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efivarfs: move variable lifetime management into the inodes

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Make the inodes the default management vehicle for struct
efivar_entry, so they are now all freed automatically if the file is
removed and on unmount in kill_litter_super().  Remove the now
superfluous iterator to free the entries after kill_litter_super().

Also fixes a bug where some entry freeing was missing causing efivarfs
to leak memory.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
This commit is contained in:
James Bottomley 2025-01-19 10:12:10 -05:00 committed by Ard Biesheuvel
parent 7e365c7e2c
commit fddca52766
4 changed files with 48 additions and 72 deletions
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23
fs/efivarfs/inode.c
View File

@ -82,26 +82,23 @@ static int efivarfs_create(struct mnt_idmap *idmap, struct inode *dir,
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)) {
if (guid_equal(&vendor, &LINUX_EFI_RANDOM_SEED_TABLE_GUID)) {
err = -EPERM;
goto out;
}
if (efivar_variable_is_removable(var->var.VendorGuid,
if (efivar_variable_is_removable(vendor,
dentry->d_name.name, namelen))
is_removable = true;
@ -110,6 +107,9 @@ static int efivarfs_create(struct mnt_idmap *idmap, struct inode *dir,
err = -ENOMEM;
goto out;
}
var = efivar_entry(inode);
var->var.VendorGuid = vendor;
for (i = 0; i < namelen; i++)
var->var.VariableName[i] = dentry->d_name.name[i];
@ -117,7 +117,6 @@ 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)
@ -126,11 +125,9 @@ static int efivarfs_create(struct mnt_idmap *idmap, struct inode *dir,
d_instantiate(dentry, inode);
dget(dentry);
out:
if (err) {
kfree(var);
if (inode)
iput(inode);
}
if (err && inode)
iput(inode);
return err;
}

7
fs/efivarfs/internal.h
View File

@ -29,15 +29,20 @@ struct efi_variable {
struct efivar_entry {
struct efi_variable var;
struct list_head list;
struct inode vfs_inode;
};
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 *,
struct list_head *),
void *data, struct list_head *head);
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);

51
fs/efivarfs/super.c
View File

@ -39,9 +39,25 @@ 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);
return &entry->vfs_inode;
}
static void efivarfs_free_inode(struct inode *inode)
{
struct efivar_entry *entry = efivar_entry(inode);
if (inode->i_private)
list_del(&entry->list);
kfree(entry);
}
static int efivarfs_show_options(struct seq_file *m, struct dentry *root)
@ -106,7 +122,8 @@ 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,
};
@ -227,21 +244,14 @@ 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));
name = efivar_get_utf8name(name16, &vendor);
if (!name)
goto fail;
return err;
/* 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;
inode = efivarfs_get_inode(sb, d_inode(root), S_IFREG | 0644, 0,
@ -249,6 +259,11 @@ static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
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);
@ -273,16 +288,8 @@ static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
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 {
@ -407,7 +414,7 @@ static void efivarfs_kill_sb(struct super_block *sb)
kill_litter_super(sb);
/* Remove all entries and destroy */
efivar_entry_iter(efivarfs_destroy, &sfi->efivarfs_list, NULL);
WARN_ON(!list_empty(&sfi->efivarfs_list));
kfree(sfi);
}

39
fs/efivarfs/vars.c
View File

@ -485,34 +485,6 @@ 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
* @entry: entry containing variable to delete
@ -536,12 +508,10 @@ 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;
}
@ -679,10 +649,7 @@ 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);