audit: log module name on init_module

This adds a new auxiliary record MODULE_INIT to the SYSCALL event.

We get finit_module for free since it made most sense to hook this in to
load_module().

https://github.com/linux-audit/audit-kernel/issues/7
https://github.com/linux-audit/audit-kernel/wiki/RFE-Module-Load-Record-Format

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Acked-by: Jessica Yu <jeyu@redhat.com>
[PM: corrected links in the commit description]
Signed-off-by: Paul Moore <paul@paul-moore.com>

include/linux/audit.h

@@ -360,6 +360,7 @@ extern int __audit_log_bprm_fcaps(struct linux_binprm *bprm,
 				  const struct cred *old);
 extern void __audit_log_capset(const struct cred *new, const struct cred *old);
 extern void __audit_mmap_fd(int fd, int flags);
+extern void __audit_log_kern_module(char *name);
 
 static inline void audit_ipc_obj(struct kern_ipc_perm *ipcp)
 {
@@ -450,6 +451,12 @@ static inline void audit_mmap_fd(int fd, int flags)
 		__audit_mmap_fd(fd, flags);
 }
 
+static inline void audit_log_kern_module(char *name)
+{
+	if (!audit_dummy_context())
+		__audit_log_kern_module(name);
+}
+
 extern int audit_n_rules;
 extern int audit_signals;
 #else /* CONFIG_AUDITSYSCALL */
@@ -561,6 +568,11 @@ static inline void audit_log_capset(const struct cred *new,
 { }
 static inline void audit_mmap_fd(int fd, int flags)
 { }
+
+static inline void audit_log_kern_module(char *name)
+{
+}
+
 static inline void audit_ptrace(struct task_struct *t)
 { }
 #define audit_n_rules 0

include/uapi/linux/audit.h

@@ -111,6 +111,7 @@
 #define AUDIT_PROCTITLE		1327	/* Proctitle emit event */
 #define AUDIT_FEATURE_CHANGE	1328	/* audit log listing feature changes */
 #define AUDIT_REPLACE		1329	/* Replace auditd if this packet unanswerd */
+#define AUDIT_KERN_MODULE	1330	/* Kernel Module events */
 
 #define AUDIT_AVC		1400	/* SE Linux avc denial or grant */
 #define AUDIT_SELINUX_ERR	1401	/* Internal SE Linux Errors */

kernel/audit.h

@@ -199,6 +199,9 @@ struct audit_context {
 		struct {
 			int			argc;
 		} execve;
+		struct {
+			char			*name;
+		} module;
 	};
 	int fds[2];
 	struct audit_proctitle proctitle;

kernel/auditsc.c

@@ -1268,6 +1268,11 @@ static void show_special(struct audit_context *context, int *call_panic)
 	case AUDIT_EXECVE: {
 		audit_log_execve_info(context, &ab);
 		break; }
+	case AUDIT_KERN_MODULE:
+		audit_log_format(ab, "name=");
+		audit_log_untrustedstring(ab, context->module.name);
+		kfree(context->module.name);
+		break;
 	}
 	audit_log_end(ab);
 }
@@ -2368,6 +2373,15 @@ void __audit_mmap_fd(int fd, int flags)
 	context->type = AUDIT_MMAP;
 }
 
+void __audit_log_kern_module(char *name)
+{
+	struct audit_context *context = current->audit_context;
+
+	context->module.name = kmalloc(strlen(name) + 1, GFP_KERNEL);
+	strcpy(context->module.name, name);
+	context->type = AUDIT_KERN_MODULE;
+}
+
 static void audit_log_task(struct audit_buffer *ab)
 {
 	kuid_t auid, uid;

kernel/module.c

@@ -61,6 +61,7 @@
 #include <linux/pfn.h>
 #include <linux/bsearch.h>
 #include <linux/dynamic_debug.h>
+#include <linux/audit.h>
 #include <uapi/linux/module.h>
 #include "module-internal.h"
 
@@ -3593,6 +3594,8 @@ static int load_module(struct load_info *info, const char __user *uargs,
 		goto free_copy;
 	}
 
+	audit_log_kern_module(mod->name);
+
 	/* Reserve our place in the list. */
 	err = add_unformed_module(mod);
 	if (err)
@@ -3681,7 +3684,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
 		       mod->name, after_dashes);
 	}
 
-	/* Link in to syfs. */
+	/* Link in to sysfs. */
 	err = mod_sysfs_setup(mod, info, mod->kp, mod->num_kp);
 	if (err < 0)
 		goto coming_cleanup;