replaced os.popen() with inbuilt file handling
What the developer wrote
Authored by S1DDHEY
replaced os.popen() with inbuilt file handling
What changed, and why it matters
This commit replaces a shell command used to read the Raspberry Pi CPU serial number with safer built-in Python file reading. The old code ran the command 'cat /proc/cpuinfo | grep Serial' through the operating system shell, which is generally discouraged because it can be risky if any part of the command string is ever influenced by untrusted input. In this specific case, the command string was hardcoded and contained no user input, so the direct risk is low. The change is a defensive hardening improvement rather than a fix for an active vulnerability.
Treat as a minor hardening improvement. Reviewers should verify that /proc/cpuinfo parsing handles missing Serial lines and unusual whitespace correctly, and confirm the entropy source still behaves deterministically across hardware variants. No urgent security response is required.
Security signals we found
Removal of os.popen shell invocation
Replacement of shell pipeline with native file I/O
Defensive hardening in entropy collection path
No user-controlled input observed in original command string
Evidence from the diff
The patch removes os.popen(‘cat /proc/cpuinfo | grep Serial’) and instead opens /proc/cpuinfo directly, iterates lines, and extracts the Serial field in pure Python. This eliminates shell invocation and pipe creation. The original code was a static, hardcoded command with no external interpolation, so command injection was not directly possible here. However, os.popen is deprecated and shell-based file access is fragile and less auditable. The change improves robustness and follows secure-coding practice. The serial number is still hashed with SHA-256 before use in mnemonic generation, so raw serial exposure is mitigated.
Changed components
src/seedsigner/views/tools_views.pyToolsImageEntropyMnemonicLengthViewInspect captured patch +6 / −4
diff --git a/src/seedsigner/views/tools_views.py b/src/seedsigner/views/tools_views.py
index b2c6b9f..798cf5b 100644
--- a/src/seedsigner/views/tools_views.py
+++ b/src/seedsigner/views/tools_views.py
@@ -1,6 +1,5 @@
import hashlib
import logging
-import os
import time
from gettext import gettext as _
@@ -148,9 +147,12 @@ class ToolsImageEntropyMnemonicLengthView(View):
# Build in some hardware-level uniqueness via CPU unique Serial num
try:
- stream = os.popen("cat /proc/cpuinfo | grep Serial")
- output = stream.read()
- serial_num = output.split(":")[-1].strip().encode('utf-8')
+ serial_num = b''
+ with open("/proc/cpuinfo", "r") as f:
+ for line in f:
+ if "Serial" in line:
+ serial_num = line.split(":")[-1].strip().encode('utf-8')
+ break
serial_hash = hashlib.sha256(serial_num)
hash_bytes = serial_hash.digest()
except Exception as e:
Why this scored 46/100
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