From patchwork Mon Nov 7 23:09:34 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kumar Kartikeya Dwivedi X-Patchwork-Id: 13035452 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 E8EC3C4332F for ; Mon, 7 Nov 2022 23:10:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232740AbiKGXK3 (ORCPT ); Mon, 7 Nov 2022 18:10:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47136 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232539AbiKGXK1 (ORCPT ); Mon, 7 Nov 2022 18:10:27 -0500 Received: from mail-pg1-x542.google.com (mail-pg1-x542.google.com [IPv6:2607:f8b0:4864:20::542]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 785262018E for ; Mon, 7 Nov 2022 15:10:26 -0800 (PST) Received: by mail-pg1-x542.google.com with SMTP id s196so11869400pgs.3 for ; Mon, 07 Nov 2022 15:10:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=oQF9hfPM6rxjnO+dc+1qEodgsXV3OQMlHxdznDYwqLY=; b=UMOlLqp5VWS45L/6NLvW0sA7a3rC3EvYkqIcDMhJFtPVdNgI2eAQPrnzfmevHL63+n OWhCZT+LQWH2BEd4P/Wm9B9fj9GbxLuYHkRn16drkvIZU/79xDcDNCCIR3elW5uEDZvN f3CKOEy6CH27OIUnmEQVjYNfMCyg+m3DDVodWEMBIYYk22oq6cPWVyqoOvv595Oa7N5U 5Y+xibOuDBXDwVMRsd3G7yUng6sD2bQC/K1xCAYcjfK2su7rVBBK3nOpHcBAp540cQfj t9rQqCVVRwTf2IoZEEwnvoDrI+fNsoDpSaRD5hJ9SmINL8AdCkceqGCPSsrwIBGEqwWw LgYQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=oQF9hfPM6rxjnO+dc+1qEodgsXV3OQMlHxdznDYwqLY=; b=rwUzeeACWYXRFcHxjdL2e+LQ7OGMjtm3DrZOVpC+iHS2z6X5UGwl68VTwYzk4miZ0A G51GsQ81QjPyQC9ceEUawaAgY4N5T5nZJE9+cTcoxCB9Z38u7xULFivZD+t0oVt/gNdr RZGO/1U6pfLl/sopNICATxm2aAhWO4aKN/Z+LR2uvLB+pDNfid8pv9hFARngPvVF77oh V4FKVzi0mcj5B/npFRrXttxRuOEpN3A0uXJwG1jhAl38J2CDhnG1Uq/LmMclG0WJqoS7 T05QhPhEN1z/STVMtt2EkHG9M727NwQSYIL4/+q4CMJGCPDq06ha1b9UNesM+yzb8UpK Rg0w== X-Gm-Message-State: ACrzQf2/2SYEptU82MULVQ/ri1kp5t2GyTM4pZBSUWdYU+mQ/NWjlMm1 e5IxWnSrPcF19sBEJtqU/kdt3Dc653ePgw== X-Google-Smtp-Source: AMsMyM5aTHtcEzH+jkky/+oLh9a4mbt/CW1xngdhedJNsseNEUWGV+lt78W/w/nT1HnM/vZdBtGOqQ== X-Received: by 2002:a65:5386:0:b0:46e:dbd3:413 with SMTP id x6-20020a655386000000b0046edbd30413mr44058866pgq.240.1667862625740; Mon, 07 Nov 2022 15:10:25 -0800 (PST) Received: from localhost ([14.96.13.220]) by smtp.gmail.com with ESMTPSA id h11-20020a170902f70b00b00182a9c27acfsm5463171plo.227.2022.11.07.15.10.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Nov 2022 15:10:25 -0800 (PST) From: Kumar Kartikeya Dwivedi To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Martin KaFai Lau , Dave Marchevsky , Delyan Kratunov Subject: [PATCH bpf-next v5 09/25] bpf: Allow locking bpf_spin_lock in local kptr Date: Tue, 8 Nov 2022 04:39:34 +0530 Message-Id: <20221107230950.7117-10-memxor@gmail.com> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221107230950.7117-1-memxor@gmail.com> References: <20221107230950.7117-1-memxor@gmail.com> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=6766; i=memxor@gmail.com; h=from:subject; bh=MVQAS2kfnE7vi+V2YwtVErsQEqRsBY+jluWi6u8U8YI=; b=owEBbQKS/ZANAwAIAUzgyIZIvxHKAcsmYgBjaY+2H8ILifZnISrzCP3Ph14a4AqtzweF6qpXkAOp 1quM72qJAjMEAAEIAB0WIQRLvip+Buz51YI8YRFM4MiGSL8RygUCY2mPtgAKCRBM4MiGSL8RynCHD/ 9td926X5UvGy4dyKVQDCS8A/XF//m9/mVx1BozmK90YPjgXC3s6ZbxKjoiZE7JGcHsnKVMDDOGl3A0 h/ATq8fJaPL2yreUcuB0VjPJXWaQ/0XzDr2JcBJ88V6ek6UOM/XauTFEQC2WsAoG15k7NxXaz/RThN sIZuARE9SKDF1CC9Z5D04SnhDa2t4uO5YK6/RdcueUI6dO8yHsXfEDz3xfWMKPS8TXPuknOpLGHpS6 Zua+jmOm/bTirkYABSoVDdh62kql9ttGRANvbHcefWJ+fKHBcE3IRac3T3jXZd9YpU9xB2IAlhRcnV /Qgleal06P3mO4xpNhREIOxNBqQHmpp2MWLXL02z26F2utDETp/frloQLy3X532R0LfYSCXAj/OBmX zOqGl0f6jOz/5XA2uG9y4c1hYYv1ihHzy4myQ//4zRExv3hJKP2xf6jrqzksK1shR3jKrzvPr77fvp g/zM5WpoWi01oZ762aImbi3+8udsOobjQ0iIZR9Kkch8RComttLSJqQJ6ZIr8UBuiVwc62TuQL7+wn O+GwTf7sGE65opYMq4Vir1akGZSYN0HR20G1BYXtRYgXDXkbe/2gvzaYX/JkcvDbe4f7tR+kUwCstW z/jssnK+WQnev+KJpS//pkYyzBgRE6CN1igQD8/VUuIM1SY5vBnTEQtOQPGg== X-Developer-Key: i=memxor@gmail.com; a=openpgp; fpr=4BBE2A7E06ECF9D5823C61114CE0C88648BF11CA Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Allow locking a bpf_spin_lock embedded in local kptr, in addition to already support map value pointers. The handling is similar to that of map values, by just preserving the reg->id of local kptrs as well, and adjusting process_spin_lock to work with non-PTR_TO_MAP_VALUE and remember the id in verifier state. Refactor the existing process_spin_lock to work with PTR_TO_BTF_ID | MEM_ALLOC in addition to PTR_TO_MAP_VALUE. We need to update the reg_may_point_to_spin_lock which is used in mark_ptr_or_null_reg to preserve reg->id, that will be used in env->cur_state->active_spin_lock to remember the currently held spin lock. Signed-off-by: Kumar Kartikeya Dwivedi --- kernel/bpf/helpers.c | 2 ++ kernel/bpf/verifier.c | 70 ++++++++++++++++++++++++++++++++----------- 2 files changed, 55 insertions(+), 17 deletions(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 7bc71995f17c..5bc0b9f0f306 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -336,6 +336,7 @@ const struct bpf_func_proto bpf_spin_lock_proto = { .gpl_only = false, .ret_type = RET_VOID, .arg1_type = ARG_PTR_TO_SPIN_LOCK, + .arg1_btf_id = BPF_PTR_POISON, }; static inline void __bpf_spin_unlock_irqrestore(struct bpf_spin_lock *lock) @@ -358,6 +359,7 @@ const struct bpf_func_proto bpf_spin_unlock_proto = { .gpl_only = false, .ret_type = RET_VOID, .arg1_type = ARG_PTR_TO_SPIN_LOCK, + .arg1_btf_id = BPF_PTR_POISON, }; void copy_map_value_locked(struct bpf_map *map, void *dst, void *src, diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 7dcb4629f764..f1170e9db699 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -453,8 +453,16 @@ static bool reg_type_not_null(enum bpf_reg_type type) static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg) { - return reg->type == PTR_TO_MAP_VALUE && - btf_record_has_field(reg->map_ptr->record, BPF_SPIN_LOCK); + struct btf_record *rec = NULL; + + if (reg->type == PTR_TO_MAP_VALUE) { + rec = reg->map_ptr->record; + } else if (reg->type == (PTR_TO_BTF_ID | MEM_ALLOC)) { + struct btf_struct_meta *meta = btf_find_struct_meta(reg->btf, reg->btf_id); + if (meta) + rec = meta->record; + } + return btf_record_has_field(rec, BPF_SPIN_LOCK); } static bool type_is_rdonly_mem(u32 type) @@ -5583,8 +5591,10 @@ static int process_spin_lock(struct bpf_verifier_env *env, int regno, struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; struct bpf_verifier_state *cur = env->cur_state; bool is_const = tnum_is_const(reg->var_off); - struct bpf_map *map = reg->map_ptr; u64 val = reg->var_off.value; + struct bpf_map *map = NULL; + struct btf_record *rec; + struct btf *btf = NULL; if (!is_const) { verbose(env, @@ -5592,19 +5602,32 @@ static int process_spin_lock(struct bpf_verifier_env *env, int regno, regno); return -EINVAL; } - if (!map->btf) { - verbose(env, - "map '%s' has to have BTF in order to use bpf_spin_lock\n", - map->name); - return -EINVAL; + if (reg->type == PTR_TO_MAP_VALUE) { + map = reg->map_ptr; + if (!map->btf) { + verbose(env, + "map '%s' has to have BTF in order to use bpf_spin_lock\n", + map->name); + return -EINVAL; + } + rec = map->record; + } else { + struct btf_struct_meta *meta; + + btf = reg->btf; + meta = btf_find_struct_meta(reg->btf, reg->btf_id); + if (meta) + rec = meta->record; } - if (!btf_record_has_field(map->record, BPF_SPIN_LOCK)) { - verbose(env, "map '%s' has no valid bpf_spin_lock\n", map->name); + + if (!btf_record_has_field(rec, BPF_SPIN_LOCK)) { + verbose(env, "%s '%s' has no valid bpf_spin_lock\n", map ? "map" : "local", + map ? map->name : "kptr"); return -EINVAL; } - if (map->record->spin_lock_off != val + reg->off) { + if (rec->spin_lock_off != val + reg->off) { verbose(env, "off %lld doesn't point to 'struct bpf_spin_lock' that is at %d\n", - val + reg->off, map->record->spin_lock_off); + val + reg->off, rec->spin_lock_off); return -EINVAL; } if (is_lock) { @@ -5810,13 +5833,19 @@ static const struct bpf_reg_types int_ptr_types = { }, }; +static const struct bpf_reg_types spin_lock_types = { + .types = { + PTR_TO_MAP_VALUE, + PTR_TO_BTF_ID | MEM_ALLOC, + } +}; + static const struct bpf_reg_types fullsock_types = { .types = { PTR_TO_SOCKET } }; static const struct bpf_reg_types scalar_types = { .types = { SCALAR_VALUE } }; static const struct bpf_reg_types context_types = { .types = { PTR_TO_CTX } }; static const struct bpf_reg_types ringbuf_mem_types = { .types = { PTR_TO_MEM | MEM_RINGBUF } }; static const struct bpf_reg_types const_map_ptr_types = { .types = { CONST_PTR_TO_MAP } }; static const struct bpf_reg_types btf_ptr_types = { .types = { PTR_TO_BTF_ID } }; -static const struct bpf_reg_types spin_lock_types = { .types = { PTR_TO_MAP_VALUE } }; static const struct bpf_reg_types percpu_btf_ptr_types = { .types = { PTR_TO_BTF_ID | MEM_PERCPU } }; static const struct bpf_reg_types func_ptr_types = { .types = { PTR_TO_FUNC } }; static const struct bpf_reg_types stack_ptr_types = { .types = { PTR_TO_STACK } }; @@ -5941,6 +5970,11 @@ static int check_reg_type(struct bpf_verifier_env *env, u32 regno, return -EACCES; } } + } else if (type_is_local_kptr(reg->type)) { + if (meta->func_id != BPF_FUNC_spin_lock && meta->func_id != BPF_FUNC_spin_unlock) { + verbose(env, "verifier internal error: unimplemented handling of local kptr\n"); + return -EFAULT; + } } return 0; @@ -6057,7 +6091,8 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, goto skip_type_check; /* arg_btf_id and arg_size are in a union. */ - if (base_type(arg_type) == ARG_PTR_TO_BTF_ID) + if (base_type(arg_type) == ARG_PTR_TO_BTF_ID || + base_type(arg_type) == ARG_PTR_TO_SPIN_LOCK) arg_btf_id = fn->arg_btf_id[arg]; err = check_reg_type(env, regno, arg_type, arg_btf_id, meta); @@ -6675,9 +6710,10 @@ static bool check_btf_id_ok(const struct bpf_func_proto *fn) int i; for (i = 0; i < ARRAY_SIZE(fn->arg_type); i++) { - if (base_type(fn->arg_type[i]) == ARG_PTR_TO_BTF_ID && !fn->arg_btf_id[i]) - return false; - + if (base_type(fn->arg_type[i]) == ARG_PTR_TO_BTF_ID) + return !!fn->arg_btf_id[i]; + if (base_type(fn->arg_type[i]) == ARG_PTR_TO_SPIN_LOCK) + return fn->arg_btf_id[i] == BPF_PTR_POISON; if (base_type(fn->arg_type[i]) != ARG_PTR_TO_BTF_ID && fn->arg_btf_id[i] && /* arg_btf_id and arg_size are in a union. */ (base_type(fn->arg_type[i]) != ARG_PTR_TO_MEM ||