-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Xen Security Advisory CVE-2013-4355 / XSA-63 version 4 Information leaks through I/O instruction emulation UPDATES IN VERSION 4 ==================== Normalize version tag to say "xen-unstable". ISSUE DESCRIPTION ================= Insufficient or missing error handling in certain routines dealing with guest memory reads can lead to uninitialized data on the hypervisor stack (potentially containing sensitive data from prior work the hypervisor performed) being copied to guest visible storage. This allows a malicious HVM guest to craft certain operations (namely, but not limited to, port or memory mapped I/O writes) involving physical or virtual addresses that have no actual memory associated with them, so that hypervisor stack contents are copied into the destination of the operation, thus becoming visible to the guest. IMPACT ====== A malicious HVM guest might be able to read sensitive data relating to other guests. VULNERABLE SYSTEMS ================== Xen 3.2.x and later are vulnerable. Xen 3.1.x and earlier have not been inspected. Only HVM guests can take advantage of this vulnerability. MITIGATION ========== Running only PV guests will avoid this issue. CREDITS ======= This issue was discovered by Coverity Scan and diagnosed by Andrew Cooper & Tim Deegan. RESOLUTION ========== Applying the appropriate attached patch resolves this issue. xsa63.patch Xen 4.2.x, 4.3.x, and xen-unstable $ sha256sum xsa63*.patch 32fa93d8ebdfbe85931c52010bf9e561fdae8846462c5b1f2fbc217ca36f3005 xsa63.patch $ -----BEGIN PGP SIGNATURE----- iQFABAEBCAAqFiEEI+MiLBRfRHX6gGCng/4UyVfoK9kFAmV8b+kMHHBncEB4ZW4u b3JnAAoJEIP+FMlX6CvZp1oIAIImYB35uDfm/MnloIJrBCG0RDn2LuU5s4J5tTVn +rDgec0rIEUCoMhFEIHS3RpPSDKCpS7qALkuljKaghtUP2cYm4R2uEEaK1d4a1Kn AZM3WXCOmVPjJwcadkxY2PxntjMNe3MuOb9ysM2x+uF/nEpbneVKOcsMETIqnmCa BgPCJm3ARuPwIzTHYnA5WmPmKY3V7oXEMzz8vza1YotLQAgnFES+4LrBLbqYMqza a35Ofn9T3YK72e5cZzokPfli+mzDHRmhgN8yypWYqGapNTsPBffJ2oLUV//Q2cG8 OuxY608bgve12SQLlx6Iskawgs/G6Lcz7QDqBtA9ddpOIWI= =uDak -----END PGP SIGNATURE-----