From: Jeremy Kerr <jeremy.kerr@canonical.com>
To: linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: <glin@suse.com>,
Lee@grenadilla.canonical.com, Chun-Yi <jlee@suse.com>,
Matthew Garrett <mjg@redhat.com>, Peter Jones <pjones@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Matt Fleming <matt.fleming@intel.com>
Subject: [PATCH 3/3] efi: Handle deletions and size changes in efivarfs_write_file
Date: Fri, 05 Oct 2012 13:54:56 +0800 [thread overview]
Message-ID: <1349416496.810982.659496647274.3.gpush@pecola> (raw)
In-Reply-To: <1349416496.810727.310563927016.1.gpush@pecola>
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>
---
drivers/firmware/efivars.c | 49 +++++++++++++++++++++++++++++--------
1 file changed, 39 insertions(+), 10 deletions(-)
diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index e1253d6..a422de3 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -647,6 +647,7 @@ 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;
@@ -685,32 +686,60 @@ 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);
next prev parent reply other threads:[~2012-10-05 6:56 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-05 5:54 [PATCH 1/3] efi: Add support for a UEFI variable filesystem Jeremy Kerr
2012-10-05 5:54 ` [PATCH 2/3] efi: add efivars kobject to efi sysfs folder Jeremy Kerr
2012-10-05 6:51 ` joeyli
2012-10-05 7:44 ` Jeremy Kerr
2012-10-05 5:54 ` Jeremy Kerr [this message]
2012-10-06 19:32 ` [PATCH 1/3] efi: Add support for a UEFI variable filesystem Matt Fleming
2012-10-11 10:32 ` [PATCH 0/5] efivarfs: fixes and cleanups Andy Whitcroft
2012-10-11 10:32 ` [PATCH 1/5] efivarfs: efivarfs_file_read ensure we free data in error paths Andy Whitcroft
2012-10-11 13:53 ` Jeremy Kerr
2012-10-11 10:32 ` [PATCH 2/5] efivarfs: efivarfs_create() ensure we drop our reference on inode on error Andy Whitcroft
2012-10-11 14:13 ` Jeremy Kerr
2012-10-12 19:03 ` Khalid Aziz
2012-10-12 19:21 ` Matt Fleming
2012-10-12 20:11 ` Khalid Aziz
2012-10-11 10:32 ` [PATCH 3/5] efivarfs: efivarfs_fill_super() fix inode reference counts Andy Whitcroft
2012-10-11 14:10 ` Jeremy Kerr
2012-10-11 10:32 ` [PATCH 4/5] efivarfs: efivarfs_fill_super() ensure we free our temporary name Andy Whitcroft
2012-10-11 13:59 ` Jeremy Kerr
2012-10-11 10:32 ` [PATCH 5/5] efivarfs: efivarfs_fill_super() ensure we clean up correctly on error Andy Whitcroft
2012-10-11 14:04 ` Jeremy Kerr
2012-10-11 16:06 ` Andy Whitcroft
2012-10-16 9:16 ` Jeremy Kerr
2012-10-11 12:40 ` [PATCH 0/5] efivarfs: fixes and cleanups Matthew Garrett
2012-10-11 12:48 ` Matt Fleming
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