From patchwork Fri Nov 18 18:34:14 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 22462 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:adf:f944:0:0:0:0:0 with SMTP id q4csp356633wrr; Fri, 18 Nov 2022 10:55:41 -0800 (PST) X-Google-Smtp-Source: AA0mqf7RhnfxykAV+vbqHxR6yJRVXgqn3niuOkLJAGW7oPfaue6m71EA8WWlmJng53ELY9uE4Dkp X-Received: by 2002:a05:6402:5308:b0:460:19c3:2992 with SMTP id eo8-20020a056402530800b0046019c32992mr7210690edb.1.1668797741270; Fri, 18 Nov 2022 10:55:41 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1668797741; cv=none; d=google.com; s=arc-20160816; b=WsiKOGhg+M4ArUbrwyE1TkRRZQ2yC9o5ApMZjSC6PCkkK8NDJidJCvBhWT2VV+mOrA Z0DmBKF5p/1LwUEChvxTTu9DOZh0ECSUkpQ1DUv7aooN/iT2T0udhnZbSDVfnGaCHB02 O0dMtOuq3vx41S9N1UvRZOfXRT7O6g04Mo73vVnvfwj7dtSJbheiGR3oc4R0NCMC+NLX nvw86fwI2iC5uS5stX3dhXFFHIAhwQUNNmR6OZ0yfrR1m91/FFrQ0tMmKxWq49chnxAJ z4LUimCH2NYfAjfoex/eEO7yivfle4/qBdGd4BkhVjDIyRT/9Wljcq0yFxgQeCobpDTy lpuA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :message-id:date:subject:cc:to:from:dkim-signature; bh=JWBg2ZM+5LY+DPWE9KaJWuwKCy+tCudVMmncE2yGD/w=; b=j6cIFcK1q4do+jOhs9WzMEflXLVlc6jcWBsP34rFXFvfIUut7gtrTcNXE5NMyOQT53 5phSokM6wGeLTWvUmaqXrThwq1kl1iTADBwYKDJolMN273lQUSl/e/e+7rDTmAFGtJyg CUd+dV7zkYQ4i7k5NgUZk6j1ugYY3IYra8yochnkHFvxAHPxXDD7EBMkhsrYSOm8YtiT xhmxj4eKZXBNqxosvFbK96DPssgTJstaE7zu3j3Q0Rd0ZlZDPFdbw7DwXmaqVziainaj p1AkfVzbO1X+zjVIckW4kcz1AcUIEcckbdDbzYWHh7v+cAEAmMTUIBsCM1cmiT9T10sh Qqyg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@chromium.org header.s=google header.b=YI9XhArX; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=chromium.org Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id t10-20020a056402240a00b004612505ece4si3750533eda.483.2022.11.18.10.55.17; Fri, 18 Nov 2022 10:55:41 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@chromium.org header.s=google header.b=YI9XhArX; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=chromium.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241103AbiKRSeZ (ORCPT + 99 others); Fri, 18 Nov 2022 13:34:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44960 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235084AbiKRSeX (ORCPT ); Fri, 18 Nov 2022 13:34:23 -0500 Received: from mail-pf1-x430.google.com (mail-pf1-x430.google.com [IPv6:2607:f8b0:4864:20::430]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E126CDEC5 for ; Fri, 18 Nov 2022 10:34:20 -0800 (PST) Received: by mail-pf1-x430.google.com with SMTP id k22so5677951pfd.3 for ; Fri, 18 Nov 2022 10:34:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=JWBg2ZM+5LY+DPWE9KaJWuwKCy+tCudVMmncE2yGD/w=; b=YI9XhArXpxIssWvzDDKUAPsPQRsDbBXsCvssOj329a1V33PILDfsCv1QtkvOXno5Uk 2ohX2Yph9tzOaS6mPz/ztfB19uu4mth+aIDdbPLR4IBpSt8KonYF2BrUrj4Tod6H+KvI nNsLOBnqjnfCAu15W83Zck7APkMPr3fT0evWU= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=JWBg2ZM+5LY+DPWE9KaJWuwKCy+tCudVMmncE2yGD/w=; b=CxtBDliMisHfdTxao1RlhOHzu9bbuPWBq2bPQkU2l5yvOQTpxGG8byRW1e0FUAUMSR 3mhHP8/1puf8RYrFi7mVSouKSsXkK9UjZlm0eLXSgdmsrD5xQT080O4sjrNbjO76ztBe 9/+R2fV1cM36UYSPve5hFjrcrDTpiCyvHeHgzjwkhnj5W9AF4Ns5HKDbBYfy3PjbPN3n 2LK7bmk4yYX77kUkdH7P/NBqpCFrnw2VxZqOZD+1tqkw4crICnZgpXzCAKtS5tfz9DRQ bitMhFBqRkbh4DtBq2lsBL3ZACtqW0Td1J7vrjF7hI1D3sGxksIaoH/4HRad7OeOZi0W KSyw== X-Gm-Message-State: ANoB5pl3PSN0hGKNecB6CiOzKhOqFUoPA/JTpmRBU9GWYfvFMiOYtG+o ZZJp3kN4pt0rxSOBMt5EQKfSDg== X-Received: by 2002:a65:6049:0:b0:477:2ac1:9d2c with SMTP id a9-20020a656049000000b004772ac19d2cmr4147048pgp.184.1668796460410; Fri, 18 Nov 2022 10:34:20 -0800 (PST) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id e7-20020aa798c7000000b0056bee23a80bsm3465524pfm.137.2022.11.18.10.34.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 18 Nov 2022 10:34:19 -0800 (PST) From: Kees Cook To: Alexei Starovoitov Cc: Kees Cook , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH bpf-next v3] bpf/verifier: Use kmalloc_size_roundup() to match ksize() usage Date: Fri, 18 Nov 2022 10:34:14 -0800 Message-Id: <20221118183409.give.387-kees@kernel.org> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4318; h=from:subject:message-id; bh=nSdV4wW4rhE2V2JgCPdZCO/CD3bcTE7aQbwWRnxWy7M=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBjd9AmEhS0Oiwnde/cDpv1CK8Q0c5N9kxXIxXFg3zD C2cfTj+JAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCY3fQJgAKCRCJcvTf3G3AJsIwD/ 4lBP73J5C3K2v0Blo/NFbBficvB0M/s/lCRJefT1g8onHiFpL7bEBFYnGI1KiObgY83cBXwkR77O8s vCOmMYNQl1M8sTrwP+MFvGDjNcNMf101GzlUi43idXgjZFRXuXAZjxMt+ClxrMbgrM+fD3sON0WgPu 4wVOkaFqdEv5wNnWz0TLbq5cgcEHYcT8Yd6p7vZNOy3UQLsdrDo5vGPtMKH1/Fs+JmyuBlid8Tslrg pLD0xf1SAShe9WI987JIok8jFcB6aGe5FOJ+BEpbt3OdRRrQpofkQcuMYn1ZlIoNLZUnFaOQODAzVs WuBZ21HtCJPiwrrZErvnZK56OCco5G80+bjrHMDgkhRAGyfE25gyv3X0TVv7Zf/1+TTDwt3OAT/HY8 pPh891vY8GOMNlmqwUG0hyBo/v1qN1E54INHRr2nY75z1ga+4AEHdAqN04U9i7v5i5m0SWNdQ3NPCZ sDPy+gnX6yeUpqKEJpUaK9ah+OmpGgDao2u2XcGTved1UPfw2wnRnpsPZrtT+tjL79O1OkS24NJKjh gSWr0EpzLaYvgrkafqVAUYTSE6pj+Ikro010v1DIpIoL7zYKrqPr7aYKNy7lyW7Wcx8QTzpFDxUBNK NxSLc0jHogciAXOErC1Y9iGAEHgOnj1Va2NrHGEieG5IsD0GBv7FY51SkDCg== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1749861260274582415?= X-GMAIL-MSGID: =?utf-8?q?1749861260274582415?= Most allocation sites in the kernel want an explicitly sized allocation (and not "more"), and that dynamic runtime analysis tools (e.g. KASAN, UBSAN_BOUNDS, FORTIFY_SOURCE, etc) are looking for precise bounds checking (i.e. not something that is rounded up). A tiny handful of allocations were doing an implicit alloc/realloc loop that actually depended on ksize(), and didn't actually always call realloc. This has created a long series of bugs and problems over many years related to the runtime bounds checking, so these callers are finally being adjusted to _not_ depend on the ksize() side-effect, by doing one of several things: - tracking the allocation size precisely and just never calling ksize() at all[1]. - always calling realloc and not using ksize() at all. (This solution ends up actually be a subset of the next solution.) - using kmalloc_size_roundup() to explicitly round up the desired allocation size immediately[2]. The bpf/verifier case is this another of this latter case, and is the last outstanding case to be fixed in the kernel. Because some of the dynamic bounds checking depends on the size being an _argument_ to an allocator function (i.e. see the __alloc_size attribute), the ksize() users are rare, and it could waste local variables, it was been deemed better to explicitly separate the rounding up from the allocation itself[3]. Round up allocations with kmalloc_size_roundup() so that the verifier's use of ksize() is always accurate. [1] e.g.: https://git.kernel.org/linus/712f210a457d https://git.kernel.org/linus/72c08d9f4c72 [2] e.g.: https://git.kernel.org/netdev/net-next/c/12d6c1d3a2ad https://git.kernel.org/netdev/net-next/c/ab3f7828c979 https://git.kernel.org/netdev/net-next/c/d6dd508080a3 [3] https://lore.kernel.org/lkml/0ea1fc165a6c6117f982f4f135093e69cb884930.camel@redhat.com/ 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: Jiri Olsa Cc: bpf@vger.kernel.org Signed-off-by: Kees Cook Acked-by: Stanislav Fomichev --- v3: - memory leak already taken into -next (daniel) - improve commit log (daniel) - drop optimization patch for now (sdf) v2: https://lore.kernel.org/lkml/20221029024444.gonna.633-kees@kernel.org/ v1: https://lore.kernel.org/lkml/20221018090550.never.834-kees@kernel.org/ --- kernel/bpf/verifier.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index beed7e03addc..c596c7c75d25 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1010,9 +1010,9 @@ static void *copy_array(void *dst, const void *src, size_t n, size_t size, gfp_t if (unlikely(check_mul_overflow(n, size, &bytes))) return NULL; - if (ksize(dst) < bytes) { + if (ksize(dst) < ksize(src)) { kfree(dst); - dst = kmalloc_track_caller(bytes, flags); + dst = kmalloc_track_caller(kmalloc_size_roundup(bytes), flags); if (!dst) return NULL; } @@ -1029,12 +1029,14 @@ static void *copy_array(void *dst, const void *src, size_t n, size_t size, gfp_t */ static void *realloc_array(void *arr, size_t old_n, size_t new_n, size_t size) { + size_t alloc_size; void *new_arr; if (!new_n || old_n == new_n) goto out; - new_arr = krealloc_array(arr, new_n, size, GFP_KERNEL); + alloc_size = kmalloc_size_roundup(size_mul(new_n, size)); + new_arr = krealloc(arr, alloc_size, GFP_KERNEL); if (!new_arr) { kfree(arr); return NULL; @@ -2506,9 +2508,11 @@ static int push_jmp_history(struct bpf_verifier_env *env, { u32 cnt = cur->jmp_history_cnt; struct bpf_idx_pair *p; + size_t alloc_size; cnt++; - p = krealloc(cur->jmp_history, cnt * sizeof(*p), GFP_USER); + alloc_size = kmalloc_size_roundup(size_mul(cnt, sizeof(*p))); + p = krealloc(cur->jmp_history, alloc_size, GFP_USER); if (!p) return -ENOMEM; p[cnt - 1].idx = env->insn_idx;