Syscall Me by Your Name: Sandboxing Wasm Programs
summary
Examines concrete isolation failures and defenses: finds two Wasmtime CVEs that leak memory via linear-memory/guard-page bugs, notes other runtime bugs that allowed file writes, and demonstrates a tool called Callander that performs whole-program static analysis to generate precise seccomp/syscall sandboxing profiles. Applied to Wasmtime post-startup, it blocks PROT_EXEC mmap paths used only during JITing so shellcode cannot be mapped. Prototype runs on x86 Linux (binary on GitHub, planned GPLv3).
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chapters (11)
- 0:00Introduction
- 0:25WebAssembly isolation vision
- 2:10Isolating Wasm programs
- 7:50Isolation bugs in runtimes
- 10:39Security trade-offs in Wasm
- 14:33Attacker goals and exploits
- 17:02Mitigating Wasm vulnerabilities
- 18:26System call sandboxing for WebAssembly
- 21:18Colander’s sandboxing approach
- 23:49Demo and future of Wasm isolation
- 24:52Q&A
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