The missing link: explaining ELF static linking, semantically

Kell, Stephen; Mulligan, Dominic P.; Sewell, Peter

doi:10.1145/3022671.2983996

Cited by 5 publications

(3 citation statements)

References 29 publications

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“…The linker provided by CompCertELF also works on this subset. Kell et al [2016] have provided the first formalization of the static linking of ELF in the specification language Lem and the proof assistant Isabelle/HOL which covers a significantly larger subset of ELF. However, their formalization of ELF linking has only been used to verify the correctness of relocation for a single instruction program.…”

Section: Related Workmentioning

confidence: 99%

CompCertELF: verified separate compilation of C programs into ELF object files

Wang

Wilke

et al. 2020

Proc. ACM Program. Lang.

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We present CompCertELF, the first extension to CompCert that supports verified compilation from C programs all the way to a standard binary file format, i.e., the ELF object format. Previous work on Stack-Aware CompCert provides a verified compilation chain from C programs to assembly programs with a realistic machine memory model. We build CompCertELF by modifying and extending this compilation chain with a verified assembler which further transforms assembly programs into ELF object files.CompCert supports large-scale verification via verified separate compilation: C modules can be written and compiled separately, and then linked together to get a target program that refines the semantics of the program linked from the source modules. However, verified separate compilation in CompCert only works for compilation to assembly programs, not to object files. For the latter, the main difficulty is to bridge the two different views of linking: one for CompCert's programs that allows arbitrary shuffling of global definitions by linking and the other for object files that treats blocks of encoded definitions as indivisible units.We propose a lightweight approach that solves the above problem without any modification to CompCert's framework for verified separate compilation: by introducing a notion of syntactical equivalence between programs and proving the commutativity between syntactical equivalence and the two different kinds of linking, we are able to transit from the more abstract linking operation in CompCert to the more concrete one for ELF object files. By applying this approach to CompCertELF, we obtain the first compiler that supports verified separate compilation of C programs into ELF object files.

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Section: Related Workmentioning

confidence: 99%

CompCertELF: verified separate compilation of C programs into ELF object files

Wang

Wilke

et al. 2020

Proc. ACM Program. Lang.

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“…The compiler blindly constructs these sections without considering any possible redundancy, as it can only process the code of a single object file at a time. In turn, when the linker observes redundant sections, it nondeterministically keeps one of them and discards the rest [82]. This deduplication process can cause discrepancies in the layout and fixup information kept as part of our metadata, and thus the corresponding information about all removed sections is discarded at this stage.…”

Section: Link-time Metadata Consolidationmentioning

confidence: 99%

Compiler-Assisted Code Randomization

Koo

Chen

et al. 2018

2018 IEEE Symposium on Security and Privacy (SP)

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Despite decades of research on software diversification, only address space layout randomization has seen widespread adoption. Code randomization, an effective defense against return-oriented programming exploits, has remained an academic exercise mainly due to i) the lack of a transparent and streamlined deployment model that does not disrupt existing software distribution norms, and ii) the inherent incompatibility of program variants with error reporting, whitelisting, patching, and other operations that rely on code uniformity. In this work we present compiler-assisted code randomization (CCR), a hybrid approach that relies on compiler-rewriter cooperation to enable fast and robust fine-grained code randomization on end-user systems, while maintaining compatibility with existing software distribution models. The main concept behind CCR is to augment binaries with a minimal set of transformationassisting metadata, which i) facilitate rapid fine-grained code transformation at installation or load time, and ii) form the basis for reversing any applied code transformation when needed, to maintain compatibility with existing mechanisms that rely on referencing the original code. We have implemented a prototype of this approach by extending the LLVM compiler toolchain, and developing a simple binary rewriter that leverages the embedded metadata to generate randomized variants using basic block reordering. The results of our experimental evaluation demonstrate the feasibility and practicality of CCR, as on average it incurs a modest file size increase of 11.46% and a negligible runtime overhead of 0.28%, while it is compatible with link-time optimization and control flow integrity.

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“…However, since the linking process and its mechanisms involved are incompatible across different platforms, most FCI methods based on static linking are individually platform specific and would not be portable. More information on the static linking process in general can be found in Presser et al and Levine and recent discussions on the formal model of static linking along with the executable file format can be found in Kell et al…”

Section: Stages In Program Build Processmentioning

confidence: 99%

Function call interception techniques

Kang¹

2017

Softw Pract Exp

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Function call interception (FCI), or method call interception (MCI) in the object-oriented programming domain, is a technique of intercepting function calls at program runtime. Without directly modifying the original code, FCI enables to undertake certain operations before and/or after the called function or even to replace the intercepted call. Thanks to this capability, FCI has been typically used to profile programs, where functions of interest are dynamically intercepted by instrumentation code so that the execution control is transferred to an external module that performs execution time measurement or logging operations. In addition, FCI allows for manipulating the runtime behavior of program components at the fine-grained function level, which can be useful in changing an application's original behavior at runtime to meet certain execution requirements such as maintaining performance characteristics for different input problem sets. Due to this capability, however, some FCI techniques can be used as a basis of many security exploits for vulnerable systems. In this paper, we survey a variety of FCI techniques and tools along with their applications to diverse areas in the computing and software domains. We describe static and dynamic FCI techniques at large and discuss the strengths and weaknesses of different implementations in this category. In addition, we also discuss aspect-oriented programming implementation techniques for intercepting method calls.

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The missing link: explaining ELF static linking, semantically

Cited by 5 publications

References 29 publications

CompCertELF: verified separate compilation of C programs into ELF object files

CompCertELF: verified separate compilation of C programs into ELF object files

Compiler-Assisted Code Randomization

Function call interception techniques

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