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 8E3BDC6FA83 for ; Mon, 12 Sep 2022 13:39:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229929AbiILNj1 (ORCPT ); Mon, 12 Sep 2022 09:39:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54640 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229759AbiILNjP (ORCPT ); Mon, 12 Sep 2022 09:39:15 -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 2650B1DA5B; Mon, 12 Sep 2022 06:39:15 -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 BC2DA61216; Mon, 12 Sep 2022 13:39:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4F889C433D6; Mon, 12 Sep 2022 13:39:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1662989954; bh=/gC32tYwwsdl+VoKZGtpIQArxWaVx/pSJAKF9P2G6TU=; h=From:To:Cc:Subject:Date:From; b=uHgnDIJ2ySzKPAyQjzfURw1qW/Y4o5rupEWLi46fbh+gybtmbBxhUvXKja37xgPLG Nzz66gAjDcj6zcQ4l74SJ2FR55qsG7JHYsKovtEDv7u2VSVRZWwKAkmbB9I//s4jrZ xkswgGHJoqVp7Apw7QXx8AFycC+zOqAfrBPPP/xFsMeHhLIH9Ne+F+kKPLt2vF2frx mUPxe5KjH8TYZKLWW/f8tF0xABV6UuJTLGG5vU+7xon++9Rp+edfN3IMPpamWGiiPq RcsniQwnIt7c5iK9UQrJGgodQnhWa7KtJppLlV7qfgsAmsoYDjaRN2ZK1F4qwTDv8l QZoFQwwROBijA== From: Lee Jones To: lee@kernel.org Cc: linux-kernel@vger.kernel.org, Jiri Olsa , Alexei Starovoitov , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , KP Singh , Stanislav Fomichev , Hao Luo , bpf@vger.kernel.org Subject: [PATCH v3 1/1] bpf: Ensure correct locking around vulnerable function find_vpid() Date: Mon, 12 Sep 2022 14:38:55 +0100 Message-Id: <20220912133855.1218900-1-lee@kernel.org> X-Mailer: git-send-email 2.37.2.789.g6183377224-goog MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The documentation for find_vpid() clearly states: "Must be called with the tasklist_lock or rcu_read_lock() held." Presently we do neither. Cc: Jiri Olsa Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: John Fastabend Cc: Andrii Nakryiko Cc: Martin KaFai Lau Cc: Song Liu Cc: Yonghong Song Cc: KP Singh Cc: Stanislav Fomichev Cc: Hao Luo Cc: bpf@vger.kernel.org Fixes: 41bdc4b40ed6f ("bpf: introduce bpf subcommand BPF_TASK_FD_QUERY") Signed-off-by: Lee Jones --- v2 => v3: * Changed strategy from find_get_pid() to rcu_read_{un}lock() * Removed Jiri's Ack v1 => v2: * Commit log update - no code differences kernel/bpf/syscall.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 69be1c612daa5..d5c77c021c043 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -4399,7 +4399,9 @@ static int bpf_task_fd_query(const union bpf_attr *attr, if (attr->task_fd_query.flags != 0) return -EINVAL; + rcu_read_lock(); task = get_pid_task(find_vpid(pid), PIDTYPE_PID); + rcu_read_unlock(); if (!task) return -ENOENT; -- 2.37.2.789.g6183377224-goog