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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4434FC433F5 for ; Wed, 16 Feb 2022 00:12:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244962AbiBPANB (ORCPT ); Tue, 15 Feb 2022 19:13:01 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:52418 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244813AbiBPANA (ORCPT ); Tue, 15 Feb 2022 19:13:00 -0500 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9B597DD460 for ; Tue, 15 Feb 2022 16:12:49 -0800 (PST) Received: by mail-yb1-xb4a.google.com with SMTP id b64-20020a256743000000b0061e169a5f19so788013ybc.11 for ; Tue, 15 Feb 2022 16:12:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=5EUxcrErCsNmjbOMc+BbJfxjTVhsz7Xhh+knicHeLos=; b=GWT4PvuRedUwXdkk9G0ey4k/5joKdqDJPJj2NV7m/7rDP2Z3u2AzUxq+VsFC/AJPVj nc24Sc+fcDS/J1tAtSBBRq0+N6hxXF8QinSQpnhmwSxnM01CT/UO+CgBMH4RwfWdqatc Y5GQxaLDmJoYoY4vk+DqR/R870sz+/xZTTggH5V74QxAqxaEB1ZU4sGEhI++dl/EnmRu Kk+TPwA1rKHlfHvY+UwxOjBmDXKcmdYltcka1tf0MeHtkRqIiH2b6PZhx7ErZ913GDZQ TNHBq9Lzvw5UmUEPYtMkXtYPgQR5FYsR19JCLCrnMT8nBu1468Q5WTuyAUVMCAmkVMeo /hHA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=5EUxcrErCsNmjbOMc+BbJfxjTVhsz7Xhh+knicHeLos=; b=u+todQSc/0lvEv+rFn5yvuz0V4DsW3QhgPfILGw4xSkhZUeAq3MZTvvD0lrIGodZrx Ydpo1FHQCv1ahCtxuWBYupnLOLh5NWtgpYsHBdzobtPnI7TuYJCHfURrEjPMZa/QnAfA qeOc+52t41BR3Se/KGdgUp+D0sc1lTKD1bLdNqfZ5T4oPKijSZoYKdG+MWBVDXpMd/mA 4RMWyACAg7911S1tTX3zawKC9NKywPhwPAkJ3T/mfM/1qso14MkXcRixBfZ1s9iD5I+1 fdBi7/AXip4UVL8dufvK4xi/eSukPayOOh4EuCQCFQIKeZ08KdWug2QeG5cI6GDxj7Mq rIRw== X-Gm-Message-State: AOAM533ia4IPjNJy/CdL5tu1gjBVLD3WSIl1S363ooM3XFVN7v2uvVmn FDtX4KPwBNTzvQaiF6vtC/qkX7jA210Xt0bGX+iGanoxSsV7s7GQCuGXR3voqACBHulf1sxgjAY SMk4eRInUnq93+b9n5235+34Z5M2kKhgKnUmc33DUIzhNVdU86V1erQ== X-Google-Smtp-Source: ABdhPJzCQyipgZ3OEAttZ9NB2xLOOHJzoEgGhxjP5lbSLKpWHRZ2IPE3icuXYQB2GBn9fsJQUKUqpFU= X-Received: from sdf2.svl.corp.google.com ([2620:15c:2c4:201:754a:e17d:48a0:d1db]) (user=sdf job=sendgmr) by 2002:a05:6902:83:b0:610:7e09:64bd with SMTP id h3-20020a056902008300b006107e0964bdmr67757ybs.653.1644970368755; Tue, 15 Feb 2022 16:12:48 -0800 (PST) Date: Tue, 15 Feb 2022 16:12:39 -0800 In-Reply-To: <20220216001241.2239703-1-sdf@google.com> Message-Id: <20220216001241.2239703-3-sdf@google.com> Mime-Version: 1.0 References: <20220216001241.2239703-1-sdf@google.com> X-Mailer: git-send-email 2.35.1.265.g69c8d7142f-goog Subject: [RFC bpf-next 2/4] bpf: allow writing to sock->sk_priority from lsm progtype From: Stanislav Fomichev To: netdev@vger.kernel.org, bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, Stanislav Fomichev Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Open up enough fields for selftests. Will be extended in the real patch series to match bpf_sock fields. Signed-off-by: Stanislav Fomichev --- kernel/bpf/bpf_lsm.c | 49 +++++++++++++++++++++++++++++++++++++++++++ kernel/bpf/verifier.c | 3 ++- 2 files changed, 51 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c index 9e4ecc990647..1a68661e1b9c 100644 --- a/kernel/bpf/bpf_lsm.c +++ b/kernel/bpf/bpf_lsm.c @@ -222,7 +222,56 @@ bool bpf_lsm_is_sleepable_hook(u32 btf_id) const struct bpf_prog_ops lsm_prog_ops = { }; +static int lsm_btf_struct_access(struct bpf_verifier_log *log, + const struct btf *btf, + const struct btf_type *t, int off, + int size, enum bpf_access_type atype, + u32 *next_btf_id, + enum bpf_type_flag *flag) +{ + const struct btf_type *sock_type; + struct btf *btf_vmlinux; + s32 type_id; + size_t end; + + if (atype == BPF_READ) + return btf_struct_access(log, btf, t, off, size, atype, next_btf_id, + flag); + + btf_vmlinux = bpf_get_btf_vmlinux(); + + type_id = btf_find_by_name_kind(btf_vmlinux, "sock", BTF_KIND_STRUCT); + if (type_id < 0) + return -EINVAL; + + sock_type = btf_type_by_id(btf_vmlinux, type_id); + + if (t != sock_type) { + bpf_log(log, "only 'struct sock' writes are supported\n"); + return -EACCES; + } + + switch (off) { + case bpf_ctx_range(struct sock, sk_priority): + end = offsetofend(struct sock, sk_priority); + break; + default: + bpf_log(log, "no write support to 'struct sock' at off %d\n", off); + return -EACCES; + } + + if (off + size > end) { + bpf_log(log, + "write access at off %d with size %d beyond the member of 'struct sock' ended at %zu\n", + off, size, end); + return -EACCES; + } + + return NOT_INIT; +} + const struct bpf_verifier_ops lsm_verifier_ops = { .get_func_proto = bpf_lsm_func_proto, .is_valid_access = btf_ctx_access, + .btf_struct_access = lsm_btf_struct_access, }; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 1563723759d9..b8991460d17d 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -12801,7 +12801,8 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) insn->code = BPF_LDX | BPF_PROBE_MEM | BPF_SIZE((insn)->code); env->prog->aux->num_exentries++; - } else if (resolve_prog_type(env->prog) != BPF_PROG_TYPE_STRUCT_OPS) { + } else if (resolve_prog_type(env->prog) != BPF_PROG_TYPE_STRUCT_OPS && + resolve_prog_type(env->prog) != BPF_PROG_TYPE_LSM) { verbose(env, "Writes through BTF pointers are not allowed\n"); return -EINVAL; } -- 2.35.1.265.g69c8d7142f-goog