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gVisor Process Memory Access

1 post · Oct 2020

What this trail covers

Cloudflare engineers are contributing to gVisor, a Linux container runtime, by implementing the /proc/[pid]/mem file interface. This enables detailed debugging and stack trace analysis within sandboxed environments, addressing limitations in accessing process memory for debugging purposes.

All Cloudflare trails
  1. Diving into /proc/[pid]/memThis post details the implementation of the /proc/[pid]/mem file within gVisor's virtual file system (VFS). It explains how the Linux kernel handles access checks for this file, including ptrace permissions and capabilities, and how gVisor's `kernel.task.CanTrace` function is leveraged. The implementation uses gVisor's memory manager and `CopyIn`/`CopyOut` methods to provide access to process memory, enabling readable stack traces in crash scenarios.