CVE-2019-15794: Operation on a Resource after Expiration or Release

Overlayfs in the Linux kernel and shiftfs, a non-upstream patch to the Linux kernel included in the Ubuntu 5.0 and 5.3 kernel series, both replace vma-vmfile in their mmap handlers. On error the original value is not restored, and the reference is put for the file to which vmfile points. On...

CVE-2019-15792: Access of Resource Using Incompatible Type

In shiftfs, a non-upstream patch to the Linux kernel included in the Ubuntu 5.0 and 5.3 kernel series, shiftfsbtrfsioctlfdreplace calls fdgetoldfd, then without further checks passes the resulting file into shiftfsrealfdget, which casts file-privatedata, a void that points to a filesystem-depende...

CVE-2019-15793: Insertion of Sensitive Information into Externally-Accessible File or Directory

In shiftfs, a non-upstream patch to the Linux kernel included in the Ubuntu 5.0 and 5.3 kernel series, several locations which shift ids translate user/group ids before performing operations in the lower filesystem were translating them into inituserns, whereas they should have been translated in...

CVE-2019-15791: Operation on a Resource after Expiration or Release

In shiftfs, a non-upstream patch to the Linux kernel included in the Ubuntu 5.0 and 5.3 kernel series, shiftfsbtrfsioctlfdreplace installs an fd referencing a file from the lower filesystem without taking an additional reference to that file. After the btrfs ioctl completes this fd is closed, whi...

The vulnerability of the shiftfs component in the Linux operating system’s kernel allows a hacker to increase their privileges.

The vulnerability of the shiftfs component in the Linux operating system’s kernel is related to deficiencies in access control. Exploiting this vulnerability can allow attackers to enhance their privileges...

The vulnerability of the shiftfs component in the Linux operating system’s kernel allows a hacker to trigger a service failure.

The vulnerability of the shiftfs component in the Linux operating system’s kernel is related to a data type conversion error. Exploiting this vulnerability can allow an attacker to cause a service failure...

The vulnerability of the shiftfs component in the Linux operating system’s kernel allows a hacker to trigger a service failure.

The vulnerability of the shiftfs component in the Linux operating system’s kernel is related to an uncontrolled consumption of resources. Exploiting this vulnerability can allow a perpetrator to cause service failures...

Ubuntu 18.04 LTS : Linux kernel vulnerabilities (USN-4209-1)

The remote Ubuntu 18.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-4209-1 advisory. Jann Horn discovered that the OverlayFS and ShiftFS Drivers in the Linux kernel did not properly handle reference counting during memory mapping operatio...

USN-4209-1: Linux kernel vulnerabilities

Jann Horn discovered that the OverlayFS and ShiftFS Drivers in the Linux kernel did not properly handle reference counting during memory mapping operations when used in conjunction with AUFS. A local attacker could use this to cause a denial of service system crash or possibly execute arbitrary...

USN-4208-1: Linux kernel vulnerabilities

Jann Horn discovered that the OverlayFS and ShiftFS Drivers in the Linux kernel did not properly handle reference counting during memory mapping operations when used in conjunction with AUFS. A local attacker could use this to cause a denial of service system crash or possibly execute arbitrary...

Linux kernel shiftfs type obfuscation vulnerability

Linux kernel is an open source operating system. A type obfuscation vulnerability exists in Linux kernel shiftfs, which allows local attackers to submit a special request that can be exploited to execute arbitrary code or conduct denial-of-service attacks...

Linux kernel shiftfs count underflow vulnerability

Linux kernel is an open source operating system. A count underflow vulnerability exists in Linux kernel shiftfs, which allows local attackers to submit a special request that can be exploited for denial of service attacks...

Ubuntu 19.10 - Refcount Underflow and Type Confusion in shiftfs

Ubuntu 19.10 - Refcount Underflow and Type Confusion in shiftfs Tested on Ubuntu 19.10, kernel "5.3.0-19-generic 20-Ubuntu". Ubuntu ships a filesystem "shiftfs" in fs/shiftfs.c in the kernel tree that doesn't exist upstream. This filesystem can be mounted from user namespaces, meaning that this i...

Ubuntu 19.10 - Refcount Underflow and Type Confusion in shiftfs

Tested on Ubuntu 19.10, kernel "5.3.0-19-generic 20-Ubuntu". Ubuntu ships a filesystem "shiftfs" in fs/shiftfs.c in the kernel tree that doesn't exist upstream. This filesystem can be mounted from user namespaces, meaning that this is attack surface from unprivileged userspace in the default...

Ubuntu 19.10 - ubuntu-aufs-modified mmap_region() Breaks Refcounting in overlayfs/shiftfs Error Path

Tested on 19.10. Ubuntu's aufs kernel patch includes the following change which I interestingly can't see in the AUFS code at https://github.com/sfjro/aufs5-linux/blob/master/mm/mmap.c: ================================================================== +define vmafputvma vmadofputvma, func, LINE...

Ubuntu 19.10 - Refcount Underflow and Type Confusion in shiftfs Exploit

Tested on Ubuntu 19.10, kernel "5.3.0-19-generic 20-Ubuntu". Ubuntu ships a filesystem "shiftfs" in fs/shiftfs.c in the kernel tree that doesn't exist upstream. This filesystem can be mounted from user namespaces, meaning that this is attack surface from unprivileged userspace in the default...

Ubuntu 19.10 - ubuntu-aufs-modified mmap_region() Breaks Refcounting in overlayfsshiftfs Error Path

Ubuntu 19.10 - ubuntu-aufs-modified mmapregion Breaks Refcounting in overlayfsshiftfs Error Path Tested on 19.10. Ubuntu's aufs kernel patch includes the following change which I interestingly can't see in the AUFS code at https://github.com/sfjro/aufs5-linux/blob/master/mm/mmap.c:...

Ubuntu 19.10 - ubuntu-aufs-modified mmap_region() Breaks Refcounting in overlayfs/shiftfs Error Path

Tested on 19.10. Ubuntu's aufs kernel patch includes the following change which I interestingly can't see in the AUFS code at https://github.com/sfjro/aufs5-linux/blob/master/mm/mmap.c: ================================================================== +define vmafputvma vmadofputvma, func, LINE...

Ubuntu shiftfs refcount Underflow / Type Confusion

Ubuntu: refcount underflow and type confusion in shiftfs Tested on Ubuntu 19.10, kernel "5.3.0-19-generic 20-Ubuntu". Ubuntu ships a filesystem "shiftfs" in fs/shiftfs.c in the kernel tree that doesn't exist upstream. This filesystem can be mounted from user namespaces, meaning that this is...

Ubuntu 18.04 LTS : Linux kernel vulnerability and regression (USN-4184-2)

The remote Ubuntu 18.04 LTS host has a package installed that is affected by a vulnerability as referenced in the USN-4184-2 advisory. USN-4184-1 fixed vulnerabilities in the Linux kernel. It was discovered that the kernel fix for CVE-2019-0155 i915 missing Blitter Command Streamer check was...