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authorPeter Jones <pjones@redhat.com>2016-02-08 14:48:15 -0500
committerMatt Fleming <matt@codeblueprint.co.uk>2016-02-10 16:25:52 +0000
commited8b0de5a33d2a2557dce7f9429dca8cb5bc5879 (patch)
tree1dcd2e49cc432ae312677ec47453ec3abc18f1d2 /fs/efivarfs/file.c
parent8282f5d9c17fe15a9e658c06e3f343efae1a2a2f (diff)
downloadlinux-ed8b0de5a33d2a2557dce7f9429dca8cb5bc5879.tar.bz2
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/file.c')
-rw-r--r--fs/efivarfs/file.c70
1 files changed, 70 insertions, 0 deletions
diff --git a/fs/efivarfs/file.c b/fs/efivarfs/file.c
index c424e4813ec8..d48e0d261d78 100644
--- a/fs/efivarfs/file.c
+++ b/fs/efivarfs/file.c
@@ -10,6 +10,7 @@
#include <linux/efi.h>
#include <linux/fs.h>
#include <linux/slab.h>
+#include <linux/mount.h>
#include "internal.h"
@@ -103,9 +104,78 @@ out_free:
return size;
}
+static int
+efivarfs_ioc_getxflags(struct file *file, void __user *arg)
+{
+ struct inode *inode = file->f_mapping->host;
+ unsigned int i_flags;
+ unsigned int flags = 0;
+
+ i_flags = inode->i_flags;
+ if (i_flags & S_IMMUTABLE)
+ flags |= FS_IMMUTABLE_FL;
+
+ if (copy_to_user(arg, &flags, sizeof(flags)))
+ return -EFAULT;
+ return 0;
+}
+
+static int
+efivarfs_ioc_setxflags(struct file *file, void __user *arg)
+{
+ struct inode *inode = file->f_mapping->host;
+ unsigned int flags;
+ unsigned int i_flags = 0;
+ int error;
+
+ if (!inode_owner_or_capable(inode))
+ return -EACCES;
+
+ if (copy_from_user(&flags, arg, sizeof(flags)))
+ return -EFAULT;
+
+ if (flags & ~FS_IMMUTABLE_FL)
+ return -EOPNOTSUPP;
+
+ if (!capable(CAP_LINUX_IMMUTABLE))
+ return -EPERM;
+
+ if (flags & FS_IMMUTABLE_FL)
+ i_flags |= S_IMMUTABLE;
+
+
+ error = mnt_want_write_file(file);
+ if (error)
+ return error;
+
+ inode_lock(inode);
+ inode_set_flags(inode, i_flags, S_IMMUTABLE);
+ inode_unlock(inode);
+
+ mnt_drop_write_file(file);
+
+ return 0;
+}
+
+long
+efivarfs_file_ioctl(struct file *file, unsigned int cmd, unsigned long p)
+{
+ void __user *arg = (void __user *)p;
+
+ switch (cmd) {
+ case FS_IOC_GETFLAGS:
+ return efivarfs_ioc_getxflags(file, arg);
+ case FS_IOC_SETFLAGS:
+ return efivarfs_ioc_setxflags(file, arg);
+ }
+
+ return -ENOTTY;
+}
+
const struct file_operations efivarfs_file_operations = {
.open = simple_open,
.read = efivarfs_file_read,
.write = efivarfs_file_write,
.llseek = no_llseek,
+ .unlocked_ioctl = efivarfs_file_ioctl,
};