On Nov 7, 2023 Roberto Sassu <roberto.sassu@xxxxxxxxxxxxxxx> wrote:
>
> In preparation for moving IMA and EVM to the LSM infrastructure, introduce
> the inode_post_create_tmpfile hook.
>
> As temp files can be made persistent, treat new temp files like other new
> files, so that the file hash is calculated and stored in the security
> xattr.
>
> LSMs could also take some action after temp files have been created.
>
> The new hook cannot return an error and cannot cause the operation to be
> canceled.
>
> Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
> Acked-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
> Reviewed-by: Mimi Zohar <zohar@xxxxxxxxxxxxx>
> ---
> fs/namei.c | 1 +
> include/linux/lsm_hook_defs.h | 2 ++
> include/linux/security.h | 6 ++++++
> security/security.c | 15 +++++++++++++++
> 4 files changed, 24 insertions(+)
...
> diff --git a/security/security.c b/security/security.c
> index 5eaf5f2aa5ea..ca650c285fd9 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -2013,6 +2013,21 @@ int security_inode_create(struct inode *dir, struct dentry *dentry,
> }
> EXPORT_SYMBOL_GPL(security_inode_create);
>
> +/**
> + * security_inode_post_create_tmpfile() - Update inode security of new tmpfile
> + * @idmap: idmap of the mount
> + * @inode: inode of the new tmpfile
> + *
> + * Update inode security data after a tmpfile has been created.
> + */
> +void security_inode_post_create_tmpfile(struct mnt_idmap *idmap,
> + struct inode *inode)
> +{
> + if (unlikely(IS_PRIVATE(inode)))
> + return;
See my previous comments/questions about checking for S_PRIVATE here.
> + call_void_hook(inode_post_create_tmpfile, idmap, inode);
> +}
> +
> /**
> * security_inode_link() - Check if creating a hard link is allowed
> * @old_dentry: existing file
> --
> 2.34.1
--
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