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Date: Tue, 25 Jun 2019 23:52:34 +0200
From: Mickaël Salaün <mic@...ikod.net>
To: linux-kernel@...r.kernel.org
Cc: Mickaël Salaün <mic@...ikod.net>,
Aleksa Sarai <cyphar@...har.com>,
Alexander Viro <viro@...iv.linux.org.uk>,
Alexei Starovoitov <ast@...nel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Andy Lutomirski <luto@...capital.net>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Casey Schaufler <casey@...aufler-ca.com>,
Daniel Borkmann <daniel@...earbox.net>,
David Drysdale <drysdale@...gle.com>,
"David S . Miller" <davem@...emloft.net>,
"Eric W . Biederman" <ebiederm@...ssion.com>,
James Morris <jmorris@...ei.org>, Jann Horn <jann@...jh.net>,
John Johansen <john.johansen@...onical.com>,
Jonathan Corbet <corbet@....net>, Kees Cook <keescook@...omium.org>,
Michael Kerrisk <mtk.manpages@...il.com>,
Mickaël Salaün <mickael.salaun@....gouv.fr>,
Paul Moore <paul@...l-moore.com>, Sargun Dhillon <sargun@...gun.me>,
"Serge E . Hallyn" <serge@...lyn.com>, Shuah Khan <shuah@...nel.org>,
Stephen Smalley <sds@...ho.nsa.gov>, Tejun Heo <tj@...nel.org>,
Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>,
Thomas Graf <tgraf@...g.ch>, Tycho Andersen <tycho@...ho.ws>,
Will Drewry <wad@...omium.org>, kernel-hardening@...ts.openwall.com,
linux-api@...r.kernel.org, linux-fsdevel@...r.kernel.org,
linux-security-module@...r.kernel.org, netdev@...r.kernel.org
Subject: [PATCH bpf-next v9 05/10] bpf,landlock: Add a new map type: inode
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 <mic@...ikod.net>
Cc: Alexei Starovoitov <ast@...nel.org>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Daniel Borkmann <daniel@...earbox.net>
Cc: David S. Miller <davem@...emloft.net>
Cc: James Morris <jmorris@...ei.org>
Cc: Kees Cook <keescook@...omium.org>
Cc: Serge E. Hallyn <serge@...lyn.com>
Cc: Jann Horn <jann@...jh.net>
---
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 <mic@...ikod.net>
+ * Copyright © 2019 ANSSI
+ */
+
+#include <asm/resource.h> /* RLIMIT_NOFILE */
+#include <linux/bpf.h>
+#include <linux/err.h>
+#include <linux/file.h> /* fput() */
+#include <linux/filter.h> /* BPF_CALL_2() */
+#include <linux/fs.h> /* struct file */
+#include <linux/mm.h>
+#include <linux/mount.h> /* MNT_INTERNAL */
+#include <linux/path.h> /* struct path */
+#include <linux/sched/signal.h> /* rlimit() */
+#include <linux/security.h>
+#include <linux/slab.h>
+
+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;
}
--
2.20.1
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