From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6B592C6786C for ; Fri, 14 Dec 2018 12:12:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2871A214DE for ; Fri, 14 Dec 2018 12:12:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1544789537; bh=m7VUbMHqUaQCNJjwo7PzD86SkxEV4xTROhZ1JEWVamQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=yxmVQOaozq1ILiAC8JgMVvD3Zt7GDvwl4dXyKJ67NQhD5W3l0XsNOyIscSltkLCzt udjc6KdK4HBQq4E81r9RLo9mhWnLoQpH7289Lpvyoz9WDqmp3pTxs6LbXCDwT9zTAd JF+HorlA4wy7TJiRxFGk2jcHztR6rA4hLtVF2fDI= DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2871A214DE Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731907AbeLNMMP (ORCPT ); Fri, 14 Dec 2018 07:12:15 -0500 Received: from mail.kernel.org ([198.145.29.99]:59198 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726670AbeLNMMJ (ORCPT ); Fri, 14 Dec 2018 07:12:09 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CFC272133F; Fri, 14 Dec 2018 12:12:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1544789528; bh=m7VUbMHqUaQCNJjwo7PzD86SkxEV4xTROhZ1JEWVamQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mW3xQFE5ONVFwm9T+O/ly3h59ZYNXbCK9tJdPKt/2UbFGTBZGW4bHCIx+/hgX57Jl WOU93jA0acf8PaLuIglkzIVirD35CU4ScEPoIBecjRwP8jdEaSaijj56p7A/Ch4dVF incwYtzsoBvmncu9M0dxzGf9XoOFsq0dq3lhbg/o= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+1ec5c5ec949c4adaa0c4@syzkaller.appspotmail.com, Martynas Pumputis , Daniel Borkmann , Sasha Levin Subject: [PATCH 4.9 28/51] bpf: fix check of allowed specifiers in bpf_trace_printk Date: Fri, 14 Dec 2018 13:00:30 +0100 Message-Id: <20181214115715.839981643@linuxfoundation.org> X-Mailer: git-send-email 2.20.0 In-Reply-To: <20181214115713.244259772@linuxfoundation.org> References: <20181214115713.244259772@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit 1efb6ee3edea57f57f9fb05dba8dcb3f7333f61f ] A format string consisting of "%p" or "%s" followed by an invalid specifier (e.g. "%p%\n" or "%s%") could pass the check which would make format_decode (lib/vsprintf.c) to warn. Fixes: 9c959c863f82 ("tracing: Allow BPF programs to call bpf_trace_printk()") Reported-by: syzbot+1ec5c5ec949c4adaa0c4@syzkaller.appspotmail.com Signed-off-by: Martynas Pumputis Signed-off-by: Daniel Borkmann Signed-off-by: Sasha Levin --- kernel/trace/bpf_trace.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 41805fb3c661..7cc06f267be5 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -161,11 +161,13 @@ BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1, i++; } else if (fmt[i] == 'p' || fmt[i] == 's') { mod[fmt_cnt]++; - i++; - if (!isspace(fmt[i]) && !ispunct(fmt[i]) && fmt[i] != 0) + /* disallow any further format extensions */ + if (fmt[i + 1] != 0 && + !isspace(fmt[i + 1]) && + !ispunct(fmt[i + 1])) return -EINVAL; fmt_cnt++; - if (fmt[i - 1] == 's') { + if (fmt[i] == 's') { if (str_seen) /* allow only one '%s' per fmt string */ return -EINVAL; -- 2.19.1