1 files changed, 131 insertions, 127 deletions

diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index fe62aa392239..f4baa11d3644 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -80,6 +80,7 @@
 #include <linux/slab.h>
 #include <linux/pstore.h>
 #include <linux/ctype.h>
+#include <linux/ucs2_string.h>
 
 #include <linux/fs.h>
 #include <linux/ramfs.h>
@@ -103,6 +104,11 @@ MODULE_VERSION(EFIVARS_VERSION);
  */
 #define GUID_LEN 36
 
+static bool efivars_pstore_disable =
+        IS_ENABLED(CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE);
+
+module_param_named(pstore_disable, efivars_pstore_disable, bool, 0644);
+
 /*
  * The maximum size of VariableName + Data = 1024
  * Therefore, it's reasonable to save that much
@@ -165,51 +171,7 @@ efivar_create_sysfs_entry(struct efivars *efivars,
 
 static void efivar_update_sysfs_entries(struct work_struct *);
 static DECLARE_WORK(efivar_work, efivar_update_sysfs_entries);
-
-/* Return the number of unicode characters in data */
-static unsigned long
-utf16_strnlen(efi_char16_t *s, size_t maxlength)
-{
-        unsigned long length = 0;
-
-        while (*s++ != 0 && length < maxlength)
-                length++;
-        return length;
-}
-
-static inline unsigned long
-utf16_strlen(efi_char16_t *s)
-{
-        return utf16_strnlen(s, ~0UL);
-}
-
-/*
- * Return the number of bytes is the length of this string
- * Note: this is NOT the same as the number of unicode characters
- */
-static inline unsigned long
-utf16_strsize(efi_char16_t *data, unsigned long maxlength)
-{
-        return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
-}
-
-static inline int
-utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
-{
-        while (1) {
-                if (len == 0)
-                        return 0;
-                if (*a < *b)
-                        return -1;
-                if (*a > *b)
-                        return 1;
-                if (*a == 0) /* implies *b == 0 */
-                        return 0;
-                a++;
-                b++;
-                len--;
-        }
-}
+static bool efivar_wq_enabled = true;
 
 static bool
 validate_device_path(struct efi_variable *var, int match, u8 *buffer,
@@ -262,7 +224,7 @@ validate_load_option(struct efi_variable *var, int match, u8 *buffer,
         u16 filepathlength;
         int i, desclength = 0, namelen;
 
-        namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
+        namelen = ucs2_strnlen(var->VariableName, sizeof(var->VariableName));
 
         /* Either "Boot" or "Driver" followed by four digits of hex */
         for (i = match; i < match+4; i++) {
@@ -285,7 +247,7 @@ validate_load_option(struct efi_variable *var, int match, u8 *buffer,
          * There's no stored length for the description, so it has to be
          * found by hand
          */
-        desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
+        desclength = ucs2_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
 
         /* Each boot entry must have a descriptor */
         if (!desclength)
@@ -430,24 +392,12 @@ 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)
+        if (!efivars->ops->query_variable_store)
                 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;
+        return fops->query_variable_store(attributes, size);
 }
 
 
@@ -587,7 +537,7 @@ efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
         spin_lock_irq(&efivars->lock);
 
         status = check_var_size_locked(efivars, new_var->Attributes,
-               new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
+               new_var->DataSize + ucs2_strsize(new_var->VariableName, 1024));
 
         if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED)
                 status = efivars->ops->set_variable(new_var->VariableName,
@@ -765,7 +715,7 @@ static ssize_t efivarfs_file_write(struct file *file,
          * QueryVariableInfo() isn't supported by the firmware.
          */
 
-        varsize = datasize + utf16_strsize(var->var.VariableName, 1024);
+        varsize = datasize + ucs2_strsize(var->var.VariableName, 1024);
         status = check_var_size(efivars, attributes, varsize);
 
         if (status != EFI_SUCCESS) {
@@ -1217,7 +1167,7 @@ static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
 
                 inode = NULL;
 
-                len = utf16_strlen(entry->var.VariableName);
+                len = ucs2_strlen(entry->var.VariableName);
 
                 /* name, plus '-', plus GUID, plus NUL*/
                 name = kmalloc(len + 1 + GUID_LEN + 1, GFP_ATOMIC);
@@ -1309,9 +1259,7 @@ static const struct inode_operations efivarfs_dir_inode_operations = {
         .create = efivarfs_create,
 };
 
-static struct pstore_info efi_pstore_info;
-
-#ifdef CONFIG_PSTORE
+#ifdef CONFIG_EFI_VARS_PSTORE
 
 static int efi_pstore_open(struct pstore_info *psi)
 {
@@ -1441,7 +1389,7 @@ static int efi_pstore_write(enum pstore_type_id type,
 
         spin_unlock_irqrestore(&efivars->lock, flags);
 
-        if (reason == KMSG_DUMP_OOPS)
+        if (reason == KMSG_DUMP_OOPS && efivar_wq_enabled)
                 schedule_work(&efivar_work);
 
         *id = part;
@@ -1477,8 +1425,8 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
 
                 if (efi_guidcmp(entry->var.VendorGuid, vendor))
                         continue;
-                if (utf16_strncmp(entry->var.VariableName, efi_name,
-                                  utf16_strlen(efi_name))) {
+                if (ucs2_strncmp(entry->var.VariableName, efi_name,
+                                  ucs2_strlen(efi_name))) {
                         /*
                          * Check if an old format,
                          * which doesn't support holding
@@ -1490,8 +1438,8 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
                         for (i = 0; i < DUMP_NAME_LEN; i++)
                                 efi_name_old[i] = name_old[i];
 
-                        if (utf16_strncmp(entry->var.VariableName, efi_name_old,
-                                          utf16_strlen(efi_name_old)))
+                        if (ucs2_strncmp(entry->var.VariableName, efi_name_old,
+                                          ucs2_strlen(efi_name_old)))
                                 continue;
                 }
 
@@ -1514,38 +1462,6 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
 
         return 0;
 }
-#else
-static int efi_pstore_open(struct pstore_info *psi)
-{
-        return 0;
-}
-
-static int efi_pstore_close(struct pstore_info *psi)
-{
-        return 0;
-}
-
-static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type, int *count,
-                               struct timespec *timespec,
-                               char **buf, struct pstore_info *psi)
-{
-        return -1;
-}
-
-static int efi_pstore_write(enum pstore_type_id type,
-                enum kmsg_dump_reason reason, u64 *id,
-                unsigned int part, int count, size_t size,
-                struct pstore_info *psi)
-{
-        return 0;
-}
-
-static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
-                            struct timespec time, struct pstore_info *psi)
-{
-        return 0;
-}
-#endif
 
 static struct pstore_info efi_pstore_info = {
         .owner          = THIS_MODULE,
@@ -1557,6 +1473,24 @@ static struct pstore_info efi_pstore_info = {
         .erase          = efi_pstore_erase,
 };
 
+static void efivar_pstore_register(struct efivars *efivars)
+{
+        efivars->efi_pstore_info = efi_pstore_info;
+        efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
+        if (efivars->efi_pstore_info.buf) {
+                efivars->efi_pstore_info.bufsize = 1024;
+                efivars->efi_pstore_info.data = efivars;
+                spin_lock_init(&efivars->efi_pstore_info.buf_lock);
+                pstore_register(&efivars->efi_pstore_info);
+        }
+}
+#else
+static void efivar_pstore_register(struct efivars *efivars)
+{
+        return;
+}
+#endif
+
 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
                              struct bin_attribute *bin_attr,
                              char *buf, loff_t pos, size_t count)
@@ -1583,8 +1517,8 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
          * Does this variable already exist?
          */
         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
-                strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
-                strsize2 = utf16_strsize(new_var->VariableName, 1024);
+                strsize1 = ucs2_strsize(search_efivar->var.VariableName, 1024);
+                strsize2 = ucs2_strsize(new_var->VariableName, 1024);
                 if (strsize1 == strsize2 &&
                         !memcmp(&(search_efivar->var.VariableName),
                                 new_var->VariableName, strsize1) &&
@@ -1600,7 +1534,7 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
         }
 
         status = check_var_size_locked(efivars, new_var->Attributes,
-               new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
+               new_var->DataSize + ucs2_strsize(new_var->VariableName, 1024));
 
         if (status && status != EFI_UNSUPPORTED) {
                 spin_unlock_irq(&efivars->lock);
@@ -1624,7 +1558,7 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
 
         /* Create the entry in sysfs.  Locking is not required here */
         status = efivar_create_sysfs_entry(efivars,
-                                           utf16_strsize(new_var->VariableName,
+                                           ucs2_strsize(new_var->VariableName,
                                                          1024),
                                            new_var->VariableName,
                                            &new_var->VendorGuid);
@@ -1654,8 +1588,8 @@ static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
          * Does this variable already exist?
          */
         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
-                strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
-                strsize2 = utf16_strsize(del_var->VariableName, 1024);
+                strsize1 = ucs2_strsize(search_efivar->var.VariableName, 1024);
+                strsize2 = ucs2_strsize(del_var->VariableName, 1024);
                 if (strsize1 == strsize2 &&
                         !memcmp(&(search_efivar->var.VariableName),
                                 del_var->VariableName, strsize1) &&
@@ -1694,16 +1628,17 @@ static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
         return count;
 }
 
-static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor)
+static bool variable_is_present(struct efivars *efivars,
+                                efi_char16_t *variable_name,
+                                efi_guid_t *vendor)
 {
         struct efivar_entry *entry, *n;
-        struct efivars *efivars = &__efivars;
         unsigned long strsize1, strsize2;
         bool found = false;
 
-        strsize1 = utf16_strsize(variable_name, 1024);
+        strsize1 = ucs2_strsize(variable_name, 1024);
         list_for_each_entry_safe(entry, n, &efivars->list, list) {
-                strsize2 = utf16_strsize(entry->var.VariableName, 1024);
+                strsize2 = ucs2_strsize(entry->var.VariableName, 1024);
                 if (strsize1 == strsize2 &&
                         !memcmp(variable_name, &(entry->var.VariableName),
                                 strsize2) &&
@@ -1716,6 +1651,31 @@ static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor)
         return found;
 }
 
+/*
+ * Returns the size of variable_name, in bytes, including the
+ * terminating NULL character, or variable_name_size if no NULL
+ * character is found among the first variable_name_size bytes.
+ */
+static unsigned long var_name_strnsize(efi_char16_t *variable_name,
+                                       unsigned long variable_name_size)
+{
+        unsigned long len;
+        efi_char16_t c;
+
+        /*
+         * The variable name is, by definition, a NULL-terminated
+         * string, so make absolutely sure that variable_name_size is
+         * the value we expect it to be. If not, return the real size.
+         */
+        for (len = 2; len <= variable_name_size; len += sizeof(c)) {
+                c = variable_name[(len / sizeof(c)) - 1];
+                if (!c)
+                        break;
+        }
+
+        return min(len, variable_name_size);
+}
+
 static void efivar_update_sysfs_entries(struct work_struct *work)
 {
         struct efivars *efivars = &__efivars;
@@ -1744,8 +1704,8 @@ static void efivar_update_sysfs_entries(struct work_struct *work)
                         if (status != EFI_SUCCESS) {
                                 break;
                         } else {
-                                if (!variable_is_present(variable_name,
-                                    &vendor)) {
+                                if (!variable_is_present(efivars,
+                                    variable_name, &vendor)) {
                                         found = true;
                                         break;
                                 }
@@ -1756,10 +1716,13 @@ static void efivar_update_sysfs_entries(struct work_struct *work)
                 if (!found) {
                         kfree(variable_name);
                         break;
-                } else
+                } else {
+                        variable_name_size = var_name_strnsize(variable_name,
+                                                               variable_name_size);
                         efivar_create_sysfs_entry(efivars,
                                                   variable_name_size,
                                                   variable_name, &vendor);
+                }
         }
 }
 
@@ -1958,6 +1921,35 @@ void unregister_efivars(struct efivars *efivars)
 }
 EXPORT_SYMBOL_GPL(unregister_efivars);
 
+/*
+ * Print a warning when duplicate EFI variables are encountered and
+ * disable the sysfs workqueue since the firmware is buggy.
+ */
+static void dup_variable_bug(efi_char16_t *s16, efi_guid_t *vendor_guid,
+                             unsigned long len16)
+{
+        size_t i, len8 = len16 / sizeof(efi_char16_t);
+        char *s8;
+
+        /*
+         * Disable the workqueue since the algorithm it uses for
+         * detecting new variables won't work with this buggy
+         * implementation of GetNextVariableName().
+         */
+        efivar_wq_enabled = false;
+
+        s8 = kzalloc(len8, GFP_KERNEL);
+        if (!s8)
+                return;
+
+        for (i = 0; i < len8; i++)
+                s8[i] = s16[i];
+
+        printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n",
+               s8, vendor_guid);
+        kfree(s8);
+}
+
 int register_efivars(struct efivars *efivars,
                      const struct efivar_operations *ops,
                      struct kobject *parent_kobj)
@@ -2006,6 +1998,25 @@ int register_efivars(struct efivars *efivars,
                                                 &vendor_guid);
                 switch (status) {
                 case EFI_SUCCESS:
+                        variable_name_size = var_name_strnsize(variable_name,
+                                                               variable_name_size);
+
+                        /*
+                         * Some firmware implementations return the
+                         * same variable name on multiple calls to
+                         * get_next_variable(). Terminate the loop
+                         * immediately as there is no guarantee that
+                         * we'll ever see a different variable name,
+                         * and may end up looping here forever.
+                         */
+                        if (variable_is_present(efivars, variable_name,
+                                                &vendor_guid)) {
+                                dup_variable_bug(variable_name, &vendor_guid,
+                                                 variable_name_size);
+                                status = EFI_NOT_FOUND;
+                                break;
+                        }
+
                         efivar_create_sysfs_entry(efivars,
                                                   variable_name_size,
                                                   variable_name,
@@ -2025,15 +2036,8 @@ int register_efivars(struct efivars *efivars,
         if (error)
                 unregister_efivars(efivars);
 
-        efivars->efi_pstore_info = efi_pstore_info;
-
-        efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
-        if (efivars->efi_pstore_info.buf) {
-                efivars->efi_pstore_info.bufsize = 1024;
-                efivars->efi_pstore_info.data = efivars;
-                spin_lock_init(&efivars->efi_pstore_info.buf_lock);
-                pstore_register(&efivars->efi_pstore_info);
-        }
+        if (!efivars_pstore_disable)
+                efivar_pstore_register(efivars);
 
         register_filesystem(&efivarfs_type);
 
@@ -2073,7 +2077,7 @@ 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;
+        ops.query_variable_store = efi_query_variable_store;
 
         error = register_efivars(&__efivars, &ops, efi_kobj);
         if (error)