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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: Seiji Aguchi <seiji.aguchi@hds.com>
Tested-by: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Matthew Garrett <matthew.garrett@nebula.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
wifi-calibration
Matt Fleming 2013-04-29 20:08:02 +01:00
parent 12abcfde1a
commit 8a415b8c05
3 changed files with 34 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/firmware/efi/efi-pstore.c
View File

@ -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;

53
drivers/firmware/efi/vars.c
View File

@ -688,32 +688,6 @@ 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
* @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)
{
const struct efivar_operations *ops = __efivars->ops;
efi_status_t status;
WARN_ON(!spin_is_locked(&__efivars->lock));
*size = 0;
status = ops->get_variable(entry->var.VariableName,
&entry->var.VendorGuid, NULL, size, NULL);
if (status != EFI_BUFFER_TOO_SMALL)
return efi_status_to_err(status);
return 0;
}
EXPORT_SYMBOL_GPL(__efivar_entry_size);
/**
* efivar_entry_size - obtain the size of a variable
* @entry: entry for this variable
@ -738,6 +712,33 @@ int efivar_entry_size(struct efivar_entry *entry, unsigned long *size)
}
EXPORT_SYMBOL_GPL(efivar_entry_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_get(struct efivar_entry *entry, u32 *attributes,
unsigned long *size, void *data)
{
const struct efivar_operations *ops = __efivars->ops;
efi_status_t status;
WARN_ON(!spin_is_locked(&__efivars->lock));
status = ops->get_variable(entry->var.VariableName,
&entry->var.VendorGuid,
attributes, size, data);
return efi_status_to_err(status);
}
EXPORT_SYMBOL_GPL(__efivar_entry_get);
/**
* efivar_entry_get - call get_variable()
* @entry: read data for this variable

3
include/linux/efi.h
View File

@ -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,