From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0C8355338D; Mon, 7 Oct 2024 14:22:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728310964; cv=none; b=jsUiUHWS4eOVd9ajW+JBIVNnfTm/qg8DYo44ji+GMbsrSgU7kuFVyCAIX1q+4AfEeMWFvkmUrFgibAUl9TQyTlj2Cu+BdyZ+xwAWfXCJFMb2QXG4EqRUYmK74WJpSSTvzK2CcNOCv7AZLww3pj5HCsRFvqaY9ISPT8NKsqyZWF8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728310964; c=relaxed/simple; bh=8+q+UdEhtowo/cYRIkBbmMZjdoDF7YOauFhtK2XM9DE=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=agGbh9qJMVpssNX2HUVPDpY9pMpuBFBurrNA84/FrcRm1at8ztjlKbH9d0DTkjrOhlwoIRDne3k/raYL7yfEPBGw2WzM6mlSRPww1T+HwrFcDWA+XCY/3Mg3r6hgXU4B3qbvHMt+IK0tVb0yyfHTH5A7or1ERyrVgsF2qEkNxBg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id BB7B5C4CEC6; Mon, 7 Oct 2024 14:22:42 +0000 (UTC) Date: Mon, 7 Oct 2024 10:22:42 -0400 From: Steven Rostedt To: Leo Yan Cc: Masami Hiramatsu , Mathieu Desnoyers , Dave.Martin@arm.com, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: Re: [PATCH] tracing: Consider the NULL character when validating the event length Message-ID: <20241007102242.18d2636e@gandalf.local.home> In-Reply-To: <20241007135126.873234-1-leo.yan@arm.com> References: <20241007135126.873234-1-leo.yan@arm.com> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Mon, 7 Oct 2024 14:51:26 +0100 Leo Yan wrote: > strlen() returns a string length excluding the null byte. This commit > adds 1 to account for the NULL terminating character when checking if an > event string is within the maximum length. > > Fixes: dec65d79fd26 ("tracing/probe: Check event name length correctly") > Signed-off-by: Leo Yan > --- > kernel/trace/trace_probe.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c > index 39877c80d6cb..376ba56c3680 100644 > --- a/kernel/trace/trace_probe.c > +++ b/kernel/trace/trace_probe.c > @@ -276,7 +276,7 @@ int traceprobe_parse_event_name(const char **pevent, const char **pgroup, > } > trace_probe_log_err(offset, NO_EVENT_NAME); > return -EINVAL; > - } else if (len > MAX_EVENT_NAME_LEN) { > + } else if (len + 1 > MAX_EVENT_NAME_LEN) { Usually, the check is: } else if (len >= MAX_EVENT_NAME_LEN) { Which is a better way to check max length. -- Steve > trace_probe_log_err(offset, EVENT_TOO_LONG); > return -EINVAL; > }