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 X-Spam-Level: X-Spam-Status: No, score=-6.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 39F0CC56201 for ; Thu, 12 Nov 2020 01:32:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B489320809 for ; Thu, 12 Nov 2020 01:32:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=dxuuu.xyz header.i=@dxuuu.xyz header.b="BpFVoSHs"; dkim=temperror (0-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="UNDDyyEs" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728256AbgKLBcD (ORCPT ); Wed, 11 Nov 2020 20:32:03 -0500 Received: from wout2-smtp.messagingengine.com ([64.147.123.25]:51535 "EHLO wout2-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726843AbgKKWqf (ORCPT ); Wed, 11 Nov 2020 17:46:35 -0500 Received: from compute3.internal (compute3.nyi.internal [10.202.2.43]) by mailout.west.internal (Postfix) with ESMTP id 372409CC; Wed, 11 Nov 2020 17:46:34 -0500 (EST) Received: from mailfrontend2 ([10.202.2.163]) by compute3.internal (MEProxy); Wed, 11 Nov 2020 17:46:34 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=dxuuu.xyz; h= from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; s=fm2; bh=6XDxQ89oRUt1iCVzejeWV7bDGk D9oU06u/1vqsZYoCc=; b=BpFVoSHsXp3GMmadYOv+KSkU3buF/32Ixsl0uSV/jL zNoleE/Q4VGIsyKHebLfAGbuXcQg5rL3d3fqLzrQQbfUTC3Vdg4tk3Bm9DI+bD1+ l829bsePCL7qOOcUHWZH/jA2w0l/OZswkdK0RLdYPjX6ZO19UkK3T/wpEH/Vkeqe czJ9XQ1uVx46YkUPvVjutQvLsCVPYVSdZWB3u19Ph9AOEbdTLnmbhm1Kb4pracap LWqTkSEGwzGgYDReROxeZa4RUHF7vPCgVbqpD1nx9+ubtq5zaZX3F9CdXy+ltkIn Ahb2G5O5RPuCff3DAGGBGc8/yanaHEKiVY0FAmMpHRwg== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:date:from :message-id:mime-version:subject:to:x-me-proxy:x-me-proxy :x-me-sender:x-me-sender:x-sasl-enc; s=fm1; bh=6XDxQ89oRUt1iCVze jeWV7bDGkD9oU06u/1vqsZYoCc=; b=UNDDyyEsq3sMO3rVZr0tBGnvWcyaYIByZ Z1cIMzyjVzuxpqOWqDe1p0ZjSNCPo4qBw4k5EkaxVUvu6fyfrajA4xhk0oEXE6Mn WvAqRVHiOz3Mq9N4KjahZReT4sDyGryOa97iqayuC7Ef5a3vaWTWavEsbVPM7b76 HtA6sqvGjaK+HfqgjvePw+3Kg1PcQWV5TgI0M3OqArDveA9hLqvr+25WGZDVNh0k lSEU+0UT5II7MGOauF26uIQ6Q5aUQ2VWIgqHPavAVLJoGOXswOsVXzUIzt5G3DML M7Mg9pRwUxIDdp0czfWoopaTVzT1erfxpAYy4Aa2Xg1WEhZTDL4AA== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedujedruddvuddgtdefucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucgfrhhlucfvnfffucdljedtmdenucfjughrpefhvf fufffkofgggfestdekredtredttdenucfhrhhomhepffgrnhhivghlucgiuhcuoegugihu segugihuuhhurdighiiiqeenucggtffrrghtthgvrhhnpeeifffgledvffeitdeljedvte effeeivdefheeiveevjeduieeigfetieevieffffenucfkphepieelrddukedurddutdeh rdeigeenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhgrihhlfhhrohhmpe gugihusegugihuuhhurdighiii X-ME-Proxy: Received: from localhost.localdomain (c-69-181-105-64.hsd1.ca.comcast.net [69.181.105.64]) by mail.messagingengine.com (Postfix) with ESMTPA id 85254306301C; Wed, 11 Nov 2020 17:46:32 -0500 (EST) From: Daniel Xu To: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net, songliubraving@fb.com, andrii.nakryiko@gmail.com Cc: Daniel Xu , kernel-team@fb.com Subject: [PATCH bpf v5 0/2] Fix bpf_probe_read_user_str() overcopying Date: Wed, 11 Nov 2020 14:45:53 -0800 Message-Id: X-Mailer: git-send-email 2.29.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org 6ae08ae3dea2 ("bpf: Add probe_read_{user, kernel} and probe_read_{user, kernel}_str helpers") introduced a subtle bug where bpf_probe_read_user_str() would potentially copy a few extra bytes after the NUL terminator. This issue is particularly nefarious when strings are used as map keys, as seemingly identical strings can occupy multiple entries in a map. This patchset fixes the issue and introduces a selftest to prevent future regressions. v4 -> v5: * don't read potentially uninitialized memory v3 -> v4: * directly pass userspace pointer to prog * test more strings of different length v2 -> v3: * set pid filter before attaching prog in selftest * use long instead of int as bpf_probe_read_user_str() retval * style changes v1 -> v2: * add Fixes: tag * add selftest Daniel Xu (2): lib/strncpy_from_user.c: Don't overcopy bytes after NUL terminator selftest/bpf: Test bpf_probe_read_user_str() strips trailing bytes after NUL lib/strncpy_from_user.c | 9 ++- .../bpf/prog_tests/probe_read_user_str.c | 71 +++++++++++++++++++ .../bpf/progs/test_probe_read_user_str.c | 25 +++++++ 3 files changed, 100 insertions(+), 5 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/probe_read_user_str.c create mode 100644 tools/testing/selftests/bpf/progs/test_probe_read_user_str.c -- 2.29.2