AUDIT_ENCODE_NV_STRING(3)

NAME
audit_encode_nv_string - encode a name/value pair in a string

SYNOPSIS
#include <libaudit.h>

char *audit_encode_nv_string(const char *name, const char *value, unsigned int vlen)"

DESCRIPTION
This function formats a name/value pair for logging by the audit system. This should be used on any field being logged that might contain a space, a double-quote, a C0 control byte, a DEL byte, or a non-ASCII byte. Values containing those bytes have to be specially encoded for the auparse library to correctly handle the value. The encoding method is designed to prevent log injection attacks where malicious values could cause parsing errors.

To use this function, pass the name string and value string in their respective arguments. The name argument must not be NULL, and is copied as-is before the '=' separator. The value is checked with audit_value_needs_encoding(3). If encoding is needed, the returned string has the form name=HEX, where HEX is the uppercase hexadecimal encoding of the value bytes. If encoding is not needed, the returned string has the form name=value.

If value is NULL, a question mark is used as the value. If vlen is 0, the function uses strlen(3) to determine the value length. If the value may contain an embedded NUL byte, pass the value length in vlen bytes.

Also be aware that the name of the field will cause auparse to do certain things when interpreting the value. If the name is uid, a user id value in decimal is expected. Make sure that well known names are used for their intended purpose or that there is no chance of name collision with something new.

RETURN VALUE
Returns a freshly malloc'ed string that the caller must free or NULL on error.

SEE ALSO
audit_log_user_message(3), audit_log_user_comm_message(3), audit_log_user_avc_message(3), audit_log_semanage_message(3), audit_encode_value(3), audit_value_needs_encoding(3).

AUTHOR
Steve Grubb