Re: [PATCH 2/2] integrity: Add errno field in audit message

[Mimi Zohar]

On Wed, 2020-06-17 at 13:44 -0700, Lakshmi Ramasubramanian wrote:
> Error code is not included in the audit messages logged by
> the integrity subsystem. Add "errno" field in the audit messages
> logged by the integrity subsystem and set the value to the error code
> passed to integrity_audit_msg() in the "result" parameter.
> 
> Sample audit messages:
> 
> [    6.284329] audit: type=1804 audit(1591756723.627:2): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=kernel op=add_boot_aggregate cause=alloc_entry comm="swapper/0" name="boot_aggregate" res=0 errno=-12
> 
> [    8.085456] audit: type=1802 audit(1592005947.297:9): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0 op=policy_update cause=completed comm="systemd" res=1 errno=0
> 
> Signed-off-by: Lakshmi Ramasubramanian <nramas@xxxxxxxxxxxxxxxxxxx>
> Suggested-by: Steve Grubb <sgrubb@xxxxxxxxxx>
> ---
>  security/integrity/integrity_audit.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/security/integrity/integrity_audit.c b/security/integrity/integrity_audit.c
> index 5109173839cc..a265024f82f3 100644
> --- a/security/integrity/integrity_audit.c
> +++ b/security/integrity/integrity_audit.c
> @@ -53,6 +53,6 @@ void integrity_audit_msg(int audit_msgno, struct inode *inode,
>  		audit_log_untrustedstring(ab, inode->i_sb->s_id);
>  		audit_log_format(ab, " ino=%lu", inode->i_ino);
>  	}
> -	audit_log_format(ab, " res=%d", !result);
> +	audit_log_format(ab, " res=%d errno=%d", !result, result);
>  	audit_log_end(ab);
>  }

For the reasons that I mentioned previously, unless others are willing
to add their Reviewed-by tag not for the audit aspect in particular,
but IMA itself, I'm not comfortable making this change all at once.

Previously I suggested making the existing integrity_audit_msg() a
wrapper for a new function with errno. ÂSteve said, "We normally do
not like to have fields that swing in and out ...", but said setting
errno to 0 is fine. ÂThe original integrity_audit_msg() function would
call the new function with errno set to 0.

Mimi