Documentation
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Overview ¶
Package sanitize provides functions for sanitizing user input before logging.
Log injection (CWE-117) occurs when untrusted data is written to logs without proper neutralization, allowing attackers to forge log entries, corrupt log integrity, or inject malicious content.
Reference: https://cwe.mitre.org/data/definitions/117.html
Example attack vectors:
- Newline injection: "legitimate\nERROR: fake entry" creates fake log lines
- Carriage return injection: overwrites log lines on some terminals
- Control character injection: can corrupt log files or exploit log viewers
Usage:
log.Printf("user=%s action=%s", sanitize.String(username), sanitize.String(action))
slog.Info("request", "session_id", sanitize.String(sessionID))
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func HasControlChars ¶
HasControlChars returns true if the string contains any Unicode control characters (category Cc), which is broader than just ASCII control chars.
func IsClean ¶
IsClean returns true if the string contains no control characters that would require sanitization.
Example:
if !sanitize.IsClean(sessionID) {
log.Warn("suspicious session ID detected")
}
func String ¶
String removes or replaces characters that could be used for log injection. This includes newlines, carriage returns, and other ASCII control characters.
Use this function when logging any user-controlled input to prevent CWE-117.
Example:
log.Printf("session=%s", sanitize.String(req.SessionID))
func StringOrTruncate ¶
StringOrTruncate sanitizes a string and truncates it to maxLen if longer. This is useful for logging potentially large user inputs.
Example:
log.Printf("body=%s", sanitize.StringOrTruncate(requestBody, 1000))
func StringReplace ¶
StringReplace is like String but replaces control characters with a replacement string instead of removing them. This preserves the visual indication that something was sanitized.
Example:
log.Printf("input=%s", sanitize.StringReplace(userInput, "?"))
func Strings ¶
Strings sanitizes multiple strings, returning a new slice.
Example:
safe := sanitize.Strings(userID, sessionID, action)
func StripAllControl ¶
StripAllControl removes all Unicode control characters (category Cc), not just ASCII control characters. Use this for stricter sanitization.
Types ¶
This section is empty.
Source Files