Hi Nikolaus, all,

Hi Nikolaus,

On Wed, 2022-10-12 at 17:09 +0200, Nikolaus Voss wrote:

quoted

Commit cd3bc044af48 ("KEYS: encrypted: Instantiate key with user-provided
decrypted data") added key instantiation with user provided decrypted data.
The user data is hex-ascii-encoded but was just memcpy'ed to the binary buffer.
Fix this to use hex2bin instead.

quoted

Keys created from user provided decrypted data saved with "keyctl pipe"
are still valid, however if the key is recreated from decrypted data the
old key must be converted to the correct format. This can be done with a
small shell script, e.g.:

quoted

BROKENKEY=abcdefABCDEF1234567890aaaaaaaaaa
NEWKEY=$(echo -ne $BROKENKEY | xxd -p -c64)
keyctl add user masterkey "$(cat masterkey.bin)" @u
keyctl add encrypted testkey "new user:masterkey 32 $NEWKEY" @u

quoted

It is encouraged to switch to a new key because the effective key size
of the old keys is only half of the specified size.

Thank you for updating the patch description.

quoted

The corresponding test for the Linux Test Project ltp has been fixed
with this patch:
https://lists.linux.it/pipermail/ltp/2022-October/031060.html

FYI, we use lore, thus:

Link: https://lore.kernel.org/ltp/20221006081709.92303897@mail.steuer-voss.de/ (local)

Perhaps make this a "Link:" line and move it before your "Signed-off-
by".

quoted

Changes
=======

As per Documentation/process/submitting-patches.rst, the changelog
belongs after the "---" separator. 

quoted

v2: - clarify commit message, add example to recover old/broken keys
    - improve example in Documentation/security/keys/trusted-encrypted.rst
    - add link to ltp patch

quoted

Fixes: cd3bc044af48 ("KEYS: encrypted: Instantiate key with user-provided decrypted data")
Cc: stable <stable@kernel.org>
Signed-off-by: Nikolaus Voss <redacted>
---
 Documentation/security/keys/trusted-encrypted.rst | 3 ++-
 security/keys/encrypted-keys/encrypted.c          | 6 +++---
 2 files changed, 5 insertions(+), 4 deletions(-)

quoted

diff --git a/Documentation/security/keys/trusted-encrypted.rst b/Documentation/security/keys/trusted-encrypted.rst
index 0bfb4c339748..e81e47db0b4c 100644
--- a/Documentation/security/keys/trusted-encrypted.rst
+++ b/Documentation/security/keys/trusted-encrypted.rst

@@ -350,7 +350,8 @@ Load an encrypted key "evm" from saved blob::

quoted

 Instantiate an encrypted key "evm" using user-provided decrypted data::

quoted

-    $ keyctl add encrypted evm "new default user:kmk 32 `cat evm_decrypted_data.blob`" @u
+    $ evmkey=abcdefABCDEF1234567890aaaaaaaaaaabcdefABCDEF1234567890aaaaaaaaaa
+    $ keyctl add encrypted evm "new default user:kmk 32 $evmkey" @u
     794890253

As example code is often re-used, I would avoid including the key data
on the command line.