BSA-2017-473

Brocade Fabric OS

2 more products

21368

24 December 2018

17 November 2017

Closed

Medium

6.1

N/A

CVE-2017-1000255

Summary

Security Advisory ID : BSA-2017-473

Component : Kernel

Revision : 2.0: Final

On Linux running on PowerPC hardware (Power8 or later) a user process can craft a signal frame and then do a sigreturn so that the kernel will take an exception (interrupt), and use the r1 value *from the signal frame* as the kernel stack pointer. As part of the exception entry the content of the signal frame is written to the kernel stack, allowing an attacker to overwrite arbitrary locations with arbitrary values. The exception handling does produce an oops, and a panic if panic_on_oops=1, but only after kernel memory has been over written. This flaw was introduced in commit: "5d176f751ee3 (powerpc: tm: Enable transactional memory (TM) lazily for userspace)" which was merged upstream into v4.9-rc1. Please note that kernels built with CONFIG_PPC_TRANSACTIONAL_MEM=n are not vulnerable.

Affected Products

No Brocade Fibre Channel technology products from Broadcom are currently known to be affected by this vulnerability.

Workaround

There are no workarounds that address this vulnerability.

Revision History

Version Change Date
1.0 Initial Publication November 17, 2017
2.0 Updated for Fiber Channel only December 24, 2018