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authorArd Biesheuvel <ardb@kernel.org>2025-01-19 17:50:58 +0100
committerArd Biesheuvel <ardb@kernel.org>2025-01-19 17:50:58 +0100
commite7b4b1f61db79fd5a3ded518526941b0e3d70abc (patch)
treeaeb3e815e2c6a9f1b4b6c7e7628383d13189d7b3
parent8a32d46b204396255462712afbef16e227423f68 (diff)
parent908af31f4896f2c0645031f8b74a89d3a8beb5b9 (diff)
Merge branch 'efivarfs' into next
-rw-r--r--fs/efivarfs/file.c59
-rw-r--r--fs/efivarfs/inode.c41
-rw-r--r--fs/efivarfs/internal.h26
-rw-r--r--fs/efivarfs/super.c106
-rw-r--r--fs/efivarfs/vars.c179
5 files changed, 179 insertions, 232 deletions
diff --git a/fs/efivarfs/file.c b/fs/efivarfs/file.c
index 23c51d62f902..cb1b6d0c3454 100644
--- a/fs/efivarfs/file.c
+++ b/fs/efivarfs/file.c
@@ -36,28 +36,41 @@ static ssize_t efivarfs_file_write(struct file *file,
if (IS_ERR(data))
return PTR_ERR(data);
+ inode_lock(inode);
+ if (var->removed) {
+ /*
+ * file got removed; don't allow a set. Caused by an
+ * unsuccessful create or successful delete write
+ * racing with us.
+ */
+ bytes = -EIO;
+ goto out;
+ }
+
bytes = efivar_entry_set_get_size(var, attributes, &datasize,
data, &set);
- if (!set && bytes) {
+ if (!set) {
if (bytes == -ENOENT)
bytes = -EIO;
goto out;
}
if (bytes == -ENOENT) {
- drop_nlink(inode);
- d_delete(file->f_path.dentry);
- dput(file->f_path.dentry);
+ /*
+ * zero size signals to release that the write deleted
+ * the variable
+ */
+ i_size_write(inode, 0);
} else {
- inode_lock(inode);
i_size_write(inode, datasize + sizeof(attributes));
inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
- inode_unlock(inode);
}
bytes = count;
out:
+ inode_unlock(inode);
+
kfree(data);
return bytes;
@@ -106,8 +119,36 @@ out_free:
return size;
}
+static int efivarfs_file_release(struct inode *inode, struct file *file)
+{
+ struct efivar_entry *var = inode->i_private;
+
+ inode_lock(inode);
+ var->removed = (--var->open_count == 0 && i_size_read(inode) == 0);
+ inode_unlock(inode);
+
+ if (var->removed)
+ simple_recursive_removal(file->f_path.dentry, NULL);
+
+ return 0;
+}
+
+static int efivarfs_file_open(struct inode *inode, struct file *file)
+{
+ struct efivar_entry *entry = inode->i_private;
+
+ file->private_data = entry;
+
+ inode_lock(inode);
+ entry->open_count++;
+ inode_unlock(inode);
+
+ return 0;
+}
+
const struct file_operations efivarfs_file_operations = {
- .open = simple_open,
- .read = efivarfs_file_read,
- .write = efivarfs_file_write,
+ .open = efivarfs_file_open,
+ .read = efivarfs_file_read,
+ .write = efivarfs_file_write,
+ .release = efivarfs_file_release,
};
diff --git a/fs/efivarfs/inode.c b/fs/efivarfs/inode.c
index a4a6587ecd2e..98a7299a9ee9 100644
--- a/fs/efivarfs/inode.c
+++ b/fs/efivarfs/inode.c
@@ -77,39 +77,34 @@ static bool efivarfs_valid_name(const char *str, int len)
static int efivarfs_create(struct mnt_idmap *idmap, struct inode *dir,
struct dentry *dentry, umode_t mode, bool excl)
{
- struct efivarfs_fs_info *info = dir->i_sb->s_fs_info;
struct inode *inode = NULL;
struct efivar_entry *var;
int namelen, i = 0, err = 0;
bool is_removable = false;
+ efi_guid_t vendor;
if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
return -EINVAL;
- var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
- if (!var)
- return -ENOMEM;
-
/* length of the variable name itself: remove GUID and separator */
namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1;
- err = guid_parse(dentry->d_name.name + namelen + 1, &var->var.VendorGuid);
+ err = guid_parse(dentry->d_name.name + namelen + 1, &vendor);
if (err)
- goto out;
- if (guid_equal(&var->var.VendorGuid, &LINUX_EFI_RANDOM_SEED_TABLE_GUID)) {
- err = -EPERM;
- goto out;
- }
+ return err;
+ if (guid_equal(&vendor, &LINUX_EFI_RANDOM_SEED_TABLE_GUID))
+ return -EPERM;
- if (efivar_variable_is_removable(var->var.VendorGuid,
+ if (efivar_variable_is_removable(vendor,
dentry->d_name.name, namelen))
is_removable = true;
inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0, is_removable);
- if (!inode) {
- err = -ENOMEM;
- goto out;
- }
+ if (!inode)
+ return -ENOMEM;
+ var = efivar_entry(inode);
+
+ var->var.VendorGuid = vendor;
for (i = 0; i < namelen; i++)
var->var.VariableName[i] = dentry->d_name.name[i];
@@ -117,21 +112,11 @@ static int efivarfs_create(struct mnt_idmap *idmap, struct inode *dir,
var->var.VariableName[i] = '\0';
inode->i_private = var;
- kmemleak_ignore(var);
-
- err = efivar_entry_add(var, &info->efivarfs_list);
- if (err)
- goto out;
d_instantiate(dentry, inode);
dget(dentry);
-out:
- if (err) {
- kfree(var);
- if (inode)
- iput(inode);
- }
- return err;
+
+ return 0;
}
static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
diff --git a/fs/efivarfs/internal.h b/fs/efivarfs/internal.h
index 74f0602a9e01..1f84844fe032 100644
--- a/fs/efivarfs/internal.h
+++ b/fs/efivarfs/internal.h
@@ -6,7 +6,6 @@
#ifndef EFIVAR_FS_INTERNAL_H
#define EFIVAR_FS_INTERNAL_H
-#include <linux/list.h>
#include <linux/efi.h>
struct efivarfs_mount_opts {
@@ -16,7 +15,6 @@ struct efivarfs_mount_opts {
struct efivarfs_fs_info {
struct efivarfs_mount_opts mount_opts;
- struct list_head efivarfs_list;
struct super_block *sb;
struct notifier_block nb;
};
@@ -24,22 +22,23 @@ struct efivarfs_fs_info {
struct efi_variable {
efi_char16_t VariableName[EFI_VAR_NAME_LEN/sizeof(efi_char16_t)];
efi_guid_t VendorGuid;
- __u32 Attributes;
};
struct efivar_entry {
struct efi_variable var;
- struct list_head list;
- struct kobject kobj;
+ struct inode vfs_inode;
+ unsigned long open_count;
+ bool removed;
};
-int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *,
- struct list_head *),
- void *data, struct list_head *head);
+static inline struct efivar_entry *efivar_entry(struct inode *inode)
+{
+ return container_of(inode, struct efivar_entry, vfs_inode);
+}
+
+int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *),
+ void *data);
-int efivar_entry_add(struct efivar_entry *entry, struct list_head *head);
-void __efivar_entry_add(struct efivar_entry *entry, struct list_head *head);
-void efivar_entry_remove(struct efivar_entry *entry);
int efivar_entry_delete(struct efivar_entry *entry);
int efivar_entry_size(struct efivar_entry *entry, unsigned long *size);
@@ -50,13 +49,14 @@ int efivar_entry_get(struct efivar_entry *entry, u32 *attributes,
int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes,
unsigned long *size, void *data, bool *set);
-int efivar_entry_iter(int (*func)(struct efivar_entry *, void *),
- struct list_head *head, void *data);
bool efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data,
unsigned long data_size);
bool efivar_variable_is_removable(efi_guid_t vendor, const char *name,
size_t len);
+char *efivar_get_utf8name(const efi_char16_t *name16, efi_guid_t *vendor);
+bool efivarfs_variable_is_present(efi_char16_t *variable_name,
+ efi_guid_t *vendor, void *data);
extern const struct file_operations efivarfs_file_operations;
extern const struct inode_operations efivarfs_dir_inode_operations;
diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c
index beba15673be8..89010c5878ce 100644
--- a/fs/efivarfs/super.c
+++ b/fs/efivarfs/super.c
@@ -39,9 +39,24 @@ static int efivarfs_ops_notifier(struct notifier_block *nb, unsigned long event,
return NOTIFY_OK;
}
-static void efivarfs_evict_inode(struct inode *inode)
+static struct inode *efivarfs_alloc_inode(struct super_block *sb)
{
- clear_inode(inode);
+ struct efivar_entry *entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+
+ if (!entry)
+ return NULL;
+
+ inode_init_once(&entry->vfs_inode);
+ entry->removed = false;
+
+ return &entry->vfs_inode;
+}
+
+static void efivarfs_free_inode(struct inode *inode)
+{
+ struct efivar_entry *entry = efivar_entry(inode);
+
+ kfree(entry);
}
static int efivarfs_show_options(struct seq_file *m, struct dentry *root)
@@ -106,7 +121,8 @@ static int efivarfs_statfs(struct dentry *dentry, struct kstatfs *buf)
static const struct super_operations efivarfs_ops = {
.statfs = efivarfs_statfs,
.drop_inode = generic_delete_inode,
- .evict_inode = efivarfs_evict_inode,
+ .alloc_inode = efivarfs_alloc_inode,
+ .free_inode = efivarfs_free_inode,
.show_options = efivarfs_show_options,
};
@@ -181,9 +197,37 @@ static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name)
return ERR_PTR(-ENOMEM);
}
+bool efivarfs_variable_is_present(efi_char16_t *variable_name,
+ efi_guid_t *vendor, void *data)
+{
+ char *name = efivar_get_utf8name(variable_name, vendor);
+ struct super_block *sb = data;
+ struct dentry *dentry;
+ struct qstr qstr;
+
+ if (!name)
+ /*
+ * If the allocation failed there'll already be an
+ * error in the log (and likely a huge and growing
+ * number of them since they system will be under
+ * extreme memory pressure), so simply assume
+ * collision for safety but don't add to the log
+ * flood.
+ */
+ return true;
+
+ qstr.name = name;
+ qstr.len = strlen(name);
+ dentry = d_hash_and_lookup(sb->s_root, &qstr);
+ kfree(name);
+ if (!IS_ERR_OR_NULL(dentry))
+ dput(dentry);
+
+ return dentry != NULL;
+}
+
static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
- unsigned long name_size, void *data,
- struct list_head *list)
+ unsigned long name_size, void *data)
{
struct super_block *sb = (struct super_block *)data;
struct efivar_entry *entry;
@@ -198,39 +242,26 @@ static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
if (guid_equal(&vendor, &LINUX_EFI_RANDOM_SEED_TABLE_GUID))
return 0;
- entry = kzalloc(sizeof(*entry), GFP_KERNEL);
- if (!entry)
- return err;
-
- memcpy(entry->var.VariableName, name16, name_size);
- memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
-
- len = ucs2_utf8size(entry->var.VariableName);
-
- /* name, plus '-', plus GUID, plus NUL*/
- name = kmalloc(len + 1 + EFI_VARIABLE_GUID_LEN + 1, GFP_KERNEL);
+ name = efivar_get_utf8name(name16, &vendor);
if (!name)
- goto fail;
+ return err;
- ucs2_as_utf8(name, entry->var.VariableName, len);
+ /* length of the variable name itself: remove GUID and separator */
+ len = strlen(name) - EFI_VARIABLE_GUID_LEN - 1;
- if (efivar_variable_is_removable(entry->var.VendorGuid, name, len))
+ if (efivar_variable_is_removable(vendor, name, len))
is_removable = true;
- name[len] = '-';
-
- efi_guid_to_str(&entry->var.VendorGuid, name + len + 1);
-
- name[len + EFI_VARIABLE_GUID_LEN+1] = '\0';
-
- /* replace invalid slashes like kobject_set_name_vargs does for /sys/firmware/efi/vars. */
- strreplace(name, '/', '!');
-
inode = efivarfs_get_inode(sb, d_inode(root), S_IFREG | 0644, 0,
is_removable);
if (!inode)
goto fail_name;
+ entry = efivar_entry(inode);
+
+ memcpy(entry->var.VariableName, name16, name_size);
+ memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
+
dentry = efivarfs_alloc_dentry(root, name);
if (IS_ERR(dentry)) {
err = PTR_ERR(dentry);
@@ -238,14 +269,13 @@ static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
}
__efivar_entry_get(entry, NULL, &size, NULL);
- __efivar_entry_add(entry, list);
/* copied by the above to local storage in the dentry. */
kfree(name);
inode_lock(inode);
inode->i_private = entry;
- i_size_write(inode, size + sizeof(entry->var.Attributes));
+ i_size_write(inode, size + sizeof(__u32)); /* attributes + data */
inode_unlock(inode);
d_add(dentry, inode);
@@ -255,16 +285,8 @@ fail_inode:
iput(inode);
fail_name:
kfree(name);
-fail:
- kfree(entry);
- return err;
-}
-static int efivarfs_destroy(struct efivar_entry *entry, void *data)
-{
- efivar_entry_remove(entry);
- kfree(entry);
- return 0;
+ return err;
}
enum {
@@ -336,7 +358,7 @@ static int efivarfs_fill_super(struct super_block *sb, struct fs_context *fc)
if (err)
return err;
- return efivar_init(efivarfs_callback, sb, &sfi->efivarfs_list);
+ return efivar_init(efivarfs_callback, sb);
}
static int efivarfs_get_tree(struct fs_context *fc)
@@ -371,8 +393,6 @@ static int efivarfs_init_fs_context(struct fs_context *fc)
if (!sfi)
return -ENOMEM;
- INIT_LIST_HEAD(&sfi->efivarfs_list);
-
sfi->mount_opts.uid = GLOBAL_ROOT_UID;
sfi->mount_opts.gid = GLOBAL_ROOT_GID;
@@ -388,8 +408,6 @@ static void efivarfs_kill_sb(struct super_block *sb)
blocking_notifier_chain_unregister(&efivar_ops_nh, &sfi->nb);
kill_litter_super(sb);
- /* Remove all entries and destroy */
- efivar_entry_iter(efivarfs_destroy, &sfi->efivarfs_list, NULL);
kfree(sfi);
}
diff --git a/fs/efivarfs/vars.c b/fs/efivarfs/vars.c
index f7d43c847ee9..d0beecbf9441 100644
--- a/fs/efivarfs/vars.c
+++ b/fs/efivarfs/vars.c
@@ -225,6 +225,31 @@ variable_matches(const char *var_name, size_t len, const char *match_name,
}
}
+char *
+efivar_get_utf8name(const efi_char16_t *name16, efi_guid_t *vendor)
+{
+ int len = ucs2_utf8size(name16);
+ char *name;
+
+ /* name, plus '-', plus GUID, plus NUL*/
+ name = kmalloc(len + 1 + EFI_VARIABLE_GUID_LEN + 1, GFP_KERNEL);
+ if (!name)
+ return NULL;
+
+ ucs2_as_utf8(name, name16, len);
+
+ name[len] = '-';
+
+ efi_guid_to_str(vendor, name + len + 1);
+
+ name[len + EFI_VARIABLE_GUID_LEN+1] = '\0';
+
+ /* replace invalid slashes like kobject_set_name_vargs does for /sys/firmware/efi/vars. */
+ strreplace(name, '/', '!');
+
+ return name;
+}
+
bool
efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data,
unsigned long data_size)
@@ -288,28 +313,6 @@ efivar_variable_is_removable(efi_guid_t vendor, const char *var_name,
return found;
}
-static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor,
- struct list_head *head)
-{
- struct efivar_entry *entry, *n;
- unsigned long strsize1, strsize2;
- bool found = false;
-
- strsize1 = ucs2_strsize(variable_name, EFI_VAR_NAME_LEN);
- list_for_each_entry_safe(entry, n, head, list) {
- strsize2 = ucs2_strsize(entry->var.VariableName, EFI_VAR_NAME_LEN);
- if (strsize1 == strsize2 &&
- !memcmp(variable_name, &(entry->var.VariableName),
- strsize2) &&
- !efi_guidcmp(entry->var.VendorGuid,
- *vendor)) {
- found = true;
- break;
- }
- }
- return found;
-}
-
/*
* Returns the size of variable_name, in bytes, including the
* terminating NULL character, or variable_name_size if no NULL
@@ -361,16 +364,14 @@ static void dup_variable_bug(efi_char16_t *str16, efi_guid_t *vendor_guid,
* efivar_init - build the initial list of EFI variables
* @func: callback function to invoke for every variable
* @data: function-specific data to pass to @func
- * @head: initialised head of variable list
*
* Get every EFI variable from the firmware and invoke @func. @func
- * should call efivar_entry_add() to build the list of variables.
+ * should populate the initial dentry and inode tree.
*
* Returns 0 on success, or a kernel error code on failure.
*/
-int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *,
- struct list_head *),
- void *data, struct list_head *head)
+int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *),
+ void *data)
{
unsigned long variable_name_size = 512;
efi_char16_t *variable_name;
@@ -414,14 +415,14 @@ int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *,
* we'll ever see a different variable name,
* and may end up looping here forever.
*/
- if (variable_is_present(variable_name, &vendor_guid,
- head)) {
+ if (efivarfs_variable_is_present(variable_name,
+ &vendor_guid, data)) {
dup_variable_bug(variable_name, &vendor_guid,
variable_name_size);
status = EFI_NOT_FOUND;
} else {
err = func(variable_name, vendor_guid,
- variable_name_size, data, head);
+ variable_name_size, data);
if (err)
status = EFI_NOT_FOUND;
}
@@ -453,70 +454,12 @@ free:
}
/**
- * efivar_entry_add - add entry to variable list
- * @entry: entry to add to list
- * @head: list head
- *
- * Returns 0 on success, or a kernel error code on failure.
- */
-int efivar_entry_add(struct efivar_entry *entry, struct list_head *head)
-{
- int err;
-
- err = efivar_lock();
- if (err)
- return err;
- list_add(&entry->list, head);
- efivar_unlock();
-
- return 0;
-}
-
-/**
- * __efivar_entry_add - add entry to variable list
- * @entry: entry to add to list
- * @head: list head
- */
-void __efivar_entry_add(struct efivar_entry *entry, struct list_head *head)
-{
- list_add(&entry->list, head);
-}
-
-/**
- * efivar_entry_remove - remove entry from variable list
- * @entry: entry to remove from list
- *
- * Returns 0 on success, or a kernel error code on failure.
- */
-void efivar_entry_remove(struct efivar_entry *entry)
-{
- list_del(&entry->list);
-}
-
-/*
- * efivar_entry_list_del_unlock - remove entry from variable list
- * @entry: entry to remove
- *
- * Remove @entry from the variable list and release the list lock.
- *
- * NOTE: slightly weird locking semantics here - we expect to be
- * called with the efivars lock already held, and we release it before
- * returning. This is because this function is usually called after
- * set_variable() while the lock is still held.
- */
-static void efivar_entry_list_del_unlock(struct efivar_entry *entry)
-{
- list_del(&entry->list);
- efivar_unlock();
-}
-
-/**
- * efivar_entry_delete - delete variable and remove entry from list
+ * efivar_entry_delete - delete variable
* @entry: entry containing variable to delete
*
- * Delete the variable from the firmware and remove @entry from the
- * variable list. It is the caller's responsibility to free @entry
- * once we return.
+ * Delete the variable from the firmware. It is the caller's
+ * responsibility to free @entry (by deleting the dentry/inode) once
+ * we return.
*
* Returns 0 on success, -EINTR if we can't grab the semaphore,
* converted EFI status code if set_variable() fails.
@@ -533,12 +476,10 @@ int efivar_entry_delete(struct efivar_entry *entry)
status = efivar_set_variable_locked(entry->var.VariableName,
&entry->var.VendorGuid,
0, 0, NULL, false);
- if (!(status == EFI_SUCCESS || status == EFI_NOT_FOUND)) {
- efivar_unlock();
+ efivar_unlock();
+ if (!(status == EFI_SUCCESS || status == EFI_NOT_FOUND))
return efi_status_to_err(status);
- }
- efivar_entry_list_del_unlock(entry);
return 0;
}
@@ -632,7 +573,7 @@ int efivar_entry_get(struct efivar_entry *entry, u32 *attributes,
* get_variable() fail.
*
* If the EFI variable does not exist when calling set_variable()
- * (EFI_NOT_FOUND), @entry is removed from the variable list.
+ * (EFI_NOT_FOUND).
*/
int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes,
unsigned long *size, void *data, bool *set)
@@ -648,9 +589,8 @@ int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes,
return -EINVAL;
/*
- * The lock here protects the get_variable call, the conditional
- * set_variable call, and removal of the variable from the efivars
- * list (in the case of an authenticated delete).
+ * The lock here protects the get_variable call and the
+ * conditional set_variable call
*/
err = efivar_lock();
if (err)
@@ -676,10 +616,7 @@ int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes,
&entry->var.VendorGuid,
NULL, size, NULL);
- if (status == EFI_NOT_FOUND)
- efivar_entry_list_del_unlock(entry);
- else
- efivar_unlock();
+ efivar_unlock();
if (status && status != EFI_BUFFER_TOO_SMALL)
return efi_status_to_err(status);
@@ -691,37 +628,3 @@ out:
return err;
}
-
-/**
- * efivar_entry_iter - iterate over variable list
- * @func: callback function
- * @head: head of variable list
- * @data: function-specific data to pass to callback
- *
- * Iterate over the list of EFI variables and call @func with every
- * entry on the list. It is safe for @func to remove entries in the
- * list via efivar_entry_delete() while iterating.
- *
- * Some notes for the callback function:
- * - a non-zero return value indicates an error and terminates the loop
- * - @func is called from atomic context
- */
-int efivar_entry_iter(int (*func)(struct efivar_entry *, void *),
- struct list_head *head, void *data)
-{
- struct efivar_entry *entry, *n;
- int err = 0;
-
- err = efivar_lock();
- if (err)
- return err;
-
- list_for_each_entry_safe(entry, n, head, list) {
- err = func(entry, data);
- if (err)
- break;
- }
- efivar_unlock();
-
- return err;
-}