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 201A3C4332F for ; Wed, 19 Oct 2022 09:05:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232375AbiJSJFt (ORCPT ); Wed, 19 Oct 2022 05:05:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47622 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232735AbiJSJFA (ORCPT ); Wed, 19 Oct 2022 05:05:00 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9CFAC80BE7; Wed, 19 Oct 2022 01:58:51 -0700 (PDT) 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 dfw.source.kernel.org (Postfix) with ESMTPS id 6DDC461852; Wed, 19 Oct 2022 08:49:39 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 81EDEC433D7; Wed, 19 Oct 2022 08:49:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666169378; bh=cWq4xP8NGRkzIrU/H+Fa2QHaOV3Z04pSDgZ9XoUKCLw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UKYvfa06Sjz5S6GBvBXckDcLfjfCIDwa3zbhFFofYvpfKOLoUX5a9bu5ILDvVg7kg qrGADoG8QkBjmioq8bP3nV4OzbB98iqhpZeFjGSIWtaNRqBSRhbnrmsNPWGSJbtv3k paB9al+SYAcqamZF2zofwIevrud9tccc1XHuupWw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hao Sun , Hou Tao , Martin KaFai Lau , Sasha Levin Subject: [PATCH 6.0 254/862] bpf: Propagate error from htab_lock_bucket() to userspace Date: Wed, 19 Oct 2022 10:25:41 +0200 Message-Id: <20221019083301.276436592@linuxfoundation.org> X-Mailer: git-send-email 2.38.0 In-Reply-To: <20221019083249.951566199@linuxfoundation.org> References: <20221019083249.951566199@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Hou Tao [ Upstream commit 66a7a92e4d0d091e79148a4c6ec15d1da65f4280 ] In __htab_map_lookup_and_delete_batch() if htab_lock_bucket() returns -EBUSY, it will go to next bucket. Going to next bucket may not only skip the elements in current bucket silently, but also incur out-of-bound memory access or expose kernel memory to userspace if current bucket_cnt is greater than bucket_size or zero. Fixing it by stopping batch operation and returning -EBUSY when htab_lock_bucket() fails, and the application can retry or skip the busy batch as needed. Fixes: 20b6cc34ea74 ("bpf: Avoid hashtab deadlock with map_locked") Reported-by: Hao Sun Signed-off-by: Hou Tao Link: https://lore.kernel.org/r/20220831042629.130006-3-houtao@huaweicloud.com Signed-off-by: Martin KaFai Lau Signed-off-by: Sasha Levin --- kernel/bpf/hashtab.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index ad09da139589..75f77df910dc 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -1704,8 +1704,11 @@ __htab_map_lookup_and_delete_batch(struct bpf_map *map, /* do not grab the lock unless need it (bucket_cnt > 0). */ if (locked) { ret = htab_lock_bucket(htab, b, batch, &flags); - if (ret) - goto next_batch; + if (ret) { + rcu_read_unlock(); + bpf_enable_instrumentation(); + goto after_loop; + } } bucket_cnt = 0; -- 2.35.1