[MINOR] send_signal_to_group assumes PGID equals PID #30

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opened 2026-05-11 10:52:02 +00:00 by thabeta · 1 comment

thabeta commented

2026-05-11 10:52:02 +00:00

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Problem

send_signal_to_group(pid) sends to -pid, assuming the process group ID equals the PID. This is true if setpgid(0, 0) succeeded in pre_exec, but:

If setpgid fails (e.g., process is already a process group leader from a parent), the signal goes to the wrong group
If the process forks a child before setpgid, the child might be in the original PGID
No verification that the signal actually reached the intended process group

Impact

Signals may be sent to the wrong process group, leaving child processes orphaned or killing unrelated processes.

Files

crates/my_init_server/src/process.rs -- send_signal_to_group
pre_exec closure -- setpgid call

Suggested Fix

Track the actual PGID (not assumed equal to PID)
Verify setpgid success and handle failures
Use cgroup-based signaling as fallback when available

## Problem `send_signal_to_group(pid)` sends to `-pid`, assuming the process group ID equals the PID. This is true if `setpgid(0, 0)` succeeded in `pre_exec`, but: 1. If `setpgid` fails (e.g., process is already a process group leader from a parent), the signal goes to the wrong group 2. If the process forks a child before `setpgid`, the child might be in the original PGID 3. No verification that the signal actually reached the intended process group ## Impact Signals may be sent to the wrong process group, leaving child processes orphaned or killing unrelated processes. ## Files - `crates/my_init_server/src/process.rs` -- `send_signal_to_group` - `pre_exec` closure -- `setpgid` call ## Suggested Fix - Track the actual PGID (not assumed equal to PID) - Verify `setpgid` success and handle failures - Use cgroup-based signaling as fallback when available

thabeta added the

bug

label

2026-05-11 10:53:00 +00:00

salmaelsoly commented

2026-05-11 13:35:24 +00:00

Member

Classification: valid-bug — send_signal_to_group sends to -pid assuming PGID equals PID; no verification of setpgid success, no tracking of actual PGID.

Confirmed by code inspection at process.rs:509-511. signal::kill(Pid::from_raw(-(pid as i32)), sig) assumes the process group leader PID equals the PGID.

> Classification: valid-bug — send_signal_to_group sends to -pid assuming PGID equals PID; no verification of setpgid success, no tracking of actual PGID. Confirmed by code inspection at process.rs:509-511. signal::kill(Pid::from_raw(-(pid as i32)), sig) assumes the process group leader PID equals the PGID.