First published: Wed Apr 10 2013(Updated: )
A check for valid userspace memory was found missing in kvm_set_memory_region() function. Because of that, memory regions pointing to kernel memory could be registered with KVM and later used when converting guest physical addresses to host virtual ones. Several call sites relied on the validation and were using read/write functions that were missing the access_ok() check when accessing userspace memory. A local unprivileged user on Red Hat Enterprise Linux 6 system could use this flaw to escalate their privileges on the system. On Red Hat Enterprise Linux 6.2 EUS and Red Hat Enterprise Linux 6.3 EUS the impact is limited to potential information leak only. A local user on Red Hat Enterprise Linux 5 system able to write to /dev/kvm could possibly use this flaw to leak kernel memory. Upstream fixes: <a href="https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=fa3d315a4ce2c0891cdde262562e710d95fba19e">https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=fa3d315a4ce2c0891cdde262562e710d95fba19e</a> <a href="https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=9e3bb6b6f6a0c535eb053fbf0005a8e79e053374">https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=9e3bb6b6f6a0c535eb053fbf0005a8e79e053374</a> Acknowledgements: This issue was discovered by Michael S. Tsirkin of Red Hat.
Credit: secalert@redhat.com secalert@redhat.com
Affected Software | Affected Version | How to fix |
---|---|---|
Linux Kernel | <3.0 | |
Red Hat Enterprise Linux | =5.0 | |
redhat enterprise Linux eus | =6.2 | |
redhat enterprise Linux eus | =6.3 | |
Ubuntu Linux | =10.04 | |
debian/linux | 5.10.223-1 5.10.226-1 6.1.123-1 6.1.119-1 6.12.10-1 6.12.11-1 |
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CVE-2013-1943 is considered to have a high severity due to its potential to allow unauthorized access to kernel memory.
To fix CVE-2013-1943, upgrade to the appropriate patched version of the Linux kernel or affected distribution as specified in the advisory.
CVE-2013-1943 affects Linux kernel versions up to 3.0 and specific versions of Red Hat Enterprise Linux and Ubuntu.
CVE-2013-1943 exploits the lack of proper validation for userspace memory in the kvm_set_memory_region() function.
There are no reliable workarounds for CVE-2013-1943; the best mitigation is to apply the security updates promptly.