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>

3 files changed, 16 insertions, 8 deletions

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 55856b2310d3..82089d8b1954 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -206,7 +206,7 @@ static efi_status_t virt_efi_get_next_variable(unsigned long *name_size,
         }
 
         if (boot_used_size && !finished) {
-                unsigned long size;
+                unsigned long size = 0;
                 u32 attr;
                 efi_status_t s;
                 void *tmp;
diff --git a/drivers/firmware/efi/efivars.c b/drivers/firmware/efi/efivars.c
index b623c599e572..8bd1bb6dbe47 100644
--- a/drivers/firmware/efi/efivars.c
+++ b/drivers/firmware/efi/efivars.c
@@ -523,13 +523,11 @@ static void efivar_update_sysfs_entries(struct work_struct *work)
         struct efivar_entry *entry;
         int err;
 
-        entry = kzalloc(sizeof(*entry), GFP_KERNEL);
-        if (!entry)
-                return;
-
         /* Add new sysfs entries */
         while (1) {
-                memset(entry, 0, sizeof(*entry));
+                entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+                if (!entry)
+                        return;
 
                 err = efivar_init(efivar_update_sysfs_entry, entry,
                                   true, false, &efivar_sysfs_list);
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);