currently audit_log_n_untrustedstring() uses audit_string_contains_control() to check if the 'string' has any control characters. If the 'string' has an embedded NULL audit_string_contains_control() will return that the data has no control characters and will then pass the string to audit_log_n_string with the total length, not the length up to the first NULL. audit_log_n_string does a memcpy of the entire length and so the actual audit record emitted may then contain a NULL and then whatever random memory is after the NULL. Since we want to log the entire octet stream (if we can't trust the data to be a string we can't trust that a NULL isn't actually a part of it) we should just consider NULL as a control character. If the caller is certain they want to stop at the first NULL they should be using audit_log_untrustedstring. Signed-off-by: Eric Paris <eparis(a)redhat.com&gt; --- Miloslav, this is also going to take care of nulls in the TTY_AUDIT_USER message from userspace. Is it going to be common to have control characters on that code path as well? Do you want to change audit_receive_msg() to also use the hex encoding directly instead of the _n_untrustedstring interface? kernel/audit.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/kernel/audit.c b/kernel/audit.c index 4414e93..ccb8d68 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -1370,7 +1370,7 @@ void audit_log_n_string(struct audit_buffer *ab, const char *string, int audit_string_contains_control(const char *string, size_t len) { const unsigned char *p; - for (p = string; p < (const unsigned char *)string + len && *p; p++) { + for (p = string; p < (const unsigned char *)string + len; p++) { if (*p == '"' || *p < 0x21 || *p > 0x7e) return 1; }