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Keylogger Program Analysis
Overview
This document reviews a C-based program designed to monitor multiple keyboard devices for input events and log them into a database. The code includes mappings of keycodes to character representations and utilizes system calls to interact with input devices efficiently.
Code Highlights
Bugs
- Key Mapping: The
keycode_to_char
array lacks comprehensive keycode definitions, leading to potential null pointer dereferences. - Security Risk: SQL injection vulnerability due to direct variable embedding in queries.
- Unhandled Returns: Undefined behavior for unknown keycodes, potentially causing
NULL
insertions in the database.
Optimizations
- Implement error handling for
snprintf
in loops and usestrncasecmp
for safer keyboard checks. - Minimize
EVIOCGNAME
calls by caching device names. - Bound checks to prevent
keycode_to_char
array access overflow and batchread
operations for performance. - Ensure proper resource cleanup, including database connection closure.
- Adopt dynamic memory allocation if
device_path
exceeds 32 characters.
Strengths
- Efficient monitoring of multiple devices using
fd_set
andselect()
. - Proper use of
snprintf
to prevent buffer overflow. - Logical division between device acquisition and event processing.
Summary
Despite its functional capability, the program presents issues primarily in security, efficiency, and resource management. Addressing vulnerabilities and performance limitations could substantially enhance its reliability.
Recommendations
Consider using open-source alternatives for better functionality:
- Logkeys: Offers broader functionality and community support.
- Keylogger: Lightweight with active development on GitHub.