linux-kernel - [PATCH v2 5/8] bootconfig: Reject subkey and value on same parent key

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Date:   Thu, 20 Feb 2020 21:19:12 +0900
From:   Masami Hiramatsu <mhiramat@...nel.org>
To:     Steven Rostedt <rostedt@...dmis.org>
Cc:     Geert Uytterhoeven <geert@...ux-m68k.org>,
        Borislav Petkov <bp@...en8.de>,
        LKML <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>
Subject: [PATCH v2 5/8] bootconfig: Reject subkey and value on same parent key

Reject if a value node is mixed with subkey node on same
parent key node.

A value node can not co-exist with subkey node under some key
node, e.g.

key = value
key.subkey = another-value

This is not be allowed because bootconfig API is not designed
to handle such case.

Signed-off-by: Masami Hiramatsu <mhiramat@...nel.org>
---
 Documentation/admin-guide/bootconfig.rst     |    7 +++++++
 lib/bootconfig.c                             |   16 ++++++++++++----
 tools/bootconfig/samples/bad-mixed-kv1.bconf |    3 +++
 tools/bootconfig/samples/bad-mixed-kv2.bconf |    3 +++
 4 files changed, 25 insertions(+), 4 deletions(-)
 create mode 100644 tools/bootconfig/samples/bad-mixed-kv1.bconf
 create mode 100644 tools/bootconfig/samples/bad-mixed-kv2.bconf

diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin-guide/bootconfig.rst
index 48675052c963..4a106584eb21 100644
--- a/Documentation/admin-guide/bootconfig.rst
+++ b/Documentation/admin-guide/bootconfig.rst
@@ -62,6 +62,13 @@ Or more shorter, written as following::
 In both styles, same key words are automatically merged when parsing it
 at boot time. So you can append similar trees or key-values.
 
+Note that a sub-key and a value can not co-exist under a parent key.
+For example, following config is NOT allowed.::
+
+ foo = value1
+ foo.bar = value2 # !ERROR! subkey "bar" and value "value1" can NOT co-exist
+
+
 Comments
 --------
 
diff --git a/lib/bootconfig.c b/lib/bootconfig.c
index 3ea601a2eba5..54ac623ca781 100644
--- a/lib/bootconfig.c
+++ b/lib/bootconfig.c
@@ -533,7 +533,7 @@ struct xbc_node *find_match_node(struct xbc_node *node, char *k)
 
 static int __init __xbc_add_key(char *k)
 {
-	struct xbc_node *node;
+	struct xbc_node *node, *child;
 
 	if (!xbc_valid_keyword(k))
 		return xbc_parse_error("Invalid keyword", k);
@@ -543,8 +543,12 @@ static int __init __xbc_add_key(char *k)
 
 	if (!last_parent)	/* the first level */
 		node = find_match_node(xbc_nodes, k);
-	else
-		node = find_match_node(xbc_node_get_child(last_parent), k);
+	else {
+		child = xbc_node_get_child(last_parent);
+		if (child && xbc_node_is_value(child))
+			return xbc_parse_error("Subkey is mixed with value", k);
+		node = find_match_node(child, k);
+	}
 
 	if (node)
 		last_parent = node;
@@ -577,7 +581,7 @@ static int __init __xbc_parse_keys(char *k)
 static int __init xbc_parse_kv(char **k, char *v)
 {
 	struct xbc_node *prev_parent = last_parent;
-	struct xbc_node *node;
+	struct xbc_node *node, *child;
 	char *next;
 	int c, ret;
 
@@ -585,6 +589,10 @@ static int __init xbc_parse_kv(char **k, char *v)
 	if (ret)
 		return ret;
 
+	child = xbc_node_get_child(last_parent);
+	if (child && xbc_node_is_key(child))
+		return xbc_parse_error("Value is mixed with subkey", v);
+
 	c = __xbc_parse_value(&v, &next);
 	if (c < 0)
 		return c;
diff --git a/tools/bootconfig/samples/bad-mixed-kv1.bconf b/tools/bootconfig/samples/bad-mixed-kv1.bconf
new file mode 100644
index 000000000000..1761547dd05c
--- /dev/null
+++ b/tools/bootconfig/samples/bad-mixed-kv1.bconf
@@ -0,0 +1,3 @@
+# value -> subkey pattern
+key = value
+key.subkey = another-value
diff --git a/tools/bootconfig/samples/bad-mixed-kv2.bconf b/tools/bootconfig/samples/bad-mixed-kv2.bconf
new file mode 100644
index 000000000000..6b32e0c3878c
--- /dev/null
+++ b/tools/bootconfig/samples/bad-mixed-kv2.bconf
@@ -0,0 +1,3 @@
+# subkey -> value pattern
+key.subkey = value
+key = another-value