From patchwork Thu Jul 23 11:50:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 11680727 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9F758913 for ; Thu, 23 Jul 2020 11:51:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 660E02086A for ; Thu, 23 Jul 2020 11:51:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="UrkTdHFC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728476AbgGWLvD (ORCPT ); Thu, 23 Jul 2020 07:51:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52772 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728553AbgGWLul (ORCPT ); Thu, 23 Jul 2020 07:50:41 -0400 Received: from mail-ed1-x544.google.com (mail-ed1-x544.google.com [IPv6:2a00:1450:4864:20::544]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 694BCC0619E4 for ; Thu, 23 Jul 2020 04:50:40 -0700 (PDT) Received: by mail-ed1-x544.google.com with SMTP id n2so4296339edr.5 for ; Thu, 23 Jul 2020 04:50:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=Ho7UHcN5fCdaU/c6pWjo7vWkoUpYEmWlMQXG5N7PUn4=; b=UrkTdHFCUT0Gh9ahkRIMPbrmOYSQp2DS/R/KX49/GU8Gz3yzDNwLooeD2wVAfgDUJA yNmFAWLtOlZA1HZLIBRSoWFa+D0a3KYsbVHhuH3kPOujbmxiAts/rUlQMkaRzCxlp5/4 glsYqQTxMWjg+XvqJj/O1tvfHFMqwqnvqmmYw= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Ho7UHcN5fCdaU/c6pWjo7vWkoUpYEmWlMQXG5N7PUn4=; b=Uy2Yivj9tExXoE2hQ/RbS2QLIixhJMlA+DYKjitu74Vj1dJ+jNl42b9e0SIoOFY5Ru LJLMZs6AG8SsbC6dYOkH01TYIXbz4PLpaYNpJ+HGjCPI+KH2b4v2mWjdFs6fSIOsELGB hRpF9cnsjc5vCW/eHWrWjsvOs7QbH3Ba7ah9MWLrEBNJZIST3IOpYbxshvun36DAV6nz nNOMxKmKvC58Ilm2jYRgWYANu335yDmqU7yMhkLeoRp/++dRcupLEgOHzCSgldIxhM3n cksQN+6K26uSZ4/ZYVnNa2N7LSCWI8+vv+gYB9JPvgwDMJxJoLJs1anKxdO/ykn3dB7F xmqQ== X-Gm-Message-State: AOAM533YBH1Wrs+PtLVCnZJKr8OfoqMAkWY3A4Ld1FGCw9YvZFdqpzvd 0ARP1tVTuU0h6sNIaHlKUPOqTg== X-Google-Smtp-Source: ABdhPJyJ+CHelMla1/e6JGv8Jyy8xWPcxAl9vMmPWOu1fchWtJw8289dDISBa/avjjk2VGyvCpwlVQ== X-Received: by 2002:a50:ec93:: with SMTP id e19mr3676080edr.254.1595505038570; Thu, 23 Jul 2020 04:50:38 -0700 (PDT) Received: from kpsingh.zrh.corp.google.com ([81.6.44.51]) by smtp.gmail.com with ESMTPSA id h27sm579302eje.23.2020.07.23.04.50.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 Jul 2020 04:50:38 -0700 (PDT) From: KP Singh To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Paul Turner , Jann Horn , Florent Revest Subject: [PATCH bpf-next v6 4/7] bpf: Split bpf_local_storage to bpf_sk_storage Date: Thu, 23 Jul 2020 13:50:29 +0200 Message-Id: <20200723115032.460770-5-kpsingh@chromium.org> X-Mailer: git-send-email 2.28.0.rc0.105.gf9edc3c819-goog In-Reply-To: <20200723115032.460770-1-kpsingh@chromium.org> References: <20200723115032.460770-1-kpsingh@chromium.org> MIME-Version: 1.0 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: From: KP Singh A purely mechanical change: bpf_sk_storage.c = bpf_sk_storage.c + bpf_local_storage.c bpf_sk_storage.h = bpf_sk_storage.h + bpf_local_storage.h Signed-off-by: KP Singh --- include/linux/bpf_local_storage.h | 165 +++++++++ include/net/bpf_sk_storage.h | 64 ---- kernel/bpf/Makefile | 1 + kernel/bpf/bpf_local_storage.c | 519 ++++++++++++++++++++++++++ net/core/bpf_sk_storage.c | 587 +----------------------------- 5 files changed, 686 insertions(+), 650 deletions(-) create mode 100644 include/linux/bpf_local_storage.h create mode 100644 kernel/bpf/bpf_local_storage.c diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h new file mode 100644 index 000000000000..d80573b11d4c --- /dev/null +++ b/include/linux/bpf_local_storage.h @@ -0,0 +1,165 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (c) 2019 Facebook + * Copyright 2020 Google LLC. + */ + +#ifndef _BPF_LOCAL_STORAGE_H +#define _BPF_LOCAL_STORAGE_H + +#include +#include +#include +#include +#include +#include + +#define BPF_LOCAL_STORAGE_CACHE_SIZE 16 + +struct bpf_local_storage_map_bucket { + struct hlist_head list; + raw_spinlock_t lock; +}; + +/* Thp map is not the primary owner of a bpf_local_storage_elem. + * Instead, the container object (eg. sk->sk_bpf_storage) is. + * + * The map (bpf_local_storage_map) is for two purposes + * 1. Define the size of the "local storage". It is + * the map's value_size. + * + * 2. Maintain a list to keep track of all elems such + * that they can be cleaned up during the map destruction. + * + * When a bpf local storage is being looked up for a + * particular object, the "bpf_map" pointer is actually used + * as the "key" to search in the list of elem in + * the respective bpf_local_storage owned by the object. + * + * e.g. sk->sk_bpf_storage is the mini-map with the "bpf_map" pointer + * as the searching key. + */ +struct bpf_local_storage_map { + struct bpf_map map; + /* Lookup elem does not require accessing the map. + * + * Updating/Deleting requires a bucket lock to + * link/unlink the elem from the map. Having + * multiple buckets to improve contention. + */ + struct bpf_local_storage_map_bucket *buckets; + u32 bucket_log; + u16 elem_size; + u16 cache_idx; +}; + +struct bpf_local_storage_data { + /* smap is used as the searching key when looking up + * from the object's bpf_local_storage. + * + * Put it in the same cacheline as the data to minimize + * the number of cachelines access during the cache hit case. + */ + struct bpf_local_storage_map __rcu *smap; + u8 data[] __aligned(8); +}; + +/* Linked to bpf_local_storage and bpf_local_storage_map */ +struct bpf_local_storage_elem { + struct hlist_node map_node; /* Linked to bpf_local_storage_map */ + struct hlist_node snode; /* Linked to bpf_local_storage */ + struct bpf_local_storage __rcu *local_storage; + struct rcu_head rcu; + /* 8 bytes hole */ + /* The data is stored in aother cacheline to minimize + * the number of cachelines access during a cache hit. + */ + struct bpf_local_storage_data sdata ____cacheline_aligned; +}; + +struct bpf_local_storage { + struct bpf_local_storage_data __rcu *cache[BPF_LOCAL_STORAGE_CACHE_SIZE]; + struct hlist_head list; /* List of bpf_local_storage_elem */ + void *owner; /* The object that owns the the above "list" of + * bpf_local_storage_elem. + */ + struct rcu_head rcu; + raw_spinlock_t lock; /* Protect adding/removing from the "list" */ +}; + +struct bpf_local_storage_cache { + spinlock_t idx_lock; + u64 idx_usage_counts[BPF_LOCAL_STORAGE_CACHE_SIZE]; +}; + +#define DEFINE_BPF_STORAGE_CACHE(name) \ +static struct bpf_local_storage_cache name = { \ + .idx_lock = __SPIN_LOCK_UNLOCKED(name.idx_lock), \ +} + +u16 bpf_local_storage_cache_idx_get(struct bpf_local_storage_cache *cache); +void bpf_local_storage_cache_idx_free(struct bpf_local_storage_cache *cache, + u16 idx); + +/* U16_MAX is much more than enough for sk local storage + * considering a tcp_sock is ~2k. + */ +#define BPF_LOCAL_STORAGE_MAX_VALUE_SIZE \ + min_t(u32, \ + (KMALLOC_MAX_SIZE - MAX_BPF_STACK - \ + sizeof(struct bpf_local_storage_elem)), \ + (U16_MAX - sizeof(struct bpf_local_storage_elem))) + +#define SELEM(_SDATA) \ + container_of((_SDATA), struct bpf_local_storage_elem, sdata) +#define SDATA(_SELEM) (&(_SELEM)->sdata) + +/* Helper functions for bpf_local_storage */ +int bpf_local_storage_map_alloc_check(union bpf_attr *attr); + +struct bpf_local_storage_map *bpf_local_storage_map_alloc(union bpf_attr *attr); + +struct bpf_local_storage_data * +bpf_local_storage_lookup(struct bpf_local_storage *local_storage, + struct bpf_local_storage_map *smap, + bool cacheit_lockit); + +void bpf_local_storage_map_free(struct bpf_local_storage_map *smap); + +int bpf_local_storage_map_check_btf(const struct bpf_map *map, + const struct btf *btf, + const struct btf_type *key_type, + const struct btf_type *value_type); + +void bpf_selem_link_storage(struct bpf_local_storage *local_storage, + struct bpf_local_storage_elem *selem); + +bool bpf_selem_unlink_storage(struct bpf_local_storage *local_storage, + struct bpf_local_storage_elem *selem, + bool uncharge_omem); + +void bpf_selem_unlink(struct bpf_local_storage_elem *selem); + +void bpf_selem_link_map(struct bpf_local_storage_map *smap, + struct bpf_local_storage_elem *selem); + +void bpf_selem_unlink_map(struct bpf_local_storage_elem *selem); + +struct bpf_local_storage_elem * +bpf_selem_alloc(struct bpf_local_storage_map *smap, void *value); + +struct bpf_local_storage * +bpf_local_storage_alloc(struct bpf_local_storage_map *smap); + +int bpf_local_storage_publish(struct bpf_local_storage_elem *first_selem, + struct bpf_local_storage **addr, + struct bpf_local_storage *curr); + +int bpf_local_storage_check_update_flags(struct bpf_map *map, u64 map_flags); + +struct bpf_local_storage_data * +bpf_local_storage_update(void *owner, struct bpf_map *map, + struct bpf_local_storage *local_storage, void *value, + u64 map_flags); + +#endif /* _BPF_LOCAL_STORAGE_H */ diff --git a/include/net/bpf_sk_storage.h b/include/net/bpf_sk_storage.h index e3185cfb91da..4cdf37ac278c 100644 --- a/include/net/bpf_sk_storage.h +++ b/include/net/bpf_sk_storage.h @@ -25,70 +25,6 @@ struct sk_buff; struct nlattr; struct sock; -#define BPF_LOCAL_STORAGE_CACHE_SIZE 16 - -struct bpf_local_storage_cache { - spinlock_t idx_lock; - u64 idx_usage_counts[BPF_LOCAL_STORAGE_CACHE_SIZE]; -}; - -#define DEFINE_BPF_STORAGE_CACHE(name) \ -static struct bpf_local_storage_cache name = { \ - .idx_lock = __SPIN_LOCK_UNLOCKED(name.idx_lock), \ -} - -u16 bpf_local_storage_cache_idx_get(struct bpf_local_storage_cache *cache); -void bpf_local_storage_cache_idx_free(struct bpf_local_storage_cache *cache, - u16 idx); - -/* Helper functions for bpf_local_storage */ -int bpf_local_storage_map_alloc_check(union bpf_attr *attr); - -struct bpf_local_storage_map *bpf_local_storage_map_alloc(union bpf_attr *attr); - -struct bpf_local_storage_data * -bpf_local_storage_lookup(struct bpf_local_storage *local_storage, - struct bpf_local_storage_map *smap, - bool cacheit_lockit); - -void bpf_local_storage_map_free(struct bpf_local_storage_map *smap); - -int bpf_local_storage_map_check_btf(const struct bpf_map *map, - const struct btf *btf, - const struct btf_type *key_type, - const struct btf_type *value_type); - -void bpf_selem_link_storage(struct bpf_local_storage *local_storage, - struct bpf_local_storage_elem *selem); - -bool bpf_selem_unlink_storage(struct bpf_local_storage *local_storage, - struct bpf_local_storage_elem *selem, - bool uncharge_omem); - -void bpf_selem_unlink(struct bpf_local_storage_elem *selem); - -void bpf_selem_link_map(struct bpf_local_storage_map *smap, - struct bpf_local_storage_elem *selem); - -void bpf_selem_unlink_map(struct bpf_local_storage_elem *selem); - -struct bpf_local_storage_elem * -bpf_selem_alloc(struct bpf_local_storage_map *smap, void *value); - -struct bpf_local_storage * -bpf_local_storage_alloc(struct bpf_local_storage_map *smap); - -int bpf_local_storage_publish(struct bpf_local_storage_elem *first_selem, - struct bpf_local_storage **addr, - struct bpf_local_storage *curr); - -int bpf_local_storage_check_update_flags(struct bpf_map *map, u64 map_flags); - -struct bpf_local_storage_data * -bpf_local_storage_update(void *owner, struct bpf_map *map, - struct bpf_local_storage *local_storage, void *value, - u64 map_flags); - #ifdef CONFIG_BPF_SYSCALL int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk); struct bpf_sk_storage_diag * diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile index e6eb9c0402da..a9a147e18600 100644 --- a/kernel/bpf/Makefile +++ b/kernel/bpf/Makefile @@ -12,6 +12,7 @@ obj-$(CONFIG_BPF_JIT) += dispatcher.o ifeq ($(CONFIG_NET),y) obj-$(CONFIG_BPF_SYSCALL) += devmap.o obj-$(CONFIG_BPF_SYSCALL) += cpumap.o +obj-$(CONFIG_BPF_SYSCALL) += bpf_local_storage.o obj-$(CONFIG_BPF_SYSCALL) += offload.o obj-$(CONFIG_BPF_SYSCALL) += net_namespace.o endif diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c new file mode 100644 index 000000000000..cefda1f6dd24 --- /dev/null +++ b/kernel/bpf/bpf_local_storage.c @@ -0,0 +1,519 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2019 Facebook + * Copyright 2020 Google LLC. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define BPF_LOCAL_STORAGE_CREATE_FLAG_MASK (BPF_F_NO_PREALLOC | BPF_F_CLONE) + +static struct bpf_local_storage_map_bucket * +select_bucket(struct bpf_local_storage_map *smap, + struct bpf_local_storage_elem *selem) +{ + return &smap->buckets[hash_ptr(selem, smap->bucket_log)]; +} + +static bool selem_linked_to_storage(const struct bpf_local_storage_elem *selem) +{ + return !hlist_unhashed(&selem->snode); +} + +static bool selem_linked_to_map(const struct bpf_local_storage_elem *selem) +{ + return !hlist_unhashed(&selem->map_node); +} + +struct bpf_local_storage_elem * +bpf_selem_alloc(struct bpf_local_storage_map *smap, void *value) +{ + struct bpf_local_storage_elem *selem; + + selem = kzalloc(smap->elem_size, GFP_ATOMIC | __GFP_NOWARN); + if (selem) { + if (value) + memcpy(SDATA(selem)->data, value, smap->map.value_size); + return selem; + } + + return NULL; +} + +/* local_storage->lock must be held and selem->local_storage == local_storage. + * The caller must ensure selem->smap is still valid to be + * dereferenced for its smap->elem_size and smap->cache_idx. + */ +bool bpf_selem_unlink_storage(struct bpf_local_storage *local_storage, + struct bpf_local_storage_elem *selem, + bool uncharge_omem) +{ + struct bpf_local_storage_map *smap; + bool free_local_storage; + + smap = rcu_dereference(SDATA(selem)->smap); + /* local_storage is not freed now. local_storage->lock is + * still held and raw_spin_unlock_bh(&local_storage->lock) + * will be done by the caller. + * Although the unlock will be done under + * rcu_read_lock(), it is more intutivie to + * read if kfree_rcu(local_storage, rcu) is done + * after the raw_spin_unlock_bh(&local_storage->lock). + * + * Hence, a "bool free_local_storage" is returned + * to the caller which then calls the kfree_rcu() + * after unlock. + */ + free_local_storage = smap->map.ops->map_local_storage_unlink( + local_storage, selem, uncharge_omem); + hlist_del_init_rcu(&selem->snode); + if (rcu_access_pointer(local_storage->cache[smap->cache_idx]) == + SDATA(selem)) + RCU_INIT_POINTER(local_storage->cache[smap->cache_idx], NULL); + + kfree_rcu(selem, rcu); + + return free_local_storage; +} + + +static void __bpf_selem_unlink_storage(struct bpf_local_storage_elem *selem) +{ + struct bpf_local_storage *local_storage; + bool free_local_storage = false; + + if (unlikely(!selem_linked_to_storage(selem))) + /* selem has already been unlinked from sk */ + return; + + local_storage = rcu_dereference(selem->local_storage); + raw_spin_lock_bh(&local_storage->lock); + if (likely(selem_linked_to_storage(selem))) + free_local_storage = + bpf_selem_unlink_storage(local_storage, selem, true); + raw_spin_unlock_bh(&local_storage->lock); + + if (free_local_storage) + kfree_rcu(local_storage, rcu); +} + +void bpf_selem_link_storage(struct bpf_local_storage *local_storage, + struct bpf_local_storage_elem *selem) +{ + RCU_INIT_POINTER(selem->local_storage, local_storage); + hlist_add_head(&selem->snode, &local_storage->list); +} + +void bpf_selem_unlink_map(struct bpf_local_storage_elem *selem) +{ + struct bpf_local_storage_map *smap; + struct bpf_local_storage_map_bucket *b; + + if (unlikely(!selem_linked_to_map(selem))) + /* selem has already be unlinked from smap */ + return; + + smap = rcu_dereference(SDATA(selem)->smap); + b = select_bucket(smap, selem); + raw_spin_lock_bh(&b->lock); + if (likely(selem_linked_to_map(selem))) + hlist_del_init_rcu(&selem->map_node); + raw_spin_unlock_bh(&b->lock); +} + +void bpf_selem_link_map(struct bpf_local_storage_map *smap, + struct bpf_local_storage_elem *selem) +{ + struct bpf_local_storage_map_bucket *b = select_bucket(smap, selem); + + raw_spin_lock_bh(&b->lock); + RCU_INIT_POINTER(SDATA(selem)->smap, smap); + hlist_add_head_rcu(&selem->map_node, &b->list); + raw_spin_unlock_bh(&b->lock); +} + +void bpf_selem_unlink(struct bpf_local_storage_elem *selem) +{ + /* Always unlink from map before unlinking from local_storage + * because selem will be freed after successfully unlinked from + * the local_storage. + */ + bpf_selem_unlink_map(selem); + __bpf_selem_unlink_storage(selem); +} + +struct bpf_local_storage_data * +bpf_local_storage_lookup(struct bpf_local_storage *local_storage, + struct bpf_local_storage_map *smap, + bool cacheit_lockit) +{ + struct bpf_local_storage_data *sdata; + struct bpf_local_storage_elem *selem; + + /* Fast path (cache hit) */ + sdata = rcu_dereference(local_storage->cache[smap->cache_idx]); + if (sdata && rcu_access_pointer(sdata->smap) == smap) + return sdata; + + /* Slow path (cache miss) */ + hlist_for_each_entry_rcu(selem, &local_storage->list, snode) + if (rcu_access_pointer(SDATA(selem)->smap) == smap) + break; + + if (!selem) + return NULL; + + sdata = SDATA(selem); + if (cacheit_lockit) { + /* spinlock is needed to avoid racing with the + * parallel delete. Otherwise, publishing an already + * deleted sdata to the cache will become a use-after-free + * problem in the next bpf_local_storage_lookup(). + */ + raw_spin_lock_bh(&local_storage->lock); + if (selem_linked_to_storage(selem)) + rcu_assign_pointer(local_storage->cache[smap->cache_idx], + sdata); + raw_spin_unlock_bh(&local_storage->lock); + } + + return sdata; +} + +struct bpf_local_storage * +bpf_local_storage_alloc(struct bpf_local_storage_map *smap) +{ + struct bpf_local_storage *storage; + + storage = kzalloc(sizeof(*storage), GFP_ATOMIC | __GFP_NOWARN); + if (!storage) + return NULL; + + INIT_HLIST_HEAD(&storage->list); + raw_spin_lock_init(&storage->lock); + return storage; +} + +static int check_flags(const struct bpf_local_storage_data *old_sdata, + u64 map_flags) +{ + if (old_sdata && (map_flags & ~BPF_F_LOCK) == BPF_NOEXIST) + /* elem already exists */ + return -EEXIST; + + if (!old_sdata && (map_flags & ~BPF_F_LOCK) == BPF_EXIST) + /* elem doesn't exist, cannot update it */ + return -ENOENT; + + return 0; +} + +/* sk cannot be going away because it is linking new elem + * to sk->sk_bpf_storage. (i.e. sk->sk_refcnt cannot be 0). + * Otherwise, it will become a leak (and other memory issues + * during map destruction). + */ +struct bpf_local_storage_data * +bpf_local_storage_update(void *owner, struct bpf_map *map, + struct bpf_local_storage *local_storage, void *value, + u64 map_flags) +{ + struct bpf_local_storage_data *old_sdata = NULL; + struct bpf_local_storage_elem *selem; + struct bpf_local_storage_map *smap; + int err; + + smap = (struct bpf_local_storage_map *)map; + + if ((map_flags & BPF_F_LOCK) && !(map_flags & BPF_NOEXIST)) { + /* Hoping to find an old_sdata to do inline update + * such that it can avoid taking the local_storage->lock + * and changing the lists. + */ + old_sdata = bpf_local_storage_lookup(local_storage, smap, false); + err = check_flags(old_sdata, map_flags); + if (err) + return ERR_PTR(err); + + if (old_sdata && selem_linked_to_storage(SELEM(old_sdata))) { + copy_map_value_locked(map, old_sdata->data, + value, false); + return old_sdata; + } + } + + raw_spin_lock_bh(&local_storage->lock); + + /* Recheck local_storage->list under local_storage->lock */ + if (unlikely(hlist_empty(&local_storage->list))) { + /* A parallel del is happening and local_storage is going + * away. It has just been checked before, so very + * unlikely. Return instead of retry to keep things + * simple. + */ + err = -EAGAIN; + goto unlock_err; + } + + old_sdata = bpf_local_storage_lookup(local_storage, smap, false); + err = check_flags(old_sdata, map_flags); + if (err) + goto unlock_err; + + if (old_sdata && (map_flags & BPF_F_LOCK)) { + copy_map_value_locked(map, old_sdata->data, value, false); + selem = SELEM(old_sdata); + goto unlock; + } + + /* local_storage->lock is held. Hence, we are sure + * we can unlink and uncharge the old_sdata successfully + * later. Hence, instead of charging the new selem now + * and then uncharge the old selem later (which may cause + * a potential but unnecessary charge failure), avoid taking + * a charge at all here (the "!old_sdata" check) and the + * old_sdata will not be uncharged later during bpf_selem_unlink(). + */ + selem = map->ops->map_selem_alloc(smap, owner, value, !old_sdata); + if (!selem) { + err = -ENOMEM; + goto unlock_err; + } + + /* First, link the new selem to the map */ + bpf_selem_link_map(smap, selem); + + /* Second, link (and publish) the new selem to local_storage */ + bpf_selem_link_storage(local_storage, selem); + + /* Third, remove old selem, SELEM(old_sdata) */ + if (old_sdata) { + bpf_selem_unlink_map(SELEM(old_sdata)); + bpf_selem_unlink_storage(local_storage, SELEM(old_sdata), false); + } + +unlock: + raw_spin_unlock_bh(&local_storage->lock); + return SDATA(selem); + +unlock_err: + raw_spin_unlock_bh(&local_storage->lock); + return ERR_PTR(err); +} + +int bpf_local_storage_check_update_flags(struct bpf_map *map, u64 map_flags) +{ + /* BPF_EXIST and BPF_NOEXIST cannot be both set */ + if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST) || + /* BPF_F_LOCK can only be used in a value with spin_lock */ + unlikely((map_flags & BPF_F_LOCK) && !map_value_has_spin_lock(map))) + return -EINVAL; + + return 0; +} + +/* Publish local_storage to the address. This is used because we are already + * in a region where we cannot grab a lock on the object owning the storage ( + * (e.g sk->sk_lock). Hence, atomic ops is used. + * + * From now on, the addr pointer is protected + * by the local_storage->lock. Hence, upon freeing, + * the local_storage->lock must be held before unlinking the storage from the + * owner. + */ +int bpf_local_storage_publish(struct bpf_local_storage_elem *first_selem, + struct bpf_local_storage **addr, + struct bpf_local_storage *curr) +{ + struct bpf_local_storage *prev; + + prev = cmpxchg(addr, NULL, curr); + if (unlikely(prev)) { + /* Note that even first_selem was linked to smap's + * bucket->list, first_selem can be freed immediately + * (instead of kfree_rcu) because + * bpf_local_storage_map_free() does a + * synchronize_rcu() before walking the bucket->list. + * Hence, no one is accessing selem from the + * bucket->list under rcu_read_lock(). + */ + bpf_selem_unlink_map(first_selem); + return -EAGAIN; + } + + return 0; +} + +u16 bpf_local_storage_cache_idx_get(struct bpf_local_storage_cache *cache) +{ + u64 min_usage = U64_MAX; + u16 i, res = 0; + + spin_lock(&cache->idx_lock); + for (i = 0; i < BPF_LOCAL_STORAGE_CACHE_SIZE; i++) { + if (cache->idx_usage_counts[i] < min_usage) { + min_usage = cache->idx_usage_counts[i]; + res = i; + + /* Found a free cache_idx */ + if (!min_usage) + break; + } + } + + cache->idx_usage_counts[res]++; + + spin_unlock(&cache->idx_lock); + + return res; +} + +void bpf_local_storage_cache_idx_free(struct bpf_local_storage_cache *cache, + u16 idx) +{ + spin_lock(&cache->idx_lock); + cache->idx_usage_counts[idx]--; + spin_unlock(&cache->idx_lock); +} + +void bpf_local_storage_map_free(struct bpf_local_storage_map *smap) +{ + struct bpf_local_storage_elem *selem; + struct bpf_local_storage_map_bucket *b; + unsigned int i; + + /* Note that this map might be concurrently cloned from + * bpf_sk_storage_clone. Wait for any existing bpf_sk_storage_clone + * RCU read section to finish before proceeding. New RCU + * read sections should be prevented via bpf_map_inc_not_zero. + */ + synchronize_rcu(); + + /* bpf prog and the userspace can no longer access this map + * now. No new selem (of this map) can be added + * to the bpf_local_storage or to the map bucket's list. + * + * The elem of this map can be cleaned up here + * or by bpf_local_storage_free() during the destruction of the + * owner object. eg. __sk_destruct. + */ + for (i = 0; i < (1U << smap->bucket_log); i++) { + b = &smap->buckets[i]; + + rcu_read_lock(); + /* No one is adding to b->list now */ + while ((selem = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(&b->list)), + struct bpf_local_storage_elem, + map_node))) { + bpf_selem_unlink(selem); + cond_resched_rcu(); + } + rcu_read_unlock(); + } + + /* bpf_local_storage_free() may still need to access the map. + * e.g. bpf_local_storage_free() has unlinked selem from the map + * which then made the above while((selem = ...)) loop + * exited immediately. + * + * However, the bpf_local_storage_free() still needs to access + * the smap->elem_size to do the uncharging in + * bpf_selem_unlink(). + * + * Hence, wait another rcu grace period for the + * bpf_local_storage_free() to finish. + */ + synchronize_rcu(); + + kvfree(smap->buckets); + kfree(smap); +} + +int bpf_local_storage_map_alloc_check(union bpf_attr *attr) +{ + if (attr->map_flags & ~BPF_LOCAL_STORAGE_CREATE_FLAG_MASK || + !(attr->map_flags & BPF_F_NO_PREALLOC) || + attr->max_entries || + attr->key_size != sizeof(int) || !attr->value_size || + /* Enforce BTF for userspace sk dumping */ + !attr->btf_key_type_id || !attr->btf_value_type_id) + return -EINVAL; + + if (!bpf_capable()) + return -EPERM; + + if (attr->value_size > BPF_LOCAL_STORAGE_MAX_VALUE_SIZE) + return -E2BIG; + + return 0; +} + +struct bpf_local_storage_map *bpf_local_storage_map_alloc(union bpf_attr *attr) +{ + struct bpf_local_storage_map *smap; + unsigned int i; + u32 nbuckets; + u64 cost; + int ret; + + smap = kzalloc(sizeof(*smap), GFP_USER | __GFP_NOWARN); + if (!smap) + return ERR_PTR(-ENOMEM); + bpf_map_init_from_attr(&smap->map, attr); + + nbuckets = roundup_pow_of_two(num_possible_cpus()); + /* Use at least 2 buckets, select_bucket() is undefined behavior with 1 bucket */ + nbuckets = max_t(u32, 2, nbuckets); + smap->bucket_log = ilog2(nbuckets); + cost = sizeof(*smap->buckets) * nbuckets + sizeof(*smap); + + ret = bpf_map_charge_init(&smap->map.memory, cost); + if (ret < 0) { + kfree(smap); + return ERR_PTR(ret); + } + + smap->buckets = kvcalloc(sizeof(*smap->buckets), nbuckets, + GFP_USER | __GFP_NOWARN); + if (!smap->buckets) { + bpf_map_charge_finish(&smap->map.memory); + kfree(smap); + return ERR_PTR(-ENOMEM); + } + + for (i = 0; i < nbuckets; i++) { + INIT_HLIST_HEAD(&smap->buckets[i].list); + raw_spin_lock_init(&smap->buckets[i].lock); + } + + smap->elem_size = + sizeof(struct bpf_local_storage_elem) + attr->value_size; + + return smap; +} + +int bpf_local_storage_map_check_btf(const struct bpf_map *map, + const struct btf *btf, + const struct btf_type *key_type, + const struct btf_type *value_type) +{ + u32 int_data; + + if (BTF_INFO_KIND(key_type->info) != BTF_KIND_INT) + return -EINVAL; + + int_data = *(u32 *)(key_type + 1); + if (BTF_INT_BITS(int_data) != 32 || BTF_INT_OFFSET(int_data)) + return -EINVAL; + + return 0; +} diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c index f6bb02f076ad..be0ed44d0887 100644 --- a/net/core/bpf_sk_storage.c +++ b/net/core/bpf_sk_storage.c @@ -7,96 +7,13 @@ #include #include #include +#include #include #include #include -#define BPF_LOCAL_STORAGE_CREATE_FLAG_MASK (BPF_F_NO_PREALLOC | BPF_F_CLONE) - DEFINE_BPF_STORAGE_CACHE(sk_cache); -struct bpf_local_storage_map_bucket { - struct hlist_head list; - raw_spinlock_t lock; -}; - -/* Thp map is not the primary owner of a bpf_local_storage_elem. - * Instead, the container object (eg. sk->sk_bpf_storage) is. - * - * The map (bpf_local_storage_map) is for two purposes - * 1. Define the size of the "local storage". It is - * the map's value_size. - * - * 2. Maintain a list to keep track of all elems such - * that they can be cleaned up during the map destruction. - * - * When a bpf local storage is being looked up for a - * particular object, the "bpf_map" pointer is actually used - * as the "key" to search in the list of elem in - * the respective bpf_local_storage owned by the object. - * - * e.g. sk->sk_bpf_storage is the mini-map with the "bpf_map" pointer - * as the searching key. - */ -struct bpf_local_storage_map { - struct bpf_map map; - /* Lookup elem does not require accessing the map. - * - * Updating/Deleting requires a bucket lock to - * link/unlink the elem from the map. Having - * multiple buckets to improve contention. - */ - struct bpf_local_storage_map_bucket *buckets; - u32 bucket_log; - u16 elem_size; - u16 cache_idx; -}; - -struct bpf_local_storage_data { - /* smap is used as the searching key when looking up - * from the object's bpf_local_storage. - * - * Put it in the same cacheline as the data to minimize - * the number of cachelines access during the cache hit case. - */ - struct bpf_local_storage_map __rcu *smap; - u8 data[] __aligned(8); -}; - -/* Linked to bpf_local_storage and bpf_local_storage_map */ -struct bpf_local_storage_elem { - struct hlist_node map_node; /* Linked to bpf_local_storage_map */ - struct hlist_node snode; /* Linked to bpf_local_storage */ - struct bpf_local_storage __rcu *local_storage; - struct rcu_head rcu; - /* 8 bytes hole */ - /* The data is stored in aother cacheline to minimize - * the number of cachelines access during a cache hit. - */ - struct bpf_local_storage_data sdata ____cacheline_aligned; -}; - -#define SELEM(_SDATA) \ - container_of((_SDATA), struct bpf_local_storage_elem, sdata) -#define SDATA(_SELEM) (&(_SELEM)->sdata) - -struct bpf_local_storage { - struct bpf_local_storage_data __rcu *cache[BPF_LOCAL_STORAGE_CACHE_SIZE]; - struct hlist_head list; /* List of bpf_local_storage_elem */ - void *owner; /* The object that owns the the above "list" of - * bpf_local_storage_elem. - */ - struct rcu_head rcu; - raw_spinlock_t lock; /* Protect adding/removing from the "list" */ -}; - -static struct bpf_local_storage_map_bucket * -select_bucket(struct bpf_local_storage_map *smap, - struct bpf_local_storage_elem *selem) -{ - return &smap->buckets[hash_ptr(selem, smap->bucket_log)]; -} - static int omem_charge(struct sock *sk, unsigned int size) { /* same check as in sock_kmalloc() */ @@ -109,31 +26,6 @@ static int omem_charge(struct sock *sk, unsigned int size) return -ENOMEM; } -static bool selem_linked_to_storage(const struct bpf_local_storage_elem *selem) -{ - return !hlist_unhashed(&selem->snode); -} - -static bool selem_linked_to_map(const struct bpf_local_storage_elem *selem) -{ - return !hlist_unhashed(&selem->map_node); -} - -struct bpf_local_storage_elem * -bpf_selem_alloc(struct bpf_local_storage_map *smap, void *value) -{ - struct bpf_local_storage_elem *selem; - - selem = kzalloc(smap->elem_size, GFP_ATOMIC | __GFP_NOWARN); - if (selem) { - if (value) - memcpy(SDATA(selem)->data, value, smap->map.value_size); - return selem; - } - - return NULL; -} - static struct bpf_local_storage_elem * sk_selem_alloc(struct bpf_local_storage_map *smap, void *owner, void *value, bool charge_omem) @@ -154,42 +46,6 @@ sk_selem_alloc(struct bpf_local_storage_map *smap, void *owner, void *value, return NULL; } -/* sk_storage->lock must be held and selem->sk_storage == sk_storage. - * The caller must ensure selem->smap is still valid to be - * dereferenced for its smap->elem_size and smap->cache_idx. - */ -bool bpf_selem_unlink_storage(struct bpf_local_storage *local_storage, - struct bpf_local_storage_elem *selem, - bool uncharge_omem) -{ - struct bpf_local_storage_map *smap; - bool free_local_storage; - - smap = rcu_dereference(SDATA(selem)->smap); - /* local_storage is not freed now. local_storage->lock is - * still held and raw_spin_unlock_bh(&local_storage->lock) - * will be done by the caller. - * Although the unlock will be done under - * rcu_read_lock(), it is more intutivie to - * read if kfree_rcu(local_storage, rcu) is done - * after the raw_spin_unlock_bh(&local_storage->lock). - * - * Hence, a "bool free_local_storage" is returned - * to the caller which then calls the kfree_rcu() - * after unlock. - */ - free_local_storage = smap->map.ops->map_local_storage_unlink( - local_storage, selem, uncharge_omem); - hlist_del_init_rcu(&selem->snode); - if (rcu_access_pointer(local_storage->cache[smap->cache_idx]) == - SDATA(selem)) - RCU_INIT_POINTER(local_storage->cache[smap->cache_idx], NULL); - - kfree_rcu(selem, rcu); - - return free_local_storage; -} - static bool unlink_sk_storage(struct bpf_local_storage *local_storage, struct bpf_local_storage_elem *selem, bool uncharge_omem) @@ -221,109 +77,6 @@ static bool unlink_sk_storage(struct bpf_local_storage *local_storage, return free_local_storage; } -static void __bpf_selem_unlink_storage(struct bpf_local_storage_elem *selem) -{ - struct bpf_local_storage *local_storage; - bool free_local_storage = false; - - if (unlikely(!selem_linked_to_storage(selem))) - /* selem has already been unlinked from sk */ - return; - - local_storage = rcu_dereference(selem->local_storage); - raw_spin_lock_bh(&local_storage->lock); - if (likely(selem_linked_to_storage(selem))) - free_local_storage = - bpf_selem_unlink_storage(local_storage, selem, true); - raw_spin_unlock_bh(&local_storage->lock); - - if (free_local_storage) - kfree_rcu(local_storage, rcu); -} - -void bpf_selem_link_storage(struct bpf_local_storage *local_storage, - struct bpf_local_storage_elem *selem) -{ - RCU_INIT_POINTER(selem->local_storage, local_storage); - hlist_add_head(&selem->snode, &local_storage->list); -} - -void bpf_selem_unlink_map(struct bpf_local_storage_elem *selem) -{ - struct bpf_local_storage_map *smap; - struct bpf_local_storage_map_bucket *b; - - if (unlikely(!selem_linked_to_map(selem))) - /* selem has already be unlinked from smap */ - return; - - smap = rcu_dereference(SDATA(selem)->smap); - b = select_bucket(smap, selem); - raw_spin_lock_bh(&b->lock); - if (likely(selem_linked_to_map(selem))) - hlist_del_init_rcu(&selem->map_node); - raw_spin_unlock_bh(&b->lock); -} - -void bpf_selem_link_map(struct bpf_local_storage_map *smap, - struct bpf_local_storage_elem *selem) -{ - struct bpf_local_storage_map_bucket *b = select_bucket(smap, selem); - - raw_spin_lock_bh(&b->lock); - RCU_INIT_POINTER(SDATA(selem)->smap, smap); - hlist_add_head_rcu(&selem->map_node, &b->list); - raw_spin_unlock_bh(&b->lock); -} - -void bpf_selem_unlink(struct bpf_local_storage_elem *selem) -{ - /* Always unlink from map before unlinking from local_storage - * because selem will be freed after successfully unlinked from - * the local_storage. - */ - bpf_selem_unlink_map(selem); - __bpf_selem_unlink_storage(selem); -} - -struct bpf_local_storage_data * -bpf_local_storage_lookup(struct bpf_local_storage *local_storage, - struct bpf_local_storage_map *smap, - bool cacheit_lockit) -{ - struct bpf_local_storage_data *sdata; - struct bpf_local_storage_elem *selem; - - /* Fast path (cache hit) */ - sdata = rcu_dereference(local_storage->cache[smap->cache_idx]); - if (sdata && rcu_access_pointer(sdata->smap) == smap) - return sdata; - - /* Slow path (cache miss) */ - hlist_for_each_entry_rcu(selem, &local_storage->list, snode) - if (rcu_access_pointer(SDATA(selem)->smap) == smap) - break; - - if (!selem) - return NULL; - - sdata = SDATA(selem); - if (cacheit_lockit) { - /* spinlock is needed to avoid racing with the - * parallel delete. Otherwise, publishing an already - * deleted sdata to the cache will become a use-after-free - * problem in the next bpf_local_storage_lookup(). - */ - raw_spin_lock_bh(&local_storage->lock); - if (selem_linked_to_storage(selem)) - rcu_assign_pointer(local_storage->cache[smap->cache_idx], - sdata); - raw_spin_unlock_bh(&local_storage->lock); - } - - return sdata; -} - static struct bpf_local_storage_data * sk_storage_lookup(struct sock *sk, struct bpf_map *map, bool cacheit_lockit) { @@ -338,34 +91,6 @@ sk_storage_lookup(struct sock *sk, struct bpf_map *map, bool cacheit_lockit) return bpf_local_storage_lookup(sk_storage, smap, cacheit_lockit); } -static int check_flags(const struct bpf_local_storage_data *old_sdata, - u64 map_flags) -{ - if (old_sdata && (map_flags & ~BPF_F_LOCK) == BPF_NOEXIST) - /* elem already exists */ - return -EEXIST; - - if (!old_sdata && (map_flags & ~BPF_F_LOCK) == BPF_EXIST) - /* elem doesn't exist, cannot update it */ - return -ENOENT; - - return 0; -} - -struct bpf_local_storage * -bpf_local_storage_alloc(struct bpf_local_storage_map *smap) -{ - struct bpf_local_storage *storage; - - storage = kzalloc(sizeof(*storage), GFP_ATOMIC | __GFP_NOWARN); - if (!storage) - return NULL; - - INIT_HLIST_HEAD(&storage->list); - raw_spin_lock_init(&storage->lock); - return storage; -} - static int sk_storage_alloc(void *owner, struct bpf_local_storage_map *smap, struct bpf_local_storage_elem *first_selem) @@ -402,142 +127,6 @@ static int sk_storage_alloc(void *owner, return err; } -/* sk cannot be going away because it is linking new elem - * to sk->sk_bpf_storage. (i.e. sk->sk_refcnt cannot be 0). - * Otherwise, it will become a leak (and other memory issues - * during map destruction). - */ -struct bpf_local_storage_data * -bpf_local_storage_update(void *owner, struct bpf_map *map, - struct bpf_local_storage *local_storage, void *value, - u64 map_flags) -{ - struct bpf_local_storage_data *old_sdata = NULL; - struct bpf_local_storage_elem *selem; - struct bpf_local_storage_map *smap; - int err; - - smap = (struct bpf_local_storage_map *)map; - - if ((map_flags & BPF_F_LOCK) && !(map_flags & BPF_NOEXIST)) { - /* Hoping to find an old_sdata to do inline update - * such that it can avoid taking the local_storage->lock - * and changing the lists. - */ - old_sdata = bpf_local_storage_lookup(local_storage, smap, false); - err = check_flags(old_sdata, map_flags); - if (err) - return ERR_PTR(err); - - if (old_sdata && selem_linked_to_storage(SELEM(old_sdata))) { - copy_map_value_locked(map, old_sdata->data, - value, false); - return old_sdata; - } - } - - raw_spin_lock_bh(&local_storage->lock); - - /* Recheck local_storage->list under local_storage->lock */ - if (unlikely(hlist_empty(&local_storage->list))) { - /* A parallel del is happening and local_storage is going - * away. It has just been checked before, so very - * unlikely. Return instead of retry to keep things - * simple. - */ - err = -EAGAIN; - goto unlock_err; - } - - old_sdata = bpf_local_storage_lookup(local_storage, smap, false); - err = check_flags(old_sdata, map_flags); - if (err) - goto unlock_err; - - if (old_sdata && (map_flags & BPF_F_LOCK)) { - copy_map_value_locked(map, old_sdata->data, value, false); - selem = SELEM(old_sdata); - goto unlock; - } - - /* local_storage->lock is held. Hence, we are sure - * we can unlink and uncharge the old_sdata successfully - * later. Hence, instead of charging the new selem now - * and then uncharge the old selem later (which may cause - * a potential but unnecessary charge failure), avoid taking - * a charge at all here (the "!old_sdata" check) and the - * old_sdata will not be uncharged later during bpf_selem_unlink(). - */ - selem = map->ops->map_selem_alloc(smap, owner, value, !old_sdata); - if (!selem) { - err = -ENOMEM; - goto unlock_err; - } - - /* First, link the new selem to the map */ - bpf_selem_link_map(smap, selem); - - /* Second, link (and publish) the new selem to local_storage */ - bpf_selem_link_storage(local_storage, selem); - - /* Third, remove old selem, SELEM(old_sdata) */ - if (old_sdata) { - bpf_selem_unlink_map(SELEM(old_sdata)); - bpf_selem_unlink_storage(local_storage, SELEM(old_sdata), false); - } - -unlock: - raw_spin_unlock_bh(&local_storage->lock); - return SDATA(selem); - -unlock_err: - raw_spin_unlock_bh(&local_storage->lock); - return ERR_PTR(err); -} - -int bpf_local_storage_check_update_flags(struct bpf_map *map, u64 map_flags) -{ - /* BPF_EXIST and BPF_NOEXIST cannot be both set */ - if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST) || - /* BPF_F_LOCK can only be used in a value with spin_lock */ - unlikely((map_flags & BPF_F_LOCK) && !map_value_has_spin_lock(map))) - return -EINVAL; - - return 0; -} - -/* Publish local_storage to the address. This is used because we are already - * in a region where we cannot grab a lock on the object owning the storage ( - * (e.g sk->sk_lock). Hence, atomic ops is used. - * - * From now on, the addr pointer is protected - * by the local_storage->lock. Hence, upon freeing, - * the local_storage->lock must be held before unlinking the storage from the - * owner. - */ -int bpf_local_storage_publish(struct bpf_local_storage_elem *first_selem, - struct bpf_local_storage **addr, - struct bpf_local_storage *curr) -{ - struct bpf_local_storage *prev; - - prev = cmpxchg(addr, NULL, curr); - if (unlikely(prev)) { - /* Note that even first_selem was linked to smap's - * bucket->list, first_selem can be freed immediately - * (instead of kfree_rcu) because - * bpf_local_storage_map_free() does a - * synchronize_rcu() before walking the bucket->list. - * Hence, no one is accessing selem from the - * bucket->list under rcu_read_lock(). - */ - bpf_selem_unlink_map(first_selem); - return -EAGAIN; - } - - return 0; -} - static struct bpf_local_storage_data * sk_storage_update(void *owner, struct bpf_map *map, void *value, u64 map_flags) { @@ -589,38 +178,6 @@ static int sk_storage_delete(struct sock *sk, struct bpf_map *map) return 0; } -u16 bpf_local_storage_cache_idx_get(struct bpf_local_storage_cache *cache) -{ - u64 min_usage = U64_MAX; - u16 i, res = 0; - - spin_lock(&cache->idx_lock); - - for (i = 0; i < BPF_LOCAL_STORAGE_CACHE_SIZE; i++) { - if (cache->idx_usage_counts[i] < min_usage) { - min_usage = cache->idx_usage_counts[i]; - res = i; - - /* Found a free cache_idx */ - if (!min_usage) - break; - } - } - cache->idx_usage_counts[res]++; - - spin_unlock(&cache->idx_lock); - - return res; -} - -void bpf_local_storage_cache_idx_free(struct bpf_local_storage_cache *cache, - u16 idx) -{ - spin_lock(&cache->idx_lock); - cache->idx_usage_counts[idx]--; - spin_unlock(&cache->idx_lock); -} - /* Called by __sk_destruct() & bpf_sk_storage_clone() */ void bpf_sk_storage_free(struct sock *sk) { @@ -661,59 +218,6 @@ void bpf_sk_storage_free(struct sock *sk) kfree_rcu(sk_storage, rcu); } -void bpf_local_storage_map_free(struct bpf_local_storage_map *smap) -{ - struct bpf_local_storage_elem *selem; - struct bpf_local_storage_map_bucket *b; - unsigned int i; - - /* Note that this map might be concurrently cloned from - * bpf_sk_storage_clone. Wait for any existing bpf_sk_storage_clone - * RCU read section to finish before proceeding. New RCU - * read sections should be prevented via bpf_map_inc_not_zero. - */ - synchronize_rcu(); - - /* bpf prog and the userspace can no longer access this map - * now. No new selem (of this map) can be added - * to the bpf_local_storage or to the map bucket's list. - * - * The elem of this map can be cleaned up here - * or by bpf_local_storage_free() during the destruction of the - * owner object. eg. __sk_destruct. - */ - for (i = 0; i < (1U << smap->bucket_log); i++) { - b = &smap->buckets[i]; - - rcu_read_lock(); - /* No one is adding to b->list now */ - while ((selem = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(&b->list)), - struct bpf_local_storage_elem, - map_node))) { - bpf_selem_unlink(selem); - cond_resched_rcu(); - } - rcu_read_unlock(); - } - - /* bpf_local_storage_free() may still need to access the map. - * e.g. bpf_local_storage_free() has unlinked selem from the map - * which then made the above while((selem = ...)) loop - * exited immediately. - * - * However, the bpf_local_storage_free() still needs to access - * the smap->elem_size to do the uncharging in - * bpf_selem_unlink(). - * - * Hence, wait another rcu grace period for the - * bpf_local_storage_free() to finish. - */ - synchronize_rcu(); - - kvfree(smap->buckets); - kfree(smap); -} - static void sk_storage_map_free(struct bpf_map *map) { struct bpf_local_storage_map *smap; @@ -723,78 +227,6 @@ static void sk_storage_map_free(struct bpf_map *map) bpf_local_storage_map_free(smap); } -/* U16_MAX is much more than enough for sk local storage - * considering a tcp_sock is ~2k. - */ -#define BPF_LOCAL_STORAGE_MAX_VALUE_SIZE \ - min_t(u32, \ - (KMALLOC_MAX_SIZE - MAX_BPF_STACK - \ - sizeof(struct bpf_local_storage_elem)), \ - (U16_MAX - sizeof(struct bpf_local_storage_elem))) - -int bpf_local_storage_map_alloc_check(union bpf_attr *attr) -{ - if (attr->map_flags & ~BPF_LOCAL_STORAGE_CREATE_FLAG_MASK || - !(attr->map_flags & BPF_F_NO_PREALLOC) || - attr->max_entries || - attr->key_size != sizeof(int) || !attr->value_size || - /* Enforce BTF for userspace sk dumping */ - !attr->btf_key_type_id || !attr->btf_value_type_id) - return -EINVAL; - - if (!bpf_capable()) - return -EPERM; - - if (attr->value_size > BPF_LOCAL_STORAGE_MAX_VALUE_SIZE) - return -E2BIG; - - return 0; -} - -struct bpf_local_storage_map *bpf_local_storage_map_alloc(union bpf_attr *attr) -{ - struct bpf_local_storage_map *smap; - unsigned int i; - u32 nbuckets; - u64 cost; - int ret; - - smap = kzalloc(sizeof(*smap), GFP_USER | __GFP_NOWARN); - if (!smap) - return ERR_PTR(-ENOMEM); - bpf_map_init_from_attr(&smap->map, attr); - - nbuckets = roundup_pow_of_two(num_possible_cpus()); - /* Use at least 2 buckets, select_bucket() is undefined behavior with 1 bucket */ - nbuckets = max_t(u32, 2, nbuckets); - smap->bucket_log = ilog2(nbuckets); - cost = sizeof(*smap->buckets) * nbuckets + sizeof(*smap); - - ret = bpf_map_charge_init(&smap->map.memory, cost); - if (ret < 0) { - kfree(smap); - return ERR_PTR(ret); - } - - smap->buckets = kvcalloc(sizeof(*smap->buckets), nbuckets, - GFP_USER | __GFP_NOWARN); - if (!smap->buckets) { - bpf_map_charge_finish(&smap->map.memory); - kfree(smap); - return ERR_PTR(-ENOMEM); - } - - for (i = 0; i < nbuckets; i++) { - INIT_HLIST_HEAD(&smap->buckets[i].list); - raw_spin_lock_init(&smap->buckets[i].lock); - } - - smap->elem_size = - sizeof(struct bpf_local_storage_elem) + attr->value_size; - - return smap; -} - static struct bpf_map *sk_storage_map_alloc(union bpf_attr *attr) { struct bpf_local_storage_map *smap; @@ -813,23 +245,6 @@ static int notsupp_get_next_key(struct bpf_map *map, void *key, return -ENOTSUPP; } -int bpf_local_storage_map_check_btf(const struct bpf_map *map, - const struct btf *btf, - const struct btf_type *key_type, - const struct btf_type *value_type) -{ - u32 int_data; - - if (BTF_INFO_KIND(key_type->info) != BTF_KIND_INT) - return -EINVAL; - - int_data = *(u32 *)(key_type + 1); - if (BTF_INT_BITS(int_data) != 32 || BTF_INT_OFFSET(int_data)) - return -EINVAL; - - return 0; -} - static void *bpf_fd_sk_storage_lookup_elem(struct bpf_map *map, void *key) { struct bpf_local_storage_data *sdata;