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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AA2ADC433EF for ; Wed, 1 Dec 2021 13:06:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349465AbhLANJk (ORCPT ); Wed, 1 Dec 2021 08:09:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54444 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233645AbhLANJk (ORCPT ); Wed, 1 Dec 2021 08:09:40 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1B9A2C061574 for ; Wed, 1 Dec 2021 05:06:19 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 24980B81ED4 for ; Wed, 1 Dec 2021 13:06:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DBAA8C53FCD; Wed, 1 Dec 2021 13:06:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1638363975; bh=S/SeL2BP7pfPep5JW0KX485zyZmOdZHTLxpgPAxrIMw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=tUgRuwVVlg3F6ujjVxyYXcOFGbkqXHMkS79DEOhnn0NFYLSEB1FlobnjtX29Ie4Oj gofIgRPHjGG/iqcpvXSgElH5rehk7rRnOuOr5dK/5ht/kYV3FaUAn5pmClxELV2UFO QG3LGpdpVnXY/aAvpBk8JzW6/nPrpmCg3yziiegpEzQ8kA4NkxFtwhTpJ1nRu1DMwJ gLnuF1RWfbm7/V3+/tgWfIi3HHykZUK2MslfH7krqs4FfgGITNVxws4rk6pWkIZS/7 THXOsg3sHr7jQZYN/mpxs4z+9MUvIcdX2bv2c1UY9LEXhN4rs4PlGOrKO9ZfmMEns7 ye2d4Y+HeCKQQ== Date: Wed, 1 Dec 2021 22:06:11 +0900 From: Masami Hiramatsu To: zhangyue Cc: naveen.n.rao@linux.ibm.com, anil.s.keshavamurthy@intel.com, davem@davemloft.net, linux-kernel@vger.kernel.org Subject: Re: [PATCH] kprobes: fix out-of-bounds in register_kretprobe Message-Id: <20211201220611.656ec911478bbf0f342ea7f1@kernel.org> In-Reply-To: <20211201054855.5449-1-zhangyue1@kylinos.cn> References: <20211201054855.5449-1-zhangyue1@kylinos.cn> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 1 Dec 2021 13:48:55 +0800 zhangyue wrote: > When the data 'rp->data_size' is negative, the code > 'sizeof(struct kretprobe_instance)+rp->data_size' > is less than 'sizeof(struct kretprobe_instance)' Hmm, rp->data_size is size_t, which is unsigned value. Of course we still need some kind of maximum limitation because if we pass enough bigger size, the sizeof(struct kretprobe_instance) + rp->data_size can be negative or smaller than sizeof(struct kretprobe_instance). Thank you, > > At this time, the pointer 'inst' may be out of > bound when it is in use. > > Signed-off-by: zhangyue > --- > kernel/kprobes.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > index 1cf8bca1ea86..71cf6bde299f 100644 > --- a/kernel/kprobes.c > +++ b/kernel/kprobes.c > @@ -1983,7 +1983,7 @@ int kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long o > int register_kretprobe(struct kretprobe *rp) > { > int ret; > - struct kretprobe_instance *inst; > + struct kretprobe_instance *inst = NULL; > int i; > void *addr; > > @@ -2024,7 +2024,8 @@ int register_kretprobe(struct kretprobe *rp) > > rp->rph->rp = rp; > for (i = 0; i < rp->maxactive; i++) { > - inst = kzalloc(sizeof(struct kretprobe_instance) + > + if (rp->data_size >= 0) > + inst = kzalloc(sizeof(struct kretprobe_instance) + > rp->data_size, GFP_KERNEL); > if (inst == NULL) { > refcount_set(&rp->rph->ref, i); > -- > 2.30.0 > -- Masami Hiramatsu