A flaw was discovered in the Linux kernel where issuing certain ioctl() -s commands to the "/dev/ppp" device file could lead to a NULL pointer dereference. A privileged user could use this flaw to cause a kernel crash and denial of service.
The following flaw was found in the Linux kernel:
In the process of using the PPP device driver, if the unit of the PPP device file has been created. On the basis of the above, the ioctl function is used to pass the PPPIOCSMAXCID command and the 0x67084000 parameter (parameters must be satisfied: arg>>16 > 255 and 0xFFFF&arg > 255), which will lead to the use of null pointers in the kernel.
Created kernel tracking bugs for this issue:
Affects: fedora-all [bug 1271135]
Ben Hutchings posted a two patch series to fix this issue, however his mailer corrupted the patches according to the netdev maintainer.
kernel-4.2.6-300.fc23 has been pushed to the Fedora 23 stable repository. If problems still persist, please make note of it in this bug report.
kernel-4.2.6-200.fc22 has been pushed to the Fedora 22 stable repository. If problems still persist, please make note of it in this bug report.
kernel-4.1.13-100.fc21 has been pushed to the Fedora 21 stable repository. If problems still persist, please make note of it in this bug report.
This issue affects the Linux kernel packages as shipped with Red Hat Enterprise Linux 5, 6, 7 and MRG-2.
This has been rated as having Low security impact as privileged access is required to exploit it, and is not currently planned to be addressed in future updates. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/.