From patchwork Thu May 19 20:20:30 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 12856014 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id ACB17C4321E for ; Thu, 19 May 2022 20:23:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BC26D6B0073; Thu, 19 May 2022 16:23:38 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B70806B0075; Thu, 19 May 2022 16:23:38 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A0FE26B0078; Thu, 19 May 2022 16:23:38 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 8D9916B0073 for ; Thu, 19 May 2022 16:23:38 -0400 (EDT) Received: from smtpin30.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 67CB061231 for ; Thu, 19 May 2022 20:23:38 +0000 (UTC) X-FDA: 79483618116.30.9C8F99A Received: from mx0b-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) by imf19.hostedemail.com (Postfix) with ESMTP id D773B1A0015 for ; Thu, 19 May 2022 20:23:26 +0000 (UTC) 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 24JFG4fs012897 for ; Thu, 19 May 2022 13:23:36 -0700 Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3g5b9vpap8-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Thu, 19 May 2022 13:23:36 -0700 Received: from twshared8307.18.frc3.facebook.com (2620:10d:c085:108::8) by mail.thefacebook.com (2620:10d:c085:21d::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.28; Thu, 19 May 2022 13:23:35 -0700 Received: by devbig932.frc1.facebook.com (Postfix, from userid 4523) id ECA637D58F62; Thu, 19 May 2022 13:20:45 -0700 (PDT) From: Song Liu To: , , CC: , , , , , , , Song Liu Subject: [PATCH v2 bpf-next 1/8] bpf: fill new bpf_prog_pack with illegal instructions Date: Thu, 19 May 2022 13:20:30 -0700 Message-ID: <20220519202037.2401584-2-song@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220519202037.2401584-1-song@kernel.org> References: <20220519202037.2401584-1-song@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-GUID: E3MqQqLYQPgnmf6gRSoyZB5Cv8ozEm-B X-Proofpoint-ORIG-GUID: E3MqQqLYQPgnmf6gRSoyZB5Cv8ozEm-B X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.874,Hydra:6.0.486,FMLib:17.11.64.514 definitions=2022-05-19_06,2022-05-19_03,2022-02-23_01 Authentication-Results: imf19.hostedemail.com; dkim=none; spf=none (imf19.hostedemail.com: domain of "prvs=61387cfd06=songliubraving@fb.com" has no SPF policy when checking 67.231.153.30) smtp.mailfrom="prvs=61387cfd06=songliubraving@fb.com"; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=kernel.org (policy=none) X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: D773B1A0015 X-Stat-Signature: 3hdfxgk651takjqns54qtjg4krxqh9um X-HE-Tag: 1652991806-518040 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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 9cc91f0f3115..2d0c9d4696ad 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;