[PATCH 2/2] audit: Handle embedded NUL in TTY input auditing

[PATCH 2/2] audit: Handle embedded NUL in TTY input auditing

[Miloslav Trmač]

From: Miloslav Trmac <mitr@redhat.com>

Data read from a TTY can contain an embedded NUL byte (e.g. after
pressing Ctrl-2, or sent to a PTY).  After the previous patch, the data
would be logged only up to the first NUL.

This patch modifies the AUDIT_TTY record to always use the hexadecimal
format, which does not terminate at the first NUL byte.  The vast
majority of recorded TTY input data will contain either ' ' or '\n', so
the hexadecimal format would have been used anyway.

Signed-off-by: Miloslav Trmac <mitr@redhat.com>
---
 tty_audit.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/char/tty_audit.c b/drivers/char/tty_audit.c
index 3582f43..5787249 100644
--- a/drivers/char/tty_audit.c
+++ b/drivers/char/tty_audit.c
@@ -93,7 +93,7 @@ static void tty_audit_buf_push(struct task_struct *tsk, uid_t loginuid,
 		get_task_comm(name, tsk);
 		audit_log_untrustedstring(ab, name);
 		audit_log_format(ab, " data=");
-		audit_log_n_untrustedstring(ab, buf->data, buf->valid);
+		audit_log_n_hex(ab, buf->data, buf->valid);
 		audit_log_end(ab);
 	}
 	buf->valid = 0;

Re: [PATCH 2/2] audit: Handle embedded NUL in TTY input auditing

[Eric Paris]

On Thu, 2008-09-11 at 00:29 +0200, Miloslav Trmač wrote:
> From: Miloslav Trmac <mitr@redhat.com>
> 
> Data read from a TTY can contain an embedded NUL byte (e.g. after
> pressing Ctrl-2, or sent to a PTY).  After the previous patch, the data
> would be logged only up to the first NUL.
> 
> This patch modifies the AUDIT_TTY record to always use the hexadecimal
> format, which does not terminate at the first NUL byte.  The vast
> majority of recorded TTY input data will contain either ' ' or '\n', so
> the hexadecimal format would have been used anyway.
> 
> Signed-off-by: Miloslav Trmac <mitr@redhat.com>

Acked-by: Eric Paris <eparis@redhat.com>

> ---
>  tty_audit.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> diff --git a/drivers/char/tty_audit.c b/drivers/char/tty_audit.c
> index 3582f43..5787249 100644
> --- a/drivers/char/tty_audit.c
> +++ b/drivers/char/tty_audit.c
> @@ -93,7 +93,7 @@ static void tty_audit_buf_push(struct task_struct *tsk, uid_t loginuid,
>  		get_task_comm(name, tsk);
>  		audit_log_untrustedstring(ab, name);
>  		audit_log_format(ab, " data=");
> -		audit_log_n_untrustedstring(ab, buf->data, buf->valid);
> +		audit_log_n_hex(ab, buf->data, buf->valid);
>  		audit_log_end(ab);
>  	}
>  	buf->valid = 0;
> 
>