ConfigManager: null-terminate config buffer before parsing - #25
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load_config allocated exactly file_size bytes, read the file into it and passed it to cJSON_Parse, which expects a null-terminated string. The parser could read past the end of the allocation, so trailing heap bytes could make a valid config fail to parse (or be misread). The fread result was also ignored, and ftell returning -1 was treated as a valid size. Allocate one extra byte and terminate the buffer, reject non-positive sizes, and fail if fewer bytes were read than expected. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01X7aYyRjzk53Sd7gxF46E3u
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Summary
ConfigManager::load_configallocates exactlyfile_sizebytes, readsconfig.jsoninto the buffer and passes it tocJSON_Parse.cJSON_Parseexpects a null-terminated string, so the parser can read past the end of the allocation: whatever heap bytes follow can make a valid config fail to parse, or in the worst case be misread. A config that fails to load puts the panel into AP mode with default settings.Two smaller issues on the same path:
freadresult is ignored, so a short read is parsed as if it were the whole file.ftellreturning-1passes thefile_size != 0check and is used as an allocation size.This PR:
file_size + 1bytes and null-terminates the buffer after reading.🤖 Generated with Claude Code
https://claude.ai/code/session_01X7aYyRjzk53Sd7gxF46E3u