On Tue, Sep 12, 2023 at 01:56:53PM -0700, Casey Schaufler wrote:
> Implement Smack support for security_[gs]etselfattr.
> Refactor the setprocattr hook to avoid code duplication.
>
> Signed-off-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
> Reviewed-by: John Johansen <john.johansen@xxxxxxxxxxxxx>
> ---
> security/smack/smack_lsm.c | 95 ++++++++++++++++++++++++++++++++++++--
> 1 file changed, 90 insertions(+), 5 deletions(-)
>
> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
> index f73f9a2834eb..12160d060cc1 100644
> --- a/security/smack/smack_lsm.c
> +++ b/security/smack/smack_lsm.c
> @@ -3626,6 +3626,46 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
> return;
> }
>
> +/**
> + * smack_getselfattr - Smack current process attribute
> + * @attr: which attribute to fetch
> + * @ctx: buffer to receive the result
> + * @size: available size in, actual size out
> + * @flags: unused
> + *
> + * Fill the passed user space @ctx with the details of the requested
> + * attribute.
> + *
> + * Returns the number of attributes on success, an error code otherwise.
> + * There will only ever be one attribute.
> + */
> +static int smack_getselfattr(unsigned int attr, struct lsm_ctx __user *ctx,
> + size_t *size, u32 flags)
> +{
> + struct smack_known *skp = smk_of_current();
> + int total;
> + int slen;
> + int rc;
> +
> + if (attr != LSM_ATTR_CURRENT)
> + return -EOPNOTSUPP;
> +
> + slen = strlen(skp->smk_known) + 1;
> + total = ALIGN(slen + sizeof(*ctx), 8);
> + if (total > *size)
> + rc = -E2BIG;
> + else if (ctx)
> + rc = lsm_fill_user_ctx(ctx, skp->smk_known, slen, LSM_ID_SMACK,
> + 0);
> + else
> + rc = 1;
Can we move these checks into lsm_fill_user_ctx()? They are similar for
AppArmor and SELinux.
> +
> + *size = total;
> + if (rc >= 0)
> + return 1;
> + return rc;
> +}
