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Date: Wed, 14 Dec 2011 16:06:31 -0500
From: Matthew Garrett <mjg@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: mikew@...gle.com, x86@...nel.org, hpa@...or.com,
Matthew Garrett <mjg@...hat.com>
Subject: [PATCH 4/4] EFI: Add support for QueryVariableInfo() call
UEFI 2.0 and later provides a call for identifying hardware variable
capabilities. Use this to work out the maximum size of the variables we
can store, and throw errors where appropriate.
Signed-off-by: Matthew Garrett <mjg@...hat.com>
---
drivers/firmware/efivars.c | 53 +++++++++++++++++++++++++++++++++++++---
drivers/firmware/google/gsmi.c | 9 +++++++
include/linux/efi.h | 1 +
3 files changed, 59 insertions(+), 4 deletions(-)
diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index 1bef80c..805dba7 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -327,8 +327,9 @@ efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
struct extended_efi_variable *new_var, *var = entry->var;
struct efi_variable *tmp_var = NULL;
struct efivars *efivars = entry->efivars;
- efi_status_t status = EFI_NOT_FOUND;
+ efi_status_t status;
int error = 0;
+ u64 storage_space, remaining_space, max_variable_size, size;
if (count == sizeof(struct efi_variable)) {
tmp_var = (struct efi_variable *)buf;
@@ -360,6 +361,22 @@ efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
}
spin_lock(&efivars->lock);
+
+ size = new_var->header.DataSize +
+ utf16_strnlen(new_var->header.VariableName, 512) * 2;
+
+ status = efivars->ops->query_variable_info(new_var->header.Attributes,
+ &storage_space,
+ &remaining_space,
+ &max_variable_size);
+ if (status == EFI_SUCCESS) {
+ if (size > remaining_space || size > max_variable_size) {
+ spin_unlock(&efivars->lock);
+ error = -ENOSPC;
+ goto out;
+ }
+ }
+
status = efivars->ops->set_variable(new_var->header.VariableName,
&new_var->header.VendorGuid,
new_var->header.Attributes,
@@ -670,9 +687,10 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
struct efivars *efivars = bin_attr->private;
struct efivar_entry *search_efivar, *n;
unsigned long strsize1, strsize2;
- efi_status_t status = EFI_NOT_FOUND;
+ efi_status_t status;
int found = 0;
int error = 0;
+ u64 storage_space, remaining_space, max_variable_size, size;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
@@ -693,6 +711,21 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
memcpy(ext_new_var->Data, new_var->Data, new_var->DataSize);
}
+ size = ext_new_var->header.DataSize +
+ utf16_strnlen(ext_new_var->header.VariableName, 512) * 2;
+
+ status = efivars->ops->query_variable_info(ext_new_var->header.Attributes,
+ &storage_space,
+ &remaining_space,
+ &max_variable_size);
+ if (status == EFI_SUCCESS) {
+ if (size > remaining_space || size > max_variable_size) {
+ spin_unlock(&efivars->lock);
+ error = -ENOSPC;
+ goto out;
+ }
+ }
+
/*
* Does this variable already exist?
*/
@@ -1009,6 +1042,7 @@ int register_efivars(struct efivars *efivars,
efi_char16_t *variable_name;
unsigned long variable_name_size = 1024;
int error = 0;
+ u64 storage_space, remaining_space, max_variable_size;
variable_name = kzalloc(variable_name_size, GFP_KERNEL);
if (!variable_name) {
@@ -1056,9 +1090,19 @@ int register_efivars(struct efivars *efivars,
efivars->efi_pstore_info = efi_pstore_info;
- efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
+ status = efivars->ops->query_variable_info(PSTORE_EFI_ATTRIBUTES,
+ &storage_space,
+ &remaining_space,
+ &max_variable_size);
+ if (status != EFI_SUCCESS)
+ max_variable_size = 1024;
+
+ max_variable_size -= DUMP_NAME_LEN * 2;
+
+ efivars->efi_pstore_info.buf = kmalloc(max_variable_size, GFP_KERNEL);
+
if (efivars->efi_pstore_info.buf) {
- efivars->efi_pstore_info.bufsize = 1024;
+ efivars->efi_pstore_info.bufsize = max_variable_size;
efivars->efi_pstore_info.data = efivars;
spin_lock_init(&efivars->efi_pstore_info.buf_lock);
pstore_register(&efivars->efi_pstore_info);
@@ -1103,6 +1147,7 @@ efivars_init(void)
ops.get_variable = efi.get_variable;
ops.set_variable = efi.set_variable;
ops.get_next_variable = efi.get_next_variable;
+ ops.query_variable_info = efi.query_variable_info;
error = register_efivars(&__efivars, &ops, efi_kobj);
if (error)
goto err_put;
diff --git a/drivers/firmware/google/gsmi.c b/drivers/firmware/google/gsmi.c
index c4e7c59..8600e3f 100644
--- a/drivers/firmware/google/gsmi.c
+++ b/drivers/firmware/google/gsmi.c
@@ -419,6 +419,14 @@ static efi_status_t gsmi_get_next_variable(unsigned long *name_size,
return ret;
}
+static efi_status_t gsmi_query_variable_info(u32 attr,
+ u64 *storage_space,
+ u64 *remaining_space,
+ u64 *max_variable_size)
+{
+ return EFI_UNSUPPORTED;
+}
+
static efi_status_t gsmi_set_variable(efi_char16_t *name,
efi_guid_t *vendor,
u32 attr,
@@ -473,6 +481,7 @@ static const struct efivar_operations efivar_ops = {
.get_variable = gsmi_get_variable,
.set_variable = gsmi_set_variable,
.get_next_variable = gsmi_get_next_variable,
+ .query_variable_info = gsmi_query_variable_info,
};
static ssize_t eventlog_write(struct file *filp, struct kobject *kobj,
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 2362a0b..f3f3860 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -446,6 +446,7 @@ struct efivar_operations {
efi_get_variable_t *get_variable;
efi_get_next_variable_t *get_next_variable;
efi_set_variable_t *set_variable;
+ efi_query_variable_info_t *query_variable_info;
};
struct efivars {
--
1.7.7.1
--
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