[RFC] [PATCH] audit: log module name on init_module

[Richard Guy Briggs]

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@xxxxxxxxxx>
---
 include/linux/audit.h      |   12 ++++++++++++
 include/uapi/linux/audit.h |    1 +
 kernel/audit.h             |    3 +++
 kernel/auditsc.c           |   20 ++++++++++++++++++++
 kernel/module.c            |    5 ++++-
 5 files changed, 40 insertions(+), 1 deletions(-)

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 2be99b2..7bb23d5 100644
--- a/include/linux/audit.h
+++ b/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_module_init(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_module_init(char *name)
+{
+	if (!audit_dummy_context())
+		__audit_module_init(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_module_init(char *name)
+{
+}
+
 static inline void audit_ptrace(struct task_struct *t)
 { }
 #define audit_n_rules 0
diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
index 3f24110..4a328b4 100644
--- a/include/uapi/linux/audit.h
+++ b/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_MODULE_INIT	1330	/* Module init event */
 
 #define AUDIT_AVC		1400	/* SE Linux avc denial or grant */
 #define AUDIT_SELINUX_ERR	1401	/* Internal SE Linux Errors */
diff --git a/kernel/audit.h b/kernel/audit.h
index 431444c..144b7eb 100644
--- a/kernel/audit.h
+++ b/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;
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index bb5f504..3e12678 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1172,6 +1172,14 @@ out:
 	kfree(buf_head);
 }
 
+static void audit_log_kern_module(struct audit_context *context,
+				  struct audit_buffer **ab)
+{
+	audit_log_format(*ab, " name=");
+	audit_log_untrustedstring(*ab, context->module.name);
+	kfree(context->module.name);
+}
+
 static void show_special(struct audit_context *context, int *call_panic)
 {
 	struct audit_buffer *ab;
@@ -1268,6 +1276,9 @@ static void show_special(struct audit_context *context, int *call_panic)
 	case AUDIT_EXECVE: {
 		audit_log_execve_info(context, &ab);
 		break; }
+	case AUDIT_MODULE_INIT:
+		audit_log_kern_module(context, &ab);
+		break;
 	}
 	audit_log_end(ab);
 }
@@ -2368,6 +2379,15 @@ void __audit_mmap_fd(int fd, int flags)
 	context->type = AUDIT_MMAP;
 }
 
+void __audit_module_init(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_MODULE_INIT;
+}
+
 static void audit_log_task(struct audit_buffer *ab)
 {
 	kuid_t auid, uid;
diff --git a/kernel/module.c b/kernel/module.c
index 529efae..678407e 100644
--- a/kernel/module.c
+++ b/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_module_init(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;
-- 
1.7.1