diff options
author | Jeremy Kerr <jeremy.kerr@canonical.com> | 2012-10-05 13:54:56 +0800 |
---|---|---|
committer | John Rigby <john.rigby@linaro.org> | 2012-11-14 18:19:43 -0700 |
commit | 6b6226bf8ed54d7d62e2c8e0ca3acaac6827acdb (patch) | |
tree | b6bfdb390ce4e538127b663e1da817741b66b6dd | |
parent | 759f3c3c14d0fdb3acfda21fb5e74f70a915bc75 (diff) |
UBUNTU: SAUCE: efi: Handle deletions and size changes in efivarfs_write_file
BugLink: http://bugs.launchpad.net/bugs/1063061
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>
(cherry-picked from commit bd5967e2702f3e918c23b3fb1590312699645608 git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi.git)
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
-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 93027ba5550..14969ceb71e 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); |