Citation Context

...“black box” to the rest of the system. Only its inputs and outputs, but no intermediate states, are observable. • Integrity: The system cannot affect the behaviour of the program, except by choosing not to execute it at all or withholding resources (denial of service attacks). If the program completes, its output is the same as a correct execution on a reference platform. While the term may be new, the underlying concept is not. In using a new term, we attempt to generalise beyond specific implementations such as cloaking [11, 12], “pieces of application logic” [33, 38, 39], protected modules [45] and high-assurance processes [25] that provide To appear in 11th USENIX Symposium on Operating Systems Design and Implementation. 2 shielded execution under a specific set of constraints. Moreover, in Haven, our goal is to relax those constraints to achieve shielded execution for unmodified application binaries with complex OS dependencies. Note that shielded execution is necessary but not sufficient to meet our goal of confidential execution in the cloud. We also require an attestation mechanism to establish confidence in the integrity of a remote shielded program, and a mechanism to provisi...

Citation Context

...These features could be provided by SVA-OS in very similar ways, at the cost of a non-trivial relative increase in the TCB size. Other recent efforts, namely TrustVisor [22], Flicker [23], and Memoir =-=[27]-=-, provide special purpose hypervisors that enable secure execution and data secrecy for pieces of application logic. They obtain isolated execution of code and data secrecy via hardware virtualization...

Citation Context

...ted form, but the TLR does not have direct access to the disk. Instead the TLR passes encrypted blobs to the disk managed by the untrusted OS. To prevent rollback attacks and enforce state continuity =-=[31]-=-, we adopt the following defense. TrustZoneenabled devices use an eMMC storage controller that offers a security feature called replay-protected memory blocks (RPMB) (see [38]). The RPMB is a storage ...

Citation Context

...igh-event applications such as networked games [16]. Similarly, although the TPM specification mandates access-controlled, non-volatile storage, most implementations provide only 1,280 bytes of NVRAM =-=[26]-=-. These limitations have led researchers to seek alternative designs for trusted devices [16]. 3.5 How cTPM Overcomes These Limitations To address these limitations, we propose cTPM, a modification to...

Citation Context

...with steps 〈3〉3 and 〈3〉4. Isabelle and Zenon can now prove all the steps. 4 Writing Real Proofs Peterson’s algorithm is a tiny example. Some larger case studies have been carried out using the system =-=[7, 9, 11]-=-. Several features of TLAPS and its Toolbox interface help in coping with the complexity of large proofs. 4.1 Hierarchical Proofs And The Proof Manager Hierarchical structure is the key to managing co...

Citation Context

...le errors. Engineers implementing such protocols face the same subtleties and, worse, must improvise to fill in gaps between abstract protocol descriptions and practical constraints, e.g., that real logs cannot grow without bound. Thorough testing is considered best practice, but its efficacy is limited by distributed systems’ combinatorially large state spaces. In theory, formal verification can categorically eliminate errors from distributed systems. However, due to the complexity of these systems, previous work has primarily focused on formally specifying [4, 13, 27, 41, 48, 64], verifying [3, 52, 53, 59, 61], or at least bug-checking [20, 31, 69] distributed protocols, often in a simplified form, without extending such formal reasoning to the implementations. In principle, one can use model checking to reason about the correctness of both protocols [42, 59] and implementations [46, 47, 69]. In practice, however, model checking is incomplete—the accuracy of the results depends on the accuracy of the model—and does not scale [4]. Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed...

Citation Context

...environments, wimps often give up a variety of basic services for application development, which greatly undermines their usefulness and viability. For example, wimps typically lack persistent memory =-=[52]-=-, file system and network services [13, 14, 16, 31, 44], flexible trusted paths to users [69], and I/O services needed for many applications; e.g., in industrial control, finance, health care, and def...

Citation Context

...), since the use of a secret key makes the MAC neither private nor subject to integrity attack by the untrusted store. Standard techniques (not implemented here) can prevent attacks on data freshness =-=[25, 31]-=-. On subsequent starts, the boot block queries the cache for the MAC it previously computed. If the MAC is present, the boot block verifies the image’s integrity with the MAC, skipping the hash altoge...