BSA-2017-473
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 |