From patchwork Tue Oct 27 17:03:13 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 11861051 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 X-Spam-Level: X-Spam-Status: No, score=-12.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CF193C4363A for ; Tue, 27 Oct 2020 17:03:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 635F420725 for ; Tue, 27 Oct 2020 17:03:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="PvFOq5nd" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1815654AbgJ0RDu (ORCPT ); Tue, 27 Oct 2020 13:03:50 -0400 Received: from mail-ed1-f67.google.com ([209.85.208.67]:40252 "EHLO mail-ed1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1815582AbgJ0RD1 (ORCPT ); Tue, 27 Oct 2020 13:03:27 -0400 Received: by mail-ed1-f67.google.com with SMTP id p93so2201184edd.7 for ; Tue, 27 Oct 2020 10:03:23 -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=Zp59KCD8sk+WI1Qt3/6v9uMdfR897YQpYeg3YMt2W7Y=; b=PvFOq5nduCLB34mh3vazruxOqEwE+CSEewGQ6lV3pbI+m7DMb/7TC/2JZubzilIhWC VqINDUCausv2X8K1oto2qxPDFNRFy7j8rtr4AXg/iVBcvvso36+67E4ujmq8VFwWMWsz tK9AIN0VFUwuUUg2nEiFEYgW5BspGSkctRXSE= 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=Zp59KCD8sk+WI1Qt3/6v9uMdfR897YQpYeg3YMt2W7Y=; b=s8FeGhneWNklO9K//oYNSx9BRDFYbZFcZvcb7kJlCmSa2lEGcURgenU+9xeWJt79Ao onDvqBG8tdSj9NDckp8BMBSaUG7cK/rAsbtJl1x7wvDeImLvkq3B/w/YNE0XqlekzXMR Lf9+cnrJBPygLnlOG52avlFwj1ad/wjO4lhdaouYVIsqQlb/PCxbLGrgVqZ8JZAtDGEk XUHFopmrrQtTcBW3LSZUmoRDx3iz4lD6QsNaGntRMzpzqEZ2qtwK+XgTUu5YzDorGbHa S6O336N6nZKHdJM18ALa6K3s5pLPeYgtp4Ua6L8Ew6d7Vh1exCi6ubeNk/I2TZ2idreG WnXQ== X-Gm-Message-State: AOAM533THibseUVcrgwFg55WiOOPNCn2L8hIkIf3zY7wSNxassTm2795 ZcqGuRYLfflyTyrDH2X4kBdopw== X-Google-Smtp-Source: ABdhPJzeJByiJ1ZTNf5Q9w15Tc/6SjiPqKt5MmZpv45fR73oD26jfb1teMDpZ6P8sFJvWDEtsq47yg== X-Received: by 2002:a05:6402:d0d:: with SMTP id eb13mr3292164edb.244.1603818202570; Tue, 27 Oct 2020 10:03:22 -0700 (PDT) Received: from kpsingh.zrh.corp.google.com ([81.6.44.51]) by smtp.gmail.com with ESMTPSA id ba6sm1315006edb.61.2020.10.27.10.03.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Oct 2020 10:03:21 -0700 (PDT) From: KP Singh To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Paul Turner , Jann Horn , Hao Luo Subject: [PATCH bpf-next 1/5] bpf: Implement task local storage Date: Tue, 27 Oct 2020 18:03:13 +0100 Message-Id: <20201027170317.2011119-2-kpsingh@chromium.org> X-Mailer: git-send-email 2.29.0.rc2.309.g374f81d7ae-goog In-Reply-To: <20201027170317.2011119-1-kpsingh@chromium.org> References: <20201027170317.2011119-1-kpsingh@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: KP Singh Similar to bpf_local_storage for sockets and inodes add local storage for task_struct. The life-cycle of storage is managed with the life-cycle of the task_struct. i.e. the storage is destroyed along with the owning task with a callback to the bpf_task_storage_free from the task_free LSM hook. The BPF LSM allocates an __rcu pointer to the bpf_local_storage in the security blob which are now stackable and can co-exist with other LSMs. The userspace map operations can be done by using a pid fd as a key passed to the lookup, update and delete operations. Signed-off-by: KP Singh --- include/linux/bpf_lsm.h | 23 ++ include/linux/bpf_types.h | 1 + include/uapi/linux/bpf.h | 39 +++ kernel/bpf/Makefile | 1 + kernel/bpf/bpf_lsm.c | 4 + kernel/bpf/bpf_task_storage.c | 327 ++++++++++++++++++ kernel/bpf/syscall.c | 3 +- kernel/bpf/verifier.c | 10 + security/bpf/hooks.c | 2 + .../bpf/bpftool/Documentation/bpftool-map.rst | 3 +- tools/bpf/bpftool/bash-completion/bpftool | 2 +- tools/bpf/bpftool/map.c | 4 +- tools/include/uapi/linux/bpf.h | 39 +++ tools/lib/bpf/libbpf_probes.c | 2 + 14 files changed, 456 insertions(+), 4 deletions(-) create mode 100644 kernel/bpf/bpf_task_storage.c diff --git a/include/linux/bpf_lsm.h b/include/linux/bpf_lsm.h index aaacb6aafc87..326cb68a3632 100644 --- a/include/linux/bpf_lsm.h +++ b/include/linux/bpf_lsm.h @@ -7,6 +7,7 @@ #ifndef _LINUX_BPF_LSM_H #define _LINUX_BPF_LSM_H +#include "linux/sched.h" #include #include @@ -35,9 +36,21 @@ static inline struct bpf_storage_blob *bpf_inode( return inode->i_security + bpf_lsm_blob_sizes.lbs_inode; } +static inline struct bpf_storage_blob *bpf_task( + const struct task_struct *task) +{ + if (unlikely(!task->security)) + return NULL; + + return task->security + bpf_lsm_blob_sizes.lbs_task; +} + extern const struct bpf_func_proto bpf_inode_storage_get_proto; extern const struct bpf_func_proto bpf_inode_storage_delete_proto; +extern const struct bpf_func_proto bpf_task_storage_get_proto; +extern const struct bpf_func_proto bpf_task_storage_delete_proto; void bpf_inode_storage_free(struct inode *inode); +void bpf_task_storage_free(struct task_struct *task); #else /* !CONFIG_BPF_LSM */ @@ -53,10 +66,20 @@ static inline struct bpf_storage_blob *bpf_inode( return NULL; } +static inline struct bpf_storage_blob *bpf_task( + const struct task_struct *task) +{ + return NULL; +} + static inline void bpf_inode_storage_free(struct inode *inode) { } +static inline void bpf_task_storage_free(struct task_struct *task) +{ +} + #endif /* CONFIG_BPF_LSM */ #endif /* _LINUX_BPF_LSM_H */ diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h index 2e6f568377f1..99f7fd657d87 100644 --- a/include/linux/bpf_types.h +++ b/include/linux/bpf_types.h @@ -109,6 +109,7 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_SOCKHASH, sock_hash_ops) #endif #ifdef CONFIG_BPF_LSM BPF_MAP_TYPE(BPF_MAP_TYPE_INODE_STORAGE, inode_storage_map_ops) +BPF_MAP_TYPE(BPF_MAP_TYPE_TASK_STORAGE, task_storage_map_ops) #endif BPF_MAP_TYPE(BPF_MAP_TYPE_CPUMAP, cpu_map_ops) #if defined(CONFIG_XDP_SOCKETS) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index e6ceac3f7d62..bb443c4f3637 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -157,6 +157,7 @@ enum bpf_map_type { BPF_MAP_TYPE_STRUCT_OPS, BPF_MAP_TYPE_RINGBUF, BPF_MAP_TYPE_INODE_STORAGE, + BPF_MAP_TYPE_TASK_STORAGE, }; /* Note that tracing related programs such as @@ -3742,6 +3743,42 @@ union bpf_attr { * Return * The helper returns **TC_ACT_REDIRECT** on success or * **TC_ACT_SHOT** on error. + * + * void *bpf_task_storage_get(struct bpf_map *map, void *task, void *value, u64 flags) + * Description + * Get a bpf_local_storage from the *task*. + * + * Logically, it could be thought of as getting the value from + * a *map* with *task* as the **key**. From this + * perspective, the usage is not much different from + * **bpf_map_lookup_elem**\ (*map*, **&**\ *task*) except this + * helper enforces the key must be an task_struct and the map must also + * be a **BPF_MAP_TYPE_TASK_STORAGE**. + * + * Underneath, the value is stored locally at *task* instead of + * the *map*. The *map* is used as the bpf-local-storage + * "type". The bpf-local-storage "type" (i.e. the *map*) is + * searched against all bpf_local_storage residing at *task*. + * + * An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be + * used such that a new bpf_local_storage will be + * created if one does not exist. *value* can be used + * together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify + * the initial value of a bpf_local_storage. If *value* is + * **NULL**, the new bpf_local_storage will be zero initialized. + * Return + * A bpf_local_storage pointer is returned on success. + * + * **NULL** if not found or there was an error in adding + * a new bpf_local_storage. + * + * int bpf_task_storage_delete(struct bpf_map *map, void *task) + * Description + * Delete a bpf_local_storage from a *task*. + * Return + * 0 on success. + * + * **-ENOENT** if the bpf_local_storage cannot be found. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3900,6 +3937,8 @@ union bpf_attr { FN(bpf_per_cpu_ptr), \ FN(bpf_this_cpu_ptr), \ FN(redirect_peer), \ + FN(task_storage_get), \ + FN(task_storage_delete), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile index bdc8cd1b6767..f0b93ced5a7f 100644 --- a/kernel/bpf/Makefile +++ b/kernel/bpf/Makefile @@ -6,6 +6,7 @@ obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o tnum.o bpf_i obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o bpf_lru_list.o lpm_trie.o map_in_map.o obj-$(CONFIG_BPF_SYSCALL) += local_storage.o queue_stack_maps.o ringbuf.o obj-${CONFIG_BPF_LSM} += bpf_inode_storage.o +obj-${CONFIG_BPF_LSM} += bpf_task_storage.o obj-$(CONFIG_BPF_SYSCALL) += disasm.o obj-$(CONFIG_BPF_JIT) += trampoline.o obj-$(CONFIG_BPF_SYSCALL) += btf.o diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c index 78ea8a7bd27f..61f8cc52fd5b 100644 --- a/kernel/bpf/bpf_lsm.c +++ b/kernel/bpf/bpf_lsm.c @@ -59,6 +59,10 @@ bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_sk_storage_get_proto; case BPF_FUNC_sk_storage_delete: return &bpf_sk_storage_delete_proto; + case BPF_FUNC_task_storage_get: + return &bpf_task_storage_get_proto; + case BPF_FUNC_task_storage_delete: + return &bpf_task_storage_delete_proto; default: return tracing_prog_func_proto(func_id, prog); } diff --git a/kernel/bpf/bpf_task_storage.c b/kernel/bpf/bpf_task_storage.c new file mode 100644 index 000000000000..774140c458cc --- /dev/null +++ b/kernel/bpf/bpf_task_storage.c @@ -0,0 +1,327 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2019 Facebook + * Copyright 2020 Google LLC. + */ + +#include "linux/pid.h" +#include "linux/sched.h" +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +DEFINE_BPF_STORAGE_CACHE(task_cache); + +static struct bpf_local_storage __rcu **task_storage_ptr(void *owner) +{ + struct task_struct *task = owner; + struct bpf_storage_blob *bsb; + + bsb = bpf_task(task); + if (!bsb) + return NULL; + return &bsb->storage; +} + +static struct bpf_local_storage_data * +task_storage_lookup(struct task_struct *task, struct bpf_map *map, + bool cacheit_lockit) +{ + struct bpf_local_storage *task_storage; + struct bpf_local_storage_map *smap; + struct bpf_storage_blob *bsb; + + bsb = bpf_task(task); + if (!bsb) + return NULL; + + task_storage = rcu_dereference(bsb->storage); + if (!task_storage) + return NULL; + + smap = (struct bpf_local_storage_map *)map; + return bpf_local_storage_lookup(task_storage, smap, cacheit_lockit); +} + +void bpf_task_storage_free(struct task_struct *task) +{ + struct bpf_local_storage_elem *selem; + struct bpf_local_storage *local_storage; + bool free_task_storage = false; + struct bpf_storage_blob *bsb; + struct hlist_node *n; + + bsb = bpf_task(task); + if (!bsb) + return; + + rcu_read_lock(); + + local_storage = rcu_dereference(bsb->storage); + if (!local_storage) { + rcu_read_unlock(); + return; + } + + /* Netiher the bpf_prog nor the bpf-map's syscall + * could be modifying the local_storage->list now. + * Thus, no elem can be added-to or deleted-from the + * local_storage->list by the bpf_prog or by the bpf-map's syscall. + * + * It is racing with bpf_local_storage_map_free() alone + * when unlinking elem from the local_storage->list and + * the map's bucket->list. + */ + raw_spin_lock_bh(&local_storage->lock); + hlist_for_each_entry_safe(selem, n, &local_storage->list, snode) { + /* Always unlink from map before unlinking from + * local_storage. + */ + bpf_selem_unlink_map(selem); + free_task_storage = bpf_selem_unlink_storage_nolock( + local_storage, selem, false); + } + raw_spin_unlock_bh(&local_storage->lock); + rcu_read_unlock(); + + /* free_task_storage should always be true as long as + * local_storage->list was non-empty. + */ + if (free_task_storage) + kfree_rcu(local_storage, rcu); +} + +static void *bpf_pid_task_storage_lookup_elem(struct bpf_map *map, void *key) +{ + struct bpf_local_storage_data *sdata; + struct task_struct *task; + struct pid *pid; + struct file *f; + int fd, err; + + fd = *(int *)key; + f = fget_raw(fd); + if (!f) + return ERR_PTR(-EBADF); + + if (f->f_op != &pidfd_fops) { + err = -EBADF; + goto out_fput; + } + + pid = get_pid(f->private_data); + task = get_pid_task(pid, PIDTYPE_PID); + if (!task || !task_storage_ptr(task)) { + err = -ENOENT; + goto out; + } + + sdata = task_storage_lookup(task, map, true); + put_pid(pid); + return sdata ? sdata->data : NULL; +out: + put_pid(pid); +out_fput: + fput(f); + return ERR_PTR(err); +} + +static int bpf_pid_task_storage_update_elem(struct bpf_map *map, void *key, + void *value, u64 map_flags) +{ + struct bpf_local_storage_data *sdata; + struct task_struct *task; + struct pid *pid; + struct file *f; + int fd, err; + + fd = *(int *)key; + f = fget_raw(fd); + if (!f) + return -EBADF; + + if (f->f_op != &pidfd_fops) { + err = -EBADF; + goto out_fput; + } + + pid = get_pid(f->private_data); + task = get_pid_task(pid, PIDTYPE_PID); + if (!task || !task_storage_ptr(task)) { + err = -ENOENT; + goto out; + } + + sdata = bpf_local_storage_update( + task, (struct bpf_local_storage_map *)map, value, map_flags); + + err = PTR_ERR_OR_ZERO(sdata); +out: + put_pid(pid); +out_fput: + fput(f); + return err; +} + +static int task_storage_delete(struct task_struct *task, struct bpf_map *map) +{ + struct bpf_local_storage_data *sdata; + + sdata = task_storage_lookup(task, map, false); + if (!sdata) + return -ENOENT; + + bpf_selem_unlink(SELEM(sdata)); + + return 0; +} + +static int bpf_pid_task_storage_delete_elem(struct bpf_map *map, void *key) +{ + struct task_struct *task; + struct pid *pid; + struct file *f; + int fd, err; + + fd = *(int *)key; + f = fget_raw(fd); + if (!f) + return -EBADF; + + if (f->f_op != &pidfd_fops) { + err = -EBADF; + goto out_fput; + } + + pid = get_pid(f->private_data); + task = get_pid_task(pid, PIDTYPE_PID); + if (!task || !task_storage_ptr(task)) { + err = -ENOENT; + goto out; + } + + err = task_storage_delete(task, map); + +out: + put_pid(pid); +out_fput: + fput(f); + return err; +} + +BPF_CALL_4(bpf_task_storage_get, struct bpf_map *, map, struct task_struct *, + task, void *, value, u64, flags) +{ + struct bpf_local_storage_data *sdata; + + if (flags & ~(BPF_LOCAL_STORAGE_GET_F_CREATE)) + return (unsigned long)NULL; + + /* explicitly check that the task_storage_ptr is not + * NULL as task_storage_lookup returns NULL in this case and + * bpf_local_storage_update expects the owner to have a + * valid storage pointer. + */ + if (!task_storage_ptr(task)) + return (unsigned long)NULL; + + sdata = task_storage_lookup(task, map, true); + if (sdata) + return (unsigned long)sdata->data; + + /* This helper must only called from where the task is guaranteed + * to have a refcount and cannot be freed. + */ + if (flags & BPF_LOCAL_STORAGE_GET_F_CREATE) { + sdata = bpf_local_storage_update( + task, (struct bpf_local_storage_map *)map, value, + BPF_NOEXIST); + return IS_ERR(sdata) ? (unsigned long)NULL : + (unsigned long)sdata->data; + } + + return (unsigned long)NULL; +} + +BPF_CALL_2(bpf_task_storage_delete, struct bpf_map *, map, struct task_struct *, + task) +{ + /* This helper must only called from where the task is guaranteed + * to have a refcount and cannot be freed. + */ + return task_storage_delete(task, map); +} + +static int notsupp_get_next_key(struct bpf_map *map, void *key, void *next_key) +{ + return -ENOTSUPP; +} + +static struct bpf_map *task_storage_map_alloc(union bpf_attr *attr) +{ + struct bpf_local_storage_map *smap; + + smap = bpf_local_storage_map_alloc(attr); + if (IS_ERR(smap)) + return ERR_CAST(smap); + + smap->cache_idx = bpf_local_storage_cache_idx_get(&task_cache); + return &smap->map; +} + +static void task_storage_map_free(struct bpf_map *map) +{ + struct bpf_local_storage_map *smap; + + smap = (struct bpf_local_storage_map *)map; + bpf_local_storage_cache_idx_free(&task_cache, smap->cache_idx); + bpf_local_storage_map_free(smap); +} + +static int task_storage_map_btf_id; +const struct bpf_map_ops task_storage_map_ops = { + .map_meta_equal = bpf_map_meta_equal, + .map_alloc_check = bpf_local_storage_map_alloc_check, + .map_alloc = task_storage_map_alloc, + .map_free = task_storage_map_free, + .map_get_next_key = notsupp_get_next_key, + .map_lookup_elem = bpf_pid_task_storage_lookup_elem, + .map_update_elem = bpf_pid_task_storage_update_elem, + .map_delete_elem = bpf_pid_task_storage_delete_elem, + .map_check_btf = bpf_local_storage_map_check_btf, + .map_btf_name = "bpf_local_storage_map", + .map_btf_id = &task_storage_map_btf_id, + .map_owner_storage_ptr = task_storage_ptr, +}; + +BTF_ID_LIST_SINGLE(bpf_task_storage_btf_ids, struct, task_struct) + +const struct bpf_func_proto bpf_task_storage_get_proto = { + .func = bpf_task_storage_get, + .gpl_only = false, + .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL, + .arg1_type = ARG_CONST_MAP_PTR, + .arg2_type = ARG_PTR_TO_BTF_ID, + .arg2_btf_id = &bpf_task_storage_btf_ids[0], + .arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL, + .arg4_type = ARG_ANYTHING, +}; + +const struct bpf_func_proto bpf_task_storage_delete_proto = { + .func = bpf_task_storage_delete, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_CONST_MAP_PTR, + .arg2_type = ARG_PTR_TO_BTF_ID, + .arg2_btf_id = &bpf_task_storage_btf_ids[0], +}; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 8f50c9c19f1b..f3fe9f53f93c 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -773,7 +773,8 @@ static int map_check_btf(struct bpf_map *map, const struct btf *btf, map->map_type != BPF_MAP_TYPE_ARRAY && map->map_type != BPF_MAP_TYPE_CGROUP_STORAGE && map->map_type != BPF_MAP_TYPE_SK_STORAGE && - map->map_type != BPF_MAP_TYPE_INODE_STORAGE) + map->map_type != BPF_MAP_TYPE_INODE_STORAGE && + map->map_type != BPF_MAP_TYPE_TASK_STORAGE) return -ENOTSUPP; if (map->spin_lock_off + sizeof(struct bpf_spin_lock) > map->value_size) { diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 6200519582a6..b0790876694f 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -4469,6 +4469,11 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env, func_id != BPF_FUNC_inode_storage_delete) goto error; break; + case BPF_MAP_TYPE_TASK_STORAGE: + if (func_id != BPF_FUNC_task_storage_get && + func_id != BPF_FUNC_task_storage_delete) + goto error; + break; default: break; } @@ -4547,6 +4552,11 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env, if (map->map_type != BPF_MAP_TYPE_INODE_STORAGE) goto error; break; + case BPF_FUNC_task_storage_get: + case BPF_FUNC_task_storage_delete: + if (map->map_type != BPF_MAP_TYPE_TASK_STORAGE) + goto error; + break; default: break; } diff --git a/security/bpf/hooks.c b/security/bpf/hooks.c index 788667d582ae..e5971fa74fd7 100644 --- a/security/bpf/hooks.c +++ b/security/bpf/hooks.c @@ -12,6 +12,7 @@ static struct security_hook_list bpf_lsm_hooks[] __lsm_ro_after_init = { #include #undef LSM_HOOK LSM_HOOK_INIT(inode_free_security, bpf_inode_storage_free), + LSM_HOOK_INIT(task_free, bpf_task_storage_free), }; static int __init bpf_lsm_init(void) @@ -23,6 +24,7 @@ static int __init bpf_lsm_init(void) struct lsm_blob_sizes bpf_lsm_blob_sizes __lsm_ro_after_init = { .lbs_inode = sizeof(struct bpf_storage_blob), + .lbs_task = sizeof(struct bpf_storage_blob), }; DEFINE_LSM(bpf) = { diff --git a/tools/bpf/bpftool/Documentation/bpftool-map.rst b/tools/bpf/bpftool/Documentation/bpftool-map.rst index dade10cdf295..3d52256ba75f 100644 --- a/tools/bpf/bpftool/Documentation/bpftool-map.rst +++ b/tools/bpf/bpftool/Documentation/bpftool-map.rst @@ -50,7 +50,8 @@ MAP COMMANDS | | **lru_percpu_hash** | **lpm_trie** | **array_of_maps** | **hash_of_maps** | | **devmap** | **devmap_hash** | **sockmap** | **cpumap** | **xskmap** | **sockhash** | | **cgroup_storage** | **reuseport_sockarray** | **percpu_cgroup_storage** -| | **queue** | **stack** | **sk_storage** | **struct_ops** | **ringbuf** | **inode_storage** } +| | **queue** | **stack** | **sk_storage** | **struct_ops** | **ringbuf** | **inode_storage** + | **task_storage** } DESCRIPTION =========== diff --git a/tools/bpf/bpftool/bash-completion/bpftool b/tools/bpf/bpftool/bash-completion/bpftool index 3f1da30c4da6..fdffbc64c65c 100644 --- a/tools/bpf/bpftool/bash-completion/bpftool +++ b/tools/bpf/bpftool/bash-completion/bpftool @@ -705,7 +705,7 @@ _bpftool() hash_of_maps devmap devmap_hash sockmap cpumap \ xskmap sockhash cgroup_storage reuseport_sockarray \ percpu_cgroup_storage queue stack sk_storage \ - struct_ops inode_storage' -- \ + struct_ops inode_storage task_storage' -- \ "$cur" ) ) return 0 ;; diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c index a7efbd84fbcc..b400364ee054 100644 --- a/tools/bpf/bpftool/map.c +++ b/tools/bpf/bpftool/map.c @@ -51,6 +51,7 @@ const char * const map_type_name[] = { [BPF_MAP_TYPE_STRUCT_OPS] = "struct_ops", [BPF_MAP_TYPE_RINGBUF] = "ringbuf", [BPF_MAP_TYPE_INODE_STORAGE] = "inode_storage", + [BPF_MAP_TYPE_TASK_STORAGE] = "task_storage", }; const size_t map_type_name_size = ARRAY_SIZE(map_type_name); @@ -1464,7 +1465,8 @@ static int do_help(int argc, char **argv) " lru_percpu_hash | lpm_trie | array_of_maps | hash_of_maps |\n" " devmap | devmap_hash | sockmap | cpumap | xskmap | sockhash |\n" " cgroup_storage | reuseport_sockarray | percpu_cgroup_storage |\n" - " queue | stack | sk_storage | struct_ops | ringbuf | inode_storage }\n" + " queue | stack | sk_storage | struct_ops | ringbuf | inode_storage |\n" + " task_storage }\n" " " HELP_SPEC_OPTIONS "\n" "", bin_name, argv[-2]); diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index e6ceac3f7d62..bb443c4f3637 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -157,6 +157,7 @@ enum bpf_map_type { BPF_MAP_TYPE_STRUCT_OPS, BPF_MAP_TYPE_RINGBUF, BPF_MAP_TYPE_INODE_STORAGE, + BPF_MAP_TYPE_TASK_STORAGE, }; /* Note that tracing related programs such as @@ -3742,6 +3743,42 @@ union bpf_attr { * Return * The helper returns **TC_ACT_REDIRECT** on success or * **TC_ACT_SHOT** on error. + * + * void *bpf_task_storage_get(struct bpf_map *map, void *task, void *value, u64 flags) + * Description + * Get a bpf_local_storage from the *task*. + * + * Logically, it could be thought of as getting the value from + * a *map* with *task* as the **key**. From this + * perspective, the usage is not much different from + * **bpf_map_lookup_elem**\ (*map*, **&**\ *task*) except this + * helper enforces the key must be an task_struct and the map must also + * be a **BPF_MAP_TYPE_TASK_STORAGE**. + * + * Underneath, the value is stored locally at *task* instead of + * the *map*. The *map* is used as the bpf-local-storage + * "type". The bpf-local-storage "type" (i.e. the *map*) is + * searched against all bpf_local_storage residing at *task*. + * + * An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be + * used such that a new bpf_local_storage will be + * created if one does not exist. *value* can be used + * together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify + * the initial value of a bpf_local_storage. If *value* is + * **NULL**, the new bpf_local_storage will be zero initialized. + * Return + * A bpf_local_storage pointer is returned on success. + * + * **NULL** if not found or there was an error in adding + * a new bpf_local_storage. + * + * int bpf_task_storage_delete(struct bpf_map *map, void *task) + * Description + * Delete a bpf_local_storage from a *task*. + * Return + * 0 on success. + * + * **-ENOENT** if the bpf_local_storage cannot be found. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3900,6 +3937,8 @@ union bpf_attr { FN(bpf_per_cpu_ptr), \ FN(bpf_this_cpu_ptr), \ FN(redirect_peer), \ + FN(task_storage_get), \ + FN(task_storage_delete), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c index 5482a9b7ae2d..bed00ca194f0 100644 --- a/tools/lib/bpf/libbpf_probes.c +++ b/tools/lib/bpf/libbpf_probes.c @@ -1,6 +1,7 @@ // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) /* Copyright (c) 2019 Netronome Systems, Inc. */ +#include "linux/bpf.h" #include #include #include @@ -230,6 +231,7 @@ bool bpf_probe_map_type(enum bpf_map_type map_type, __u32 ifindex) break; case BPF_MAP_TYPE_SK_STORAGE: case BPF_MAP_TYPE_INODE_STORAGE: + case BPF_MAP_TYPE_TASK_STORAGE: btf_key_type_id = 1; btf_value_type_id = 3; value_size = 8; From patchwork Tue Oct 27 17:03:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 11861047 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 X-Spam-Level: X-Spam-Status: No, score=-12.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CE0AAC55179 for ; Tue, 27 Oct 2020 17:03:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 74385221F8 for ; 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Tue, 27 Oct 2020 10:03:22 -0700 (PDT) From: KP Singh To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Paul Turner , Jann Horn , Hao Luo Subject: [PATCH bpf-next 2/5] bpf: Implement get_current_task_btf and RET_PTR_TO_BTF_ID Date: Tue, 27 Oct 2020 18:03:14 +0100 Message-Id: <20201027170317.2011119-3-kpsingh@chromium.org> X-Mailer: git-send-email 2.29.0.rc2.309.g374f81d7ae-goog In-Reply-To: <20201027170317.2011119-1-kpsingh@chromium.org> References: <20201027170317.2011119-1-kpsingh@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: KP Singh The currently available bpf_get_current_task returns an unsigned integer which can be used along with BPF_CORE_READ to read data from the task_struct but still cannot be used as an input argument to a helper that accepts an ARG_PTR_TO_BTF_ID of type task_struct. In order to implement this helper a new return type, RET_PTR_TO_BTF_ID, is added. This is similar to RET_PTR_TO_BTF_ID_OR_NULL but does not require checking the nullness of returned pointer. Signed-off-by: KP Singh Reported-by: kernel test robot --- include/linux/bpf.h | 1 + include/uapi/linux/bpf.h | 9 +++++++++ kernel/bpf/verifier.c | 10 +++++++--- kernel/trace/bpf_trace.c | 16 ++++++++++++++++ tools/include/uapi/linux/bpf.h | 9 +++++++++ 5 files changed, 42 insertions(+), 3 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 2b16bf48aab6..05ea8c55d893 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -310,6 +310,7 @@ enum bpf_return_type { RET_PTR_TO_BTF_ID_OR_NULL, /* returns a pointer to a btf_id or NULL */ RET_PTR_TO_MEM_OR_BTF_ID_OR_NULL, /* returns a pointer to a valid memory or a btf_id or NULL */ RET_PTR_TO_MEM_OR_BTF_ID, /* returns a pointer to a valid memory or a btf_id */ + RET_PTR_TO_BTF_ID, /* returns a pointer to a btf_id */ }; /* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index bb443c4f3637..05c997913872 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -3779,6 +3779,14 @@ union bpf_attr { * 0 on success. * * **-ENOENT** if the bpf_local_storage cannot be found. + * + * struct task_struct *bpf_get_current_task_btf(void) + * Description + * Return a BTF pointer to the "current" task. + * This pointer can also be used in helpers that accept an + * *ARG_PTR_TO_BTF_ID* of type *task_struct*. + * Return + * Pointer to the current task. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3939,6 +3947,7 @@ union bpf_attr { FN(redirect_peer), \ FN(task_storage_get), \ FN(task_storage_delete), \ + FN(get_current_task_btf), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index b0790876694f..eb0aef85fc11 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -493,7 +493,8 @@ static bool is_ptr_cast_function(enum bpf_func_id func_id) func_id == BPF_FUNC_skc_to_tcp6_sock || func_id == BPF_FUNC_skc_to_udp6_sock || func_id == BPF_FUNC_skc_to_tcp_timewait_sock || - func_id == BPF_FUNC_skc_to_tcp_request_sock; + func_id == BPF_FUNC_skc_to_tcp_request_sock || + func_id == BPF_FUNC_get_current_task_btf; } /* string representation of 'enum bpf_reg_type' */ @@ -5186,11 +5187,14 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn PTR_TO_BTF_ID : PTR_TO_BTF_ID_OR_NULL; regs[BPF_REG_0].btf_id = meta.ret_btf_id; } - } else if (fn->ret_type == RET_PTR_TO_BTF_ID_OR_NULL) { + } else if (fn->ret_type == RET_PTR_TO_BTF_ID_OR_NULL || + fn->ret_type == RET_PTR_TO_BTF_ID) { int ret_btf_id; mark_reg_known_zero(env, regs, BPF_REG_0); - regs[BPF_REG_0].type = PTR_TO_BTF_ID_OR_NULL; + regs[BPF_REG_0].type = fn->ret_type == RET_PTR_TO_BTF_ID ? + PTR_TO_BTF_ID : + PTR_TO_BTF_ID_OR_NULL; ret_btf_id = *fn->ret_btf_id; if (ret_btf_id == 0) { verbose(env, "invalid return type %d of func %s#%d\n", diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 4517c8b66518..7b48aa1c695a 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1022,6 +1022,20 @@ const struct bpf_func_proto bpf_get_current_task_proto = { .ret_type = RET_INTEGER, }; +BPF_CALL_0(bpf_get_current_task_btf) +{ + return (unsigned long) current; +} + +BTF_ID_LIST_SINGLE(bpf_get_current_btf_ids, struct, task_struct) + +const struct bpf_func_proto bpf_get_current_task_btf_proto = { + .func = bpf_get_current_task_btf, + .gpl_only = true, + .ret_type = RET_PTR_TO_BTF_ID, + .ret_btf_id = &bpf_get_current_btf_ids[0], +}; + BPF_CALL_2(bpf_current_task_under_cgroup, struct bpf_map *, map, u32, idx) { struct bpf_array *array = container_of(map, struct bpf_array, map); @@ -1265,6 +1279,8 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_get_current_pid_tgid_proto; case BPF_FUNC_get_current_task: return &bpf_get_current_task_proto; + case BPF_FUNC_get_current_task_btf: + return &bpf_get_current_task_btf_proto; case BPF_FUNC_get_current_uid_gid: return &bpf_get_current_uid_gid_proto; case BPF_FUNC_get_current_comm: diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index bb443c4f3637..05c997913872 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -3779,6 +3779,14 @@ union bpf_attr { * 0 on success. * * **-ENOENT** if the bpf_local_storage cannot be found. + * + * struct task_struct *bpf_get_current_task_btf(void) + * Description + * Return a BTF pointer to the "current" task. + * This pointer can also be used in helpers that accept an + * *ARG_PTR_TO_BTF_ID* of type *task_struct*. + * Return + * Pointer to the current task. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3939,6 +3947,7 @@ union bpf_attr { FN(redirect_peer), \ FN(task_storage_get), \ FN(task_storage_delete), \ + FN(get_current_task_btf), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper From patchwork Tue Oct 27 17:03:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 11861055 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 X-Spam-Level: X-Spam-Status: No, score=-12.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AE52CC55178 for ; Tue, 27 Oct 2020 17:03:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3C94820809 for ; Tue, 27 Oct 2020 17:03:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="BcP2nYHJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1815604AbgJ0RD1 (ORCPT ); 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Fixes: cd324d7abb3d ("bpf: Add selftests for local_storage") Signed-off-by: KP Singh --- .../testing/selftests/bpf/progs/local_storage.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/tools/testing/selftests/bpf/progs/local_storage.c b/tools/testing/selftests/bpf/progs/local_storage.c index 0758ba229ae0..a3d034eb768e 100644 --- a/tools/testing/selftests/bpf/progs/local_storage.c +++ b/tools/testing/selftests/bpf/progs/local_storage.c @@ -58,6 +58,7 @@ int BPF_PROG(unlink_hook, struct inode *dir, struct dentry *victim) { __u32 pid = bpf_get_current_pid_tgid() >> 32; struct dummy_storage *storage; + int err; if (pid != monitored_pid) return 0; @@ -67,11 +68,12 @@ int BPF_PROG(unlink_hook, struct inode *dir, struct dentry *victim) if (!storage) return 0; - if (storage->value == DUMMY_STORAGE_VALUE) + if (storage->value != DUMMY_STORAGE_VALUE) inode_storage_result = -1; - inode_storage_result = - bpf_inode_storage_delete(&inode_storage_map, victim->d_inode); + err = bpf_inode_storage_delete(&inode_storage_map, victim->d_inode); + if (!err) + inode_storage_result = err; return 0; } @@ -82,6 +84,7 @@ int BPF_PROG(socket_bind, struct socket *sock, struct sockaddr *address, { __u32 pid = bpf_get_current_pid_tgid() >> 32; struct dummy_storage *storage; + int err; if (pid != monitored_pid) return 0; @@ -91,10 +94,13 @@ int BPF_PROG(socket_bind, struct socket *sock, struct sockaddr *address, if (!storage) return 0; - if (storage->value == DUMMY_STORAGE_VALUE) + if (storage->value != DUMMY_STORAGE_VALUE) sk_storage_result = -1; - sk_storage_result = bpf_sk_storage_delete(&sk_storage_map, sock->sk); + err = bpf_sk_storage_delete(&sk_storage_map, sock->sk); + if (!err) + sk_storage_result = err; + return 0; } From patchwork Tue Oct 27 17:03:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 11861049 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 X-Spam-Level: X-Spam-Status: No, score=-12.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 26844C56201 for ; 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Tue, 27 Oct 2020 10:03:25 -0700 (PDT) Received: from kpsingh.zrh.corp.google.com ([81.6.44.51]) by smtp.gmail.com with ESMTPSA id ba6sm1315006edb.61.2020.10.27.10.03.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Oct 2020 10:03:24 -0700 (PDT) From: KP Singh To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Paul Turner , Jann Horn , Hao Luo Subject: [PATCH bpf-next 4/5] bpf: Update selftests for local_storage to use vmlinux.h Date: Tue, 27 Oct 2020 18:03:16 +0100 Message-Id: <20201027170317.2011119-5-kpsingh@chromium.org> X-Mailer: git-send-email 2.29.0.rc2.309.g374f81d7ae-goog In-Reply-To: <20201027170317.2011119-1-kpsingh@chromium.org> References: <20201027170317.2011119-1-kpsingh@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: KP Singh With the fixing of BTF pruning of embedded types being fixed, the test can be simplified to use vmlinux.h Signed-off-by: KP Singh --- .../selftests/bpf/progs/local_storage.c | 20 +------------------ 1 file changed, 1 insertion(+), 19 deletions(-) diff --git a/tools/testing/selftests/bpf/progs/local_storage.c b/tools/testing/selftests/bpf/progs/local_storage.c index a3d034eb768e..5acf9203a69a 100644 --- a/tools/testing/selftests/bpf/progs/local_storage.c +++ b/tools/testing/selftests/bpf/progs/local_storage.c @@ -4,9 +4,8 @@ * Copyright 2020 Google LLC. */ +#include "vmlinux.h" #include -#include -#include #include #include @@ -36,23 +35,6 @@ struct { __type(value, struct dummy_storage); } sk_storage_map SEC(".maps"); -/* TODO Use vmlinux.h once BTF pruning for embedded types is fixed. - */ -struct sock {} __attribute__((preserve_access_index)); -struct sockaddr {} __attribute__((preserve_access_index)); -struct socket { - struct sock *sk; -} __attribute__((preserve_access_index)); - -struct inode {} __attribute__((preserve_access_index)); -struct dentry { - struct inode *d_inode; -} __attribute__((preserve_access_index)); -struct file { - struct inode *f_inode; -} __attribute__((preserve_access_index)); - - SEC("lsm/inode_unlink") int BPF_PROG(unlink_hook, struct inode *dir, struct dentry *victim) { From patchwork Tue Oct 27 17:03:17 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 11861045 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 X-Spam-Level: X-Spam-Status: No, score=-12.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 14DBDC388F9 for ; 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Tue, 27 Oct 2020 10:03:26 -0700 (PDT) Received: from kpsingh.zrh.corp.google.com ([81.6.44.51]) by smtp.gmail.com with ESMTPSA id ba6sm1315006edb.61.2020.10.27.10.03.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Oct 2020 10:03:25 -0700 (PDT) From: KP Singh To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Paul Turner , Jann Horn , Hao Luo Subject: [PATCH bpf-next 5/5] bpf: Add tests for task_local_storage Date: Tue, 27 Oct 2020 18:03:17 +0100 Message-Id: <20201027170317.2011119-6-kpsingh@chromium.org> X-Mailer: git-send-email 2.29.0.rc2.309.g374f81d7ae-goog In-Reply-To: <20201027170317.2011119-1-kpsingh@chromium.org> References: <20201027170317.2011119-1-kpsingh@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: KP Singh The test implements a simple MAC policy which denies an executable from unlinking itself. The LSM program bprm_committed_creds sets a task_local_storage with a pointer to the inode. This is then used to detect if the task is trying to unlink itself in the inode_unlink LSM hook. The test copies /bin/rm to /tmp and executes it in a child thread with the intention of deleting itself. A successful test should prevent the the running executable from deleting itself. The temporary file is cleaned up later in the test. Signed-off-by: KP Singh --- .../bpf/prog_tests/test_local_storage.c | 89 ++++++++++++++++--- .../selftests/bpf/progs/local_storage.c | 44 +++++++-- 2 files changed, 116 insertions(+), 17 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/test_local_storage.c b/tools/testing/selftests/bpf/prog_tests/test_local_storage.c index 91cd6f357246..0e41b27f3471 100644 --- a/tools/testing/selftests/bpf/prog_tests/test_local_storage.c +++ b/tools/testing/selftests/bpf/prog_tests/test_local_storage.c @@ -4,30 +4,83 @@ * Copyright (C) 2020 Google LLC. */ +#define _GNU_SOURCE + +#include +#include +#include #include #include #include "local_storage.skel.h" #include "network_helpers.h" -int create_and_unlink_file(void) +/* Copies an rm binary to a temp file. dest is a mkstemp template */ +int copy_rm(char *dest) { - char fname[PATH_MAX] = "/tmp/fileXXXXXX"; - int fd; + int ret, fd_in, fd_out; + struct stat stat; + + fd_in = open("/bin/rm", O_RDONLY); + if (fd_in < 0) + return fd_in; + + fd_out = mkstemp(dest); + if (fd_out < 0) + return fd_out; - fd = mkstemp(fname); - if (fd < 0) - return fd; + ret = fstat(fd_in, &stat); + if (ret == -1) + return errno; - close(fd); - unlink(fname); + ret = copy_file_range(fd_in, NULL, fd_out, NULL, stat.st_size, 0); + if (ret == -1) + return errno; + + /* Set executable permission on the copied file */ + ret = chmod(dest, 0100); + if (ret == -1) + return errno; + + close(fd_in); + close(fd_out); return 0; } +/* Fork and exec the provided rm binary and return the exit code of the + * forked process and its pid. + */ +int run_self_unlink(int *monitored_pid, const char *rm_path) +{ + int child_pid, child_status, ret; + int null_fd; + + child_pid = fork(); + if (child_pid == 0) { + null_fd = open("/dev/null", O_WRONLY); + dup2(null_fd, STDOUT_FILENO); + dup2(null_fd, STDERR_FILENO); + close(null_fd); + + *monitored_pid = getpid(); + /* Use the copied /usr/bin/rm to delete itself + * /tmp/copy_of_rm /tmp/copy_of_rm. + */ + ret = execlp(rm_path, rm_path, rm_path, NULL); + if (ret) + exit(errno); + } else if (child_pid > 0) { + waitpid(child_pid, &child_status, 0); + return WEXITSTATUS(child_status); + } + + return -EINVAL; +} void test_test_local_storage(void) { struct local_storage *skel = NULL; int err, duration = 0, serv_sk = -1; + char tmp_exec_path[PATH_MAX] = "/tmp/copy_of_rmXXXXXX"; skel = local_storage__open_and_load(); if (CHECK(!skel, "skel_load", "lsm skeleton failed\n")) @@ -37,10 +90,26 @@ void test_test_local_storage(void) if (CHECK(err, "attach", "lsm attach failed: %d\n", err)) goto close_prog; + err = copy_rm(tmp_exec_path); + if (CHECK(err < 0, "copy_executable", "err %d errno %d\n", err, errno)) + goto close_prog; + + /* Sets skel->bss->monitored_pid to the pid of the forked child + * forks a child process that executes tmp_exec_path and tries to + * unlink its executable. This operation should be denied by the loaded + * LSM program. + */ + err = run_self_unlink(&skel->bss->monitored_pid, tmp_exec_path); + if (CHECK(err != EPERM, "run_self_unlink", "err %d want EPERM\n", err)) + goto close_prog; + + /* Set the process being monitored to be the current process */ skel->bss->monitored_pid = getpid(); - err = create_and_unlink_file(); - if (CHECK(err < 0, "exec_cmd", "err %d errno %d\n", err, errno)) + /* Remove the temporary created executable */ + err = unlink(tmp_exec_path); + if (CHECK(err != 0, "unlink", "unable to unlink %s: %d", tmp_exec_path, + errno)) goto close_prog; CHECK(skel->data->inode_storage_result != 0, "inode_storage_result", diff --git a/tools/testing/selftests/bpf/progs/local_storage.c b/tools/testing/selftests/bpf/progs/local_storage.c index 5acf9203a69a..eb280cd0c416 100644 --- a/tools/testing/selftests/bpf/progs/local_storage.c +++ b/tools/testing/selftests/bpf/progs/local_storage.c @@ -17,7 +17,8 @@ int monitored_pid = 0; int inode_storage_result = -1; int sk_storage_result = -1; -struct dummy_storage { +struct local_storage { + struct inode *exec_inode; __u32 value; }; @@ -25,26 +26,40 @@ struct { __uint(type, BPF_MAP_TYPE_INODE_STORAGE); __uint(map_flags, BPF_F_NO_PREALLOC); __type(key, int); - __type(value, struct dummy_storage); + __type(value, struct local_storage); } inode_storage_map SEC(".maps"); struct { __uint(type, BPF_MAP_TYPE_SK_STORAGE); __uint(map_flags, BPF_F_NO_PREALLOC | BPF_F_CLONE); __type(key, int); - __type(value, struct dummy_storage); + __type(value, struct local_storage); } sk_storage_map SEC(".maps"); +struct { + __uint(type, BPF_MAP_TYPE_TASK_STORAGE); + __uint(map_flags, BPF_F_NO_PREALLOC | BPF_F_CLONE); + __type(key, int); + __type(value, struct local_storage); +} task_storage_map SEC(".maps"); + SEC("lsm/inode_unlink") int BPF_PROG(unlink_hook, struct inode *dir, struct dentry *victim) { __u32 pid = bpf_get_current_pid_tgid() >> 32; - struct dummy_storage *storage; + struct local_storage *storage; int err; if (pid != monitored_pid) return 0; + storage = bpf_task_storage_get(&task_storage_map, + bpf_get_current_task_btf(), 0, 0); + + /* Don't let an executable delete itself */ + if (storage && storage->exec_inode == victim->d_inode) + return -EPERM; + storage = bpf_inode_storage_get(&inode_storage_map, victim->d_inode, 0, BPF_SK_STORAGE_GET_F_CREATE); if (!storage) @@ -65,7 +80,7 @@ int BPF_PROG(socket_bind, struct socket *sock, struct sockaddr *address, int addrlen) { __u32 pid = bpf_get_current_pid_tgid() >> 32; - struct dummy_storage *storage; + struct local_storage *storage; int err; if (pid != monitored_pid) @@ -91,7 +106,7 @@ int BPF_PROG(socket_post_create, struct socket *sock, int family, int type, int protocol, int kern) { __u32 pid = bpf_get_current_pid_tgid() >> 32; - struct dummy_storage *storage; + struct local_storage *storage; if (pid != monitored_pid) return 0; @@ -110,7 +125,7 @@ SEC("lsm/file_open") int BPF_PROG(file_open, struct file *file) { __u32 pid = bpf_get_current_pid_tgid() >> 32; - struct dummy_storage *storage; + struct local_storage *storage; if (pid != monitored_pid) return 0; @@ -126,3 +141,18 @@ int BPF_PROG(file_open, struct file *file) storage->value = DUMMY_STORAGE_VALUE; return 0; } + +/* This uses the local storage to remember the inode of the binary that a + * process was originally executing. + */ +SEC("lsm/bprm_committed_creds") +void BPF_PROG(exec, struct linux_binprm *bprm) +{ + struct local_storage *storage; + + storage = bpf_task_storage_get(&task_storage_map, + bpf_get_current_task_btf(), 0, + BPF_LOCAL_STORAGE_GET_F_CREATE); + if (storage) + storage->exec_inode = bprm->file->f_inode; +}