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Tue, 26 Jan 2021 07:37:07 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 734D0AE91; Tue, 26 Jan 2021 07:37:06 +0000 (UTC) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 3e631714-eaa1-4f05-aa19-6ce78bf1af28 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1611646626; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=7G6M7VLWX2HfWjv+I3yeJvp2R6zYlznnwDW9sQHn3Zo=; b=ZMjFlVFo6ZjQcA1AubsU4mO0loUnYglkVC0oZ1rZ2Z63ICoJ37j3ltwdlHltbebw2XvJGv n1XKD4JReyldqTiuj+US0l/I1eVd6ZzMeHZFgsW24bCmlxxspsLRMWaUazbmnIYTcnKY6o nxsNaBuR48bvne5sJ2oPBO6aWdFMA2Q= Subject: Re: [PATCH v7 04/10] xen/memory: Add a vmtrace_buf resource type From: Jan Beulich To: Andrew Cooper Cc: =?UTF-8?Q?Micha=c5=82_Leszczy=c5=84ski?= , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , Wei Liu , Tamas K Lengyel , Xen-devel References: <20210121212718.2441-1-andrew.cooper3@citrix.com> <20210121212718.2441-5-andrew.cooper3@citrix.com> <7702d1d6-86c9-af43-c9a9-f5ec082bad2d@suse.com> Message-ID: <226c4857-b0f7-f7f8-f353-e7331cce6e46@suse.com> Date: Tue, 26 Jan 2021 08:37:02 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.1 MIME-Version: 1.0 In-Reply-To: <7702d1d6-86c9-af43-c9a9-f5ec082bad2d@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 25.01.2021 17:31, Jan Beulich wrote: > On 21.01.2021 22:27, Andrew Cooper wrote: >> --- a/xen/common/memory.c >> +++ b/xen/common/memory.c >> @@ -1068,11 +1068,35 @@ static unsigned int resource_max_frames(const struct domain *d, >> case XENMEM_resource_grant_table: >> return gnttab_resource_max_frames(d, id); >> >> + case XENMEM_resource_vmtrace_buf: >> + return d->vmtrace_frames; >> + >> default: >> return arch_resource_max_frames(d, type, id); >> } >> } >> >> +static int acquire_vmtrace_buf( >> + struct domain *d, unsigned int id, unsigned long frame, >> + unsigned int nr_frames, xen_pfn_t mfn_list[]) >> +{ >> + const struct vcpu *v = domain_vcpu(d, id); >> + unsigned int i; >> + mfn_t mfn; >> + >> + if ( !v || !v->vmtrace.buf || >> + nr_frames > d->vmtrace_frames || >> + (frame + nr_frames) > d->vmtrace_frames ) >> + return -EINVAL; > > > I think that for this to guard against overflow, the first nr_frames > needs to be replaced by frame (as having the wider type), or else a > very large value of frame coming in will not yield the intended > -EINVAL. Actually, besides this then wanting to be >= instead of >, this wouldn't take care of the 32-bit case (or more generally the sizeof(long) == sizeof(int) one). So I think you want if ( !v || !v->vmtrace.buf || (frame + nr_frames) < frame || (frame + nr_frames) > d->vmtrace_frames ) return -EINVAL; > If you agree, with this changed, > Reviewed-by: Jan Beulich This holds. Jan