-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Xen Security Advisory CVE-2017-17046 / XSA-245 version 3 ARM: Some memory not scrubbed at boot UPDATES IN VERSION 3 ==================== Normalize version tags NOTE REGARDING LACK OF EMBARGO ============================== This bug was discussed publicly before it was realised that it was a security vulnerability. ISSUE DESCRIPTION ================= Data can remain readable in DRAM across soft and even hard reboots. To ensure that sensitive data is not leaked from one domain to another after a reboot, Xen must "scrub" all memory on boot (write it with zeroes). Unfortunately, it was discovered that when memory was in disjoint blocks, or when the first block didn't begin at physical address 0, arithmetic errors meant that some memory was not scrubbed. IMPACT ====== Sensitive information from one domain before a reboot might be visible to another domain after a reboot. VULNERABLE SYSTEMS ================== Only ARM systems are vulnerable. All versions of Xen since 4.5 are vulnerable. Only hardware with disjoint blocks, or physical addresses not starting at 0 are vulnerable; this includes the majority of ARM systems. MITIGATION ========== None. RESOLUTION ========== Applying the appropriate attached patches resolves this issue. xsa245/*.patch Xen (All versions) $ sha256sum xsa245* xsa245*/* 121829263b85fcb5eac8e38fb44e77d3aab1dd7ae6ef665bf84bb49e5e161d24 xsa245.meta 526f9e1b127fbb316762ce8e8f4563bc9de0c55a1db581456a3017d570d35bdd xsa245/0001-xen-page_alloc-Cover-memory-unreserved-after-boot-in.patch 7164010112fcccd9cd88e72ace2eeabdb364dd6f4d05c434686267d18067f420 xsa245/0002-xen-arm-Correctly-report-the-memory-region-in-the-du.patch $ -----BEGIN PGP SIGNATURE----- iQFABAEBCAAqFiEEI+MiLBRfRHX6gGCng/4UyVfoK9kFAmV8b/cMHHBncEB4ZW4u b3JnAAoJEIP+FMlX6CvZ61wH/jgt5kcdlwzHnABoj9kWyd83WkiG9Rut5qlfhva8 Lnsw/fkkp9XNJzB5I4W1a6GGb/jF3lR+Xzz7RPhS7FL17Cb+NvglNbq66AJ7jiyq NL1gUBgyO5cT8xL8NWWh5h9L/kt25N6lH/8Pr6uNmui4gYM9slSOvC6eiFj6dUa2 q5qpt6U+A5n8iYHHFuCIfY213CuRb/ltlbFGuRlpyPr8fhM3+ViWN5M1HCEMnvAn qtIL9JuHEUONsCRK3o7FHdaHm60uF5S5hL8ETSnxWiOf7bJrfytU6D6y44tCcCQ+ 6bVesvdZzgQR07dpSAaGvHMCt1y+WU2fCQ2sRus9+iA01QM= =Vejn -----END PGP SIGNATURE-----