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| author | Peter Jones <pjones@redhat.com> | 2016-02-08 22:48:15 +0300 |
|---|---|---|
| committer | Luis Henriques <luis.henriques@canonical.com> | 2016-03-24 13:01:20 +0300 |
| commit | a3c70636ed1ed48f874193bc397ee0087dad7c0a (patch) | |
| tree | 1f22bc1571d1229862306e1f05266d8b578cc084 /Documentation | |
| parent | 67217cf59d0aa23bb8bba12aae0dff65f23f26a5 (diff) | |
| download | linux-a3c70636ed1ed48f874193bc397ee0087dad7c0a.tar.xz | |
efi: Make efivarfs entries immutable by default
commit ed8b0de5a33d2a2557dce7f9429dca8cb5bc5879 upstream.
"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>
[ luis: backported to 3.16:
- use mutex_lock/unlock() instead of inode_lock/unlock()
- use root->d_inode instead of d_inode() ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/filesystems/efivarfs.txt | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/Documentation/filesystems/efivarfs.txt b/Documentation/filesystems/efivarfs.txt index c477af086e65..686a64bba775 100644 --- a/Documentation/filesystems/efivarfs.txt +++ b/Documentation/filesystems/efivarfs.txt @@ -14,3 +14,10 @@ filesystem. efivarfs is typically mounted like this, mount -t efivarfs none /sys/firmware/efi/efivars + +Due to the presence of numerous firmware bugs where removing non-standard +UEFI variables causes the system firmware to fail to POST, efivarfs +files that are not well-known standardized variables are created +as immutable files. This doesn't prevent removal - "chattr -i" will work - +but it does prevent this kind of failure from being accomplished +accidentally. |