From patchwork Sun Aug 21 03:32:23 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hou Tao X-Patchwork-Id: 12949856 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 EF87CC32793 for ; Sun, 21 Aug 2022 03:14:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231214AbiHUDOa (ORCPT ); Sat, 20 Aug 2022 23:14:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50548 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233430AbiHUDOW (ORCPT ); Sat, 20 Aug 2022 23:14:22 -0400 Received: from dggsgout11.his.huawei.com (unknown [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0A46711822 for ; Sat, 20 Aug 2022 20:14:21 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.143]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4M9LCc5Rbfzll2D for ; Sun, 21 Aug 2022 11:13:00 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.124.27]) by APP2 (Coremail) with SMTP id Syh0CgAH8r0DowFjsgGLAg--.45130S7; Sun, 21 Aug 2022 11:14:19 +0800 (CST) From: Hou Tao To: bpf@vger.kernel.org, Song Liu Cc: Hao Sun , Sebastian Andrzej Siewior , Andrii Nakryiko , Yonghong Song , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , KP Singh , "David S . Miller" , Jakub Kicinski , Stanislav Fomichev , Hao Luo , Jiri Olsa , John Fastabend , Lorenz Bauer , houtao1@huawei.com Subject: [PATCH 3/3] bpf: Propagate error from htab_lock_bucket() to userspace Date: Sun, 21 Aug 2022 11:32:23 +0800 Message-Id: <20220821033223.2598791-4-houtao@huaweicloud.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20220821033223.2598791-1-houtao@huaweicloud.com> References: <20220821033223.2598791-1-houtao@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: Syh0CgAH8r0DowFjsgGLAg--.45130S7 X-Coremail-Antispam: 1UD129KBjvJXoWruFWfZw48Gry7WFWrtr4Dtwb_yoW8Jryrpa yIk347Kw40vrZFyas3JFs7K3y5Zwn5Wr4UGFZ8J34Fvr1qqr9agw18t3sIqFyFqry3tr4Y vr42vFyFg345AFJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBYb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6r1S6rWUM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUWw A2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxS w2x7M28EF7xvwVC0I7IYx2IY67AKxVWDJVCq3wA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxV W8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v2 6rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMc Ij6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_ Jr0_Gr1lF7xvr2IYc2Ij64vIr41lFIxGxcIEc7CjxVA2Y2ka0xkIwI1l42xK82IYc2Ij64 vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8G jcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r4a6rW5MIIYrxkI7VAKI48JMIIF0xvE2I x0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26F4j6r4UJwCI42IY6xAI w20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aVCY1x 0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7IU1c4S7UUUUU== X-CM-SenderInfo: xkrx3t3r6k3tpzhluzxrxghudrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Hou Tao 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. Reported-by: Hao Sun Signed-off-by: Hou Tao --- 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 3ef7a853c737..ffd39048e6da 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -1711,8 +1711,11 @@ __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;