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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
commit4352b8aee98005853aa63f57d6377282de17a33f (patch)
tree27614d7a9ef05c32d089004e104364ce42324837 /fs/anon_inodes.c
downloadlinux-stable-4352b8aee98005853aa63f57d6377282de17a33f.tar.gz
linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.zip
Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni: "A new driver this cycle, for the AMD AXI I3C controller. There are also new features such as IBI wakeup support, SETAASA device discovery and ACPI support for the the DAA methods, meaning we can now communicate with the SPD devices on DDR5 modules. New driver: - AMD AXI I3C master controller Subsystem: - I3C Common Command Code (CCC) handling improvements, especially around GET CCCs - SETAASA device discovery support - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as well as I2C devices on I3C bus - IBI-based wakeup support Drivers: - dw: SETAASA support - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C controller support, PIO queue management support for HCI v1.2 - renesas: improve suspend to RAM support, add runtime PM support" * tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits) i3c: dw: reduce do_daa time if there's no client i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2 i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode i3c: dw: rename "pclk" to "apb" to match dt-binding i3c: dw: make struct dw_i3c_cmd smaller i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding i3c: renesas: Don't register devices when ENTDAA times out i3c: master: dw-i3c-master: fix OD timing for first broadcast i3c: mipi-i3c-hci: Advertise IBI wakeup capability i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev() i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI i3c: master: Reject IBI requests from non-IBI-capable devices i3c: master: Add helper to query bus wakeup requirements i3c: master: Report wakeup events for IBIs i3c: master: Support IBI-based wakeup capability i3c: master: Fix potential UAF in i3c_device_match() i3c: master: Fix potential UAF in i3c_device_uevent() i3c: Make dev->desc locking assumptions explicit i3c: master: Fix use-after-free of master->this ...
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);
+