EFI fixes for v6.8 #2

- Fix phys_addr_t size confusion in 32-bit capsule loader
 - Reduce maximum EFI variable name size to 512 to work around buggy
   firmware
 - Drop some redundant code from efivarfs while at it
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Merge tag 'efi-fixes-for-v6.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi

Pull EFI fixes from Ard Biesheuvel:
 "Only the EFI variable name size change is significant, and will be
  backported once it lands. The others are cleanup.

   - Fix phys_addr_t size confusion in 32-bit capsule loader

   - Reduce maximum EFI variable name size to 512 to work around buggy
     firmware

   - Drop some redundant code from efivarfs while at it"

* tag 'efi-fixes-for-v6.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
  efivarfs: Drop 'duplicates' bool parameter on efivar_init()
  efivarfs: Drop redundant cleanup on fill_super() failure
  efivarfs: Request at most 512 bytes for variable names
  efi/capsule-loader: fix incorrect allocation size

drivers/firmware/efi/capsule-loader.c

@@ -292,7 +292,7 @@ static int efi_capsule_open(struct inode *inode, struct file *file)
 		return -ENOMEM;
 	}
 
-	cap_info->phys = kzalloc(sizeof(void *), GFP_KERNEL);
+	cap_info->phys = kzalloc(sizeof(phys_addr_t), GFP_KERNEL);
 	if (!cap_info->phys) {
 		kfree(cap_info->pages);
 		kfree(cap_info);

fs/efivarfs/internal.h

@@ -38,7 +38,7 @@ struct efivar_entry {
 
 int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *,
 			    struct list_head *),
-		void *data, bool duplicates, struct list_head *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);

fs/efivarfs/super.c

@@ -343,12 +343,7 @@ static int efivarfs_fill_super(struct super_block *sb, struct fs_context *fc)
 	if (err)
 		return err;
 
-	err = efivar_init(efivarfs_callback, (void *)sb, true,
-			  &sfi->efivarfs_list);
-	if (err)
-		efivar_entry_iter(efivarfs_destroy, &sfi->efivarfs_list, NULL);
-
-	return err;
+	return efivar_init(efivarfs_callback, sb, &sfi->efivarfs_list);
 }
 
 static int efivarfs_get_tree(struct fs_context *fc)

fs/efivarfs/vars.c

@@ -361,7 +361,6 @@ static void dup_variable_bug(efi_char16_t *str16, efi_guid_t *vendor_guid,
  * efivar_init - build the initial list of EFI variables
  * @func: callback function to invoke for every variable
  * @data: function-specific data to pass to @func
- * @duplicates: error if we encounter duplicates on @head?
  * @head: initialised head of variable list
  *
  * Get every EFI variable from the firmware and invoke @func. @func
@@ -371,9 +370,9 @@ static void dup_variable_bug(efi_char16_t *str16, efi_guid_t *vendor_guid,
  */
 int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *,
 			    struct list_head *),
-		void *data, bool duplicates, struct list_head *head)
+		void *data, struct list_head *head)
 {
-	unsigned long variable_name_size = 1024;
+	unsigned long variable_name_size = 512;
 	efi_char16_t *variable_name;
 	efi_status_t status;
 	efi_guid_t vendor_guid;
@@ -390,12 +389,13 @@ int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *,
 		goto free;
 
 	/*
-	 * Per EFI spec, the maximum storage allocated for both
-	 * the variable name and variable data is 1024 bytes.
+	 * A small set of old UEFI implementations reject sizes
+	 * above a certain threshold, the lowest seen in the wild
+	 * is 512.
 	 */
 
 	do {
-		variable_name_size = 1024;
+		variable_name_size = 512;
 
 		status = efivar_get_next_variable(&variable_name_size,
 						  variable_name,
@@ -413,8 +413,7 @@ int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *,
 			 * we'll ever see a different variable name,
 			 * and may end up looping here forever.
 			 */
-			if (duplicates &&
-			    variable_is_present(variable_name, &vendor_guid,
+			if (variable_is_present(variable_name, &vendor_guid,
 						head)) {
 				dup_variable_bug(variable_name, &vendor_guid,
 						 variable_name_size);
@@ -432,9 +431,13 @@ int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *,
 			break;
 		case EFI_NOT_FOUND:
 			break;
+		case EFI_BUFFER_TOO_SMALL:
+			pr_warn("efivars: Variable name size exceeds maximum (%lu > 512)\n",
+				variable_name_size);
+			status = EFI_NOT_FOUND;
+			break;
 		default:
-			printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
-				status);
+			pr_warn("efivars: get_next_variable: status=%lx\n", status);
 			status = EFI_NOT_FOUND;
 			break;
 		}