Re: [PATCH v5 1/6] reiserfs: Switch to security_inode_init_security()

From: Mimi Zohar
Date: Wed Nov 23 2022 - 08:32:36 EST


On Wed, 2022-11-23 at 10:51 +0100, Roberto Sassu wrote:
> From: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
>
> In preparation for removing security_old_inode_init_security(), switch to
> security_inode_init_security().
>
> Define the initxattrs callback reiserfs_initxattrs(), to populate the
> name/value/len triple in the reiserfs_security_handle() with the first
> xattr provided by LSMs. Multiple xattrs are currently not supported, as the
> reiserfs_security_handle structure is exported to user space.

The security_old_inode_init_security() hook doesn't support EVM.
Missing from this patch description is whether the move to the
security_inode_init_security() hook changes security.evm. FYI, I'm not
suggesting it should. Please update the patch description accordingly.

Mimi

>
> In reiserfs_initxattrs(), make a copy of the first xattr value, as
> security_inode_init_security() frees it.
>
> After the call to security_inode_init_security(), remove the check for
> returning -EOPNOTSUPP, as security_inode_init_security() changes it to
> zero.
>
> Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
> ---
> fs/reiserfs/xattr_security.c | 23 ++++++++++++++++++-----
> 1 file changed, 18 insertions(+), 5 deletions(-)
>
> diff --git a/fs/reiserfs/xattr_security.c b/fs/reiserfs/xattr_security.c
> index 857a65b05726..0ba96757681d 100644
> --- a/fs/reiserfs/xattr_security.c
> +++ b/fs/reiserfs/xattr_security.c
> @@ -39,6 +39,22 @@ static bool security_list(struct dentry *dentry)
> return !IS_PRIVATE(d_inode(dentry));
> }
>
> +static int
> +reiserfs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
> + void *fs_info)
> +{
> + struct reiserfs_security_handle *sec = fs_info;
> +
> + sec->value = kmemdup(xattr_array->value, xattr_array->value_len,
> + GFP_KERNEL);
> + if (!sec->value)
> + return -ENOMEM;
> +
> + sec->name = xattr_array->name;
> + sec->length = xattr_array->value_len;
> + return 0;
> +}
> +
> /* Initializes the security context for a new inode and returns the number
> * of blocks needed for the transaction. If successful, reiserfs_security
> * must be released using reiserfs_security_free when the caller is done. */
> @@ -56,12 +72,9 @@ int reiserfs_security_init(struct inode *dir, struct inode *inode,
> if (IS_PRIVATE(dir))
> return 0;
>
> - error = security_old_inode_init_security(inode, dir, qstr, &sec->name,
> - &sec->value, &sec->length);
> + error = security_inode_init_security(inode, dir, qstr,
> + &reiserfs_initxattrs, sec);
> if (error) {
> - if (error == -EOPNOTSUPP)
> - error = 0;
> -
> sec->name = NULL;
> sec->value = NULL;
> sec->length = 0;