Buffer overflow in IBM Powerpc Power8
CVE-2017-1000255
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.
Vulnerability class: Buffer Overflow
EPSS: 0.004 (30.8th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N.
Affected products
- Ibm Powerpc_power8
- Ibm Powerpc_power9
- Linux Linux_kernel
- N/a — versions n/a
Weakness classification (CWE)
References
- cve@mitre.org (x_refsource_REDHAT, vendor-advisory)
- cve@mitre.org (Third Party Advisory, x_refsource_MISC, Issue Tracking)
- cve@mitre.org (VDB Entry, Third Party Advisory, vdb-entry, x_refsource_BID)
Frequently asked questions
- What is CVE-2017-1000255?
- CVE-2017-1000255 is a medium-severity vulnerability in IBM Powerpc Power8, classified under Out-of-bounds Write. CVSS score: 5.5/10. Published 2017-10-30.
- How severe is CVE-2017-1000255?
- Medium severity. CVSS v3 base score is 5.5 out of 10.