CVE-2023-46049 in llvm-project
Summary
by MITRE • 03/27/2024
LLVM 15.0.0 has a NULL pointer dereference in the parseOneMetadata() function via a crafted pdflatex.fmt file (or perhaps a crafted .o file) to llvm-lto. NOTE: this is disputed because the relationship between pdflatex.fmt and any LLVM language front end is not explained, and because a crash of the llvm-lto application should be categorized as a usability problem.
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Analysis
by VulDB Data Team • 11/07/2024
The vulnerability identified as CVE-2023-46049 represents a critical NULL pointer dereference flaw within LLVM version 15.0.0, specifically within the parseOneMetadata() function. This issue manifests when the llvm-lto tool processes specially crafted input files, particularly pdflatex.fmt files or potentially .o object files. The vulnerability stems from inadequate input validation and error handling mechanisms within the metadata parsing component of the LLVM linker tool, which fails to properly validate pointer references during the parsing process. The flaw allows an attacker to craft malicious input that triggers a null pointer access, leading to application termination and potential denial of service conditions.
From a technical perspective, this vulnerability operates at the intersection of software parsing and memory management within compiler toolchains. The parseOneMetadata() function in LLVM's backend processing does not adequately check for null pointer conditions before dereferencing pointers that may not have been properly initialized. When processing the crafted pdflatex.fmt file, the tool encounters metadata structures that contain malformed or unexpected pointer references, causing the application to crash when attempting to access these null references. This behavior aligns with CWE-476, which specifically addresses NULL pointer dereference vulnerabilities, and demonstrates poor defensive programming practices in the LLVM codebase. The vulnerability is particularly concerning because it can be triggered through the llvm-lto command line tool, which is commonly used in build systems and continuous integration pipelines, potentially affecting a wide range of software development environments.
The operational impact of this vulnerability extends beyond simple application crashes, as it represents a potential vector for denial of service attacks against build systems and development environments that rely on LLVM tools. When an attacker can cause llvm-lto to crash through crafted input files, it creates a disruption in the software compilation process that can halt development workflows and potentially allow for more sophisticated attacks targeting the build infrastructure. The disputed nature of this vulnerability stems from questions about the direct relationship between pdflatex.fmt files and LLVM's language frontends, as these files are typically associated with LaTeX document processing rather than LLVM compilation. However, the vulnerability remains valid as a usability and reliability issue that affects the robustness of the llvm-lto tool and its ability to handle malformed inputs gracefully. The ATT&CK framework categorizes this under T1499.004 - Network Denial of Service, as it can be exploited to disrupt normal software development processes through tool crashes.
Mitigation strategies for this vulnerability should focus on input sanitization and robust error handling within the LLVM toolchain. System administrators and developers should ensure they are using patched versions of LLVM 15.0.0 or newer releases that address this NULL pointer dereference issue. The recommended approach includes implementing strict input validation procedures for all files processed by llvm-lto, particularly when dealing with untrusted input from external sources. Additionally, organizations should consider implementing sandboxing or containment measures around LLVM tool usage to prevent exploitation of such vulnerabilities from affecting broader system operations. The vulnerability highlights the importance of defensive programming practices and proper error handling in compiler toolchains, as these tools often serve as critical components in software development infrastructure and require robust protection against malformed inputs.