diff options
author | Jeremy Kerr <jeremy.kerr@canonical.com> | 2012-10-05 07:54:56 +0200 |
---|---|---|
committer | Matt Fleming <matt.fleming@intel.com> | 2012-10-30 11:39:17 +0100 |
commit | 0c542edde3cecc99b180a440ae33dcb7f28642ce (patch) | |
tree | 585dc08504412ff15610f4e716e93b485a4fb2ed /drivers/firmware/efivars.c | |
parent | efi: Add support for a UEFI variable filesystem (diff) | |
download | linux-0c542edde3cecc99b180a440ae33dcb7f28642ce.tar.xz linux-0c542edde3cecc99b180a440ae33dcb7f28642ce.zip |
efi: Handle deletions and size changes in efivarfs_write_file
A write to an efivarfs file will not always result in a variable of
'count' size after the EFI SetVariable() call. We may have appended to
the existing data (ie, with the EFI_VARIABLE_APPEND_WRITE attribute), or
even have deleted the variable (with an authenticated variable update,
with a zero datasize).
This change re-reads the updated variable from firmware, to check for
size changes and deletions. In the latter case, we need to drop the
dentry.
Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Diffstat (limited to 'drivers/firmware/efivars.c')
-rw-r--r-- | drivers/firmware/efivars.c | 49 |
1 files changed, 39 insertions, 10 deletions
diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c index b605c4849772..d7658b4a5010 100644 --- a/drivers/firmware/efivars.c +++ b/drivers/firmware/efivars.c @@ -658,6 +658,7 @@ static ssize_t efivarfs_file_write(struct file *file, u32 attributes; struct inode *inode = file->f_mapping->host; int datasize = count - sizeof(attributes); + unsigned long newdatasize; if (count < sizeof(attributes)) return -EINVAL; @@ -696,32 +697,60 @@ static ssize_t efivarfs_file_write(struct file *file, switch (status) { case EFI_SUCCESS: - mutex_lock(&inode->i_mutex); - i_size_write(inode, count); - mutex_unlock(&inode->i_mutex); break; case EFI_INVALID_PARAMETER: count = -EINVAL; - break; + goto out; case EFI_OUT_OF_RESOURCES: count = -ENOSPC; - break; + goto out; case EFI_DEVICE_ERROR: count = -EIO; - break; + goto out; case EFI_WRITE_PROTECTED: count = -EROFS; - break; + goto out; case EFI_SECURITY_VIOLATION: count = -EACCES; - break; + goto out; case EFI_NOT_FOUND: count = -ENOENT; - break; + goto out; default: count = -EINVAL; - break; + goto out; } + + /* + * Writing to the variable may have caused a change in size (which + * could either be an append or an overwrite), or the variable to be + * deleted. Perform a GetVariable() so we can tell what actually + * happened. + */ + newdatasize = 0; + status = efivars->ops->get_variable(var->var.VariableName, + &var->var.VendorGuid, + NULL, &newdatasize, + NULL); + + if (status == EFI_BUFFER_TOO_SMALL) { + mutex_lock(&inode->i_mutex); + i_size_write(inode, newdatasize + sizeof(attributes)); + mutex_unlock(&inode->i_mutex); + + } else if (status == EFI_NOT_FOUND) { + spin_lock(&efivars->lock); + list_del(&var->list); + spin_unlock(&efivars->lock); + efivar_unregister(var); + drop_nlink(inode); + dput(file->f_dentry); + + } else { + pr_warn("efivarfs: inconsistent EFI variable implementation? " + "status = %lx\n", status); + } + out: kfree(data); |