Commit 8a415b8c authored by Matt Fleming's avatar Matt Fleming
Browse files

efi, pstore: Read data from variable store before memcpy() 



Seiji reported getting empty dmesg-* files, because the data was never
actually read in efi_pstore_read_func(), and so the memcpy() was copying
garbage data.

This patch necessitated adding __efivar_entry_get() which is callable
between efivar_entry_iter_{begin,end}(). We can also delete
__efivar_entry_size() because efi_pstore_read_func() was the only
caller.

Reported-by: default avatarSeiji Aguchi <seiji.aguchi@hds.com>
Tested-by: default avatarSeiji Aguchi <seiji.aguchi@hds.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Matthew Garrett <matthew.garrett@nebula.com>
Signed-off-by: default avatarMatt Fleming <matt.fleming@intel.com>
parent 12abcfde

drivers/firmware/efi/efi-pstore.c

+5 −1
Original line number Diff line number Diff line
@@ -73,7 +73,11 @@ static int efi_pstore_read_func(struct efivar_entry *entry, void *data) 
	} else

		return 0;



	__efivar_entry_size(entry, &size);

	entry->var.DataSize = 1024;

	__efivar_entry_get(entry, &entry->var.Attributes,

			   &entry->var.DataSize, entry->var.Data);

	size = entry->var.DataSize;



	*cb_data->buf = kmalloc(size, GFP_KERNEL);

	if (*cb_data->buf == NULL)

		return -ENOMEM;

drivers/firmware/efi/vars.c

+23 −22
Original line number Diff line number Diff line
@@ -689,54 +689,55 @@ struct efivar_entry *efivar_entry_find(efi_char16_t *name, efi_guid_t guid, 
EXPORT_SYMBOL_GPL(efivar_entry_find);



/**

 * __efivar_entry_size - obtain the size of a variable

 * efivar_entry_size - obtain the size of a variable

 * @entry: entry for this variable

 * @size: location to store the variable's size

 *

 * The caller MUST call efivar_entry_iter_begin() and

 * efivar_entry_iter_end() before and after the invocation of this

 * function, respectively.

 */

int __efivar_entry_size(struct efivar_entry *entry, unsigned long *size)

int efivar_entry_size(struct efivar_entry *entry, unsigned long *size)

{

	const struct efivar_operations *ops = __efivars->ops;

	efi_status_t status;



	WARN_ON(!spin_is_locked(&__efivars->lock));



	*size = 0;



	spin_lock_irq(&__efivars->lock);

	status = ops->get_variable(entry->var.VariableName,

				   &entry->var.VendorGuid, NULL, size, NULL);

	spin_unlock_irq(&__efivars->lock);



	if (status != EFI_BUFFER_TOO_SMALL)

		return efi_status_to_err(status);



	return 0;

}

EXPORT_SYMBOL_GPL(__efivar_entry_size);

EXPORT_SYMBOL_GPL(efivar_entry_size);



/**

 * efivar_entry_size - obtain the size of a variable

 * @entry: entry for this variable

 * @size: location to store the variable's size

 * __efivar_entry_get - call get_variable()

 * @entry: read data for this variable

 * @attributes: variable attributes

 * @size: size of @data buffer

 * @data: buffer to store variable data

 *

 * The caller MUST call efivar_entry_iter_begin() and

 * efivar_entry_iter_end() before and after the invocation of this

 * function, respectively.

 */

int efivar_entry_size(struct efivar_entry *entry, unsigned long *size)

int __efivar_entry_get(struct efivar_entry *entry, u32 *attributes,

		       unsigned long *size, void *data)

{

	const struct efivar_operations *ops = __efivars->ops;

	efi_status_t status;



	*size = 0;

	WARN_ON(!spin_is_locked(&__efivars->lock));



	spin_lock_irq(&__efivars->lock);

	status = ops->get_variable(entry->var.VariableName,

				   &entry->var.VendorGuid, NULL, size, NULL);

	spin_unlock_irq(&__efivars->lock);

				   &entry->var.VendorGuid,

				   attributes, size, data);



	if (status != EFI_BUFFER_TOO_SMALL)

	return efi_status_to_err(status);



	return 0;

}

EXPORT_SYMBOL_GPL(efivar_entry_size);

EXPORT_SYMBOL_GPL(__efivar_entry_get);



/**

 * efivar_entry_get - call get_variable()

include/linux/efi.h

+2 −1
Original line number Diff line number Diff line
@@ -808,8 +808,9 @@ void efivar_entry_remove(struct efivar_entry *entry); 
int __efivar_entry_delete(struct efivar_entry *entry);

int efivar_entry_delete(struct efivar_entry *entry);



int __efivar_entry_size(struct efivar_entry *entry, unsigned long *size);

int efivar_entry_size(struct efivar_entry *entry, unsigned long *size);

int __efivar_entry_get(struct efivar_entry *entry, u32 *attributes,

		       unsigned long *size, void *data);

int efivar_entry_get(struct efivar_entry *entry, u32 *attributes,

		     unsigned long *size, void *data);

int efivar_entry_set(struct efivar_entry *entry, u32 attributes,

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