Affected: Ubuntu Linux kernel

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->vm_file in their mmap handlers. On error the original value is not restored, and the reference is put for the file to which vm_file points. On upstream kernels this is not an issue, as no callers dereference vm_file following after call_mmap() returns an error. However, the aufs patchs change mmap_region() to replace the fput() using a local variable with vma_fput(), which will fput() vm_file, leading to a refcount underflow.

Affected: Ubuntu:18.04:LTS: linux-gcp-5.3

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 code. (CVE-2019-15794)

Nicolas Waisman discovered that the WiFi driver stack in the Linux kernel did not properly validate SSID lengths. A physically proximate attacker could use this to cause a denial of service (system crash). (CVE-2019-17133)

It was discovered that the ARM Komeda display driver for the Linux kernel did not properly deallocate memory in certain error conditions. A local attacker could use this to cause a denial of service (memory exhaustion). (CVE-2019-18810)

It was discovered that the VirtualBox guest driver implementation in the Linux kernel did not properly deallocate memory in certain error conditions. A local attacker could use this to cause a denial of service (memory exhaustion). (CVE-2019-19048)

It was discovered that the ADIS16400 IIO IMU Driver for the Linux kernel did not properly deallocate memory in certain error conditions. A local attacker could use this to cause a denial of service (memory exhaustion). (CVE-2019-19060, CVE-2019-19061)

It was discovered that the Intel OPA Gen1 Infiniband Driver for the Linux kernel did not properly deallocate memory in certain error conditions. A local attacker could use this to cause a denial of service (memor…