Re: [PATCH 1/2] audit: fix NUL handling in untrusted strings
Thanks for the review.
Eric Paris píše v Čt 11. 09. 2008 v 10:25 -0400:
On Thu, 2008-09-11 at 00:23 +0200, Miloslav Trmač wrote:
> This patch modifies audit_log_n_untrustedstring() to only log the data
> before the first NUL byte, if any.
I'm going to have to say NAK on this patch.
It's still not right looking at the other user,
audit_log_single_execve_arg(). An execve arg with a NULL could loose
the stuff after the NULL (not break the record like audit_tty) since the
execve uses %s rather than calling trusted string.
execve() arguments are
NUL-terminated strings:
audit_log_single_execve_arg() starts with
len_left = len = strnlen_user(p, MAX_ARG_STRLEN) - 1;
and the two cycles handle chunks in the first "len" bytes of "p".
audit_log_single_execve_arg() never touches any bytes after the first
NUL.
So, when audit_log_single_execve_arg() calls
audit_string_contains_control(buf, to_send), strlen(buf) == to_send and
the patch does not change anything.
How about we change the meaning of audit_string_contains_control()
return values? If it returns positive that is the number of bytes in a
legitimate string up to the first null. -1 means it is hex.
That is possible,
although the return value convention is somewhat
complex. Anyway, no change to the semantics of
audit_string_contains_control() is necessary for execve() argument
logging.
Mirek