From patchwork Tue Jun 25 21:52:34 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= X-Patchwork-Id: 11016513 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 958D4112C for ; Tue, 25 Jun 2019 22:14:05 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8712228471 for ; Tue, 25 Jun 2019 22:14:05 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 784B8209CD; Tue, 25 Jun 2019 22:14:05 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0F539209CD for ; Tue, 25 Jun 2019 22:14:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726387AbfFYWN6 (ORCPT ); Tue, 25 Jun 2019 18:13:58 -0400 Received: from smtp-sh.infomaniak.ch ([128.65.195.4]:53472 "EHLO smtp-sh.infomaniak.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725782AbfFYWN5 (ORCPT ); Tue, 25 Jun 2019 18:13:57 -0400 Received: from smtp5.infomaniak.ch (smtp5.infomaniak.ch [83.166.132.18]) by smtp-sh.infomaniak.ch (8.14.5/8.14.5) with ESMTP id x5PLrLve019831 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 25 Jun 2019 23:53:21 +0200 Received: from localhost (ns3096276.ip-94-23-54.eu [94.23.54.103]) (authenticated bits=0) by smtp5.infomaniak.ch (8.14.5/8.14.5) with ESMTP id x5PLrLhB038785; Tue, 25 Jun 2019 23:53:21 +0200 From: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= To: linux-kernel@vger.kernel.org Cc: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Aleksa Sarai , Alexander Viro , Alexei Starovoitov , Andrew Morton , Andy Lutomirski , Arnaldo Carvalho de Melo , Casey Schaufler , Daniel Borkmann , David Drysdale , "David S . Miller" , "Eric W . Biederman" , James Morris , Jann Horn , John Johansen , Jonathan Corbet , Kees Cook , Michael Kerrisk , =?utf-8?q?Micka=C3=ABl_Sala=C3=BC?= =?utf-8?q?n?= , Paul Moore , Sargun Dhillon , "Serge E . Hallyn" , Shuah Khan , Stephen Smalley , Tejun Heo , Tetsuo Handa , Thomas Graf , Tycho Andersen , Will Drewry , kernel-hardening@lists.openwall.com, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH bpf-next v9 05/10] bpf,landlock: Add a new map type: inode Date: Tue, 25 Jun 2019 23:52:34 +0200 Message-Id: <20190625215239.11136-6-mic@digikod.net> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190625215239.11136-1-mic@digikod.net> References: <20190625215239.11136-1-mic@digikod.net> MIME-Version: 1.0 X-Antivirus: Dr.Web (R) for Unix mail servers drweb plugin ver.6.0.2.8 X-Antivirus-Code: 0x100000 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This new map store arbitrary 64-bits values referenced by inode keys. The map can be updated from user space with file descriptor pointing to inodes tied to a file system. From an eBPF (Landlock) program point of view, such a map is read-only and can only be used to retrieved a 64-bits value tied to a given inode. This is useful to recognize an inode tagged by user space, without access right to this inode (i.e. no need to have a write access to this inode). Add dedicated BPF functions to handle this type of map: * bpf_inode_map_update_elem() * bpf_inode_map_lookup_elem() * bpf_inode_map_delete_elem() Signed-off-by: Mickaël Salaün Cc: Alexei Starovoitov Cc: Andy Lutomirski Cc: Daniel Borkmann Cc: David S. Miller Cc: James Morris Cc: Kees Cook Cc: Serge E. Hallyn Cc: Jann Horn --- Changes since v8: * remove prog chaining and object tagging to ease review * use bpf_map_init_from_attr() Changes since v7: * new design with a dedicated map and a BPF function to tie a value to an inode * add the ability to set or get a tag on an inode from a Landlock program Changes since v6: * remove WARN_ON() for missing dentry->d_inode * refactor bpf_landlock_func_proto() (suggested by Kees Cook) Changes since v5: * cosmetic fixes and rebase Changes since v4: * use a file abstraction (handle) to wrap inode, dentry, path and file structs * remove bpf_landlock_cmp_fs_beneath() * rename the BPF helper and move it to kernel/bpf/ * tighten helpers accessible by a Landlock rule Changes since v3: * remove bpf_landlock_cmp_fs_prop() (suggested by Alexei Starovoitov) * add hooks dealing with struct inode and struct path pointers: inode_permission and inode_getattr * add abstraction over eBPF helper arguments thanks to wrapping structs * add bpf_landlock_get_fs_mode() helper to check file type and mode * merge WARN_ON() (suggested by Kees Cook) * fix and update bpf_helpers.h * use BPF_CALL_* for eBPF helpers (suggested by Alexei Starovoitov) * make handle arraymap safe (RCU) and remove buggy synchronize_rcu() * factor out the arraymay walk * use size_t to index array (suggested by Jann Horn) Changes since v2: * add MNT_INTERNAL check to only add file handle from user-visible FS (e.g. no anonymous inode) * replace struct file* with struct path* in map_landlock_handle * add BPF protos * fix bpf_landlock_cmp_fs_prop_with_struct_file() --- include/linux/bpf.h | 9 + include/linux/bpf_types.h | 3 + include/uapi/linux/bpf.h | 12 +- kernel/bpf/Makefile | 3 + kernel/bpf/core.c | 2 + kernel/bpf/inodemap.c | 315 +++++++++++++++++++++++++++++++++ kernel/bpf/syscall.c | 27 ++- kernel/bpf/verifier.c | 14 ++ tools/include/uapi/linux/bpf.h | 12 +- tools/lib/bpf/libbpf_probes.c | 1 + 10 files changed, 395 insertions(+), 3 deletions(-) create mode 100644 kernel/bpf/inodemap.c diff --git a/include/linux/bpf.h b/include/linux/bpf.h index da167d3afecc..cc72ec18f0f6 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -208,6 +208,8 @@ enum bpf_arg_type { ARG_PTR_TO_INT, /* pointer to int */ ARG_PTR_TO_LONG, /* pointer to long */ ARG_PTR_TO_SOCKET, /* pointer to bpf_sock (fullsock) */ + + ARG_PTR_TO_INODE, /* pointer to a struct inode */ }; /* type of values returned from helper functions */ @@ -278,6 +280,7 @@ enum bpf_reg_type { PTR_TO_TCP_SOCK_OR_NULL, /* reg points to struct tcp_sock or NULL */ PTR_TO_TP_BUFFER, /* reg points to a writable raw tp's buffer */ PTR_TO_XDP_SOCK, /* reg points to struct xdp_sock */ + PTR_TO_INODE, /* reg points to struct inode */ }; /* The information passed from prog-specific *_is_valid_access @@ -485,6 +488,7 @@ struct bpf_event_entry { struct rcu_head rcu; }; + bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp); int bpf_prog_calc_tag(struct bpf_prog *fp); @@ -689,6 +693,10 @@ int bpf_fd_array_map_lookup_elem(struct bpf_map *map, void *key, u32 *value); int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file, void *key, void *value, u64 map_flags); int bpf_fd_htab_map_lookup_elem(struct bpf_map *map, void *key, u32 *value); +int bpf_inode_map_update_elem(struct bpf_map *map, int *key, u64 *value, + u64 flags); +int bpf_inode_map_lookup_elem(struct bpf_map *map, int *key, u64 *value); +int bpf_inode_map_delete_elem(struct bpf_map *map, int *key); int bpf_get_file_flag(int flags); int bpf_check_uarg_tail_zero(void __user *uaddr, size_t expected_size, @@ -1059,6 +1067,7 @@ extern const struct bpf_func_proto bpf_spin_unlock_proto; extern const struct bpf_func_proto bpf_get_local_storage_proto; extern const struct bpf_func_proto bpf_strtol_proto; extern const struct bpf_func_proto bpf_strtoul_proto; +extern const struct bpf_func_proto bpf_inode_map_lookup_proto; /* Shared helpers among cBPF and eBPF. */ void bpf_user_rnd_init_once(void); diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h index dee8b82e31b1..9e385473b57a 100644 --- a/include/linux/bpf_types.h +++ b/include/linux/bpf_types.h @@ -79,3 +79,6 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_REUSEPORT_SOCKARRAY, reuseport_array_ops) #endif BPF_MAP_TYPE(BPF_MAP_TYPE_QUEUE, queue_map_ops) BPF_MAP_TYPE(BPF_MAP_TYPE_STACK, stack_map_ops) +#ifdef CONFIG_SECURITY_LANDLOCK +BPF_MAP_TYPE(BPF_MAP_TYPE_INODE, inode_ops) +#endif diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 50145d448bc3..08ff720835ba 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -134,6 +134,7 @@ enum bpf_map_type { BPF_MAP_TYPE_QUEUE, BPF_MAP_TYPE_STACK, BPF_MAP_TYPE_SK_STORAGE, + BPF_MAP_TYPE_INODE, }; /* Note that tracing related programs such as @@ -2716,6 +2717,14 @@ union bpf_attr { * **-EPERM** if no permission to send the *sig*. * * **-EAGAIN** if bpf program can try again. + * + * u64 bpf_inode_map_lookup(map, key) + * Description + * Perform a lookup in *map* for an entry associated to an inode + * *key*. + * Return + * Map value associated to *key*, or **NULL** if no entry was + * found. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -2827,7 +2836,8 @@ union bpf_attr { FN(strtoul), \ FN(sk_storage_get), \ FN(sk_storage_delete), \ - FN(send_signal), + FN(send_signal), \ + FN(inode_map_lookup), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile index 29d781061cd5..e6fe613b3105 100644 --- a/kernel/bpf/Makefile +++ b/kernel/bpf/Makefile @@ -22,3 +22,6 @@ obj-$(CONFIG_CGROUP_BPF) += cgroup.o ifeq ($(CONFIG_INET),y) obj-$(CONFIG_BPF_SYSCALL) += reuseport_array.o endif +ifeq ($(CONFIG_SECURITY_LANDLOCK),y) +obj-$(CONFIG_BPF_SYSCALL) += inodemap.o +endif diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 8ad392e52328..3cf5d16a8496 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -2032,6 +2032,8 @@ const struct bpf_func_proto bpf_get_current_comm_proto __weak; const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak; const struct bpf_func_proto bpf_get_local_storage_proto __weak; +const struct bpf_func_proto bpf_inode_map_update_proto __weak; + const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) { return NULL; diff --git a/kernel/bpf/inodemap.c b/kernel/bpf/inodemap.c new file mode 100644 index 000000000000..fcad0de51557 --- /dev/null +++ b/kernel/bpf/inodemap.c @@ -0,0 +1,315 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * inode map for Landlock + * + * Copyright © 2017-2019 Mickaël Salaün + * Copyright © 2019 ANSSI + */ + +#include /* RLIMIT_NOFILE */ +#include +#include +#include /* fput() */ +#include /* BPF_CALL_2() */ +#include /* struct file */ +#include +#include /* MNT_INTERNAL */ +#include /* struct path */ +#include /* rlimit() */ +#include +#include + +struct inode_elem { + struct inode *inode; + u64 value; +}; + +struct inode_array { + struct bpf_map map; + size_t nb_entries; + struct inode_elem elems[0]; +}; + +/* must call iput(inode) after this call */ +static struct inode *inode_from_fd(int ufd, bool check_access) +{ + struct inode *ret; + struct fd f; + int deny; + + f = fdget(ufd); + if (unlikely(!f.file || !file_inode(f.file))) { + ret = ERR_PTR(-EBADF); + goto put_fd; + } + /* TODO: add this check when called from an eBPF program too (already + * checked by the LSM parent hooks anyway) */ + if (unlikely(IS_PRIVATE(file_inode(f.file)))) { + ret = ERR_PTR(-EINVAL); + goto put_fd; + } + /* check if the FD is tied to a mount point */ + /* TODO: add this check when called from an eBPF program too */ + if (unlikely(!f.file->f_path.mnt || f.file->f_path.mnt->mnt_flags & + MNT_INTERNAL)) { + ret = ERR_PTR(-EINVAL); + goto put_fd; + } + if (check_access) { + /* + * need to be allowed to access attributes from this file to + * then be able to compare an inode to this entry + */ + deny = security_inode_getattr(&f.file->f_path); + if (deny) { + ret = ERR_PTR(deny); + goto put_fd; + } + } + ret = file_inode(f.file); + ihold(ret); + +put_fd: + fdput(f); + return ret; +} + +/* (never) called from eBPF program */ +static int fake_map_delete_elem(struct bpf_map *map, void *key) +{ + WARN_ON(1); + return -EINVAL; +} + +/* called from syscall */ +static int sys_inode_map_delete_elem(struct bpf_map *map, struct inode *key) +{ + struct inode_array *array = container_of(map, struct inode_array, map); + struct inode *inode; + int i; + + WARN_ON_ONCE(!rcu_read_lock_held()); + for (i = 0; i < array->map.max_entries; i++) { + if (array->elems[i].inode == key) { + inode = xchg(&array->elems[i].inode, NULL); + array->nb_entries--; + iput(inode); + return 0; + } + } + return -ENOENT; +} + +/* called from syscall */ +int bpf_inode_map_delete_elem(struct bpf_map *map, int *key) +{ + struct inode *inode; + int err; + + inode = inode_from_fd(*key, false); + if (IS_ERR(inode)) + return PTR_ERR(inode); + err = sys_inode_map_delete_elem(map, inode); + iput(inode); + return err; +} + +static void inode_map_free(struct bpf_map *map) +{ + struct inode_array *array = container_of(map, struct inode_array, map); + int i; + + synchronize_rcu(); + for (i = 0; i < array->map.max_entries; i++) + iput(array->elems[i].inode); + bpf_map_area_free(array); +} + +static struct bpf_map *inode_map_alloc(union bpf_attr *attr) +{ + int numa_node = bpf_map_attr_numa_node(attr); + struct inode_array *array; + u64 array_size; + + /* only allow root to create this type of map (for now), should be + * removed when Landlock will be usable by unprivileged users */ + if (!capable(CAP_SYS_ADMIN)) + return ERR_PTR(-EPERM); + + /* the key is a file descriptor and the value must be 64-bits (for + * now) */ + if (attr->max_entries == 0 || attr->key_size != sizeof(u32) || + attr->value_size != FIELD_SIZEOF(struct inode_elem, value) || + attr->map_flags & ~(BPF_F_RDONLY | BPF_F_WRONLY) || + numa_node != NUMA_NO_NODE) + return ERR_PTR(-EINVAL); + + if (attr->value_size > KMALLOC_MAX_SIZE) + /* if value_size is bigger, the user space won't be able to + * access the elements. + */ + return ERR_PTR(-E2BIG); + + /* + * Limit number of entries in an inode map to the maximum number of + * open files for the current process. The maximum number of file + * references (including all inode maps) for a process is then + * (RLIMIT_NOFILE - 1) * RLIMIT_NOFILE. If the process' RLIMIT_NOFILE + * is 0, then any entry update is forbidden. + * + * An eBPF program can inherit all the inode map FD. The worse case is + * to fill a bunch of arraymaps, create an eBPF program, close the + * inode map FDs, and start again. The maximum number of inode map + * entries can then be close to RLIMIT_NOFILE^3. + */ + if (attr->max_entries > rlimit(RLIMIT_NOFILE)) + return ERR_PTR(-EMFILE); + + array_size = sizeof(*array); + array_size += (u64) attr->max_entries * sizeof(struct inode_elem); + + /* make sure there is no u32 overflow later in round_up() */ + if (array_size >= U32_MAX - PAGE_SIZE) + return ERR_PTR(-ENOMEM); + + /* allocate all map elements and zero-initialize them */ + array = bpf_map_area_alloc(array_size, numa_node); + if (!array) + return ERR_PTR(-ENOMEM); + + /* copy mandatory map attributes */ + bpf_map_init_from_attr(&array->map, attr); + array->map.memory.pages = round_up(array_size, PAGE_SIZE) >> PAGE_SHIFT; + + return &array->map; +} + +/* (never) called from eBPF program */ +static void *fake_map_lookup_elem(struct bpf_map *map, void *key) +{ + WARN_ON(1); + return ERR_PTR(-EINVAL); +} + +/* called from syscall (wrapped) and eBPF program */ +static u64 inode_map_lookup_elem(struct bpf_map *map, struct inode *key) +{ + struct inode_array *array = container_of(map, struct inode_array, map); + size_t i; + u64 ret = 0; + + WARN_ON_ONCE(!rcu_read_lock_held()); + /* TODO: use rbtree to switch to O(log n) */ + for (i = 0; i < array->map.max_entries; i++) { + if (array->elems[i].inode == key) { + ret = array->elems[i].value; + break; + } + } + return ret; +} + +/* + * The key is a FD when called from a syscall, but an inode pointer when called + * from an eBPF program. + */ + +/* called from syscall */ +int bpf_inode_map_lookup_elem(struct bpf_map *map, int *key, u64 *value) +{ + struct inode *inode; + + inode = inode_from_fd(*key, false); + if (IS_ERR(inode)) + return PTR_ERR(inode); + *value = inode_map_lookup_elem(map, inode); + iput(inode); + if (!value) + return -ENOENT; + return 0; +} + +/* (never) called from eBPF program */ +static int fake_map_update_elem(struct bpf_map *map, void *key, void *value, + u64 flags) +{ + WARN_ON(1); + /* do not leak an inode accessed by a Landlock program */ + return -EINVAL; +} + +/* called from syscall */ +static int sys_inode_map_update_elem(struct bpf_map *map, struct inode *key, + u64 *value, u64 flags) +{ + struct inode_array *array = container_of(map, struct inode_array, map); + size_t i; + + if (unlikely(flags != BPF_ANY)) + return -EINVAL; + + if (unlikely(array->nb_entries >= array->map.max_entries)) + /* all elements were pre-allocated, cannot insert a new one */ + return -E2BIG; + + for (i = 0; i < array->map.max_entries; i++) { + if (!array->elems[i].inode) { + /* the inode (key) is already grabbed by the caller */ + ihold(key); + array->elems[i].inode = key; + array->elems[i].value = *value; + array->nb_entries++; + return 0; + } + } + WARN_ON(1); + return -ENOENT; +} + +/* called from syscall */ +int bpf_inode_map_update_elem(struct bpf_map *map, int *key, u64 *value, + u64 flags) +{ + struct inode *inode; + int err; + + WARN_ON_ONCE(!rcu_read_lock_held()); + inode = inode_from_fd(*key, true); + if (IS_ERR(inode)) + return PTR_ERR(inode); + err = sys_inode_map_update_elem(map, inode, value, flags); + iput(inode); + return err; +} + +/* called from syscall or (never) from eBPF program */ +static int fake_map_get_next_key(struct bpf_map *map, void *key, + void *next_key) +{ + /* do not leak a file descriptor */ + return -EINVAL; +} + +/* void map for eBPF program */ +const struct bpf_map_ops inode_ops = { + .map_alloc = inode_map_alloc, + .map_free = inode_map_free, + .map_get_next_key = fake_map_get_next_key, + .map_lookup_elem = fake_map_lookup_elem, + .map_delete_elem = fake_map_delete_elem, + .map_update_elem = fake_map_update_elem, +}; + +BPF_CALL_2(bpf_inode_map_lookup, struct bpf_map *, map, void *, key) +{ + WARN_ON_ONCE(!rcu_read_lock_held()); + return inode_map_lookup_elem(map, key); +} + +const struct bpf_func_proto bpf_inode_map_lookup_proto = { + .func = bpf_inode_map_lookup, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_CONST_MAP_PTR, + .arg2_type = ARG_PTR_TO_INODE, +}; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 7dd3376904d4..ba2a09a7f813 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -720,6 +720,22 @@ static void *__bpf_copy_key(void __user *ukey, u64 key_size) return NULL; } +int __weak bpf_inode_map_update_elem(struct bpf_map *map, int *key, + u64 *value, u64 flags) +{ + return -ENOTSUPP; +} + +int __weak bpf_inode_map_lookup_elem(struct bpf_map *map, int *key, u64 *value) +{ + return -ENOTSUPP; +} + +int __weak bpf_inode_map_delete_elem(struct bpf_map *map, int *key) +{ + return -ENOTSUPP; +} + /* last field in 'union bpf_attr' used by this command */ #define BPF_MAP_LOOKUP_ELEM_LAST_FIELD flags @@ -801,6 +817,8 @@ static int map_lookup_elem(union bpf_attr *attr) } else if (map->map_type == BPF_MAP_TYPE_QUEUE || map->map_type == BPF_MAP_TYPE_STACK) { err = map->ops->map_peek_elem(map, value); + } else if (map->map_type == BPF_MAP_TYPE_INODE) { + err = bpf_inode_map_lookup_elem(map, key, value); } else { rcu_read_lock(); if (map->ops->map_lookup_elem_sys_only) @@ -951,6 +969,10 @@ static int map_update_elem(union bpf_attr *attr) } else if (map->map_type == BPF_MAP_TYPE_QUEUE || map->map_type == BPF_MAP_TYPE_STACK) { err = map->ops->map_push_elem(map, value, attr->flags); + } else if (map->map_type == BPF_MAP_TYPE_INODE) { + rcu_read_lock(); + err = bpf_inode_map_update_elem(map, key, value, attr->flags); + rcu_read_unlock(); } else { rcu_read_lock(); err = map->ops->map_update_elem(map, key, value, attr->flags); @@ -1006,7 +1028,10 @@ static int map_delete_elem(union bpf_attr *attr) preempt_disable(); __this_cpu_inc(bpf_prog_active); rcu_read_lock(); - err = map->ops->map_delete_elem(map, key); + if (map->map_type == BPF_MAP_TYPE_INODE) + err = bpf_inode_map_delete_elem(map, key); + else + err = map->ops->map_delete_elem(map, key); rcu_read_unlock(); __this_cpu_dec(bpf_prog_active); preempt_enable(); diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 930260683d0a..ce3cd7fd8882 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -400,6 +400,7 @@ static const char * const reg_type_str[] = { [PTR_TO_TCP_SOCK_OR_NULL] = "tcp_sock_or_null", [PTR_TO_TP_BUFFER] = "tp_buffer", [PTR_TO_XDP_SOCK] = "xdp_sock", + [PTR_TO_INODE] = "inode", }; static char slot_type_char[] = { @@ -1801,6 +1802,7 @@ static bool is_spillable_regtype(enum bpf_reg_type type) case PTR_TO_TCP_SOCK: case PTR_TO_TCP_SOCK_OR_NULL: case PTR_TO_XDP_SOCK: + case PTR_TO_INODE: return true; default: return false; @@ -3254,6 +3256,10 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, verbose(env, "verifier internal error\n"); return -EFAULT; } + } else if (arg_type == ARG_PTR_TO_INODE) { + expected_type = PTR_TO_INODE; + if (type != expected_type) + goto err_type; } else if (arg_type_is_mem_ptr(arg_type)) { expected_type = PTR_TO_STACK; /* One exception here. In case function allows for NULL to be @@ -3462,6 +3468,10 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env, func_id != BPF_FUNC_sk_storage_delete) goto error; break; + case BPF_MAP_TYPE_INODE: + if (func_id != BPF_FUNC_inode_map_lookup) + goto error; + break; default: break; } @@ -3530,6 +3540,10 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env, if (map->map_type != BPF_MAP_TYPE_SK_STORAGE) goto error; break; + case BPF_FUNC_inode_map_lookup: + if (map->map_type != BPF_MAP_TYPE_INODE) + goto error; + break; default: break; } diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 50145d448bc3..08ff720835ba 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -134,6 +134,7 @@ enum bpf_map_type { BPF_MAP_TYPE_QUEUE, BPF_MAP_TYPE_STACK, BPF_MAP_TYPE_SK_STORAGE, + BPF_MAP_TYPE_INODE, }; /* Note that tracing related programs such as @@ -2716,6 +2717,14 @@ union bpf_attr { * **-EPERM** if no permission to send the *sig*. * * **-EAGAIN** if bpf program can try again. + * + * u64 bpf_inode_map_lookup(map, key) + * Description + * Perform a lookup in *map* for an entry associated to an inode + * *key*. + * Return + * Map value associated to *key*, or **NULL** if no entry was + * found. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -2827,7 +2836,8 @@ union bpf_attr { FN(strtoul), \ FN(sk_storage_get), \ FN(sk_storage_delete), \ - FN(send_signal), + FN(send_signal), \ + FN(inode_map_lookup), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c index f4f34cb8869a..000319a95bfb 100644 --- a/tools/lib/bpf/libbpf_probes.c +++ b/tools/lib/bpf/libbpf_probes.c @@ -249,6 +249,7 @@ bool bpf_probe_map_type(enum bpf_map_type map_type, __u32 ifindex) case BPF_MAP_TYPE_XSKMAP: case BPF_MAP_TYPE_SOCKHASH: case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY: + case BPF_MAP_TYPE_INODE: default: break; }