linux-kernel - Re: [PATCH v2 08/29] ktap: add bytecode reader(kernel/trace/ktap/kp

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Message-ID: <20140330024701.GA22728@two.firstfloor.org>
Date:	Sun, 30 Mar 2014 04:47:01 +0200
From:	Andi Kleen <andi@...stfloor.org>
To:	Jovi Zhangwei <jovi.zhangwei@...il.com>
Cc:	Ingo Molnar <mingo@...hat.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	linux-kernel@...r.kernel.org,
	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Andi Kleen <andi@...stfloor.org>
Subject: Re: [PATCH v2 08/29] ktap: add bytecode
 reader(kernel/trace/ktap/kp_bcread.[c|h])

> +/* Read debug info of a prototype. */
> +static void bcread_dbg(BCReadCtx *ctx, ktap_proto_t *pt, int sizedbg)
> +{
> +	void *lineinfo = (void *)proto_lineinfo(pt);
> +
> +	bcread_block(ctx, lineinfo, sizedbg);
> +	/* Swap lineinfo if the endianess differs. */


Why does this care about endianness? Can't that be handled in the user
space? And why would the user space create different endianness than
the host is?

> +	for (i = 0; i < sizekgc; i++, kr++) {
> +		int tp = bcread_uint32(ctx);
> +		if (tp >= BCDUMP_KGC_STR) {

The signedness handling all over this file is a scary.
What happens if the user puts in negative values or near overflow
values.

Most likely a lot of these checks should be unsigned
and need to be audited again (and ideally fuzzed too)

> +
> +	/* Allocate prototype object and initialize its fields. */
> +	pt = (ktap_proto_t *)kp_obj_new(ctx->ks, (int)sizept);

Error check?

Lots of other similar cases.


-Andi

-- 
ak@...ux.intel.com -- Speaking for myself only.
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