From patchwork Wed May 18 12:22:19 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eugene Syromiatnikov X-Patchwork-Id: 12853592 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CDCAAC433FE for ; Wed, 18 May 2022 12:22:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236390AbiERMWc (ORCPT ); Wed, 18 May 2022 08:22:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55214 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236399AbiERMWc (ORCPT ); Wed, 18 May 2022 08:22:32 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 58FB695A17 for ; Wed, 18 May 2022 05:22:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1652876550; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=K/ITSQPv+FLUqNfqJZ10C1qnyJTCcwgFhb/0q95NHko=; b=gwCu77hQLbJ+sljVxa6nxIo7C2bCH8FKUEKrzmhUeIqQAXzziWvvbLTabFh+elowIhJBEe XDzJwwUQIUgxoe7aUW2B1rU6bBg84GwdKac/eXenPqIO+Mr7Gmv14+6tqiGe0a4ivGp227 TI6v2uSnjIlKFDxQK079vgzyj2FRgGM= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-34-xp3zU66eO3iCnVuiEJu30A-1; Wed, 18 May 2022 08:22:26 -0400 X-MC-Unique: xp3zU66eO3iCnVuiEJu30A-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 794C38015BA; Wed, 18 May 2022 12:22:25 +0000 (UTC) Received: from asgard.redhat.com (unknown [10.36.110.4]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 280CF40C1438; Wed, 18 May 2022 12:22:21 +0000 (UTC) Date: Wed, 18 May 2022 14:22:19 +0200 From: Eugene Syromiatnikov To: Jiri Olsa , Masami Hiramatsu , Steven Rostedt , Ingo Molnar , Alexei Starovoitov , Daniel Borkmann Cc: Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH bpf v3 1/2] bpf_trace: check size for overflow in bpf_kprobe_multi_link_attach Message-ID: <39c4a91f2867684dc51c5395d26cb56ffe9d995d.1652876188.git.esyr@redhat.com> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) X-Scanned-By: MIMEDefang 2.84 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Check that size would not overflow before calculation (and return -EOVERFLOW if it will), to prevent potential out-of-bounds write with the following copy_from_user. Add the same check to kprobe_multi_resolve_syms in case it will be called from elsewhere in the future. Fixes: 0dcac272540613d4 ("bpf: Add multi kprobe link") Signed-off-by: Eugene Syromiatnikov --- kernel/trace/bpf_trace.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index d8553f4..212faa4 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2352,13 +2352,15 @@ static int kprobe_multi_resolve_syms(const void __user *usyms, u32 cnt, unsigned long *addrs) { - unsigned long addr, size; + unsigned long addr, sym_size; + u32 size; const char __user **syms; int err = -ENOMEM; unsigned int i; char *func; - size = cnt * sizeof(*syms); + if (check_mul_overflow(cnt, (u32)sizeof(*syms), &size)) + return -EOVERFLOW; syms = kvzalloc(size, GFP_KERNEL); if (!syms) return -ENOMEM; @@ -2382,9 +2384,9 @@ kprobe_multi_resolve_syms(const void __user *usyms, u32 cnt, addr = kallsyms_lookup_name(func); if (!addr) goto error; - if (!kallsyms_lookup_size_offset(addr, &size, NULL)) + if (!kallsyms_lookup_size_offset(addr, &sym_size, NULL)) goto error; - addr = ftrace_location_range(addr, addr + size - 1); + addr = ftrace_location_range(addr, addr + sym_size - 1); if (!addr) goto error; addrs[i] = addr; @@ -2429,7 +2431,8 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr if (!cnt) return -EINVAL; - size = cnt * sizeof(*addrs); + if (check_mul_overflow(cnt, (u32)sizeof(*addrs), &size)) + return -EOVERFLOW; addrs = kvmalloc(size, GFP_KERNEL); if (!addrs) return -ENOMEM;