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| author | Kees Cook <kees+treewide@kernel.org> | 2026-09-02 15:31:14 -0700 |
|---|---|---|
| committer | Kees Cook <kees@kernel.org> | 2026-09-04 21:37:00 -0700 |
| commit | 3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d (patch) | |
| tree | c65086f9bdcd48c6360fb7cb4598bca084da1f32 /fs/anon_inodes.c | |
| download | linux-stable-3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d.tar.gz linux-stable-3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d.zip | |
treewide: refresh kmalloc_obj() conversionsgrafted
This is another run of the Coccinelle script for converting kmalloc()
family of allocations to kmalloc_obj() via the existing rules in
scripts/coccinelle/api/kmalloc_objs.cocci
This catches both the set of kmalloc() uses added since the first
kmalloc_obj() conversions in v7.0 and adds a large group missed in the
first pass due to Coccinelle not interacting well with the cleanup.h
scoped_...() family of macros[1]. I worked around this with spatch's
"--macro-file" argument to a file with all the scoped_...() macros mapped
to Coccinelle's YACFE_ITERATOR[2] as that was the closest viable control
flow indicator I could find.
Build tested allmodconfig on x86, arm64, arm, loongarch, mips, powerpc,
riscv, and s390 with no new warnings.
Link: https://lore.kernel.org/lkml/202609021314.8A9C0B8@keescook/ [1]
Link: https://github.com/coccinelle/coccinelle/blob/master/standard.h [2]
Signed-off-by: Kees Cook <kees+treewide@kernel.org>
Diffstat (limited to 'fs/anon_inodes.c')
| -rw-r--r-- | fs/anon_inodes.c | 358 |
1 files changed, 358 insertions, 0 deletions
diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c new file mode 100644 index 000000000..a7b9b948e --- /dev/null +++ b/fs/anon_inodes.c @@ -0,0 +1,358 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * fs/anon_inodes.c + * + * Copyright (C) 2007 Davide Libenzi <davidel@xmailserver.org> + * + * Thanks to Arnd Bergmann for code review and suggestions. + * More changes for Thomas Gleixner suggestions. + * + */ + +#include <linux/cred.h> +#include <linux/file.h> +#include <linux/poll.h> +#include <linux/sched.h> +#include <linux/init.h> +#include <linux/fs.h> +#include <linux/mount.h> +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/magic.h> +#include <linux/anon_inodes.h> +#include <linux/pseudo_fs.h> + +#include <linux/uaccess.h> + +#include "internal.h" + +static struct vfsmount *anon_inode_mnt __ro_after_init; +static struct inode *anon_inode_inode __ro_after_init; + +/* + * User space expects anonymous inodes to have no file type in st_mode. + * + * In particular, 'lsof' has this legacy logic: + * + * type = s->st_mode & S_IFMT; + * switch (type) { + * ... + * case 0: + * if (!strcmp(p, "anon_inode")) + * Lf->ntype = Ntype = N_ANON_INODE; + * + * to detect our old anon_inode logic. + * + * Rather than mess with our internal sane inode data, just fix it + * up here in getattr() by masking off the format bits. + */ +int anon_inode_getattr(struct mnt_idmap *idmap, const struct path *path, + struct kstat *stat, u32 request_mask, + unsigned int query_flags) +{ + struct inode *inode = d_inode(path->dentry); + + generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat); + stat->mode &= ~S_IFMT; + return 0; +} + +int anon_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry, + struct iattr *attr) +{ + return -EOPNOTSUPP; +} + +static const struct inode_operations anon_inode_operations = { + .getattr = anon_inode_getattr, + .setattr = anon_inode_setattr, +}; + +/* + * 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, +}; + +/** + * anon_inode_make_secure_inode - allocate an anonymous inode with security context + * @sb: [in] Superblock to allocate from + * @name: [in] Name of the class of the newfile (e.g., "secretmem") + * @context_inode: + * [in] Optional parent inode for security inheritance + * + * The function ensures proper security initialization through the LSM hook + * security_inode_init_security_anon(). + * + * Return: Pointer to new inode on success, ERR_PTR on failure. + */ +struct inode *anon_inode_make_secure_inode(struct super_block *sb, const char *name, + const struct inode *context_inode) +{ + struct inode *inode; + int error; + + inode = alloc_anon_inode(sb); + if (IS_ERR(inode)) + return inode; + inode->i_flags &= ~S_PRIVATE; + inode->i_op = &anon_inode_operations; + error = security_inode_init_security_anon(inode, &QSTR(name), + context_inode); + if (error) { + iput(inode); + return ERR_PTR(error); + } + return inode; +} +EXPORT_SYMBOL_FOR_MODULES(anon_inode_make_secure_inode, "kvm"); + +static struct file *__anon_inode_getfile(const char *name, + const struct file_operations *fops, + void *priv, int flags, + const struct inode *context_inode, + bool make_inode) +{ + struct inode *inode; + struct file *file; + + if (fops->owner && !try_module_get(fops->owner)) + return ERR_PTR(-ENOENT); + + if (make_inode) { + inode = anon_inode_make_secure_inode(anon_inode_mnt->mnt_sb, + 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_fmode - 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 + * @f_mode: [in] fmode + * + * 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. Allows setting the fmode. Returns the newly created file* or an error + * pointer. + */ +struct file *anon_inode_getfile_fmode(const char *name, + const struct file_operations *fops, + void *priv, int flags, fmode_t f_mode) +{ + struct file *file; + + file = __anon_inode_getfile(name, fops, priv, flags, NULL, false); + if (!IS_ERR(file)) + file->f_mode |= f_mode; + + return file; +} +EXPORT_SYMBOL_GPL(anon_inode_getfile_fmode); + +/** + * anon_inode_create_getfile - 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. + * + * @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) + * + * Create a new anonymous inode and file pair. This can be done for two + * reasons: + * + * - for the inode to have its own security context, so that LSMs can enforce + * policy on the inode's creation; + * + * - if the caller needs a unique inode, for example in order to customize + * the size returned by fstat() + * + * 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. + */ +struct file *anon_inode_create_getfile(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); +} +EXPORT_SYMBOL_GPL(anon_inode_create_getfile); + +static int __anon_inode_getfd(const char *name, + const struct file_operations *fops, + void *priv, int flags, + const struct inode *context_inode, + bool make_inode) +{ + return FD_ADD(flags, __anon_inode_getfile(name, fops, priv, flags, + context_inode, make_inode)); +} + +/** + * 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_create_getfd - 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. + * + * @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) + * + * Create a new anonymous inode and file pair. This can be done for two + * reasons: + * + * - for the inode to have its own security context, so that LSMs can enforce + * policy on the inode's creation; + * + * - if the caller needs a unique inode, for example in order to customize + * the size returned by fstat() + * + * The LSM may use @context_inode in inode_init_security_anon(), but a + * reference to it is not held. + * + * Returns a newly created file descriptor or an error code. + */ +int anon_inode_create_getfd(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); +} + + +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)); + anon_inode_inode->i_op = &anon_inode_operations; + + return 0; +} + +fs_initcall(anon_inode_init); + |
