From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- fs/anon_inodes.c | 271 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 271 insertions(+) create mode 100644 fs/anon_inodes.c (limited to 'fs/anon_inodes.c') diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c new file mode 100644 index 000000000..24192a766 --- /dev/null +++ b/fs/anon_inodes.c @@ -0,0 +1,271 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * fs/anon_inodes.c + * + * Copyright (C) 2007 Davide Libenzi + * + * Thanks to Arnd Bergmann for code review and suggestions. + * More changes for Thomas Gleixner suggestions. + * + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +static struct vfsmount *anon_inode_mnt __read_mostly; +static struct inode *anon_inode_inode; + +/* + * anon_inodefs_dname() is called from d_path(). + */ +static char *anon_inodefs_dname(struct dentry *dentry, char *buffer, int buflen) +{ + return dynamic_dname(buffer, buflen, "anon_inode:%s", + dentry->d_name.name); +} + +static const struct dentry_operations anon_inodefs_dentry_operations = { + .d_dname = anon_inodefs_dname, +}; + +static int anon_inodefs_init_fs_context(struct fs_context *fc) +{ + struct pseudo_fs_context *ctx = init_pseudo(fc, ANON_INODE_FS_MAGIC); + if (!ctx) + return -ENOMEM; + ctx->dops = &anon_inodefs_dentry_operations; + return 0; +} + +static struct file_system_type anon_inode_fs_type = { + .name = "anon_inodefs", + .init_fs_context = anon_inodefs_init_fs_context, + .kill_sb = kill_anon_super, +}; + +static struct inode *anon_inode_make_secure_inode( + const char *name, + const struct inode *context_inode) +{ + struct inode *inode; + const struct qstr qname = QSTR_INIT(name, strlen(name)); + int error; + + inode = alloc_anon_inode(anon_inode_mnt->mnt_sb); + if (IS_ERR(inode)) + return inode; + inode->i_flags &= ~S_PRIVATE; + error = security_inode_init_security_anon(inode, &qname, context_inode); + if (error) { + iput(inode); + return ERR_PTR(error); + } + return inode; +} + +static struct file *__anon_inode_getfile(const char *name, + const struct file_operations *fops, + void *priv, int flags, + const struct inode *context_inode, + bool secure) +{ + struct inode *inode; + struct file *file; + + if (fops->owner && !try_module_get(fops->owner)) + return ERR_PTR(-ENOENT); + + if (secure) { + inode = anon_inode_make_secure_inode(name, context_inode); + if (IS_ERR(inode)) { + file = ERR_CAST(inode); + goto err; + } + } else { + inode = anon_inode_inode; + if (IS_ERR(inode)) { + file = ERR_PTR(-ENODEV); + goto err; + } + /* + * We know the anon_inode inode count is always + * greater than zero, so ihold() is safe. + */ + ihold(inode); + } + + file = alloc_file_pseudo(inode, anon_inode_mnt, name, + flags & (O_ACCMODE | O_NONBLOCK), fops); + if (IS_ERR(file)) + goto err_iput; + + file->f_mapping = inode->i_mapping; + + file->private_data = priv; + + return file; + +err_iput: + iput(inode); +err: + module_put(fops->owner); + return file; +} + +/** + * anon_inode_getfile - creates a new file instance by hooking it up to an + * anonymous inode, and a dentry that describe the "class" + * of the file + * + * @name: [in] name of the "class" of the new file + * @fops: [in] file operations for the new file + * @priv: [in] private data for the new file (will be file's private_data) + * @flags: [in] flags + * + * Creates a new file by hooking it on a single inode. This is useful for files + * that do not need to have a full-fledged inode in order to operate correctly. + * All the files created with anon_inode_getfile() will share a single inode, + * hence saving memory and avoiding code duplication for the file/inode/dentry + * setup. Returns the newly created file* or an error pointer. + */ +struct file *anon_inode_getfile(const char *name, + const struct file_operations *fops, + void *priv, int flags) +{ + return __anon_inode_getfile(name, fops, priv, flags, NULL, false); +} +EXPORT_SYMBOL_GPL(anon_inode_getfile); + +/** + * anon_inode_getfile_secure - Like anon_inode_getfile(), but creates a new + * !S_PRIVATE anon inode rather than reuse the + * singleton anon inode and calls the + * inode_init_security_anon() LSM hook. This + * allows for both the inode to have its own + * security context and for the LSM to enforce + * policy on the inode's creation. + * + * @name: [in] name of the "class" of the new file + * @fops: [in] file operations for the new file + * @priv: [in] private data for the new file (will be file's private_data) + * @flags: [in] flags + * @context_inode: + * [in] the logical relationship with the new inode (optional) + * + * The LSM may use @context_inode in inode_init_security_anon(), but a + * reference to it is not held. Returns the newly created file* or an error + * pointer. See the anon_inode_getfile() documentation for more information. + */ +struct file *anon_inode_getfile_secure(const char *name, + const struct file_operations *fops, + void *priv, int flags, + const struct inode *context_inode) +{ + return __anon_inode_getfile(name, fops, priv, flags, + context_inode, true); +} + +static int __anon_inode_getfd(const char *name, + const struct file_operations *fops, + void *priv, int flags, + const struct inode *context_inode, + bool secure) +{ + int error, fd; + struct file *file; + + error = get_unused_fd_flags(flags); + if (error < 0) + return error; + fd = error; + + file = __anon_inode_getfile(name, fops, priv, flags, context_inode, + secure); + if (IS_ERR(file)) { + error = PTR_ERR(file); + goto err_put_unused_fd; + } + fd_install(fd, file); + + return fd; + +err_put_unused_fd: + put_unused_fd(fd); + return error; +} + +/** + * anon_inode_getfd - creates a new file instance by hooking it up to + * an anonymous inode and a dentry that describe + * the "class" of the file + * + * @name: [in] name of the "class" of the new file + * @fops: [in] file operations for the new file + * @priv: [in] private data for the new file (will be file's private_data) + * @flags: [in] flags + * + * Creates a new file by hooking it on a single inode. This is + * useful for files that do not need to have a full-fledged inode in + * order to operate correctly. All the files created with + * anon_inode_getfd() will use the same singleton inode, reducing + * memory use and avoiding code duplication for the file/inode/dentry + * setup. Returns a newly created file descriptor or an error code. + */ +int anon_inode_getfd(const char *name, const struct file_operations *fops, + void *priv, int flags) +{ + return __anon_inode_getfd(name, fops, priv, flags, NULL, false); +} +EXPORT_SYMBOL_GPL(anon_inode_getfd); + +/** + * anon_inode_getfd_secure - Like anon_inode_getfd(), but creates a new + * !S_PRIVATE anon inode rather than reuse the singleton anon inode, and calls + * the inode_init_security_anon() LSM hook. This allows the inode to have its + * own security context and for a LSM to reject creation of the inode. + * + * @name: [in] name of the "class" of the new file + * @fops: [in] file operations for the new file + * @priv: [in] private data for the new file (will be file's private_data) + * @flags: [in] flags + * @context_inode: + * [in] the logical relationship with the new inode (optional) + * + * The LSM may use @context_inode in inode_init_security_anon(), but a + * reference to it is not held. + */ +int anon_inode_getfd_secure(const char *name, const struct file_operations *fops, + void *priv, int flags, + const struct inode *context_inode) +{ + return __anon_inode_getfd(name, fops, priv, flags, context_inode, true); +} +EXPORT_SYMBOL_GPL(anon_inode_getfd_secure); + +static int __init anon_inode_init(void) +{ + anon_inode_mnt = kern_mount(&anon_inode_fs_type); + if (IS_ERR(anon_inode_mnt)) + panic("anon_inode_init() kernel mount failed (%ld)\n", PTR_ERR(anon_inode_mnt)); + + anon_inode_inode = alloc_anon_inode(anon_inode_mnt->mnt_sb); + if (IS_ERR(anon_inode_inode)) + panic("anon_inode_init() inode allocation failed (%ld)\n", PTR_ERR(anon_inode_inode)); + + return 0; +} + +fs_initcall(anon_inode_init); + -- cgit v1.2.3