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process_vm_writev

Intro

process_vm_writev - transfer data between the address spaces of two processes.

Description

The process_vm_writev() system call facilitates a vectorized write to a specified process's address space from another process's address space, enabling direct memory-to-memory data transfers. Like its counterpart process_vm_readv(), this syscall provides a mechanism for direct inter-process memory access, which is particularly beneficial for debugging tools or certain specialized inter-process communication methods.

Arguments

  • pid:pid_t[K] - Process ID of the target process to which data is to be written.
  • local_iov:struct iovec *[U] - Pointer to an array of iovec structures indicating the local memory segments.
  • liovcnt:unsigned long[K] - Number of elements in local_iov.
  • remote_iov:struct iovec *[U] - Pointer to an array of iovec structures pointing to the remote memory segments in the target process.
  • riovcnt:unsigned long[K] - Number of elements in remote_iov.
  • flags:unsigned long[K] - Flag bits to modify operation (typically set to 0).

Available Tags

  • K - Originated from kernel-space.
  • U - Originated from user space.
  • TOCTOU - Vulnerable to TOCTOU (time of check, time of use).
  • OPT - Optional argument - might not always be available (passed with null value).

Hooks

sys_process_vm_writev

Type

Tracepoint (through sys_enter).

Purpose

To monitor and capture instances when the process_vm_writev() system call is invoked, detailing the source and destination memory regions and the processes involved.

Example Use Case

Crafting a tool or utility that necessitates direct writing to the memory of a target process, bypassing file-based methods or other indirect techniques. This is seen in some advanced debugging or monitoring tools.

Issues

The use of process_vm_writev() can introduce security risks, especially when not appropriately guarded. Unauthorized memory writes can compromise process integrity, and as such, proper permissions and checks must always be enforced to prevent malicious actions.

  • process_vm_readv() - Transfer data from the address space of another process.

This document was automatically generated by OpenAI and reviewed by a Human.