Commit-ID: 0c542edde3cecc99b180a440ae33dcb7f28642ce
Gitweb: http://git.kernel.org/tip/0c542edde3cecc99b180a440ae33dcb7f28642ce
Author: Jeremy Kerr <jeremy.kerr@xxxxxxxxxxxxx>
AuthorDate: Fri, 5 Oct 2012 13:54:56 +0800
Committer: Matt Fleming <matt.fleming@xxxxxxxxx>
CommitDate: Tue, 30 Oct 2012 10:39:17 +0000
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@xxxxxxxxxxxxx>
Signed-off-by: Matt Fleming <matt.fleming@xxxxxxxxx>
---
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 b605c48..d7658b4 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);
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|