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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: Mimi 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: Jessica Yu <jeyu@kernel.org>
Acked-by: Paul Moore <paul@paul-moore.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.morris@microsoft.com>
This commit is contained in:
Mimi Zohar 2018-07-13 14:06:02 -04:00 committed by James Morris
parent ef96837b0d
commit c77b8cdf74
4 changed files with 32 additions and 14 deletions
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2
kernel/module.c
View File

@ -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;

23
security/integrity/ima/ima_main.c
View File

@ -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;
}

6
security/loadpin/loadpin.c
View File

@ -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)

15
security/selinux/hooks.c
View File

@ -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),