Merge tag 'efi-urgent' into x86/urgent

 * Avoid confusing the user by returning -EIO instead of -ENOENT in
   efivarfs if an EFI variable gets deleted from under us and return EOF
   when reading from a zero-length file - Lingzhu Xiang

 * Fix an oops in efivar_update_sysfs_entries() caused by reusing (and
   therefore corrupting) a kzalloc() allocation - Seiji Aguchi

 * Initialise the DataSize argument to GetVariable() otherwise it will
   not be updated with the actual size of the variable on return.
   Discovered on a Acer Aspire V3 BIOS - Lee, Chun-Yi

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 12 insertions, 2 deletions

diff --git a/fs/efivarfs/file.c b/fs/efivarfs/file.c
index bfb531564319..8dd524f32284 100644
--- a/fs/efivarfs/file.c
+++ b/fs/efivarfs/file.c
@@ -44,8 +44,11 @@ static ssize_t efivarfs_file_write(struct file *file,
 
 	bytes = efivar_entry_set_get_size(var, attributes, &datasize,
 					  data, &set);
-	if (!set && bytes)
+	if (!set && bytes) {
+		if (bytes == -ENOENT)
+			bytes = -EIO;
 		goto out;
+	}
 
 	if (bytes == -ENOENT) {
 		drop_nlink(inode);
@@ -76,7 +79,14 @@ static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
 	int err;
 
 	err = efivar_entry_size(var, &datasize);
-	if (err)
+
+	/*
+	 * efivarfs represents uncommitted variables with
+	 * zero-length files. Reading them should return EOF.
+	 */
+	if (err == -ENOENT)
+		return 0;
+	else if (err)
 		return err;
 
 	data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);