Re: [PATCH v9 11/25] security: Introduce inode_post_removexattr hook

From: Paul Moore
Date: Wed Feb 07 2024 - 22:24:44 EST


On Jan 15, 2024 Roberto Sassu <roberto.sassu@xxxxxxxxxxxxxxx> wrote:
>
> In preparation for moving IMA and EVM to the LSM infrastructure, introduce
> the inode_post_removexattr hook.
>
> At inode_removexattr hook, EVM verifies the file's existing HMAC value. At
> inode_post_removexattr, EVM re-calculates the file's HMAC with the passed
> xattr removed and other file metadata.
>
> Other LSMs could similarly take some action after successful xattr removal.
>
> The new hook cannot return an error and cannot cause the operation to be
> reverted.
>
> Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
> Reviewed-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>
> Reviewed-by: Mimi Zohar <zohar@xxxxxxxxxxxxx>
> Reviewed-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
> ---
> fs/xattr.c | 9 +++++----
> include/linux/lsm_hook_defs.h | 2 ++
> include/linux/security.h | 5 +++++
> security/security.c | 14 ++++++++++++++
> 4 files changed, 26 insertions(+), 4 deletions(-)

Acked-by: Paul Moore <paul@xxxxxxxxxxxxxx>

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