From 0b842c3c819971cdbe0915469759c40f6eb3db7e Mon Sep 17 00:00:00 2001
From: David Gibson <david@gibson.dropbear.id.au>
Date: Mon, 27 Feb 2023 23:11:29 +1100
Subject: [PATCH] Make build_property() xstrdup its name argument

The name field of 'struct property' was really always supposed to be a
malloc()ed string, that is owned by the structure.  To avoid an extra
strdup() for strings coming up from the lexer, build_property() and
build_property_delete() expect to take such an already malloc()ed string,
which means it's not correct to pass it a static string literal.

That's a pretty non-obvious constraint, so a bunch of incorrect uses have
crept in.  Really, avoiding the extra dup from the lexer isn't a big enough
benefit for this demonstrably dangerous interface.  So change it to do the
xstrdup() itself, removing the burden from callers.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 dtc-parser.y | 3 +++
 dtc.h        | 4 ++--
 fstree.c     | 2 +-
 livetree.c   | 8 ++++----
 4 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/dtc-parser.y b/dtc-parser.y
index bff1337..9b724e5 100644
--- a/dtc-parser.y
+++ b/dtc-parser.y
@@ -284,14 +284,17 @@ propdef:
 	  DT_PROPNODENAME '=' propdata ';'
 		{
 			$$ = build_property($1, $3, &@$);
+			free($1);
 		}
 	| DT_PROPNODENAME ';'
 		{
 			$$ = build_property($1, empty_data, &@$);
+			free($1);
 		}
 	| DT_DEL_PROP DT_PROPNODENAME ';'
 		{
 			$$ = build_property_delete($2);
+			free($2);
 		}
 	| DT_LABEL propdef
 		{
diff --git a/dtc.h b/dtc.h
index 0a1f549..0fca726 100644
--- a/dtc.h
+++ b/dtc.h
@@ -260,9 +260,9 @@ struct node {
 void add_label(struct label **labels, char *label);
 void delete_labels(struct label **labels);
 
-struct property *build_property(char *name, struct data val,
+struct property *build_property(const char *name, struct data val,
 				struct srcpos *srcpos);
-struct property *build_property_delete(char *name);
+struct property *build_property_delete(const char *name);
 struct property *chain_property(struct property *first, struct property *list);
 struct property *reverse_properties(struct property *first);
 
diff --git a/fstree.c b/fstree.c
index 5e59594..0f9a534 100644
--- a/fstree.c
+++ b/fstree.c
@@ -43,7 +43,7 @@ static struct node *read_fstree(const char *dirname)
 					"WARNING: Cannot open %s: %s\n",
 					tmpname, strerror(errno));
 			} else {
-				prop = build_property(xstrdup(de->d_name),
+				prop = build_property(de->d_name,
 						      data_copy_file(pfile,
 								     st.st_size),
 						      NULL);
diff --git a/livetree.c b/livetree.c
index f46a098..f76ad7f 100644
--- a/livetree.c
+++ b/livetree.c
@@ -36,27 +36,27 @@ void delete_labels(struct label **labels)
 		label->deleted = 1;
 }
 
-struct property *build_property(char *name, struct data val,
+struct property *build_property(const char *name, struct data val,
 				struct srcpos *srcpos)
 {
 	struct property *new = xmalloc(sizeof(*new));
 
 	memset(new, 0, sizeof(*new));
 
-	new->name = name;
+	new->name = xstrdup(name);
 	new->val = val;
 	new->srcpos = srcpos_copy(srcpos);
 
 	return new;
 }
 
-struct property *build_property_delete(char *name)
+struct property *build_property_delete(const char *name)
 {
 	struct property *new = xmalloc(sizeof(*new));
 
 	memset(new, 0, sizeof(*new));
 
-	new->name = name;
+	new->name = xstrdup(name);
 	new->deleted = 1;
 
 	return new;