an out of bounds read during the processing of text runs in some circumstances. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit this to cause a denial of service via application crash. (CVE-2016-5271) Abhishek Arya discovered a bad cast when processing layout with input elements in some circumstances. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit this to cause a denial of service via application crash, or execute arbitrary code. (CVE-2016-5272) A crash was discovered in accessibility. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit this to execute arbitrary code. (CVE-2016-5273) A use-after-free was discovered in web animations during restyling. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit this to cause a denial of service via application crash, or execute arbitrary code. (CVE-2016-5274) A buffer overflow was discovered when working with empty filters during canvas rendering. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit this to cause a denial of service via application crash, or execute arbitrary code. (CVE-2016-5275) A use-after-free was discovered in accessibility. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit this to cause a denial of service via application crash, or execute arbitrary code. (CVE-2016-5276) A use-after-free was discovered in web animations when destroying a timeline. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit this to cause a denial of service via application crash, or execute arbitrary code. (CVE-2016-5277) A buffer overflow was discovered when encoding image frames to images in some circumstances. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit this to cause a denial of service via application crash, or execute arbitrary code. (CVE-2016-5278) Rafael Gieschke discovered that the full path of files is available to web pages after a drag and drop operation. An attacker could potentially exploit this to obtain sensitive information. (CVE-2016-5279) Mei Wang discovered a use-after-free when changing text direction. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit this to cause a denial of service via application crash, or execute arbitrary code. (CVE-2016-5280) Brian Carpenter discovered a use-after-free when manipulating SVG content in some circumstances. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit this to cause a denial of service via application crash, or execute arbitrary code. (CVE-2016-5281) Richard Newman discovered that favicons can be loaded through protocols not in the allowlist, such as jar:. (CVE-2016-5282) Gavin Sharp discovered a timing attack vulnerability involving document resizes and link colours. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit this to obtain sensitive information. (CVE-2016-5283) An issue was discovered with the preloaded Public Key Pinning (HPKP). If a machine-in-the-middle (MITM) attacker was able to obtain a fraudulent certificate for a Mozilla site, they could exploit this by providing malicious addon updates. (CVE-2016-5284)

USN-4376-1 fixed several vulnerabilities in OpenSSL. This update provides the corresponding update for Ubuntu 12.04 ESM and Ubuntu 14.04 ESM. Original advisory details: Cesar Pereida García, Sohaib ul Hassan, Nicola Tuveri, Iaroslav Gridin, Alejandro Cabrera Aldaya, and Billy Brumley discovered that OpenSSL incorrectly handled ECDSA signatures. An attacker could possibly use this issue to perform a timing side-channel attack and recover private ECDSA keys. (CVE-2019-1547) Juraj Somorovsky, Robert Merget, and Nimrod Aviram discovered that certain applications incorrectly used OpenSSL and could be exposed to a padding oracle attack. A remote attacker could possibly use this issue to decrypt data. (CVE-2019-1559) Bernd Edlinger discovered that OpenSSL incorrectly handled certain decryption functions. In certain scenarios, a remote attacker could possibly use this issue to perform a padding oracle attack and decrypt traffic. (CVE-2019-1563)

USN-4236-1 fixed a vulnerability in Libgcrypt. This update provides the corresponding update for Ubuntu 12.04 ESM and Ubuntu 14.04 ESM. Original advisory details: It was discovered that Libgcrypt was susceptible to a ECDSA timing attack. An attacker could possibly use this attack to recover sensitive information.

USN-3692-1 fixed a vulnerability in OpenSSL. This update provides the corresponding update for Ubuntu 12.04 ESM. Original advisory details: Keegan Ryan discovered that OpenSSL incorrectly handled ECDSA key generation. An attacker could possibly use this issue to perform a cache-timing attack and recover private ECDSA keys. (CVE-2018-0495) Guido Vranken discovered that OpenSSL incorrectly handled very large prime values during a key agreement. A remote attacker could possibly use this issue to consume resources, leading to a denial of service. (CVE-2018-0732) Alejandro Cabrera Aldaya, Billy Brumley, Cesar Pereida Garcia and Luis Manuel Alvarez Tapia discovered that OpenSSL incorrectly handled RSA key generation. An attacker could possibly use this issue to perform a cache-timing attack and recover private RSA keys. (CVE-2018-0737)

USN-3689-1 fixed a vulnerability in Libgcrypt. This update provides the corresponding update for Ubuntu 12.04 ESM. Original advisory details: Keegan Ryan discovered that Libgcrypt was susceptible to a side-channel attack. A local attacker could possibly use this attack to recover ECDSA private keys.

USN-3850-1 fixed several vulnerabilities in NSS. This update provides the corresponding update for Ubuntu 12.04 ESM. Original advisory details: Keegan Ryan discovered that NSS incorrectly handled ECDSA key generation. A local attacker could possibly use this issue to perform a cache-timing attack and recover private ECDSA keys. (CVE-2018-0495) It was discovered that NSS incorrectly handled certain v2-compatible ClientHello messages. A remote attacker could possibly use this issue to perform a replay attack. (CVE-2018-12384) It was discovered that NSS incorrectly handled certain padding oracles. A remote attacker could possibly use this issue to perform a variant of the Bleichenbacher attack. (CVE-2018-12404)

USN-3628-1 fixed a vulnerability in OpenSSL. This update provides the corresponding update for Ubuntu 12.04 ESM. Original advisory details: Alejandro Cabrera Aldaya, Billy Brumley, Cesar Pereida Garcia and Luis Manuel Alvarez Tapia discovered that OpenSSL incorrectly handled RSA key generation. An attacker could possibly use this issue to perform a cache-timing attack and recover private RSA keys.

USN-4397-1 fixed a vulnerability in NSS. This update provides the corresponding update for Ubuntu 12.04 ESM and Ubuntu 14.04 ESM. Original advisory details: Cesar Pereida Garcia discovered that NSS incorrectly handled DSA key generation. A local attacker could possibly use this issue to perform a timing attack and recover DSA keys. (CVE-2020-12399)

It was discovered that Python incorrectly handled certain character sequences. A remote attacker could possibly use this issue to perform CRLF injection.

USN-4352-1 fixed a vulnerability in OpenLDAP. This update provides the corresponding update for Ubuntu 12.04 ESM and Ubuntu 14.04 ESM. Original advisory details: It was discovered that OpenLDAP incorrectly handled certain queries. A remote attacker could possibly use this issue to cause OpenLDAP to consume resources, resulting in a denial of service.

It was discovered that Python documentation had a misleading information. A security issue could be possibly caused by wrong assumptions of this information. This issue only affected Ubuntu 12.04 ESM, Ubuntu 14.04 ESM, Ubuntu 16.04 LTS and Ubuntu 18.04 LTS. (CVE-2019-17514) It was discovered that Python incorrectly handled certain TAR archives. An attacker could possibly use this issue to cause a denial of service. (CVE-2019-20907) It was discovered that incorrectly handled certain ZIP files. An attacker could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 12.04 ESM, Ubuntu 14.04 ESM, Ubuntu 16.04 LTS and Ubuntu 18.04 LTS. (CVE-2019-9674) It was discovered that Python incorrectly handled certain IP values. An attacker could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 14.04 ESM, Ubuntu 16.04 LTS, Ubuntu 18.04 LTS and Ubuntu 20.04 LTS. (CVE-2020-14422)

André Bargull discovered that ICU incorrectly handled certain strings. An attacker could possibly use this issue to execute arbitrary code.

USN-4127-1 fixed several vulnerabilities in Python. This update provides the corresponding update for Ubuntu 12.04 ESM and Ubuntu 14.04 ESM. Original advisory details: It was discovered that Python incorrectly handled certain pickle files. An attacker could possibly use this issue to consume memory, leading to a denial of service. This issue only affected Ubuntu 14.04 ESM. (CVE-2018-20406) It was discovered that Python incorrectly validated the domain when handling cookies. An attacker could possibly trick Python into sending cookies to the wrong domain. (CVE-2018-20852) Jonathan Birch and Panayiotis Panayiotou discovered that Python incorrectly handled Unicode encoding during NFKC normalization. An attacker could possibly use this issue to obtain sensitive information. (CVE-2019-9636, CVE-2019-10160) Colin Read and Nicolas Edet discovered that Python incorrectly handled parsing certain X509 certificates. An attacker could possibly use this issue to cause Python to crash, resulting in a denial of service. This issue only affected Ubuntu 14.04 ESM. (CVE-2019-5010) It was discovered that Python incorrectly handled certain urls. A remote attacker could possibly use this issue to perform CRLF injection attacks. (CVE-2019-9740, CVE-2019-9947) Sihoon Lee discovered that Python incorrectly handled the localfile: scheme. A remote attacker could possibly use this issue to bypass blocklist meschanisms. (CVE-2019-9948)

Catalin Dumitru discovered that URLs of resources loaded after a navigation start could be leaked to the following page via the Resource Timing API. If a user were tricked in to opening a specially crafted website in a browsing context, an attacker could potentially exploit this to obtain sensitive information. (CVE-2016-5250) Christoph Diehl, Andrew McCreight, Dan Minor, Byron Campen, Jon Coppeard, Steve Fink, Tyson Smith, and Carsten Book discovered multiple memory safety issues in Thunderbird. If a user were tricked in to opening a specially crafted message, an attacker could potentially exploit these to cause a denial of service via application crash, or execute arbitrary code. (CVE-2016-5257) Atte Kettunen discovered a heap buffer overflow during text conversion with some unicode characters. If a user were tricked in to opening a specially crafted message, an attacker could potentially exploit this to cause a denial of service via application crash, or execute arbitrary code. (CVE-2016-5270) Abhishek Arya discovered a bad cast when processing layout with input elements in some circumstances. If a user were tricked in to opening a specially crafted website in a browsing context, an attacker could potentially exploit this to cause a denial of service via application crash, or execute arbitrary code. (CVE-2016-5272) A use-after-free was discovered in web animations during restyling. If a user were tricked in to opening a specially crafted website in a browsing context, an attacker could potentially exploit this to cause a denial of service via application crash, or execute arbitrary code. (CVE-2016-5274) A use-after-free was discovered in accessibility. If a user were tricked in to opening a specially crafted website in a browsing context, an attacker could potentially exploit this to cause a denial of service via application crash, or execute arbitrary code. (CVE-2016-5276) A use-after-free was discovered in web animations when destroying a timeline. If a user were tricked in to opening a specially crafted website in a browsing context, an attacker could potentially exploit this to cause a denial of service via application crash, or execute arbitrary code. (CVE-2016-5277) A buffer overflow was discovered when encoding image frames to images in some circumstances. If a user were tricked in to opening a specially crafted message, an attacker could potentially exploit this to cause a denial of service via application crash, or execute arbitrary code. (CVE-2016-5278) Mei Wang discovered a use-after-free when changing text direction. If a user were tricked in to opening a specially crafted website in a browsing context, an attacker could potentially exploit this to cause a denial of service via application crash, or execute arbitrary code. (CVE-2016-5280) Brian Carpenter discovered a use-after-free when manipulating SVG content in some circumstances. If a user were tricked in to opening a specially crafted website in a browsing context, an attacker could potentially exploit this to cause a denial of service via application crash, or execute arbitrary code. (CVE-2016-5281) An issue was discovered with the preloaded Public Key Pinning (HPKP). If a machine-in-the-middle (MITM) attacker was able to obtain a fraudulent certificate for a Mozilla site, they could exploit this by providing malicious addon updates. (CVE-2016-5284)

USN-4203-1 fixed a vulnerability in NSS. This update provides the corresponding update for Ubuntu 12.04 ESM and Ubuntu 14.04 ESM. Original advisory details: It was discovered that NSS incorrectly handled certain memory operations. A remote attacker could use this issue to cause NSS to crash, resulting in a denial of service, or possibly execute arbitrary code.

USN-4132-1 fixed a vulnerability in Expat. This update provides the corresponding update for Ubuntu 12.04 ESM and Ubuntu 14.04 ESM. Original advisory details: It was discovered that Expat incorrectly handled certain XML files. An attacker could possibly use this issue to expose sensitive information.

USN-4040-1 fixed a vulnerability in expat. This update provides the corresponding update for Ubuntu 12.04 ESM and Ubuntu 14.04 ESM. Original advisory details: It was discovered that Expat incorrectly handled certain XML files. An attacker could possibly use this issue to cause a denial of service.