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Commit c77b8cdf authored by Mimi Zohar's avatar Mimi Zohar Committed by James Morris
Browse files

module: replace the existing LSM hook in init_module 



Both the init_module and finit_module syscalls call either directly
or indirectly the security_kernel_read_file LSM hook.  This patch
replaces the direct call in init_module with a call to the new
security_kernel_load_data hook and makes the corresponding changes
in SELinux, LoadPin, and IMA.

Signed-off-by: default avatarMimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Jeff Vander Stoep <jeffv@google.com>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Cc: Kees Cook <keescook@chromium.org>
Acked-by: default avatarJessica Yu <jeyu@kernel.org>
Acked-by: default avatarPaul Moore <paul@paul-moore.com>
Acked-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarJames Morris <james.morris@microsoft.com>
parent ef96837b

kernel/module.c

+1 −1
Original line number Diff line number Diff line
@@ -2876,7 +2876,7 @@ static int copy_module_from_user(const void __user *umod, unsigned long len, 
	if (info->len < sizeof(*(info->hdr)))

		return -ENOEXEC;



	err = security_kernel_read_file(NULL, READING_MODULE);

	err = security_kernel_load_data(LOADING_MODULE);

	if (err)

		return err;

security/integrity/ima/ima_main.c

+10 −13
Original line number Diff line number Diff line
@@ -429,16 +429,6 @@ 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) {

		if (!sig_enforce && (ima_appraise & IMA_APPRAISE_MODULES) &&

		    (ima_appraise & IMA_APPRAISE_ENFORCE)) {

			pr_err("impossible to appraise a module without a file descriptor. sig_enforce kernel parameter might help\n");

			return -EACCES;	/* INTEGRITY_UNKNOWN */

		}

		return 0;	/* We rely on module signature checking */

	}

	return 0;

}
@@ -479,9 +469,6 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size, 
		return 0;

	}



	if (!file && read_id == READING_MODULE) /* MODULE_SIG_FORCE enabled */

		return 0;



	/* permit signed certs */

	if (!file && read_id == READING_X509_CERTIFICATE)

		return 0;
@@ -510,6 +497,8 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size, 
 */

int ima_load_data(enum kernel_load_data_id id)

{

	bool sig_enforce;



	if ((ima_appraise & IMA_APPRAISE_ENFORCE) != IMA_APPRAISE_ENFORCE)

		return 0;
@@ -525,6 +514,14 @@ int ima_load_data(enum kernel_load_data_id id) 
			pr_err("Prevent firmware sysfs fallback loading.\n");

			return -EACCES;	/* INTEGRITY_UNKNOWN */

		}

		break;

	case LOADING_MODULE:

		sig_enforce = is_module_sig_enforced();



		if (!sig_enforce && (ima_appraise & IMA_APPRAISE_MODULES)) {

			pr_err("impossible to appraise a module without a file descriptor. sig_enforce kernel parameter might help\n");

			return -EACCES;	/* INTEGRITY_UNKNOWN */

		}

	default:

		break;

	}

security/loadpin/loadpin.c

+6 −0
Original line number Diff line number Diff line
@@ -173,9 +173,15 @@ static int loadpin_read_file(struct file *file, enum kernel_read_file_id id) 
	return 0;

}



static int loadpin_load_data(enum kernel_load_data_id id)

{

	return loadpin_read_file(NULL, (enum kernel_read_file_id) id);

}



static struct security_hook_list loadpin_hooks[] __lsm_ro_after_init = {

	LSM_HOOK_INIT(sb_free_security, loadpin_sb_free_security),

	LSM_HOOK_INIT(kernel_read_file, loadpin_read_file),

	LSM_HOOK_INIT(kernel_load_data, loadpin_load_data),

};



void __init loadpin_add_hooks(void)

security/selinux/hooks.c

+15 −0
Original line number Diff line number Diff line
@@ -4073,6 +4073,20 @@ static int selinux_kernel_read_file(struct file *file, 
	return rc;

}



static int selinux_kernel_load_data(enum kernel_load_data_id id)

{

	int rc = 0;



	switch (id) {

	case LOADING_MODULE:

		rc = selinux_kernel_module_from_file(NULL);

	default:

		break;

	}



	return rc;

}



static int selinux_task_setpgid(struct task_struct *p, pid_t pgid)

{

	return avc_has_perm(&selinux_state,
@@ -6972,6 +6986,7 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = { 
	LSM_HOOK_INIT(kernel_act_as, selinux_kernel_act_as),

	LSM_HOOK_INIT(kernel_create_files_as, selinux_kernel_create_files_as),

	LSM_HOOK_INIT(kernel_module_request, selinux_kernel_module_request),

	LSM_HOOK_INIT(kernel_load_data, selinux_kernel_load_data),

	LSM_HOOK_INIT(kernel_read_file, selinux_kernel_read_file),

	LSM_HOOK_INIT(task_setpgid, selinux_task_setpgid),

	LSM_HOOK_INIT(task_getpgid, selinux_task_getpgid),