diff options
author | Christian Brauner <christian@brauner.io> | 2019-01-21 11:48:05 +0100 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-01-22 12:25:53 +0100 |
commit | 01b3f1fc568352a1ffdcd3ee82a0297f16cc9bd9 (patch) | |
tree | 8af8649554d683e76d9f3fd12e5f0d748ee189e6 /drivers/android/binderfs.c | |
parent | binderfs: rework binderfs_fill_super() (diff) | |
download | linux-01b3f1fc568352a1ffdcd3ee82a0297f16cc9bd9.tar.xz linux-01b3f1fc568352a1ffdcd3ee82a0297f16cc9bd9.zip |
binderfs: rework binderfs_binder_device_create()
- switch from d_alloc_name() + d_lookup() to lookup_one_len():
Instead of using d_alloc_name() and then doing a d_lookup() with the
allocated dentry to find whether a device with the name we're trying to
create already exists switch to using lookup_one_len(). The latter will
either return the existing dentry or a new one.
- switch from kmalloc() + strscpy() to kmemdup():
Use a more idiomatic way to copy the name for the new dentry that
userspace gave us.
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Christian Brauner <christian@brauner.io>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/android/binderfs.c')
-rw-r--r-- | drivers/android/binderfs.c | 39 |
1 files changed, 19 insertions, 20 deletions
diff --git a/drivers/android/binderfs.c b/drivers/android/binderfs.c index 89a2ee1a02f6..1e077498a507 100644 --- a/drivers/android/binderfs.c +++ b/drivers/android/binderfs.c @@ -11,6 +11,7 @@ #include <linux/kdev_t.h> #include <linux/kernel.h> #include <linux/list.h> +#include <linux/namei.h> #include <linux/magic.h> #include <linux/major.h> #include <linux/miscdevice.h> @@ -106,7 +107,7 @@ bool is_binderfs_device(const struct inode *inode) * @userp: buffer to copy information about new device for userspace to * @req: struct binderfs_device as copied from userspace * - * This function allocated a new binder_device and reserves a new minor + * This function allocates a new binder_device and reserves a new minor * number for it. * Minor numbers are limited and tracked globally in binderfs_minors. The * function will stash a struct binder_device for the specific binder @@ -122,10 +123,10 @@ static int binderfs_binder_device_create(struct inode *ref_inode, struct binderfs_device *req) { int minor, ret; - struct dentry *dentry, *dup, *root; + struct dentry *dentry, *root; struct binder_device *device; - size_t name_len = BINDERFS_MAX_NAME + 1; char *name = NULL; + size_t name_len; struct inode *inode = NULL; struct super_block *sb = ref_inode->i_sb; struct binderfs_info *info = sb->s_fs_info; @@ -168,12 +169,13 @@ static int binderfs_binder_device_create(struct inode *ref_inode, inode->i_uid = info->root_uid; inode->i_gid = info->root_gid; - name = kmalloc(name_len, GFP_KERNEL); + req->name[BINDERFS_MAX_NAME] = '\0'; /* NUL-terminate */ + name_len = strlen(req->name); + /* Make sure to include terminating NUL byte */ + name = kmemdup(req->name, name_len + 1, GFP_KERNEL); if (!name) goto err; - strscpy(name, req->name, name_len); - device->binderfs_inode = inode; device->context.binder_context_mgr_uid = INVALID_UID; device->context.name = name; @@ -192,24 +194,21 @@ static int binderfs_binder_device_create(struct inode *ref_inode, root = sb->s_root; inode_lock(d_inode(root)); - dentry = d_alloc_name(root, name); - if (!dentry) { + + /* look it up */ + dentry = lookup_one_len(name, root, name_len); + if (IS_ERR(dentry)) { inode_unlock(d_inode(root)); - ret = -ENOMEM; + ret = PTR_ERR(dentry); goto err; } - /* Verify that the name userspace gave us is not already in use. */ - dup = d_lookup(root, &dentry->d_name); - if (dup) { - if (d_really_is_positive(dup)) { - dput(dup); - dput(dentry); - inode_unlock(d_inode(root)); - ret = -EEXIST; - goto err; - } - dput(dup); + if (d_really_is_positive(dentry)) { + /* already exists */ + dput(dentry); + inode_unlock(d_inode(root)); + ret = -EEXIST; + goto err; } inode->i_private = device; |