Utilize existing kernel_read_file hook on kernel module load.
Add module_load permission to the system class.
Enforces restrictions on kernel module origin when calling the
finit_module syscall. The hook checks that source type has
permission module_load for the target type.
Example for finit_module:
allow foo bar_file:system module_load;
Similarly restrictions are enforced on kernel module loading when
calling the init_module syscall. The hook checks that source
type has permission module_load with itself as the target object
because the kernel module is sourced from the calling process.
Example for init_module:
allow foo foo:system module_load;
Signed-off-by: Jeff Vander Stoep <jeffv@xxxxxxxxxx>
---
v2: The target type for init_module changed from SECINITSID_KERNEL
to the same type as the source.
v3: Use inode_security() to ensure inode's label is revalidated.
security/selinux/hooks.c | 46 +++++++++++++++++++++++++++++++++++++
security/selinux/include/classmap.h | 2 +-
2 files changed, 47 insertions(+), 1 deletion(-)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 3fa3ca5..231c897 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3719,6 +3719,51 @@ static int selinux_kernel_module_request(char *kmod_name)
SYSTEM__MODULE_REQUEST, &ad);
}
+static int selinux_kernel_module_from_file(struct file *file)
+{
+ struct common_audit_data ad;
+ struct inode_security_struct *isec;
+ struct file_security_struct *fsec;
+ u32 sid = current_sid();
+ int rc;
+
+ /* init_module */
+ if (file == NULL)
+ return avc_has_perm(sid, sid, SECCLASS_SYSTEM,
+ SYSTEM__MODULE_LOAD, NULL);
+
+ /* finit_module */
+ ad.type = LSM_AUDIT_DATA_PATH;
+ ad.u.path = file->f_path;
+
+ isec = inode_security(file_inode(file));
+ fsec = file->f_security;
+
+ if (sid != fsec->sid) {
+ rc = avc_has_perm(sid, fsec->sid, SECCLASS_FD, FD__USE, &ad);
+ if (rc)
+ return rc;
+ }
+
+ return avc_has_perm(sid, isec->sid, SECCLASS_SYSTEM,
+ SYSTEM__MODULE_LOAD, &ad);
+}
+
+static selinux_kernel_read_file(struct file *file, enum kernel_read_file_id id)
+{
+ int rc = 0;
+
+ switch (id) {
+ case READING_MODULE:
+ rc = selinux_kernel_module_from_file(file);
+ break;
+ default:
+ break;
+ }
+
+ return rc;
+}
+
static int selinux_task_setpgid(struct task_struct *p, pid_t pgid)
{
return current_has_perm(p, PROCESS__SETPGID);
@@ -6022,6 +6067,7 @@ static struct security_hook_list selinux_hooks[] = {
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_read_file, selinux_kernel_read_file),
LSM_HOOK_INIT(task_setpgid, selinux_task_setpgid),
LSM_HOOK_INIT(task_getpgid, selinux_task_getpgid),
LSM_HOOK_INIT(task_getsid, selinux_task_getsid),
diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h
index ef83c4b..8fbd138 100644
--- a/security/selinux/include/classmap.h
+++ b/security/selinux/include/classmap.h
@@ -32,7 +32,7 @@ struct security_class_mapping secclass_map[] = {
"setsockcreate", NULL } },
{ "system",
{ "ipc_info", "syslog_read", "syslog_mod",
- "syslog_console", "module_request", NULL } },
+ "syslog_console", "module_request", "module_load", NULL } },
{ "capability",
{ "chown", "dac_override", "dac_read_search",
"fowner", "fsetid", "kill", "setgid", "setuid", "setpcap",
--
2.8.0.rc3.226.g39d4020
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