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authorKees Cook <kees+treewide@kernel.org>2026-09-02 15:31:14 -0700
committerKees Cook <kees@kernel.org>2026-09-04 21:37:00 -0700
commit3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d (patch)
treec65086f9bdcd48c6360fb7cb4598bca084da1f32 /fs/anon_inodes.c
downloadlinux-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.c358
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);
+