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authorPeter Jones <pjones@redhat.com>2016-02-08 22:48:15 +0300
committerMatt Fleming <matt@codeblueprint.co.uk>2016-02-10 19:25:52 +0300
commited8b0de5a33d2a2557dce7f9429dca8cb5bc5879 (patch)
tree1dcd2e49cc432ae312677ec47453ec3abc18f1d2 /fs/efivarfs/inode.c
parent8282f5d9c17fe15a9e658c06e3f343efae1a2a2f (diff)
downloadlinux-ed8b0de5a33d2a2557dce7f9429dca8cb5bc5879.tar.xz
efi: Make efivarfs entries immutable by default
"rm -rf" is bricking some peoples' laptops because of variables being used to store non-reinitializable firmware driver data that's required to POST the hardware. These are 100% bugs, and they need to be fixed, but in the mean time it shouldn't be easy to *accidentally* brick machines. We have to have delete working, and picking which variables do and don't work for deletion is quite intractable, so instead make everything immutable by default (except for a whitelist), and make tools that aren't quite so broad-spectrum unset the immutable flag. Signed-off-by: Peter Jones <pjones@redhat.com> Tested-by: Lee, Chun-Yi <jlee@suse.com> Acked-by: Matthew Garrett <mjg59@coreos.com> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Diffstat (limited to 'fs/efivarfs/inode.c')
-rw-r--r--fs/efivarfs/inode.c30
1 files changed, 19 insertions, 11 deletions
diff --git a/fs/efivarfs/inode.c b/fs/efivarfs/inode.c
index 3381b9da9ee6..e2ab6d0497f2 100644
--- a/fs/efivarfs/inode.c
+++ b/fs/efivarfs/inode.c
@@ -15,7 +15,8 @@
#include "internal.h"
struct inode *efivarfs_get_inode(struct super_block *sb,
- const struct inode *dir, int mode, dev_t dev)
+ const struct inode *dir, int mode,
+ dev_t dev, bool is_removable)
{
struct inode *inode = new_inode(sb);
@@ -23,6 +24,7 @@ struct inode *efivarfs_get_inode(struct super_block *sb,
inode->i_ino = get_next_ino();
inode->i_mode = mode;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+ inode->i_flags = is_removable ? 0 : S_IMMUTABLE;
switch (mode & S_IFMT) {
case S_IFREG:
inode->i_fop = &efivarfs_file_operations;
@@ -102,22 +104,17 @@ static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid)
static int efivarfs_create(struct inode *dir, struct dentry *dentry,
umode_t mode, bool excl)
{
- struct inode *inode;
+ struct inode *inode = NULL;
struct efivar_entry *var;
int namelen, i = 0, err = 0;
+ bool is_removable = false;
if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
return -EINVAL;
- inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0);
- if (!inode)
- return -ENOMEM;
-
var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
- if (!var) {
- err = -ENOMEM;
- goto out;
- }
+ if (!var)
+ return -ENOMEM;
/* length of the variable name itself: remove GUID and separator */
namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1;
@@ -125,6 +122,16 @@ static int efivarfs_create(struct inode *dir, struct dentry *dentry,
efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1,
&var->var.VendorGuid);
+ if (efivar_variable_is_removable(var->var.VendorGuid,
+ dentry->d_name.name, namelen))
+ is_removable = true;
+
+ inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0, is_removable);
+ if (!inode) {
+ err = -ENOMEM;
+ goto out;
+ }
+
for (i = 0; i < namelen; i++)
var->var.VariableName[i] = dentry->d_name.name[i];
@@ -138,7 +145,8 @@ static int efivarfs_create(struct inode *dir, struct dentry *dentry,
out:
if (err) {
kfree(var);
- iput(inode);
+ if (inode)
+ iput(inode);
}
return err;
}