[PATCH ghak105 V2] audit: remove audit_context when CONFIG_ AUDIT and not AUDITSYSCALL

[Richard Guy Briggs]

Remove audit_context from struct task_struct and struct audit_buffer
when CONFIG_AUDIT is enabled but CONFIG_AUDITSYSCALL is not.

Also, audit_log_name() (and supporting inode and fcaps functions) should
have been put back in auditsc.c when soft and hard link logging was
normalized since it is only used by syscall auditing.

See github issue https://github.com/linux-audit/audit-kernel/issues/105

Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx>
---
Changelog:
v2:
- resolve merge conflicts from rebase on upstreamed ghak103 patch
- wrap task_struct audit_context in CONFIG_AUDITSYSCALL

 include/linux/sched.h |   4 +-
 kernel/audit.c        | 157 +++-----------------------------------------------
 kernel/audit.h        |   9 ---
 kernel/auditsc.c      | 150 +++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 161 insertions(+), 159 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index f9788bb122c5..765119df759a 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -885,8 +885,10 @@ struct task_struct {
 
 	struct callback_head		*task_works;
 
-	struct audit_context		*audit_context;
 #ifdef CONFIG_AUDIT
+#ifdef CONFIG_AUDITSYSCALL
+	struct audit_context		*audit_context;
+#endif
 	kuid_t				loginuid;
 	unsigned int			sessionid;
 #endif
diff --git a/kernel/audit.c b/kernel/audit.c
index 3f3f1888cac7..15e41603fd34 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -205,7 +205,9 @@ struct audit_net {
  * use simultaneously. */
 struct audit_buffer {
 	struct sk_buff       *skb;	/* formatted skb ready to send */
+#ifdef CONFIG_AUDITSYSCALL
 	struct audit_context *ctx;	/* NULL or associated context */
+#endif
 	gfp_t		     gfp_mask;
 };
 
@@ -1696,7 +1698,9 @@ static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx,
 	if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0))
 		goto err;
 
+#ifdef CONFIG_AUDITSYSCALL
 	ab->ctx = ctx;
+#endif
 	ab->gfp_mask = gfp_mask;
 
 	return ab;
@@ -1809,7 +1813,11 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
 		return NULL;
 	}
 
+#ifdef CONFIG_AUDITSYSCALL
 	audit_get_stamp(ab->ctx, &t, &serial);
+#else
+	audit_get_stamp(NULL, &t, &serial);
+#endif
 	audit_log_format(ab, "audit(%llu.%03lu:%u): ",
 			 (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
 
@@ -2067,155 +2075,6 @@ void audit_log_key(struct audit_buffer *ab, char *key)
 		audit_log_format(ab, "(null)");
 }
 
-void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap)
-{
-	int i;
-
-	if (cap_isclear(*cap)) {
-		audit_log_format(ab, " %s=0", prefix);
-		return;
-	}
-	audit_log_format(ab, " %s=", prefix);
-	CAP_FOR_EACH_U32(i)
-		audit_log_format(ab, "%08x", cap->cap[CAP_LAST_U32 - i]);
-}
-
-static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
-{
-	audit_log_cap(ab, "cap_fp", &name->fcap.permitted);
-	audit_log_cap(ab, "cap_fi", &name->fcap.inheritable);
-	audit_log_format(ab, " cap_fe=%d cap_fver=%x cap_frootid=%d",
-			 name->fcap.fE, name->fcap_ver,
-			 from_kuid(&init_user_ns, name->fcap.rootid));
-}
-
-static inline int audit_copy_fcaps(struct audit_names *name,
-				   const struct dentry *dentry)
-{
-	struct cpu_vfs_cap_data caps;
-	int rc;
-
-	if (!dentry)
-		return 0;
-
-	rc = get_vfs_caps_from_disk(dentry, &caps);
-	if (rc)
-		return rc;
-
-	name->fcap.permitted = caps.permitted;
-	name->fcap.inheritable = caps.inheritable;
-	name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
-	name->fcap.rootid = caps.rootid;
-	name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >>
-				VFS_CAP_REVISION_SHIFT;
-
-	return 0;
-}
-
-/* Copy inode data into an audit_names. */
-void audit_copy_inode(struct audit_names *name, const struct dentry *dentry,
-		      struct inode *inode)
-{
-	name->ino   = inode->i_ino;
-	name->dev   = inode->i_sb->s_dev;
-	name->mode  = inode->i_mode;
-	name->uid   = inode->i_uid;
-	name->gid   = inode->i_gid;
-	name->rdev  = inode->i_rdev;
-	security_inode_getsecid(inode, &name->osid);
-	audit_copy_fcaps(name, dentry);
-}
-
-/**
- * audit_log_name - produce AUDIT_PATH record from struct audit_names
- * @context: audit_context for the task
- * @n: audit_names structure with reportable details
- * @path: optional path to report instead of audit_names->name
- * @record_num: record number to report when handling a list of names
- * @call_panic: optional pointer to int that will be updated if secid fails
- */
-void audit_log_name(struct audit_context *context, struct audit_names *n,
-		    const struct path *path, int record_num, int *call_panic)
-{
-	struct audit_buffer *ab;
-	ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH);
-	if (!ab)
-		return;
-
-	audit_log_format(ab, "item=%d", record_num);
-
-	if (path)
-		audit_log_d_path(ab, " name=", path);
-	else if (n->name) {
-		switch (n->name_len) {
-		case AUDIT_NAME_FULL:
-			/* log the full path */
-			audit_log_format(ab, " name=");
-			audit_log_untrustedstring(ab, n->name->name);
-			break;
-		case 0:
-			/* name was specified as a relative path and the
-			 * directory component is the cwd */
-			audit_log_d_path(ab, " name=", &context->pwd);
-			break;
-		default:
-			/* log the name's directory component */
-			audit_log_format(ab, " name=");
-			audit_log_n_untrustedstring(ab, n->name->name,
-						    n->name_len);
-		}
-	} else
-		audit_log_format(ab, " name=(null)");
-
-	if (n->ino != AUDIT_INO_UNSET)
-		audit_log_format(ab, " inode=%lu"
-				 " dev=%02x:%02x mode=%#ho"
-				 " ouid=%u ogid=%u rdev=%02x:%02x",
-				 n->ino,
-				 MAJOR(n->dev),
-				 MINOR(n->dev),
-				 n->mode,
-				 from_kuid(&init_user_ns, n->uid),
-				 from_kgid(&init_user_ns, n->gid),
-				 MAJOR(n->rdev),
-				 MINOR(n->rdev));
-	if (n->osid != 0) {
-		char *ctx = NULL;
-		u32 len;
-		if (security_secid_to_secctx(
-			n->osid, &ctx, &len)) {
-			audit_log_format(ab, " osid=%u", n->osid);
-			if (call_panic)
-				*call_panic = 2;
-		} else {
-			audit_log_format(ab, " obj=%s", ctx);
-			security_release_secctx(ctx, len);
-		}
-	}
-
-	/* log the audit_names record type */
-	switch(n->type) {
-	case AUDIT_TYPE_NORMAL:
-		audit_log_format(ab, " nametype=NORMAL");
-		break;
-	case AUDIT_TYPE_PARENT:
-		audit_log_format(ab, " nametype=PARENT");
-		break;
-	case AUDIT_TYPE_CHILD_DELETE:
-		audit_log_format(ab, " nametype=DELETE");
-		break;
-	case AUDIT_TYPE_CHILD_CREATE:
-		audit_log_format(ab, " nametype=CREATE");
-		break;
-	default:
-		audit_log_format(ab, " nametype=UNKNOWN");
-		break;
-	}
-
-	audit_log_fcaps(ab, n);
-	audit_log_end(ab);
-}
-
 int audit_log_task_context(struct audit_buffer *ab)
 {
 	char *ctx = NULL;
diff --git a/kernel/audit.h b/kernel/audit.h
index 9acb8691ed87..82734f438ddd 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -213,15 +213,6 @@ struct audit_context {
 
 extern void audit_log_session_info(struct audit_buffer *ab);
 
-extern void audit_copy_inode(struct audit_names *name,
-			     const struct dentry *dentry,
-			     struct inode *inode);
-extern void audit_log_cap(struct audit_buffer *ab, char *prefix,
-			  kernel_cap_t *cap);
-extern void audit_log_name(struct audit_context *context,
-			   struct audit_names *n, const struct path *path,
-			   int record_num, int *call_panic);
-
 extern int auditd_test_task(struct task_struct *task);
 
 #define AUDIT_INODE_BUCKETS	32
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index a2696ce790f9..5a56f3ec156c 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1136,6 +1136,28 @@ static void audit_log_execve_info(struct audit_context *context,
 	kfree(buf_head);
 }
 
+void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap)
+{
+	int i;
+
+	if (cap_isclear(*cap)) {
+		audit_log_format(ab, " %s=0", prefix);
+		return;
+	}
+	audit_log_format(ab, " %s=", prefix);
+	CAP_FOR_EACH_U32(i)
+		audit_log_format(ab, "%08x", cap->cap[CAP_LAST_U32 - i]);
+}
+
+static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
+{
+	audit_log_cap(ab, "cap_fp", &name->fcap.permitted);
+	audit_log_cap(ab, "cap_fi", &name->fcap.inheritable);
+	audit_log_format(ab, " cap_fe=%d cap_fver=%x cap_frootid=%d",
+			 name->fcap.fE, name->fcap_ver,
+			 from_kuid(&init_user_ns, name->fcap.rootid));
+}
+
 static void show_special(struct audit_context *context, int *call_panic)
 {
 	struct audit_buffer *ab;
@@ -1258,6 +1280,97 @@ static inline int audit_proctitle_rtrim(char *proctitle, int len)
 	return len;
 }
 
+/*
+ * audit_log_name - produce AUDIT_PATH record from struct audit_names
+ * @context: audit_context for the task
+ * @n: audit_names structure with reportable details
+ * @path: optional path to report instead of audit_names->name
+ * @record_num: record number to report when handling a list of names
+ * @call_panic: optional pointer to int that will be updated if secid fails
+ */
+static void audit_log_name(struct audit_context *context, struct audit_names *n,
+		    const struct path *path, int record_num, int *call_panic)
+{
+	struct audit_buffer *ab;
+
+	ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH);
+	if (!ab)
+		return;
+
+	audit_log_format(ab, "item=%d", record_num);
+
+	if (path)
+		audit_log_d_path(ab, " name=", path);
+	else if (n->name) {
+		switch (n->name_len) {
+		case AUDIT_NAME_FULL:
+			/* log the full path */
+			audit_log_format(ab, " name=");
+			audit_log_untrustedstring(ab, n->name->name);
+			break;
+		case 0:
+			/* name was specified as a relative path and the
+			 * directory component is the cwd
+			 */
+			audit_log_d_path(ab, " name=", &context->pwd);
+			break;
+		default:
+			/* log the name's directory component */
+			audit_log_format(ab, " name=");
+			audit_log_n_untrustedstring(ab, n->name->name,
+						    n->name_len);
+		}
+	} else
+		audit_log_format(ab, " name=(null)");
+
+	if (n->ino != AUDIT_INO_UNSET)
+		audit_log_format(ab, " inode=%lu dev=%02x:%02x mode=%#ho ouid=%u ogid=%u rdev=%02x:%02x",
+				 n->ino,
+				 MAJOR(n->dev),
+				 MINOR(n->dev),
+				 n->mode,
+				 from_kuid(&init_user_ns, n->uid),
+				 from_kgid(&init_user_ns, n->gid),
+				 MAJOR(n->rdev),
+				 MINOR(n->rdev));
+	if (n->osid != 0) {
+		char *ctx = NULL;
+		u32 len;
+
+		if (security_secid_to_secctx(
+			n->osid, &ctx, &len)) {
+			audit_log_format(ab, " osid=%u", n->osid);
+			if (call_panic)
+				*call_panic = 2;
+		} else {
+			audit_log_format(ab, " obj=%s", ctx);
+			security_release_secctx(ctx, len);
+		}
+	}
+
+	/* log the audit_names record type */
+	switch (n->type) {
+	case AUDIT_TYPE_NORMAL:
+		audit_log_format(ab, " nametype=NORMAL");
+		break;
+	case AUDIT_TYPE_PARENT:
+		audit_log_format(ab, " nametype=PARENT");
+		break;
+	case AUDIT_TYPE_CHILD_DELETE:
+		audit_log_format(ab, " nametype=DELETE");
+		break;
+	case AUDIT_TYPE_CHILD_CREATE:
+		audit_log_format(ab, " nametype=CREATE");
+		break;
+	default:
+		audit_log_format(ab, " nametype=UNKNOWN");
+		break;
+	}
+
+	audit_log_fcaps(ab, n);
+	audit_log_end(ab);
+}
+
 static void audit_log_proctitle(void)
 {
 	int res;
@@ -1753,6 +1866,43 @@ void __audit_getname(struct filename *name)
 		get_fs_pwd(current->fs, &context->pwd);
 }
 
+static inline int audit_copy_fcaps(struct audit_names *name,
+				   const struct dentry *dentry)
+{
+	struct cpu_vfs_cap_data caps;
+	int rc;
+
+	if (!dentry)
+		return 0;
+
+	rc = get_vfs_caps_from_disk(dentry, &caps);
+	if (rc)
+		return rc;
+
+	name->fcap.permitted = caps.permitted;
+	name->fcap.inheritable = caps.inheritable;
+	name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
+	name->fcap.rootid = caps.rootid;
+	name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >>
+				VFS_CAP_REVISION_SHIFT;
+
+	return 0;
+}
+
+/* Copy inode data into an audit_names. */
+void audit_copy_inode(struct audit_names *name, const struct dentry *dentry,
+		      struct inode *inode)
+{
+	name->ino   = inode->i_ino;
+	name->dev   = inode->i_sb->s_dev;
+	name->mode  = inode->i_mode;
+	name->uid   = inode->i_uid;
+	name->gid   = inode->i_gid;
+	name->rdev  = inode->i_rdev;
+	security_inode_getsecid(inode, &name->osid);
+	audit_copy_fcaps(name, dentry);
+}
+
 /**
  * __audit_inode - store the inode and device from a lookup
  * @name: name being audited
-- 
1.8.3.1