This is a note to let you know that I've just added the patch titled
efi: be more paranoid about available space when creating variables
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
efi-be-more-paranoid-about-available-space-when-creating-variables.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 7feecf3f2b587e535550bb3e7bf75b2fee06fccf Mon Sep 17 00:00:00 2001
From: Josh Boyer <jwboyer@xxxxxxxxxx>
Date: Mon, 11 Mar 2013 17:48:53 -0400
Subject: efi: be more paranoid about available space when creating variables
From: Josh Boyer <jwboyer@xxxxxxxxxx>
commit 68d929862e29a8b52a7f2f2f86a0600423b093cd upstream.
UEFI variables are typically stored in flash. For various reasons, avaiable
space is typically not reclaimed immediately upon the deletion of a
variable - instead, the system will garbage collect during initialisation
after a reboot.
Some systems appear to handle this garbage collection extremely poorly,
failing if more than 50% of the system flash is in use. This can result in
the machine refusing to boot. The safest thing to do for the moment is to
forbid writes if they'd end up using more than half of the storage space.
We can make this more finegrained later if we come up with a method for
identifying the broken machines.
Signed-off-by: Matthew Garrett <matthew.garrett@xxxxxxxxxx>
Signed-off-by: Matt Fleming <matt.fleming@xxxxxxxxx>
[bwh: Backported to 3.2:
- Drop efivarfs changes and unused check_var_size()
- Add error codes to include/linux/efi.h, added upstream by
commit 5d9db883761a ('efi: Add support for a UEFI variable filesystem')
- Add efi_status_to_err(), added upstream by commit 7253eaba7b17
('efivarfs: Return an error if we fail to read a variable')]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Cc: Rui Xiang <rui.xiang@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/firmware/efivars.c | 88 +++++++++++++++++++++++++++++++++++++++------
include/linux/efi.h | 5 ++
2 files changed, 82 insertions(+), 11 deletions(-)
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -409,6 +409,30 @@ get_var_data(struct efivars *efivars, st
return status;
}
+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)
+ 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;
+}
+
static ssize_t
efivar_guid_read(struct efivar_entry *entry, char *buf)
{
@@ -530,11 +554,16 @@ efivar_store_raw(struct efivar_entry *en
}
spin_lock_irq(&efivars->lock);
- status = efivars->ops->set_variable(new_var->VariableName,
- &new_var->VendorGuid,
- new_var->Attributes,
- new_var->DataSize,
- new_var->Data);
+
+ status = check_var_size_locked(efivars, new_var->Attributes,
+ new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
+
+ if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED)
+ status = efivars->ops->set_variable(new_var->VariableName,
+ &new_var->VendorGuid,
+ new_var->Attributes,
+ new_var->DataSize,
+ new_var->Data);
spin_unlock_irq(&efivars->lock);
@@ -641,6 +670,36 @@ efivar_unregister(struct efivar_entry *v
kobject_put(&var->kobj);
}
+static int efi_status_to_err(efi_status_t status)
+{
+ int err;
+
+ switch (status) {
+ case EFI_INVALID_PARAMETER:
+ err = -EINVAL;
+ break;
+ case EFI_OUT_OF_RESOURCES:
+ err = -ENOSPC;
+ break;
+ case EFI_DEVICE_ERROR:
+ err = -EIO;
+ break;
+ case EFI_WRITE_PROTECTED:
+ err = -EROFS;
+ break;
+ case EFI_SECURITY_VIOLATION:
+ err = -EACCES;
+ break;
+ case EFI_NOT_FOUND:
+ err = -ENOENT;
+ break;
+ default:
+ err = -EINVAL;
+ }
+
+ return err;
+}
+
#ifdef CONFIG_PSTORE
static int efi_pstore_open(struct pstore_info *psi)
@@ -711,7 +770,6 @@ static int efi_pstore_write(enum pstore_
struct efivars *efivars = psi->data;
struct efivar_entry *entry, *found = NULL;
int i, ret = 0;
- u64 storage_space, remaining_space, max_variable_size;
efi_status_t status = EFI_NOT_FOUND;
unsigned long flags;
@@ -725,11 +783,11 @@ static int efi_pstore_write(enum pstore_
* size: a size of logging data
* DUMP_NAME_LEN * 2: a maximum size of variable name
*/
- status = efivars->ops->query_variable_info(PSTORE_EFI_ATTRIBUTES,
- &storage_space,
- &remaining_space,
- &max_variable_size);
- if (status || remaining_space < size + DUMP_NAME_LEN * 2) {
+
+ status = check_var_size_locked(efivars, PSTORE_EFI_ATTRIBUTES,
+ size + DUMP_NAME_LEN * 2);
+
+ if (status) {
spin_unlock_irqrestore(&efivars->lock, flags);
*id = part;
return -ENOSPC;
@@ -877,6 +935,14 @@ static ssize_t efivar_create(struct file
return -EINVAL;
}
+ status = check_var_size_locked(efivars, new_var->Attributes,
+ new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
+
+ if (status && status != EFI_UNSUPPORTED) {
+ spin_unlock_irq(&efivars->lock);
+ return efi_status_to_err(status);
+ }
+
/* now *really* create the variable via EFI */
status = efivars->ops->set_variable(new_var->VariableName,
&new_var->VendorGuid,
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -29,7 +29,12 @@
#define EFI_UNSUPPORTED ( 3 | (1UL << (BITS_PER_LONG-1)))
#define EFI_BAD_BUFFER_SIZE ( 4 | (1UL << (BITS_PER_LONG-1)))
#define EFI_BUFFER_TOO_SMALL ( 5 | (1UL << (BITS_PER_LONG-1)))
+#define EFI_NOT_READY ( 6 | (1UL << (BITS_PER_LONG-1)))
+#define EFI_DEVICE_ERROR ( 7 | (1UL << (BITS_PER_LONG-1)))
+#define EFI_WRITE_PROTECTED ( 8 | (1UL << (BITS_PER_LONG-1)))
+#define EFI_OUT_OF_RESOURCES ( 9 | (1UL << (BITS_PER_LONG-1)))
#define EFI_NOT_FOUND (14 | (1UL << (BITS_PER_LONG-1)))
+#define EFI_SECURITY_VIOLATION (26 | (1UL << (BITS_PER_LONG-1)))
typedef unsigned long efi_status_t;
typedef u8 efi_bool_t;
Patches currently in stable-queue which might be from jwboyer@xxxxxxxxxx are
queue-3.4/efi-be-more-paranoid-about-available-space-when-creating-variables.patch
queue-3.4/efivars-disable-external-interrupt-while-holding-efivars-lock.patch
queue-3.4/efivars-allow-disabling-use-as-a-pstore-backend.patch
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