Merge branch 'next' into for-linus

Prepare first round of input updates for 3.20.

1 files changed, 606 insertions, 0 deletions

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
new file mode 100644
index 000000000000..088ac0b1b106
--- /dev/null
+++ b/kernel/bpf/syscall.c
@@ -0,0 +1,606 @@
+/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+#include <linux/bpf.h>
+#include <linux/syscalls.h>
+#include <linux/slab.h>
+#include <linux/anon_inodes.h>
+#include <linux/file.h>
+#include <linux/license.h>
+#include <linux/filter.h>
+
+static LIST_HEAD(bpf_map_types);
+
+static struct bpf_map *find_and_alloc_map(union bpf_attr *attr)
+{
+        struct bpf_map_type_list *tl;
+        struct bpf_map *map;
+
+        list_for_each_entry(tl, &bpf_map_types, list_node) {
+                if (tl->type == attr->map_type) {
+                        map = tl->ops->map_alloc(attr);
+                        if (IS_ERR(map))
+                                return map;
+                        map->ops = tl->ops;
+                        map->map_type = attr->map_type;
+                        return map;
+                }
+        }
+        return ERR_PTR(-EINVAL);
+}
+
+/* boot time registration of different map implementations */
+void bpf_register_map_type(struct bpf_map_type_list *tl)
+{
+        list_add(&tl->list_node, &bpf_map_types);
+}
+
+/* called from workqueue */
+static void bpf_map_free_deferred(struct work_struct *work)
+{
+        struct bpf_map *map = container_of(work, struct bpf_map, work);
+
+        /* implementation dependent freeing */
+        map->ops->map_free(map);
+}
+
+/* decrement map refcnt and schedule it for freeing via workqueue
+ * (unrelying map implementation ops->map_free() might sleep)
+ */
+void bpf_map_put(struct bpf_map *map)
+{
+        if (atomic_dec_and_test(&map->refcnt)) {
+                INIT_WORK(&map->work, bpf_map_free_deferred);
+                schedule_work(&map->work);
+        }
+}
+
+static int bpf_map_release(struct inode *inode, struct file *filp)
+{
+        struct bpf_map *map = filp->private_data;
+
+        bpf_map_put(map);
+        return 0;
+}
+
+static const struct file_operations bpf_map_fops = {
+        .release = bpf_map_release,
+};
+
+/* helper macro to check that unused fields 'union bpf_attr' are zero */
+#define CHECK_ATTR(CMD) \
+        memchr_inv((void *) &attr->CMD##_LAST_FIELD + \
+                   sizeof(attr->CMD##_LAST_FIELD), 0, \
+                   sizeof(*attr) - \
+                   offsetof(union bpf_attr, CMD##_LAST_FIELD) - \
+                   sizeof(attr->CMD##_LAST_FIELD)) != NULL
+
+#define BPF_MAP_CREATE_LAST_FIELD max_entries
+/* called via syscall */
+static int map_create(union bpf_attr *attr)
+{
+        struct bpf_map *map;
+        int err;
+
+        err = CHECK_ATTR(BPF_MAP_CREATE);
+        if (err)
+                return -EINVAL;
+
+        /* find map type and init map: hashtable vs rbtree vs bloom vs ... */
+        map = find_and_alloc_map(attr);
+        if (IS_ERR(map))
+                return PTR_ERR(map);
+
+        atomic_set(&map->refcnt, 1);
+
+        err = anon_inode_getfd("bpf-map", &bpf_map_fops, map, O_RDWR | O_CLOEXEC);
+
+        if (err < 0)
+                /* failed to allocate fd */
+                goto free_map;
+
+        return err;
+
+free_map:
+        map->ops->map_free(map);
+        return err;
+}
+
+/* if error is returned, fd is released.
+ * On success caller should complete fd access with matching fdput()
+ */
+struct bpf_map *bpf_map_get(struct fd f)
+{
+        struct bpf_map *map;
+
+        if (!f.file)
+                return ERR_PTR(-EBADF);
+
+        if (f.file->f_op != &bpf_map_fops) {
+                fdput(f);
+                return ERR_PTR(-EINVAL);
+        }
+
+        map = f.file->private_data;
+
+        return map;
+}
+
+/* helper to convert user pointers passed inside __aligned_u64 fields */
+static void __user *u64_to_ptr(__u64 val)
+{
+        return (void __user *) (unsigned long) val;
+}
+
+/* last field in 'union bpf_attr' used by this command */
+#define BPF_MAP_LOOKUP_ELEM_LAST_FIELD value
+
+static int map_lookup_elem(union bpf_attr *attr)
+{
+        void __user *ukey = u64_to_ptr(attr->key);
+        void __user *uvalue = u64_to_ptr(attr->value);
+        int ufd = attr->map_fd;
+        struct fd f = fdget(ufd);
+        struct bpf_map *map;
+        void *key, *value;
+        int err;
+
+        if (CHECK_ATTR(BPF_MAP_LOOKUP_ELEM))
+                return -EINVAL;
+
+        map = bpf_map_get(f);
+        if (IS_ERR(map))
+                return PTR_ERR(map);
+
+        err = -ENOMEM;
+        key = kmalloc(map->key_size, GFP_USER);
+        if (!key)
+                goto err_put;
+
+        err = -EFAULT;
+        if (copy_from_user(key, ukey, map->key_size) != 0)
+                goto free_key;
+
+        err = -ENOENT;
+        rcu_read_lock();
+        value = map->ops->map_lookup_elem(map, key);
+        if (!value)
+                goto err_unlock;
+
+        err = -EFAULT;
+        if (copy_to_user(uvalue, value, map->value_size) != 0)
+                goto err_unlock;
+
+        err = 0;
+
+err_unlock:
+        rcu_read_unlock();
+free_key:
+        kfree(key);
+err_put:
+        fdput(f);
+        return err;
+}
+
+#define BPF_MAP_UPDATE_ELEM_LAST_FIELD flags
+
+static int map_update_elem(union bpf_attr *attr)
+{
+        void __user *ukey = u64_to_ptr(attr->key);
+        void __user *uvalue = u64_to_ptr(attr->value);
+        int ufd = attr->map_fd;
+        struct fd f = fdget(ufd);
+        struct bpf_map *map;
+        void *key, *value;
+        int err;
+
+        if (CHECK_ATTR(BPF_MAP_UPDATE_ELEM))
+                return -EINVAL;
+
+        map = bpf_map_get(f);
+        if (IS_ERR(map))
+                return PTR_ERR(map);
+
+        err = -ENOMEM;
+        key = kmalloc(map->key_size, GFP_USER);
+        if (!key)
+                goto err_put;
+
+        err = -EFAULT;
+        if (copy_from_user(key, ukey, map->key_size) != 0)
+                goto free_key;
+
+        err = -ENOMEM;
+        value = kmalloc(map->value_size, GFP_USER);
+        if (!value)
+                goto free_key;
+
+        err = -EFAULT;
+        if (copy_from_user(value, uvalue, map->value_size) != 0)
+                goto free_value;
+
+        /* eBPF program that use maps are running under rcu_read_lock(),
+         * therefore all map accessors rely on this fact, so do the same here
+         */
+        rcu_read_lock();
+        err = map->ops->map_update_elem(map, key, value, attr->flags);
+        rcu_read_unlock();
+
+free_value:
+        kfree(value);
+free_key:
+        kfree(key);
+err_put:
+        fdput(f);
+        return err;
+}
+
+#define BPF_MAP_DELETE_ELEM_LAST_FIELD key
+
+static int map_delete_elem(union bpf_attr *attr)
+{
+        void __user *ukey = u64_to_ptr(attr->key);
+        int ufd = attr->map_fd;
+        struct fd f = fdget(ufd);
+        struct bpf_map *map;
+        void *key;
+        int err;
+
+        if (CHECK_ATTR(BPF_MAP_DELETE_ELEM))
+                return -EINVAL;
+
+        map = bpf_map_get(f);
+        if (IS_ERR(map))
+                return PTR_ERR(map);
+
+        err = -ENOMEM;
+        key = kmalloc(map->key_size, GFP_USER);
+        if (!key)
+                goto err_put;
+
+        err = -EFAULT;
+        if (copy_from_user(key, ukey, map->key_size) != 0)
+                goto free_key;
+
+        rcu_read_lock();
+        err = map->ops->map_delete_elem(map, key);
+        rcu_read_unlock();
+
+free_key:
+        kfree(key);
+err_put:
+        fdput(f);
+        return err;
+}
+
+/* last field in 'union bpf_attr' used by this command */
+#define BPF_MAP_GET_NEXT_KEY_LAST_FIELD next_key
+
+static int map_get_next_key(union bpf_attr *attr)
+{
+        void __user *ukey = u64_to_ptr(attr->key);
+        void __user *unext_key = u64_to_ptr(attr->next_key);
+        int ufd = attr->map_fd;
+        struct fd f = fdget(ufd);
+        struct bpf_map *map;
+        void *key, *next_key;
+        int err;
+
+        if (CHECK_ATTR(BPF_MAP_GET_NEXT_KEY))
+                return -EINVAL;
+
+        map = bpf_map_get(f);
+        if (IS_ERR(map))
+                return PTR_ERR(map);
+
+        err = -ENOMEM;
+        key = kmalloc(map->key_size, GFP_USER);
+        if (!key)
+                goto err_put;
+
+        err = -EFAULT;
+        if (copy_from_user(key, ukey, map->key_size) != 0)
+                goto free_key;
+
+        err = -ENOMEM;
+        next_key = kmalloc(map->key_size, GFP_USER);
+        if (!next_key)
+                goto free_key;
+
+        rcu_read_lock();
+        err = map->ops->map_get_next_key(map, key, next_key);
+        rcu_read_unlock();
+        if (err)
+                goto free_next_key;
+
+        err = -EFAULT;
+        if (copy_to_user(unext_key, next_key, map->key_size) != 0)
+                goto free_next_key;
+
+        err = 0;
+
+free_next_key:
+        kfree(next_key);
+free_key:
+        kfree(key);
+err_put:
+        fdput(f);
+        return err;
+}
+
+static LIST_HEAD(bpf_prog_types);
+
+static int find_prog_type(enum bpf_prog_type type, struct bpf_prog *prog)
+{
+        struct bpf_prog_type_list *tl;
+
+        list_for_each_entry(tl, &bpf_prog_types, list_node) {
+                if (tl->type == type) {
+                        prog->aux->ops = tl->ops;
+                        prog->aux->prog_type = type;
+                        return 0;
+                }
+        }
+        return -EINVAL;
+}
+
+void bpf_register_prog_type(struct bpf_prog_type_list *tl)
+{
+        list_add(&tl->list_node, &bpf_prog_types);
+}
+
+/* fixup insn->imm field of bpf_call instructions:
+ * if (insn->imm == BPF_FUNC_map_lookup_elem)
+ *      insn->imm = bpf_map_lookup_elem - __bpf_call_base;
+ * else if (insn->imm == BPF_FUNC_map_update_elem)
+ *      insn->imm = bpf_map_update_elem - __bpf_call_base;
+ * else ...
+ *
+ * this function is called after eBPF program passed verification
+ */
+static void fixup_bpf_calls(struct bpf_prog *prog)
+{
+        const struct bpf_func_proto *fn;
+        int i;
+
+        for (i = 0; i < prog->len; i++) {
+                struct bpf_insn *insn = &prog->insnsi[i];
+
+                if (insn->code == (BPF_JMP | BPF_CALL)) {
+                        /* we reach here when program has bpf_call instructions
+                         * and it passed bpf_check(), means that
+                         * ops->get_func_proto must have been supplied, check it
+                         */
+                        BUG_ON(!prog->aux->ops->get_func_proto);
+
+                        fn = prog->aux->ops->get_func_proto(insn->imm);
+                        /* all functions that have prototype and verifier allowed
+                         * programs to call them, must be real in-kernel functions
+                         */
+                        BUG_ON(!fn->func);
+                        insn->imm = fn->func - __bpf_call_base;
+                }
+        }
+}
+
+/* drop refcnt on maps used by eBPF program and free auxilary data */
+static void free_used_maps(struct bpf_prog_aux *aux)
+{
+        int i;
+
+        for (i = 0; i < aux->used_map_cnt; i++)
+                bpf_map_put(aux->used_maps[i]);
+
+        kfree(aux->used_maps);
+}
+
+void bpf_prog_put(struct bpf_prog *prog)
+{
+        if (atomic_dec_and_test(&prog->aux->refcnt)) {
+                free_used_maps(prog->aux);
+                bpf_prog_free(prog);
+        }
+}
+
+static int bpf_prog_release(struct inode *inode, struct file *filp)
+{
+        struct bpf_prog *prog = filp->private_data;
+
+        bpf_prog_put(prog);
+        return 0;
+}
+
+static const struct file_operations bpf_prog_fops = {
+        .release = bpf_prog_release,
+};
+
+static struct bpf_prog *get_prog(struct fd f)
+{
+        struct bpf_prog *prog;
+
+        if (!f.file)
+                return ERR_PTR(-EBADF);
+
+        if (f.file->f_op != &bpf_prog_fops) {
+                fdput(f);
+                return ERR_PTR(-EINVAL);
+        }
+
+        prog = f.file->private_data;
+
+        return prog;
+}
+
+/* called by sockets/tracing/seccomp before attaching program to an event
+ * pairs with bpf_prog_put()
+ */
+struct bpf_prog *bpf_prog_get(u32 ufd)
+{
+        struct fd f = fdget(ufd);
+        struct bpf_prog *prog;
+
+        prog = get_prog(f);
+
+        if (IS_ERR(prog))
+                return prog;
+
+        atomic_inc(&prog->aux->refcnt);
+        fdput(f);
+        return prog;
+}
+
+/* last field in 'union bpf_attr' used by this command */
+#define BPF_PROG_LOAD_LAST_FIELD log_buf
+
+static int bpf_prog_load(union bpf_attr *attr)
+{
+        enum bpf_prog_type type = attr->prog_type;
+        struct bpf_prog *prog;
+        int err;
+        char license[128];
+        bool is_gpl;
+
+        if (CHECK_ATTR(BPF_PROG_LOAD))
+                return -EINVAL;
+
+        /* copy eBPF program license from user space */
+        if (strncpy_from_user(license, u64_to_ptr(attr->license),
+                              sizeof(license) - 1) < 0)
+                return -EFAULT;
+        license[sizeof(license) - 1] = 0;
+
+        /* eBPF programs must be GPL compatible to use GPL-ed functions */
+        is_gpl = license_is_gpl_compatible(license);
+
+        if (attr->insn_cnt >= BPF_MAXINSNS)
+                return -EINVAL;
+
+        /* plain bpf_prog allocation */
+        prog = bpf_prog_alloc(bpf_prog_size(attr->insn_cnt), GFP_USER);
+        if (!prog)
+                return -ENOMEM;
+
+        prog->len = attr->insn_cnt;
+
+        err = -EFAULT;
+        if (copy_from_user(prog->insns, u64_to_ptr(attr->insns),
+                           prog->len * sizeof(struct bpf_insn)) != 0)
+                goto free_prog;
+
+        prog->orig_prog = NULL;
+        prog->jited = false;
+
+        atomic_set(&prog->aux->refcnt, 1);
+        prog->aux->is_gpl_compatible = is_gpl;
+
+        /* find program type: socket_filter vs tracing_filter */
+        err = find_prog_type(type, prog);
+        if (err < 0)
+                goto free_prog;
+
+        /* run eBPF verifier */
+        err = bpf_check(prog, attr);
+
+        if (err < 0)
+                goto free_used_maps;
+
+        /* fixup BPF_CALL->imm field */
+        fixup_bpf_calls(prog);
+
+        /* eBPF program is ready to be JITed */
+        bpf_prog_select_runtime(prog);
+
+        err = anon_inode_getfd("bpf-prog", &bpf_prog_fops, prog, O_RDWR | O_CLOEXEC);
+
+        if (err < 0)
+                /* failed to allocate fd */
+                goto free_used_maps;
+
+        return err;
+
+free_used_maps:
+        free_used_maps(prog->aux);
+free_prog:
+        bpf_prog_free(prog);
+        return err;
+}
+
+SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size)
+{
+        union bpf_attr attr = {};
+        int err;
+
+        /* the syscall is limited to root temporarily. This restriction will be
+         * lifted when security audit is clean. Note that eBPF+tracing must have
+         * this restriction, since it may pass kernel data to user space
+         */
+        if (!capable(CAP_SYS_ADMIN))
+                return -EPERM;
+
+        if (!access_ok(VERIFY_READ, uattr, 1))
+                return -EFAULT;
+
+        if (size > PAGE_SIZE)   /* silly large */
+                return -E2BIG;
+
+        /* If we're handed a bigger struct than we know of,
+         * ensure all the unknown bits are 0 - i.e. new
+         * user-space does not rely on any kernel feature
+         * extensions we dont know about yet.
+         */
+        if (size > sizeof(attr)) {
+                unsigned char __user *addr;
+                unsigned char __user *end;
+                unsigned char val;
+
+                addr = (void __user *)uattr + sizeof(attr);
+                end  = (void __user *)uattr + size;
+
+                for (; addr < end; addr++) {
+                        err = get_user(val, addr);
+                        if (err)
+                                return err;
+                        if (val)
+                                return -E2BIG;
+                }
+                size = sizeof(attr);
+        }
+
+        /* copy attributes from user space, may be less than sizeof(bpf_attr) */
+        if (copy_from_user(&attr, uattr, size) != 0)
+                return -EFAULT;
+
+        switch (cmd) {
+        case BPF_MAP_CREATE:
+                err = map_create(&attr);
+                break;
+        case BPF_MAP_LOOKUP_ELEM:
+                err = map_lookup_elem(&attr);
+                break;
+        case BPF_MAP_UPDATE_ELEM:
+                err = map_update_elem(&attr);
+                break;
+        case BPF_MAP_DELETE_ELEM:
+                err = map_delete_elem(&attr);
+                break;
+        case BPF_MAP_GET_NEXT_KEY:
+                err = map_get_next_key(&attr);
+                break;
+        case BPF_PROG_LOAD:
+                err = bpf_prog_load(&attr);
+                break;
+        default:
+                err = -EINVAL;
+                break;
+        }
+
+        return err;
+}