On Tue, 2017-10-24 at 15:37 -0200, Bruno E. O. Meneguele wrote:
> When the user requests MODULE_CHECK policy and its kernel is compiled
> with CONFIG_MODULE_SIG_FORCE not set, all modules would not load, just
> those loaded in initram time. One option the user would have would be
> set a kernel cmdline param (module.sig_enforce) to true, but the IMA
> module check code doesn't rely on this value, it checks just
> CONFIG_MODULE_SIG_FORCE.
>
> This patch solves this problem checking for the exported value of
> module.sig_enforce cmdline param intead of CONFIG_MODULE_SIG_FORCE,
> which holds the effective value (CONFIG || param).
>
> Signed-off-by: Bruno E. O. Meneguele <brdeoliv@xxxxxxxxxx>
> ---
> security/integrity/ima/ima_main.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
> index e4ab8ef8016e..d11a7fcc5c8b 100644
> --- a/security/integrity/ima/ima_main.c
> +++ b/security/integrity/ima/ima_main.c
> @@ -356,12 +356,12 @@ void ima_post_path_mknod(struct dentry *dentry)
> */
> int ima_read_file(struct file *file, enum kernel_read_file_id read_id)
> {
> + bool sig_enforce = is_module_sig_enforced();
> +
> if (!file && read_id == READING_MODULE) {
The only reason for getting here is that you're using the old module
load syscall. Is there a reason for not using the new one, which
passes the file descriptor?
thanks,
Mimi
> -#ifndef CONFIG_MODULE_SIG_FORCE
> - if ((ima_appraise & IMA_APPRAISE_MODULES) &&
> + if (!sig_enforce && (ima_appraise & IMA_APPRAISE_MODULES) &&
> (ima_appraise & IMA_APPRAISE_ENFORCE))
> return -EACCES; /* INTEGRITY_UNKNOWN */
> -#endif
> return 0; /* We rely on module signature checking */
> }
> return 0;
