#include <linux/device.h>
#include <linux/slab.h>
#include <linux/pstore.h>
+#include <linux/ctype.h>
#include <linux/fs.h>
#include <linux/ramfs.h>
return status;
}
+static efi_status_t
+check_var_size_locked(struct efivars *efivars, u32 attributes,
+ unsigned long size)
+{
+ u64 storage_size, remaining_size, max_size;
+ efi_status_t status;
+ const struct efivar_operations *fops = efivars->ops;
+
+ if (!efivars->ops->query_variable_info)
+ return EFI_UNSUPPORTED;
+
+ status = fops->query_variable_info(attributes, &storage_size,
+ &remaining_size, &max_size);
+
+ if (status != EFI_SUCCESS)
+ return status;
+
+ if (!storage_size || size > remaining_size || size > max_size ||
+ (remaining_size - size) < (storage_size / 2))
+ return EFI_OUT_OF_RESOURCES;
+
+ return status;
+}
+
+
+static efi_status_t
+check_var_size(struct efivars *efivars, u32 attributes, unsigned long size)
+{
+ efi_status_t status;
+ unsigned long flags;
+
+ spin_lock_irqsave(&efivars->lock, flags);
+ status = check_var_size_locked(efivars, attributes, size);
+ spin_unlock_irqrestore(&efivars->lock, flags);
+
+ return status;
+}
+
static ssize_t
efivar_guid_read(struct efivar_entry *entry, char *buf)
{
}
spin_lock_irq(&efivars->lock);
- status = efivars->ops->set_variable(new_var->VariableName,
- &new_var->VendorGuid,
- new_var->Attributes,
- new_var->DataSize,
- new_var->Data);
+
+ status = check_var_size_locked(efivars, new_var->Attributes,
+ new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
+
+ if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED)
+ status = efivars->ops->set_variable(new_var->VariableName,
+ &new_var->VendorGuid,
+ new_var->Attributes,
+ new_var->DataSize,
+ new_var->Data);
spin_unlock_irq(&efivars->lock);
u32 attributes;
struct inode *inode = file->f_mapping->host;
unsigned long datasize = count - sizeof(attributes);
- unsigned long newdatasize;
- u64 storage_size, remaining_size, max_size;
+ unsigned long newdatasize, varsize;
ssize_t bytes = 0;
if (count < sizeof(attributes))
* amounts of memory. Pick a default size of 64K if
* QueryVariableInfo() isn't supported by the firmware.
*/
- spin_lock_irq(&efivars->lock);
-
- if (!efivars->ops->query_variable_info)
- status = EFI_UNSUPPORTED;
- else {
- const struct efivar_operations *fops = efivars->ops;
- status = fops->query_variable_info(attributes, &storage_size,
- &remaining_size, &max_size);
- }
- spin_unlock_irq(&efivars->lock);
+ varsize = datasize + utf16_strsize(var->var.VariableName, 1024);
+ status = check_var_size(efivars, attributes, varsize);
if (status != EFI_SUCCESS) {
if (status != EFI_UNSUPPORTED)
return efi_status_to_err(status);
- remaining_size = 65536;
+ if (datasize > 65536)
+ return -ENOSPC;
}
- if (datasize > remaining_size)
- return -ENOSPC;
-
data = kmalloc(datasize, GFP_KERNEL);
if (!data)
return -ENOMEM;
*/
spin_lock_irq(&efivars->lock);
+ /*
+ * Ensure that the available space hasn't shrunk below the safe level
+ */
+
+ status = check_var_size_locked(efivars, attributes, varsize);
+
+ if (status != EFI_SUCCESS && status != EFI_UNSUPPORTED) {
+ spin_unlock_irq(&efivars->lock);
+ kfree(data);
+
+ return efi_status_to_err(status);
+ }
+
status = efivars->ops->set_variable(var->var.VariableName,
&var->var.VendorGuid,
attributes, datasize,
return inode;
}
+/*
+ * Return true if 'str' is a valid efivarfs filename of the form,
+ *
+ * VariableName-12345678-1234-1234-1234-1234567891bc
+ */
+static bool efivarfs_valid_name(const char *str, int len)
+{
+ static const char dashes[GUID_LEN] = {
+ [8] = 1, [13] = 1, [18] = 1, [23] = 1
+ };
+ const char *s = str + len - GUID_LEN;
+ int i;
+
+ /*
+ * We need a GUID, plus at least one letter for the variable name,
+ * plus the '-' separator
+ */
+ if (len < GUID_LEN + 2)
+ return false;
+
+ /* GUID must be preceded by a '-' */
+ if (*(s - 1) != '-')
+ return false;
+
+ /*
+ * Validate that 's' is of the correct format, e.g.
+ *
+ * 12345678-1234-1234-1234-123456789abc
+ */
+ for (i = 0; i < GUID_LEN; i++) {
+ if (dashes[i]) {
+ if (*s++ != '-')
+ return false;
+ } else {
+ if (!isxdigit(*s++))
+ return false;
+ }
+ }
+
+ return true;
+}
+
static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid)
{
guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]);
struct efivar_entry *var;
int namelen, i = 0, err = 0;
- /*
- * We need a GUID, plus at least one letter for the variable name,
- * plus the '-' separator
- */
- if (dentry->d_name.len < GUID_LEN + 2)
+ if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
return -EINVAL;
inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0);
return -EINVAL;
};
+/*
+ * Compare two efivarfs file names.
+ *
+ * An efivarfs filename is composed of two parts,
+ *
+ * 1. A case-sensitive variable name
+ * 2. A case-insensitive GUID
+ *
+ * So we need to perform a case-sensitive match on part 1 and a
+ * case-insensitive match on part 2.
+ */
+static int efivarfs_d_compare(const struct dentry *parent, const struct inode *pinode,
+ const struct dentry *dentry, const struct inode *inode,
+ unsigned int len, const char *str,
+ const struct qstr *name)
+{
+ int guid = len - GUID_LEN;
+
+ if (name->len != len)
+ return 1;
+
+ /* Case-sensitive compare for the variable name */
+ if (memcmp(str, name->name, guid))
+ return 1;
+
+ /* Case-insensitive compare for the GUID */
+ return strncasecmp(name->name + guid, str + guid, GUID_LEN);
+}
+
+static int efivarfs_d_hash(const struct dentry *dentry,
+ const struct inode *inode, struct qstr *qstr)
+{
+ unsigned long hash = init_name_hash();
+ const unsigned char *s = qstr->name;
+ unsigned int len = qstr->len;
+
+ if (!efivarfs_valid_name(s, len))
+ return -EINVAL;
+
+ while (len-- > GUID_LEN)
+ hash = partial_name_hash(*s++, hash);
+
+ /* GUID is case-insensitive. */
+ while (len--)
+ hash = partial_name_hash(tolower(*s++), hash);
+
+ qstr->hash = end_name_hash(hash);
+ return 0;
+}
+
+/*
+ * Retaining negative dentries for an in-memory filesystem just wastes
+ * memory and lookup time: arrange for them to be deleted immediately.
+ */
+static int efivarfs_delete_dentry(const struct dentry *dentry)
+{
+ return 1;
+}
+
+static struct dentry_operations efivarfs_d_ops = {
+ .d_compare = efivarfs_d_compare,
+ .d_hash = efivarfs_d_hash,
+ .d_delete = efivarfs_delete_dentry,
+};
+
+static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name)
+{
+ struct dentry *d;
+ struct qstr q;
+ int err;
+
+ q.name = name;
+ q.len = strlen(name);
+
+ err = efivarfs_d_hash(NULL, NULL, &q);
+ if (err)
+ return ERR_PTR(err);
+
+ d = d_alloc(parent, &q);
+ if (d)
+ return d;
+
+ return ERR_PTR(-ENOMEM);
+}
+
static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
{
struct inode *inode = NULL;
struct efivar_entry *entry, *n;
struct efivars *efivars = &__efivars;
char *name;
+ int err = -ENOMEM;
efivarfs_sb = sb;
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
sb->s_magic = EFIVARFS_MAGIC;
sb->s_op = &efivarfs_ops;
+ sb->s_d_op = &efivarfs_d_ops;
sb->s_time_gran = 1;
inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0);
if (!inode)
goto fail_name;
- dentry = d_alloc_name(root, name);
- if (!dentry)
+ dentry = efivarfs_alloc_dentry(root, name);
+ if (IS_ERR(dentry)) {
+ err = PTR_ERR(dentry);
goto fail_inode;
+ }
/* copied by the above to local storage in the dentry. */
kfree(name);
mutex_lock(&inode->i_mutex);
inode->i_private = entry;
- i_size_write(inode, size+4);
+ i_size_write(inode, size + sizeof(entry->var.Attributes));
mutex_unlock(&inode->i_mutex);
d_add(dentry, inode);
}
fail_name:
kfree(name);
fail:
- return -ENOMEM;
+ return err;
}
static struct dentry *efivarfs_mount(struct file_system_type *fs_type,
.mount = efivarfs_mount,
.kill_sb = efivarfs_kill_sb,
};
+MODULE_ALIAS_FS("efivarfs");
+
+/*
+ * Handle negative dentry.
+ */
+static struct dentry *efivarfs_lookup(struct inode *dir, struct dentry *dentry,
+ unsigned int flags)
+{
+ if (dentry->d_name.len > NAME_MAX)
+ return ERR_PTR(-ENAMETOOLONG);
+ d_add(dentry, NULL);
+ return NULL;
+}
static const struct inode_operations efivarfs_dir_inode_operations = {
- .lookup = simple_lookup,
+ .lookup = efivarfs_lookup,
.unlink = efivarfs_unlink,
.create = efivarfs_create,
};
efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
struct efivars *efivars = psi->data;
int i, ret = 0;
- u64 storage_space, remaining_space, max_variable_size;
efi_status_t status = EFI_NOT_FOUND;
unsigned long flags;
* size: a size of logging data
* DUMP_NAME_LEN * 2: a maximum size of variable name
*/
- status = efivars->ops->query_variable_info(PSTORE_EFI_ATTRIBUTES,
- &storage_space,
- &remaining_space,
- &max_variable_size);
- if (status || remaining_space < size + DUMP_NAME_LEN * 2) {
+
+ status = check_var_size_locked(efivars, PSTORE_EFI_ATTRIBUTES,
+ size + DUMP_NAME_LEN * 2);
+
+ if (status) {
spin_unlock_irqrestore(&efivars->lock, flags);
*id = part;
return -ENOSPC;
return -EINVAL;
}
+ status = check_var_size_locked(efivars, new_var->Attributes,
+ new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
+
+ if (status && status != EFI_UNSUPPORTED) {
+ spin_unlock_irq(&efivars->lock);
+ return efi_status_to_err(status);
+ }
+
/* now *really* create the variable via EFI */
status = efivars->ops->set_variable(new_var->VariableName,
&new_var->VendorGuid,
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