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fc470abf54
Provide userspace with a mechanism to discover features supported by the binder driver to refrain from using any unsupported ones in the first place. Starting with "oneway_spam_detection" only new features are to be listed under binderfs and all previous ones are assumed to be supported. Assuming an instance of binderfs has been mounted at /dev/binderfs, binder feature files can be found under /dev/binderfs/features/. Usage example: $ mkdir /dev/binderfs $ mount -t binder binder /dev/binderfs $ cat /dev/binderfs/features/oneway_spam_detection 1 Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: Carlos Llamas <cmllamas@google.com> Link: https://lore.kernel.org/r/20210715031805.1725878-1-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
845 lines
20 KiB
C
845 lines
20 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/compiler_types.h>
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/fsnotify.h>
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#include <linux/gfp.h>
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#include <linux/idr.h>
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#include <linux/init.h>
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#include <linux/ipc_namespace.h>
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#include <linux/kdev_t.h>
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#include <linux/kernel.h>
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#include <linux/list.h>
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#include <linux/namei.h>
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#include <linux/magic.h>
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#include <linux/major.h>
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#include <linux/miscdevice.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/mount.h>
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#include <linux/fs_parser.h>
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#include <linux/radix-tree.h>
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#include <linux/sched.h>
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#include <linux/seq_file.h>
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#include <linux/slab.h>
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#include <linux/spinlock_types.h>
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#include <linux/stddef.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include <linux/uaccess.h>
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#include <linux/user_namespace.h>
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#include <linux/xarray.h>
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#include <uapi/asm-generic/errno-base.h>
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#include <uapi/linux/android/binder.h>
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#include <uapi/linux/android/binderfs.h>
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#include "binder_internal.h"
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#define FIRST_INODE 1
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#define SECOND_INODE 2
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#define INODE_OFFSET 3
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#define INTSTRLEN 21
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#define BINDERFS_MAX_MINOR (1U << MINORBITS)
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/* Ensure that the initial ipc namespace always has devices available. */
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#define BINDERFS_MAX_MINOR_CAPPED (BINDERFS_MAX_MINOR - 4)
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static dev_t binderfs_dev;
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static DEFINE_MUTEX(binderfs_minors_mutex);
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static DEFINE_IDA(binderfs_minors);
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enum binderfs_param {
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Opt_max,
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Opt_stats_mode,
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};
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enum binderfs_stats_mode {
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binderfs_stats_mode_unset,
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binderfs_stats_mode_global,
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};
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struct binder_features {
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bool oneway_spam_detection;
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};
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static const struct constant_table binderfs_param_stats[] = {
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{ "global", binderfs_stats_mode_global },
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{}
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};
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static const struct fs_parameter_spec binderfs_fs_parameters[] = {
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fsparam_u32("max", Opt_max),
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fsparam_enum("stats", Opt_stats_mode, binderfs_param_stats),
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{}
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};
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static struct binder_features binder_features = {
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.oneway_spam_detection = true,
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};
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static inline struct binderfs_info *BINDERFS_SB(const struct super_block *sb)
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{
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return sb->s_fs_info;
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}
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bool is_binderfs_device(const struct inode *inode)
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{
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if (inode->i_sb->s_magic == BINDERFS_SUPER_MAGIC)
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return true;
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return false;
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}
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/**
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* binderfs_binder_device_create - allocate inode from super block of a
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* binderfs mount
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* @ref_inode: inode from wich the super block will be taken
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* @userp: buffer to copy information about new device for userspace to
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* @req: struct binderfs_device as copied from userspace
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*
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* This function allocates a new binder_device and reserves a new minor
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* number for it.
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* Minor numbers are limited and tracked globally in binderfs_minors. The
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* function will stash a struct binder_device for the specific binder
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* device in i_private of the inode.
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* It will go on to allocate a new inode from the super block of the
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* filesystem mount, stash a struct binder_device in its i_private field
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* and attach a dentry to that inode.
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*
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* Return: 0 on success, negative errno on failure
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*/
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static int binderfs_binder_device_create(struct inode *ref_inode,
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struct binderfs_device __user *userp,
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struct binderfs_device *req)
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{
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int minor, ret;
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struct dentry *dentry, *root;
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struct binder_device *device;
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char *name = NULL;
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size_t name_len;
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struct inode *inode = NULL;
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struct super_block *sb = ref_inode->i_sb;
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struct binderfs_info *info = sb->s_fs_info;
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#if defined(CONFIG_IPC_NS)
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bool use_reserve = (info->ipc_ns == &init_ipc_ns);
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#else
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bool use_reserve = true;
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#endif
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/* Reserve new minor number for the new device. */
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mutex_lock(&binderfs_minors_mutex);
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if (++info->device_count <= info->mount_opts.max)
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minor = ida_alloc_max(&binderfs_minors,
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use_reserve ? BINDERFS_MAX_MINOR :
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BINDERFS_MAX_MINOR_CAPPED,
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GFP_KERNEL);
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else
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minor = -ENOSPC;
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if (minor < 0) {
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--info->device_count;
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mutex_unlock(&binderfs_minors_mutex);
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return minor;
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}
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mutex_unlock(&binderfs_minors_mutex);
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ret = -ENOMEM;
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device = kzalloc(sizeof(*device), GFP_KERNEL);
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if (!device)
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goto err;
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inode = new_inode(sb);
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if (!inode)
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goto err;
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inode->i_ino = minor + INODE_OFFSET;
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inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
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init_special_inode(inode, S_IFCHR | 0600,
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MKDEV(MAJOR(binderfs_dev), minor));
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inode->i_fop = &binder_fops;
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inode->i_uid = info->root_uid;
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inode->i_gid = info->root_gid;
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req->name[BINDERFS_MAX_NAME] = '\0'; /* NUL-terminate */
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name_len = strlen(req->name);
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/* Make sure to include terminating NUL byte */
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name = kmemdup(req->name, name_len + 1, GFP_KERNEL);
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if (!name)
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goto err;
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refcount_set(&device->ref, 1);
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device->binderfs_inode = inode;
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device->context.binder_context_mgr_uid = INVALID_UID;
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device->context.name = name;
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device->miscdev.name = name;
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device->miscdev.minor = minor;
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mutex_init(&device->context.context_mgr_node_lock);
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req->major = MAJOR(binderfs_dev);
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req->minor = minor;
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if (userp && copy_to_user(userp, req, sizeof(*req))) {
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ret = -EFAULT;
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goto err;
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}
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root = sb->s_root;
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inode_lock(d_inode(root));
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/* look it up */
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dentry = lookup_one_len(name, root, name_len);
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if (IS_ERR(dentry)) {
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inode_unlock(d_inode(root));
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ret = PTR_ERR(dentry);
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goto err;
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}
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if (d_really_is_positive(dentry)) {
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/* already exists */
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dput(dentry);
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inode_unlock(d_inode(root));
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ret = -EEXIST;
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goto err;
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}
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inode->i_private = device;
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d_instantiate(dentry, inode);
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fsnotify_create(root->d_inode, dentry);
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inode_unlock(d_inode(root));
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return 0;
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err:
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kfree(name);
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kfree(device);
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mutex_lock(&binderfs_minors_mutex);
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--info->device_count;
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ida_free(&binderfs_minors, minor);
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mutex_unlock(&binderfs_minors_mutex);
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iput(inode);
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return ret;
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}
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/**
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* binderfs_ctl_ioctl - handle binder device node allocation requests
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*
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* The request handler for the binder-control device. All requests operate on
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* the binderfs mount the binder-control device resides in:
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* - BINDER_CTL_ADD
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* Allocate a new binder device.
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*
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* Return: 0 on success, negative errno on failure
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*/
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static long binder_ctl_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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int ret = -EINVAL;
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struct inode *inode = file_inode(file);
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struct binderfs_device __user *device = (struct binderfs_device __user *)arg;
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struct binderfs_device device_req;
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switch (cmd) {
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case BINDER_CTL_ADD:
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ret = copy_from_user(&device_req, device, sizeof(device_req));
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if (ret) {
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ret = -EFAULT;
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break;
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}
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ret = binderfs_binder_device_create(inode, device, &device_req);
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break;
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default:
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break;
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}
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return ret;
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}
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static void binderfs_evict_inode(struct inode *inode)
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{
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struct binder_device *device = inode->i_private;
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struct binderfs_info *info = BINDERFS_SB(inode->i_sb);
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clear_inode(inode);
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if (!S_ISCHR(inode->i_mode) || !device)
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return;
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mutex_lock(&binderfs_minors_mutex);
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--info->device_count;
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ida_free(&binderfs_minors, device->miscdev.minor);
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mutex_unlock(&binderfs_minors_mutex);
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if (refcount_dec_and_test(&device->ref)) {
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kfree(device->context.name);
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kfree(device);
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}
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}
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static int binderfs_fs_context_parse_param(struct fs_context *fc,
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struct fs_parameter *param)
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{
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int opt;
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struct binderfs_mount_opts *ctx = fc->fs_private;
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struct fs_parse_result result;
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opt = fs_parse(fc, binderfs_fs_parameters, param, &result);
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if (opt < 0)
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return opt;
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switch (opt) {
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case Opt_max:
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if (result.uint_32 > BINDERFS_MAX_MINOR)
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return invalfc(fc, "Bad value for '%s'", param->key);
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ctx->max = result.uint_32;
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break;
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case Opt_stats_mode:
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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ctx->stats_mode = result.uint_32;
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break;
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default:
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return invalfc(fc, "Unsupported parameter '%s'", param->key);
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}
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return 0;
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}
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static int binderfs_fs_context_reconfigure(struct fs_context *fc)
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{
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struct binderfs_mount_opts *ctx = fc->fs_private;
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struct binderfs_info *info = BINDERFS_SB(fc->root->d_sb);
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if (info->mount_opts.stats_mode != ctx->stats_mode)
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return invalfc(fc, "Binderfs stats mode cannot be changed during a remount");
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info->mount_opts.stats_mode = ctx->stats_mode;
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info->mount_opts.max = ctx->max;
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return 0;
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}
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static int binderfs_show_options(struct seq_file *seq, struct dentry *root)
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{
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struct binderfs_info *info = BINDERFS_SB(root->d_sb);
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if (info->mount_opts.max <= BINDERFS_MAX_MINOR)
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seq_printf(seq, ",max=%d", info->mount_opts.max);
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switch (info->mount_opts.stats_mode) {
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case binderfs_stats_mode_unset:
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break;
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case binderfs_stats_mode_global:
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seq_printf(seq, ",stats=global");
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break;
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}
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return 0;
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}
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static void binderfs_put_super(struct super_block *sb)
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{
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struct binderfs_info *info = sb->s_fs_info;
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if (info && info->ipc_ns)
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put_ipc_ns(info->ipc_ns);
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kfree(info);
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sb->s_fs_info = NULL;
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}
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static const struct super_operations binderfs_super_ops = {
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.evict_inode = binderfs_evict_inode,
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.show_options = binderfs_show_options,
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.statfs = simple_statfs,
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.put_super = binderfs_put_super,
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};
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static inline bool is_binderfs_control_device(const struct dentry *dentry)
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{
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struct binderfs_info *info = dentry->d_sb->s_fs_info;
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return info->control_dentry == dentry;
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}
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static int binderfs_rename(struct user_namespace *mnt_userns,
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struct inode *old_dir, struct dentry *old_dentry,
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struct inode *new_dir, struct dentry *new_dentry,
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unsigned int flags)
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{
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if (is_binderfs_control_device(old_dentry) ||
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is_binderfs_control_device(new_dentry))
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return -EPERM;
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return simple_rename(&init_user_ns, old_dir, old_dentry, new_dir,
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new_dentry, flags);
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}
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static int binderfs_unlink(struct inode *dir, struct dentry *dentry)
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{
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if (is_binderfs_control_device(dentry))
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return -EPERM;
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return simple_unlink(dir, dentry);
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}
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static const struct file_operations binder_ctl_fops = {
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.owner = THIS_MODULE,
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.open = nonseekable_open,
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.unlocked_ioctl = binder_ctl_ioctl,
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.compat_ioctl = binder_ctl_ioctl,
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.llseek = noop_llseek,
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};
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/**
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* binderfs_binder_ctl_create - create a new binder-control device
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* @sb: super block of the binderfs mount
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*
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* This function creates a new binder-control device node in the binderfs mount
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* referred to by @sb.
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*
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* Return: 0 on success, negative errno on failure
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*/
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static int binderfs_binder_ctl_create(struct super_block *sb)
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{
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int minor, ret;
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struct dentry *dentry;
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struct binder_device *device;
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struct inode *inode = NULL;
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struct dentry *root = sb->s_root;
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struct binderfs_info *info = sb->s_fs_info;
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#if defined(CONFIG_IPC_NS)
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bool use_reserve = (info->ipc_ns == &init_ipc_ns);
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#else
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bool use_reserve = true;
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#endif
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device = kzalloc(sizeof(*device), GFP_KERNEL);
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if (!device)
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return -ENOMEM;
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/* If we have already created a binder-control node, return. */
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if (info->control_dentry) {
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ret = 0;
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goto out;
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}
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ret = -ENOMEM;
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inode = new_inode(sb);
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if (!inode)
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goto out;
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/* Reserve a new minor number for the new device. */
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mutex_lock(&binderfs_minors_mutex);
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minor = ida_alloc_max(&binderfs_minors,
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use_reserve ? BINDERFS_MAX_MINOR :
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BINDERFS_MAX_MINOR_CAPPED,
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GFP_KERNEL);
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mutex_unlock(&binderfs_minors_mutex);
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if (minor < 0) {
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ret = minor;
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goto out;
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}
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inode->i_ino = SECOND_INODE;
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inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
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init_special_inode(inode, S_IFCHR | 0600,
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MKDEV(MAJOR(binderfs_dev), minor));
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inode->i_fop = &binder_ctl_fops;
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inode->i_uid = info->root_uid;
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inode->i_gid = info->root_gid;
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refcount_set(&device->ref, 1);
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device->binderfs_inode = inode;
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device->miscdev.minor = minor;
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dentry = d_alloc_name(root, "binder-control");
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if (!dentry)
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goto out;
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inode->i_private = device;
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info->control_dentry = dentry;
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d_add(dentry, inode);
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return 0;
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out:
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kfree(device);
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iput(inode);
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return ret;
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}
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|
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static const struct inode_operations binderfs_dir_inode_operations = {
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.lookup = simple_lookup,
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.rename = binderfs_rename,
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.unlink = binderfs_unlink,
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};
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static struct inode *binderfs_make_inode(struct super_block *sb, int mode)
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{
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struct inode *ret;
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ret = new_inode(sb);
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if (ret) {
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ret->i_ino = iunique(sb, BINDERFS_MAX_MINOR + INODE_OFFSET);
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ret->i_mode = mode;
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ret->i_atime = ret->i_mtime = ret->i_ctime = current_time(ret);
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}
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return ret;
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}
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|
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static struct dentry *binderfs_create_dentry(struct dentry *parent,
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const char *name)
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{
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struct dentry *dentry;
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dentry = lookup_one_len(name, parent, strlen(name));
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if (IS_ERR(dentry))
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return dentry;
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|
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/* Return error if the file/dir already exists. */
|
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if (d_really_is_positive(dentry)) {
|
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dput(dentry);
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return ERR_PTR(-EEXIST);
|
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}
|
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|
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return dentry;
|
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}
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|
|
void binderfs_remove_file(struct dentry *dentry)
|
|
{
|
|
struct inode *parent_inode;
|
|
|
|
parent_inode = d_inode(dentry->d_parent);
|
|
inode_lock(parent_inode);
|
|
if (simple_positive(dentry)) {
|
|
dget(dentry);
|
|
simple_unlink(parent_inode, dentry);
|
|
d_delete(dentry);
|
|
dput(dentry);
|
|
}
|
|
inode_unlock(parent_inode);
|
|
}
|
|
|
|
struct dentry *binderfs_create_file(struct dentry *parent, const char *name,
|
|
const struct file_operations *fops,
|
|
void *data)
|
|
{
|
|
struct dentry *dentry;
|
|
struct inode *new_inode, *parent_inode;
|
|
struct super_block *sb;
|
|
|
|
parent_inode = d_inode(parent);
|
|
inode_lock(parent_inode);
|
|
|
|
dentry = binderfs_create_dentry(parent, name);
|
|
if (IS_ERR(dentry))
|
|
goto out;
|
|
|
|
sb = parent_inode->i_sb;
|
|
new_inode = binderfs_make_inode(sb, S_IFREG | 0444);
|
|
if (!new_inode) {
|
|
dput(dentry);
|
|
dentry = ERR_PTR(-ENOMEM);
|
|
goto out;
|
|
}
|
|
|
|
new_inode->i_fop = fops;
|
|
new_inode->i_private = data;
|
|
d_instantiate(dentry, new_inode);
|
|
fsnotify_create(parent_inode, dentry);
|
|
|
|
out:
|
|
inode_unlock(parent_inode);
|
|
return dentry;
|
|
}
|
|
|
|
static struct dentry *binderfs_create_dir(struct dentry *parent,
|
|
const char *name)
|
|
{
|
|
struct dentry *dentry;
|
|
struct inode *new_inode, *parent_inode;
|
|
struct super_block *sb;
|
|
|
|
parent_inode = d_inode(parent);
|
|
inode_lock(parent_inode);
|
|
|
|
dentry = binderfs_create_dentry(parent, name);
|
|
if (IS_ERR(dentry))
|
|
goto out;
|
|
|
|
sb = parent_inode->i_sb;
|
|
new_inode = binderfs_make_inode(sb, S_IFDIR | 0755);
|
|
if (!new_inode) {
|
|
dput(dentry);
|
|
dentry = ERR_PTR(-ENOMEM);
|
|
goto out;
|
|
}
|
|
|
|
new_inode->i_fop = &simple_dir_operations;
|
|
new_inode->i_op = &simple_dir_inode_operations;
|
|
|
|
set_nlink(new_inode, 2);
|
|
d_instantiate(dentry, new_inode);
|
|
inc_nlink(parent_inode);
|
|
fsnotify_mkdir(parent_inode, dentry);
|
|
|
|
out:
|
|
inode_unlock(parent_inode);
|
|
return dentry;
|
|
}
|
|
|
|
static int binder_features_show(struct seq_file *m, void *unused)
|
|
{
|
|
bool *feature = m->private;
|
|
|
|
seq_printf(m, "%d\n", *feature);
|
|
|
|
return 0;
|
|
}
|
|
DEFINE_SHOW_ATTRIBUTE(binder_features);
|
|
|
|
static int init_binder_features(struct super_block *sb)
|
|
{
|
|
struct dentry *dentry, *dir;
|
|
|
|
dir = binderfs_create_dir(sb->s_root, "features");
|
|
if (IS_ERR(dir))
|
|
return PTR_ERR(dir);
|
|
|
|
dentry = binderfs_create_file(dir, "oneway_spam_detection",
|
|
&binder_features_fops,
|
|
&binder_features.oneway_spam_detection);
|
|
if (IS_ERR(dentry))
|
|
return PTR_ERR(dentry);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int init_binder_logs(struct super_block *sb)
|
|
{
|
|
struct dentry *binder_logs_root_dir, *dentry, *proc_log_dir;
|
|
struct binderfs_info *info;
|
|
int ret = 0;
|
|
|
|
binder_logs_root_dir = binderfs_create_dir(sb->s_root,
|
|
"binder_logs");
|
|
if (IS_ERR(binder_logs_root_dir)) {
|
|
ret = PTR_ERR(binder_logs_root_dir);
|
|
goto out;
|
|
}
|
|
|
|
dentry = binderfs_create_file(binder_logs_root_dir, "stats",
|
|
&binder_stats_fops, NULL);
|
|
if (IS_ERR(dentry)) {
|
|
ret = PTR_ERR(dentry);
|
|
goto out;
|
|
}
|
|
|
|
dentry = binderfs_create_file(binder_logs_root_dir, "state",
|
|
&binder_state_fops, NULL);
|
|
if (IS_ERR(dentry)) {
|
|
ret = PTR_ERR(dentry);
|
|
goto out;
|
|
}
|
|
|
|
dentry = binderfs_create_file(binder_logs_root_dir, "transactions",
|
|
&binder_transactions_fops, NULL);
|
|
if (IS_ERR(dentry)) {
|
|
ret = PTR_ERR(dentry);
|
|
goto out;
|
|
}
|
|
|
|
dentry = binderfs_create_file(binder_logs_root_dir,
|
|
"transaction_log",
|
|
&binder_transaction_log_fops,
|
|
&binder_transaction_log);
|
|
if (IS_ERR(dentry)) {
|
|
ret = PTR_ERR(dentry);
|
|
goto out;
|
|
}
|
|
|
|
dentry = binderfs_create_file(binder_logs_root_dir,
|
|
"failed_transaction_log",
|
|
&binder_transaction_log_fops,
|
|
&binder_transaction_log_failed);
|
|
if (IS_ERR(dentry)) {
|
|
ret = PTR_ERR(dentry);
|
|
goto out;
|
|
}
|
|
|
|
proc_log_dir = binderfs_create_dir(binder_logs_root_dir, "proc");
|
|
if (IS_ERR(proc_log_dir)) {
|
|
ret = PTR_ERR(proc_log_dir);
|
|
goto out;
|
|
}
|
|
info = sb->s_fs_info;
|
|
info->proc_log_dir = proc_log_dir;
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static int binderfs_fill_super(struct super_block *sb, struct fs_context *fc)
|
|
{
|
|
int ret;
|
|
struct binderfs_info *info;
|
|
struct binderfs_mount_opts *ctx = fc->fs_private;
|
|
struct inode *inode = NULL;
|
|
struct binderfs_device device_info = {};
|
|
const char *name;
|
|
size_t len;
|
|
|
|
sb->s_blocksize = PAGE_SIZE;
|
|
sb->s_blocksize_bits = PAGE_SHIFT;
|
|
|
|
/*
|
|
* The binderfs filesystem can be mounted by userns root in a
|
|
* non-initial userns. By default such mounts have the SB_I_NODEV flag
|
|
* set in s_iflags to prevent security issues where userns root can
|
|
* just create random device nodes via mknod() since it owns the
|
|
* filesystem mount. But binderfs does not allow to create any files
|
|
* including devices nodes. The only way to create binder devices nodes
|
|
* is through the binder-control device which userns root is explicitly
|
|
* allowed to do. So removing the SB_I_NODEV flag from s_iflags is both
|
|
* necessary and safe.
|
|
*/
|
|
sb->s_iflags &= ~SB_I_NODEV;
|
|
sb->s_iflags |= SB_I_NOEXEC;
|
|
sb->s_magic = BINDERFS_SUPER_MAGIC;
|
|
sb->s_op = &binderfs_super_ops;
|
|
sb->s_time_gran = 1;
|
|
|
|
sb->s_fs_info = kzalloc(sizeof(struct binderfs_info), GFP_KERNEL);
|
|
if (!sb->s_fs_info)
|
|
return -ENOMEM;
|
|
info = sb->s_fs_info;
|
|
|
|
info->ipc_ns = get_ipc_ns(current->nsproxy->ipc_ns);
|
|
|
|
info->root_gid = make_kgid(sb->s_user_ns, 0);
|
|
if (!gid_valid(info->root_gid))
|
|
info->root_gid = GLOBAL_ROOT_GID;
|
|
info->root_uid = make_kuid(sb->s_user_ns, 0);
|
|
if (!uid_valid(info->root_uid))
|
|
info->root_uid = GLOBAL_ROOT_UID;
|
|
info->mount_opts.max = ctx->max;
|
|
info->mount_opts.stats_mode = ctx->stats_mode;
|
|
|
|
inode = new_inode(sb);
|
|
if (!inode)
|
|
return -ENOMEM;
|
|
|
|
inode->i_ino = FIRST_INODE;
|
|
inode->i_fop = &simple_dir_operations;
|
|
inode->i_mode = S_IFDIR | 0755;
|
|
inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
|
|
inode->i_op = &binderfs_dir_inode_operations;
|
|
set_nlink(inode, 2);
|
|
|
|
sb->s_root = d_make_root(inode);
|
|
if (!sb->s_root)
|
|
return -ENOMEM;
|
|
|
|
ret = binderfs_binder_ctl_create(sb);
|
|
if (ret)
|
|
return ret;
|
|
|
|
name = binder_devices_param;
|
|
for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) {
|
|
strscpy(device_info.name, name, len + 1);
|
|
ret = binderfs_binder_device_create(inode, NULL, &device_info);
|
|
if (ret)
|
|
return ret;
|
|
name += len;
|
|
if (*name == ',')
|
|
name++;
|
|
}
|
|
|
|
ret = init_binder_features(sb);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (info->mount_opts.stats_mode == binderfs_stats_mode_global)
|
|
return init_binder_logs(sb);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int binderfs_fs_context_get_tree(struct fs_context *fc)
|
|
{
|
|
return get_tree_nodev(fc, binderfs_fill_super);
|
|
}
|
|
|
|
static void binderfs_fs_context_free(struct fs_context *fc)
|
|
{
|
|
struct binderfs_mount_opts *ctx = fc->fs_private;
|
|
|
|
kfree(ctx);
|
|
}
|
|
|
|
static const struct fs_context_operations binderfs_fs_context_ops = {
|
|
.free = binderfs_fs_context_free,
|
|
.get_tree = binderfs_fs_context_get_tree,
|
|
.parse_param = binderfs_fs_context_parse_param,
|
|
.reconfigure = binderfs_fs_context_reconfigure,
|
|
};
|
|
|
|
static int binderfs_init_fs_context(struct fs_context *fc)
|
|
{
|
|
struct binderfs_mount_opts *ctx;
|
|
|
|
ctx = kzalloc(sizeof(struct binderfs_mount_opts), GFP_KERNEL);
|
|
if (!ctx)
|
|
return -ENOMEM;
|
|
|
|
ctx->max = BINDERFS_MAX_MINOR;
|
|
ctx->stats_mode = binderfs_stats_mode_unset;
|
|
|
|
fc->fs_private = ctx;
|
|
fc->ops = &binderfs_fs_context_ops;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct file_system_type binder_fs_type = {
|
|
.name = "binder",
|
|
.init_fs_context = binderfs_init_fs_context,
|
|
.parameters = binderfs_fs_parameters,
|
|
.kill_sb = kill_litter_super,
|
|
.fs_flags = FS_USERNS_MOUNT,
|
|
};
|
|
|
|
int __init init_binderfs(void)
|
|
{
|
|
int ret;
|
|
const char *name;
|
|
size_t len;
|
|
|
|
/* Verify that the default binderfs device names are valid. */
|
|
name = binder_devices_param;
|
|
for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) {
|
|
if (len > BINDERFS_MAX_NAME)
|
|
return -E2BIG;
|
|
name += len;
|
|
if (*name == ',')
|
|
name++;
|
|
}
|
|
|
|
/* Allocate new major number for binderfs. */
|
|
ret = alloc_chrdev_region(&binderfs_dev, 0, BINDERFS_MAX_MINOR,
|
|
"binder");
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = register_filesystem(&binder_fs_type);
|
|
if (ret) {
|
|
unregister_chrdev_region(binderfs_dev, BINDERFS_MAX_MINOR);
|
|
return ret;
|
|
}
|
|
|
|
return ret;
|
|
}
|