From patchwork Mon Apr 25 20:39:45 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 12826217 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 4CD61C433EF for ; Mon, 25 Apr 2022 20:43:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245629AbiDYUq0 convert rfc822-to-8bit (ORCPT ); Mon, 25 Apr 2022 16:46:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45854 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245622AbiDYUqY (ORCPT ); Mon, 25 Apr 2022 16:46:24 -0400 Received: from mx0b-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0F65BECCEC for ; Mon, 25 Apr 2022 13:43:17 -0700 (PDT) Received: from pps.filterd (m0109332.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 23PIVi2F009635 for ; Mon, 25 Apr 2022 13:43:17 -0700 Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3fp10e910a-3 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Mon, 25 Apr 2022 13:43:17 -0700 Received: from twshared19572.14.frc2.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::4) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 25 Apr 2022 13:43:15 -0700 Received: by devbig932.frc1.facebook.com (Postfix, from userid 4523) id 56C29652E7A1; Mon, 25 Apr 2022 13:40:35 -0700 (PDT) From: Song Liu To: , , CC: , , , , , , , Song Liu Subject: [PATCH v2 bpf 1/3] bpf: fill new bpf_prog_pack with illegal instructions Date: Mon, 25 Apr 2022 13:39:45 -0700 Message-ID: <20220425203947.3311308-2-song@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220425203947.3311308-1-song@kernel.org> References: <20220425203947.3311308-1-song@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-GUID: MNLorSazeK9Ou72qR_BHSDuX1mCNhyxQ X-Proofpoint-ORIG-GUID: MNLorSazeK9Ou72qR_BHSDuX1mCNhyxQ X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.858,Hydra:6.0.486,FMLib:17.11.64.514 definitions=2022-04-25_10,2022-04-25_03,2022-02-23_01 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net bpf_prog_pack enables sharing huge pages among multiple BPF programs. These pages are marked as executable before the JIT engine fill it with BPF programs. To make these pages safe, fill the hole bpf_prog_pack with illegal instructions before making it executable. Fixes: 57631054fae6 ("bpf: Introduce bpf_prog_pack allocator") Fixes: 33c9805860e5 ("bpf: Introduce bpf_jit_binary_pack_[alloc|finalize|free]") Signed-off-by: Song Liu --- kernel/bpf/core.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 13e9dbeeedf3..132dfba389be 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -873,7 +873,7 @@ static size_t select_bpf_prog_pack_size(void) return size; } -static struct bpf_prog_pack *alloc_new_pack(void) +static struct bpf_prog_pack *alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns) { struct bpf_prog_pack *pack; @@ -886,6 +886,7 @@ static struct bpf_prog_pack *alloc_new_pack(void) kfree(pack); return NULL; } + bpf_fill_ill_insns(pack->ptr, bpf_prog_pack_size); bitmap_zero(pack->bitmap, bpf_prog_pack_size / BPF_PROG_CHUNK_SIZE); list_add_tail(&pack->list, &pack_list); @@ -895,7 +896,7 @@ static struct bpf_prog_pack *alloc_new_pack(void) return pack; } -static void *bpf_prog_pack_alloc(u32 size) +static void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns) { unsigned int nbits = BPF_PROG_SIZE_TO_NBITS(size); struct bpf_prog_pack *pack; @@ -910,6 +911,7 @@ static void *bpf_prog_pack_alloc(u32 size) size = round_up(size, PAGE_SIZE); ptr = module_alloc(size); if (ptr) { + bpf_fill_ill_insns(ptr, size); set_vm_flush_reset_perms(ptr); set_memory_ro((unsigned long)ptr, size / PAGE_SIZE); set_memory_x((unsigned long)ptr, size / PAGE_SIZE); @@ -923,7 +925,7 @@ static void *bpf_prog_pack_alloc(u32 size) goto found_free_area; } - pack = alloc_new_pack(); + pack = alloc_new_pack(bpf_fill_ill_insns); if (!pack) goto out; @@ -1102,7 +1104,7 @@ bpf_jit_binary_pack_alloc(unsigned int proglen, u8 **image_ptr, if (bpf_jit_charge_modmem(size)) return NULL; - ro_header = bpf_prog_pack_alloc(size); + ro_header = bpf_prog_pack_alloc(size, bpf_fill_ill_insns); if (!ro_header) { bpf_jit_uncharge_modmem(size); return NULL;