On Jun 29, 2023 Casey Schaufler <casey@xxxxxxxxxxxxxxxx> wrote:
>
> Implement Smack support for security_[gs]etselfattr.
> Refactor the setprocattr hook to avoid code duplication.
>
> Signed-off-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
> ---
> security/smack/smack_lsm.c | 106 +++++++++++++++++++++++++++++++++++--
> 1 file changed, 101 insertions(+), 5 deletions(-)
>
> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
> index cf847cfe5ed8..4a84639e9db9 100644
> --- a/security/smack/smack_lsm.c
> +++ b/security/smack/smack_lsm.c
...
> @@ -3629,6 +3668,61 @@ static int smack_setprocattr(const char *name, void *value, size_t size)
> return size;
> }
>
> +/**
> + * smack_setselfattr - Set a Smack process attribute
> + * @attr: which attribute to set
> + * @ctx: buffer containing the data
> + * @size: size of @ctx
> + * @flags: unused
> + *
> + * Fill the passed user space @ctx with the details of the requested
> + * attribute.
> + *
> + * Returns 0 on success, an error code otherwise.
> + */
> +static int smack_setselfattr(unsigned int attr, struct lsm_ctx __user *ctx,
> + size_t size, u32 flags)
> +{
> + struct lsm_ctx *lctx;
> + int rc;
> +
> + lctx = kmalloc(size, GFP_KERNEL);
> + if (lctx == NULL)
> + return -ENOMEM;
> +
> + if (copy_from_user(lctx, ctx, size))
> + rc = -EFAULT;
> + else if (lctx->ctx_len > size)
> + rc = -E2BIG;
> + else
> + rc = do_setattr(attr, lctx->ctx, lctx->ctx_len);
> +
> + kfree(lctx);
> + if (rc > 0)
> + return 0;
> + return rc;
> +}
> +
> +/**
> + * smack_setprocattr - Smack process attribute setting
> + * @name: the name of the attribute in /proc/.../attr
> + * @value: the value to set
> + * @size: the size of the value
> + *
> + * Sets the Smack value of the task. Only setting self
> + * is permitted and only with privilege
> + *
> + * Returns the length of the smack label or an error code
> + */
> +static int smack_setprocattr(const char *name, void *value, size_t size)
> +{
> + int attr = lsm_name_to_attr(name);
> +
> + if (attr == LSM_ATTR_UNDEF)
That should be '(attr != LSM_ATTR_UNDEF)', right?
> + return do_setattr(attr, value, size);
> + return -EINVAL;
> +}
> +
> /**
> * smack_unix_stream_connect - Smack access on UDS
> * @sock: one sock
> @@ -4939,6 +5033,8 @@ static struct security_hook_list smack_hooks[] __ro_after_init = {
>
> LSM_HOOK_INIT(d_instantiate, smack_d_instantiate),
>
> + LSM_HOOK_INIT(getselfattr, smack_getselfattr),
> + LSM_HOOK_INIT(setselfattr, smack_setselfattr),
> LSM_HOOK_INIT(getprocattr, smack_getprocattr),
> LSM_HOOK_INIT(setprocattr, smack_setprocattr),
>
> --
> 2.40.1
--
paul-moore.com
