On Thu, 30 Jul 2020 16:29:12 +0200
peter enderborg <[email protected]> wrote:
> +#undef TRACE_SYSTEM
> +#define TRACE_SYSTEM avc
> +
> +#if !defined(_TRACE_AVC_H) || defined(TRACE_HEADER_MULTI_READ)
> +#define _TRACE_AVC_H
> +
> +#include <linux/tracepoint.h>
> +TRACE_EVENT(avc_data,
> + TP_PROTO(u32 requested,
> + u32 denied,
> + u32 audited,
> + int result,
> + const char *msg
> + ),
> +
> + TP_ARGS(requested, denied, audited, result,msg),
> +
> + TP_STRUCT__entry(
> + __field(u32, requested)
> + __field(u32, denied)
> + __field(u32, audited)
> + __field(int, result)
> + __array(char, msg, 255)
You want to use __string() here, otherwise you are wasting a lot of
buffer space.
__string( msg, msg)
> + ),
> +
> + TP_fast_assign(
> + __entry->requested = requested;
> + __entry->denied = denied;
> + __entry->audited = audited;
> + __entry->result = result;
> + memcpy(__entry->msg, msg, 255);
Not to mention, the above is a bug. As the msg being passed in, is
highly unlikely to be 255 bytes. You just leaked all that memory after
the sting to user space.
Where you want here:
__assign_str( msg, msg );
-- Steve
> + ),
> +
> + TP_printk("requested=0x%x denied=%d audited=%d result=%d
> msg=%s",
> + __entry->requested, __entry->denied, __entry->audited,
> __entry->result, __entry->msg
> + )
