From patchwork Tue Apr 25 22:51:04 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Beau Belgrave X-Patchwork-Id: 13223831 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 8E283C77B61 for ; Tue, 25 Apr 2023 22:51:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236270AbjDYWvT (ORCPT ); Tue, 25 Apr 2023 18:51:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58020 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231834AbjDYWvR (ORCPT ); Tue, 25 Apr 2023 18:51:17 -0400 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 043A06A77; Tue, 25 Apr 2023 15:51:17 -0700 (PDT) Received: from W11-BEAU-MD.localdomain (unknown [76.135.27.212]) by linux.microsoft.com (Postfix) with ESMTPSA id 589F021C2B30; Tue, 25 Apr 2023 15:51:16 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 589F021C2B30 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1682463076; bh=9bQADjcnzfitEajWNwld8GIEX6pWZSTccoW5aErnhjg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JvURQ2Ip9pc67fmVIrDnS2crFVC3TbLJfVjV4785RlJ99bl4qP1Zrcqac0h1PsLXr h51QQEVosx7sude/AaN3V0LG0YXFYUYhjQTBWlueiuU9ZgCSTH5JEHWmbkdspZRsc9 t+VFltbgo+l0PWmZ6Sei5h4r9Hk6bX5or6F5GaCc= From: Beau Belgrave To: rostedt@goodmis.org, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, dcook@linux.microsoft.com, alanau@linux.microsoft.com Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: [PATCH v2 1/4] tracing/user_events: Ensure write index cannot be negative Date: Tue, 25 Apr 2023 15:51:04 -0700 Message-Id: <20230425225107.8525-2-beaub@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230425225107.8525-1-beaub@linux.microsoft.com> References: <20230425225107.8525-1-beaub@linux.microsoft.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org The write index indicates which event the data is for and accesses a per-file array. The index is passed by user processes during write() calls as the first 4 bytes. Ensure that it cannot be negative by returning -EINVAL to prevent out of bounds accesses. Update ftrace self-test to ensure this occurs properly. Fixes: 7f5a08c79df3 ("user_events: Add minimal support for trace_event into ftrace") Reported-by: Doug Cook Signed-off-by: Beau Belgrave --- kernel/trace/trace_events_user.c | 3 +++ tools/testing/selftests/user_events/ftrace_test.c | 5 +++++ 2 files changed, 8 insertions(+) diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c index cc8c6d8b69b5..e7dff24aa724 100644 --- a/kernel/trace/trace_events_user.c +++ b/kernel/trace/trace_events_user.c @@ -1821,6 +1821,9 @@ static ssize_t user_events_write_core(struct file *file, struct iov_iter *i) if (unlikely(copy_from_iter(&idx, sizeof(idx), i) != sizeof(idx))) return -EFAULT; + if (idx < 0) + return -EINVAL; + rcu_read_lock_sched(); refs = rcu_dereference_sched(info->refs); diff --git a/tools/testing/selftests/user_events/ftrace_test.c b/tools/testing/selftests/user_events/ftrace_test.c index aceafacfb126..91272f9d6fce 100644 --- a/tools/testing/selftests/user_events/ftrace_test.c +++ b/tools/testing/selftests/user_events/ftrace_test.c @@ -296,6 +296,11 @@ TEST_F(user, write_events) { ASSERT_NE(-1, writev(self->data_fd, (const struct iovec *)io, 3)); after = trace_bytes(); ASSERT_GT(after, before); + + /* Negative index should fail with EINVAL */ + reg.write_index = -1; + ASSERT_EQ(-1, writev(self->data_fd, (const struct iovec *)io, 3)); + ASSERT_EQ(EINVAL, errno); } TEST_F(user, write_fault) {