audit: remove audit_context when CONFIG_ AUDIT and not AUDITSYSCALL

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@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

1 files changed, 158 insertions, 0 deletions

diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 7d37cb1e4aef..d1eab1d4a930 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1139,6 +1139,32 @@ out:
 	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)
+{
+	if (name->fcap_ver == -1) {
+		audit_log_format(ab, " cap_fe=? cap_fver=? cap_fp=? cap_fi=?");
+		return;
+	}
+	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;
@@ -1261,6 +1287,97 @@ 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;
@@ -1756,6 +1873,47 @@ 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, unsigned int flags)
+{
+	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);
+	if (flags & AUDIT_INODE_NOEVAL) {
+		name->fcap_ver = -1;
+		return;
+	}
+	audit_copy_fcaps(name, dentry);
+}
+
 /**
  * __audit_inode - store the inode and device from a lookup
  * @name: name being audited