From 4352b8aee98005853aa63f57d6377282de17a33f Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 23 Aug 2026 13:28:57 -0700 Subject: Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux 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 ... --- fs/fsopen.c | 491 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 491 insertions(+) create mode 100644 fs/fsopen.c (limited to 'fs/fsopen.c') diff --git a/fs/fsopen.c b/fs/fsopen.c new file mode 100644 index 000000000..ae19e5136 --- /dev/null +++ b/fs/fsopen.c @@ -0,0 +1,491 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Filesystem access-by-fd. + * + * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "internal.h" +#include "mount.h" + +static inline const char *fetch_message_locked(struct fc_log *log, size_t len, + bool *need_free) +{ + const char *p; + int index; + + if (unlikely(log->head == log->tail)) + return ERR_PTR(-ENODATA); + + index = log->tail & (ARRAY_SIZE(log->buffer) - 1); + p = log->buffer[index]; + if (unlikely(strlen(p) > len)) + return ERR_PTR(-EMSGSIZE); + + log->buffer[index] = NULL; + *need_free = log->need_free & (1 << index); + log->need_free &= ~(1 << index); + log->tail++; + + return p; +} + +/* + * Allow the user to read back any error, warning or informational messages. + * Only one message is returned for each read(2) call. + */ +static ssize_t fscontext_read(struct file *file, + char __user *_buf, size_t len, loff_t *pos) +{ + struct fs_context *fc = file->private_data; + ssize_t err; + const char *p __free(kfree) = NULL, *message; + bool need_free; + int n; + + err = mutex_lock_interruptible(&fc->uapi_mutex); + if (err < 0) + return err; + message = fetch_message_locked(fc->log.log, len, &need_free); + mutex_unlock(&fc->uapi_mutex); + if (IS_ERR(message)) + return PTR_ERR(message); + + if (need_free) + p = message; + + n = strlen(message); + if (copy_to_user(_buf, message, n)) + return -EFAULT; + return n; +} + +static int fscontext_release(struct inode *inode, struct file *file) +{ + struct fs_context *fc = file->private_data; + + if (fc) { + file->private_data = NULL; + put_fs_context(fc); + } + return 0; +} + +const struct file_operations fscontext_fops = { + .read = fscontext_read, + .release = fscontext_release, +}; + +/* + * Attach a filesystem context to a file and an fd. + */ +static int fscontext_create_fd(struct fs_context *fc, unsigned int o_flags) +{ + int fd; + + fd = anon_inode_getfd("[fscontext]", &fscontext_fops, fc, + O_RDWR | o_flags); + if (fd < 0) + put_fs_context(fc); + return fd; +} + +static int fscontext_alloc_log(struct fs_context *fc) +{ + fc->log.log = kzalloc_obj(*fc->log.log); + if (!fc->log.log) + return -ENOMEM; + refcount_set(&fc->log.log->usage, 1); + fc->log.log->owner = fc->fs_type->owner; + return 0; +} + +/* + * Open a filesystem by name so that it can be configured for mounting. + * + * We are allowed to specify a container in which the filesystem will be + * opened, thereby indicating which namespaces will be used (notably, which + * network namespace will be used for network filesystems). + */ +SYSCALL_DEFINE2(fsopen, const char __user *, _fs_name, unsigned int, flags) +{ + struct file_system_type *fs_type; + struct fs_context *fc; + const char *fs_name; + int ret; + + if (!may_mount()) + return -EPERM; + + if (flags & ~FSOPEN_CLOEXEC) + return -EINVAL; + + fs_name = strndup_user(_fs_name, PAGE_SIZE); + if (IS_ERR(fs_name)) + return PTR_ERR(fs_name); + + fs_type = get_fs_type(fs_name); + kfree(fs_name); + if (!fs_type) + return -ENODEV; + + fc = fs_context_for_mount(fs_type, 0); + put_filesystem(fs_type); + if (IS_ERR(fc)) + return PTR_ERR(fc); + + fc->phase = FS_CONTEXT_CREATE_PARAMS; + + ret = fscontext_alloc_log(fc); + if (ret < 0) + goto err_fc; + + return fscontext_create_fd(fc, flags & FSOPEN_CLOEXEC ? O_CLOEXEC : 0); + +err_fc: + put_fs_context(fc); + return ret; +} + +/* + * Pick a superblock into a context for reconfiguration. + */ +SYSCALL_DEFINE3(fspick, int, dfd, const char __user *, path, unsigned int, flags) +{ + struct fs_context *fc; + struct path target; + unsigned int lookup_flags; + int ret; + + if (!may_mount()) + return -EPERM; + + if ((flags & ~(FSPICK_CLOEXEC | + FSPICK_SYMLINK_NOFOLLOW | + FSPICK_NO_AUTOMOUNT | + FSPICK_EMPTY_PATH)) != 0) + return -EINVAL; + + lookup_flags = LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT; + if (flags & FSPICK_SYMLINK_NOFOLLOW) + lookup_flags &= ~LOOKUP_FOLLOW; + if (flags & FSPICK_NO_AUTOMOUNT) + lookup_flags &= ~LOOKUP_AUTOMOUNT; + CLASS(filename_flags, filename)(path, + (flags & FSPICK_EMPTY_PATH) ? LOOKUP_EMPTY : 0); + ret = filename_lookup(dfd, filename, lookup_flags, &target, NULL); + if (ret < 0) + goto err; + + ret = -EINVAL; + if (target.mnt->mnt_root != target.dentry) + goto err_path; + + fc = fs_context_for_reconfigure(target.dentry, 0, 0); + if (IS_ERR(fc)) { + ret = PTR_ERR(fc); + goto err_path; + } + + fc->phase = FS_CONTEXT_RECONF_PARAMS; + + ret = fscontext_alloc_log(fc); + if (ret < 0) + goto err_fc; + + path_put(&target); + return fscontext_create_fd(fc, flags & FSPICK_CLOEXEC ? O_CLOEXEC : 0); + +err_fc: + put_fs_context(fc); +err_path: + path_put(&target); +err: + return ret; +} + +static int vfs_cmd_create(struct fs_context *fc, bool exclusive) +{ + struct super_block *sb; + int ret; + + if (fc->phase != FS_CONTEXT_CREATE_PARAMS) + return -EBUSY; + + if (!mount_capable(fc)) + return -EPERM; + + fc->phase = FS_CONTEXT_CREATING; + fc->exclusive = exclusive; + + ret = vfs_get_tree(fc); + if (ret) { + fc->phase = FS_CONTEXT_FAILED; + return ret; + } + + sb = fc->root->d_sb; + ret = security_sb_kern_mount(sb); + if (unlikely(ret)) { + fc_drop_locked(fc); + fc->phase = FS_CONTEXT_FAILED; + return ret; + } + + /* vfs_get_tree() callchains will have grabbed @s_umount */ + up_write(&sb->s_umount); + fc->phase = FS_CONTEXT_AWAITING_MOUNT; + return 0; +} + +static int vfs_cmd_reconfigure(struct fs_context *fc) +{ + struct super_block *sb; + int ret; + + if (fc->phase != FS_CONTEXT_RECONF_PARAMS) + return -EBUSY; + + fc->phase = FS_CONTEXT_RECONFIGURING; + + sb = fc->root->d_sb; + if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN)) { + fc->phase = FS_CONTEXT_FAILED; + return -EPERM; + } + + down_write(&sb->s_umount); + ret = reconfigure_super(fc); + up_write(&sb->s_umount); + if (ret) { + fc->phase = FS_CONTEXT_FAILED; + return ret; + } + + vfs_clean_context(fc); + return 0; +} + +/* + * Check the state and apply the configuration. Note that this function is + * allowed to 'steal' the value by setting param->xxx to NULL before returning. + */ +static int vfs_fsconfig_locked(struct fs_context *fc, int cmd, + struct fs_parameter *param) +{ + int ret; + + ret = finish_clean_context(fc); + if (ret) + return ret; + switch (cmd) { + case FSCONFIG_CMD_CREATE: + return vfs_cmd_create(fc, false); + case FSCONFIG_CMD_CREATE_EXCL: + return vfs_cmd_create(fc, true); + case FSCONFIG_CMD_RECONFIGURE: + return vfs_cmd_reconfigure(fc); + default: + if (fc->phase != FS_CONTEXT_CREATE_PARAMS && + fc->phase != FS_CONTEXT_RECONF_PARAMS) + return -EBUSY; + + return vfs_parse_fs_param(fc, param); + } +} + +/** + * sys_fsconfig - Set parameters and trigger actions on a context + * @fd: The filesystem context to act upon + * @cmd: The action to take + * @_key: Where appropriate, the parameter key to set + * @_value: Where appropriate, the parameter value to set + * @aux: Additional information for the value + * + * This system call is used to set parameters on a context, including + * superblock settings, data source and security labelling. + * + * Actions include triggering the creation of a superblock and the + * reconfiguration of the superblock attached to the specified context. + * + * When setting a parameter, @cmd indicates the type of value being proposed + * and @_key indicates the parameter to be altered. + * + * @_value and @aux are used to specify the value, should a value be required: + * + * (*) fsconfig_set_flag: No value is specified. The parameter must be boolean + * in nature. The key may be prefixed with "no" to invert the + * setting. @_value must be NULL and @aux must be 0. + * + * (*) fsconfig_set_string: A string value is specified. The parameter can be + * expecting boolean, integer, string or take a path. A conversion to an + * appropriate type will be attempted (which may include looking up as a + * path). @_value points to a NUL-terminated string and @aux must be 0. + * + * (*) fsconfig_set_binary: A binary blob is specified. @_value points to the + * blob and @aux indicates its size. The parameter must be expecting a + * blob. + * + * (*) fsconfig_set_path: A non-empty path is specified. The parameter must be + * expecting a path object. @_value points to a NUL-terminated string that + * is the path and @aux is a file descriptor at which to start a relative + * lookup or AT_FDCWD. + * + * (*) fsconfig_set_path_empty: As fsconfig_set_path, but with AT_EMPTY_PATH + * implied. + * + * (*) fsconfig_set_fd: An open file descriptor is specified. @_value must be + * NULL and @aux indicates the file descriptor. + */ +SYSCALL_DEFINE5(fsconfig, + int, fd, + unsigned int, cmd, + const char __user *, _key, + const void __user *, _value, + int, aux) +{ + struct fs_context *fc; + int ret; + int lookup_flags = 0; + + struct fs_parameter param = { + .type = fs_value_is_undefined, + }; + + if (fd < 0) + return -EINVAL; + + switch (cmd) { + case FSCONFIG_SET_FLAG: + if (!_key || _value || aux) + return -EINVAL; + break; + case FSCONFIG_SET_STRING: + if (!_key || !_value || aux) + return -EINVAL; + break; + case FSCONFIG_SET_BINARY: + if (!_key || !_value || aux <= 0 || aux > 1024 * 1024) + return -EINVAL; + break; + case FSCONFIG_SET_PATH: + case FSCONFIG_SET_PATH_EMPTY: + if (!_key || !_value || (aux != AT_FDCWD && aux < 0)) + return -EINVAL; + break; + case FSCONFIG_SET_FD: + if (!_key || _value || aux < 0) + return -EINVAL; + break; + case FSCONFIG_CMD_CREATE: + case FSCONFIG_CMD_CREATE_EXCL: + case FSCONFIG_CMD_RECONFIGURE: + if (_key || _value || aux) + return -EINVAL; + break; + default: + return -EOPNOTSUPP; + } + + CLASS(fd, f)(fd); + if (fd_empty(f)) + return -EBADF; + if (fd_file(f)->f_op != &fscontext_fops) + return -EINVAL; + + fc = fd_file(f)->private_data; + + if (_key) { + param.key = strndup_user(_key, 256); + if (IS_ERR(param.key)) + return PTR_ERR(param.key); + } + + switch (cmd) { + case FSCONFIG_SET_FLAG: + param.type = fs_value_is_flag; + break; + case FSCONFIG_SET_STRING: + param.type = fs_value_is_string; + param.string = strndup_user(_value, 256); + if (IS_ERR(param.string)) { + ret = PTR_ERR(param.string); + goto out_key; + } + param.size = strlen(param.string); + break; + case FSCONFIG_SET_BINARY: + param.type = fs_value_is_blob; + param.size = aux; + param.blob = memdup_user_nul(_value, aux); + if (IS_ERR(param.blob)) { + ret = PTR_ERR(param.blob); + goto out_key; + } + break; + case FSCONFIG_SET_PATH_EMPTY: + lookup_flags = LOOKUP_EMPTY; + fallthrough; + case FSCONFIG_SET_PATH: + param.type = fs_value_is_filename; + param.name = getname_flags(_value, lookup_flags); + if (IS_ERR(param.name)) { + ret = PTR_ERR(param.name); + goto out_key; + } + param.dirfd = aux; + param.size = strlen(param.name->name); + break; + case FSCONFIG_SET_FD: + param.type = fs_value_is_file; + ret = -EBADF; + param.file = fget_raw(aux); + if (!param.file) + goto out_key; + param.dirfd = aux; + break; + default: + break; + } + + ret = mutex_lock_interruptible(&fc->uapi_mutex); + if (ret == 0) { + ret = vfs_fsconfig_locked(fc, cmd, ¶m); + mutex_unlock(&fc->uapi_mutex); + } + + /* Clean up the our record of any value that we obtained from + * userspace. Note that the value may have been stolen by the LSM or + * filesystem, in which case the value pointer will have been cleared. + */ + switch (cmd) { + case FSCONFIG_SET_STRING: + case FSCONFIG_SET_BINARY: + kfree(param.string); + break; + case FSCONFIG_SET_PATH: + case FSCONFIG_SET_PATH_EMPTY: + if (param.name) + putname(param.name); + break; + case FSCONFIG_SET_FD: + if (param.file) + fput(param.file); + break; + default: + break; + } +out_key: + kfree(param.key); + return ret; +} -- cgit v1.3.1