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path: root/drivers/firmware/efivars.c
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Diffstat (limited to 'drivers/firmware/efivars.c')
-rw-r--r--drivers/firmware/efivars.c131
1 files changed, 97 insertions, 34 deletions
diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index 7320bf89170..fe62aa39223 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -426,6 +426,44 @@ get_var_data(struct efivars *efivars, struct efi_variable *var)
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)
{
@@ -547,11 +585,16 @@ efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
}
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);
@@ -702,8 +745,7 @@ static ssize_t efivarfs_file_write(struct file *file,
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))
@@ -722,28 +764,18 @@ static ssize_t efivarfs_file_write(struct file *file,
* 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;
@@ -765,6 +797,19 @@ static ssize_t efivarfs_file_write(struct file *file,
*/
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,
@@ -929,8 +974,8 @@ static bool efivarfs_valid_name(const char *str, int len)
if (len < GUID_LEN + 2)
return false;
- /* GUID should be right after the first '-' */
- if (s - 1 != strchr(str, '-'))
+ /* GUID must be preceded by a '-' */
+ if (*(s - 1) != '-')
return false;
/*
@@ -1118,15 +1163,22 @@ static struct dentry_operations efivarfs_d_ops = {
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);
- if (efivarfs_d_hash(NULL, NULL, &q))
- return NULL;
+ err = efivarfs_d_hash(NULL, NULL, &q);
+ if (err)
+ return ERR_PTR(err);
+
+ d = d_alloc(parent, &q);
+ if (d)
+ return d;
- return d_alloc(parent, &q);
+ return ERR_PTR(-ENOMEM);
}
static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
@@ -1136,6 +1188,7 @@ static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
struct efivar_entry *entry, *n;
struct efivars *efivars = &__efivars;
char *name;
+ int err = -ENOMEM;
efivarfs_sb = sb;
@@ -1186,8 +1239,10 @@ static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
goto fail_name;
dentry = efivarfs_alloc_dentry(root, name);
- if (!dentry)
+ if (IS_ERR(dentry)) {
+ err = PTR_ERR(dentry);
goto fail_inode;
+ }
/* copied by the above to local storage in the dentry. */
kfree(name);
@@ -1214,7 +1269,7 @@ fail_inode:
fail_name:
kfree(name);
fail:
- return -ENOMEM;
+ return err;
}
static struct dentry *efivarfs_mount(struct file_system_type *fs_type,
@@ -1234,6 +1289,7 @@ static struct file_system_type efivarfs_type = {
.mount = efivarfs_mount,
.kill_sb = efivarfs_kill_sb,
};
+MODULE_ALIAS_FS("efivarfs");
/*
* Handle negative dentry.
@@ -1345,7 +1401,6 @@ static int efi_pstore_write(enum pstore_type_id type,
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;
@@ -1365,11 +1420,11 @@ static int efi_pstore_write(enum pstore_type_id type,
* 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;
@@ -1544,6 +1599,14 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
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,
generated by cgit v1.2.3-70-g09d2 (git 2.51.2) at 2025-11-04 03:17:58 +0000