diff --git a/builtin/apply.c b/builtin/apply.c
index aff1d9f75d..04cd8d38b0 100644
--- a/builtin/apply.c
+++ b/builtin/apply.c
@@ -207,6 +207,9 @@ static void free_patch(struct patch *patch)
 		free(fragment);
 		fragment = fragment_next;
 	}
+	free(patch->def_name);
+	free(patch->old_name);
+	free(patch->new_name);
 	free(patch);
 }
 
@@ -439,7 +442,7 @@ static char *squash_slash(char *name)
 	return name;
 }
 
-static char *find_name_gnu(const char *line, char *def, int p_value)
+static char *find_name_gnu(const char *line, const char *def, int p_value)
 {
 	struct strbuf name = STRBUF_INIT;
 	char *cp;
@@ -462,11 +465,7 @@ static char *find_name_gnu(const char *line, char *def, int p_value)
 		cp++;
 	}
 
-	/* name can later be freed, so we need
-	 * to memmove, not just return cp
-	 */
 	strbuf_remove(&name, 0, cp - name.buf);
-	free(def);
 	if (root)
 		strbuf_insert(&name, 0, root, root_len);
 	return squash_slash(strbuf_detach(&name, NULL));
@@ -631,8 +630,13 @@ static size_t diff_timestamp_len(const char *line, size_t len)
 	return line + len - end;
 }
 
-static char *find_name_common(const char *line, char *def, int p_value,
-				const char *end, int terminate)
+static char *null_strdup(const char *s)
+{
+	return s ? xstrdup(s) : NULL;
+}
+
+static char *find_name_common(const char *line, const char *def,
+			      int p_value, const char *end, int terminate)
 {
 	int len;
 	const char *start = NULL;
@@ -653,10 +657,10 @@ static char *find_name_common(const char *line, char *def, int p_value,
 			start = line;
 	}
 	if (!start)
-		return squash_slash(def);
+		return squash_slash(null_strdup(def));
 	len = line - start;
 	if (!len)
-		return squash_slash(def);
+		return squash_slash(null_strdup(def));
 
 	/*
 	 * Generally we prefer the shorter name, especially
@@ -667,8 +671,7 @@ static char *find_name_common(const char *line, char *def, int p_value,
 	if (def) {
 		int deflen = strlen(def);
 		if (deflen < len && !strncmp(start, def, deflen))
-			return squash_slash(def);
-		free(def);
+			return squash_slash(xstrdup(def));
 	}
 
 	if (root) {
@@ -865,8 +868,10 @@ static void parse_traditional_patch(const char *first, const char *second, struc
 		name = find_name_traditional(first, NULL, p_value);
 		patch->old_name = name;
 	} else {
-		name = find_name_traditional(first, NULL, p_value);
-		name = find_name_traditional(second, name, p_value);
+		char *first_name;
+		first_name = find_name_traditional(first, NULL, p_value);
+		name = find_name_traditional(second, first_name, p_value);
+		free(first_name);
 		if (has_epoch_timestamp(first)) {
 			patch->is_new = 1;
 			patch->is_delete = 0;
@@ -876,7 +881,8 @@ static void parse_traditional_patch(const char *first, const char *second, struc
 			patch->is_delete = 1;
 			patch->old_name = name;
 		} else {
-			patch->old_name = patch->new_name = name;
+			patch->old_name = name;
+			patch->new_name = xstrdup(name);
 		}
 	}
 	if (!name)
@@ -926,13 +932,19 @@ static char *gitdiff_verify_name(const char *line, int isnull, char *orig_name,
 
 static int gitdiff_oldname(const char *line, struct patch *patch)
 {
+	char *orig = patch->old_name;
 	patch->old_name = gitdiff_verify_name(line, patch->is_new, patch->old_name, "old");
+	if (orig != patch->old_name)
+		free(orig);
 	return 0;
 }
 
 static int gitdiff_newname(const char *line, struct patch *patch)
 {
+	char *orig = patch->new_name;
 	patch->new_name = gitdiff_verify_name(line, patch->is_delete, patch->new_name, "new");
+	if (orig != patch->new_name)
+		free(orig);
 	return 0;
 }
 
@@ -951,20 +963,23 @@ static int gitdiff_newmode(const char *line, struct patch *patch)
 static int gitdiff_delete(const char *line, struct patch *patch)
 {
 	patch->is_delete = 1;
-	patch->old_name = patch->def_name;
+	free(patch->old_name);
+	patch->old_name = null_strdup(patch->def_name);
 	return gitdiff_oldmode(line, patch);
 }
 
 static int gitdiff_newfile(const char *line, struct patch *patch)
 {
 	patch->is_new = 1;
-	patch->new_name = patch->def_name;
+	free(patch->new_name);
+	patch->new_name = null_strdup(patch->def_name);
 	return gitdiff_newmode(line, patch);
 }
 
 static int gitdiff_copysrc(const char *line, struct patch *patch)
 {
 	patch->is_copy = 1;
+	free(patch->old_name);
 	patch->old_name = find_name(line, NULL, p_value ? p_value - 1 : 0, 0);
 	return 0;
 }
@@ -972,6 +987,7 @@ static int gitdiff_copysrc(const char *line, struct patch *patch)
 static int gitdiff_copydst(const char *line, struct patch *patch)
 {
 	patch->is_copy = 1;
+	free(patch->new_name);
 	patch->new_name = find_name(line, NULL, p_value ? p_value - 1 : 0, 0);
 	return 0;
 }
@@ -979,6 +995,7 @@ static int gitdiff_copydst(const char *line, struct patch *patch)
 static int gitdiff_renamesrc(const char *line, struct patch *patch)
 {
 	patch->is_rename = 1;
+	free(patch->old_name);
 	patch->old_name = find_name(line, NULL, p_value ? p_value - 1 : 0, 0);
 	return 0;
 }
@@ -986,6 +1003,7 @@ static int gitdiff_renamesrc(const char *line, struct patch *patch)
 static int gitdiff_renamedst(const char *line, struct patch *patch)
 {
 	patch->is_rename = 1;
+	free(patch->new_name);
 	patch->new_name = find_name(line, NULL, p_value ? p_value - 1 : 0, 0);
 	return 0;
 }
@@ -1426,7 +1444,8 @@ static int find_header(char *line, unsigned long size, int *hdrsize, struct patc
 				if (!patch->def_name)
 					die("git diff header lacks filename information when removing "
 					    "%d leading pathname components (line %d)" , p_value, linenr);
-				patch->old_name = patch->new_name = patch->def_name;
+				patch->old_name = xstrdup(patch->def_name);
+				patch->new_name = xstrdup(patch->def_name);
 			}
 			if (!patch->is_delete && !patch->new_name)
 				die("git diff header lacks filename information "
@@ -3109,6 +3128,7 @@ static int check_preimage(struct patch *patch, struct cache_entry **ce, struct s
  is_new:
 	patch->is_new = 1;
 	patch->is_delete = 0;
+	free(patch->old_name);
 	patch->old_name = NULL;
 	return 0;
 }
@@ -3689,15 +3709,8 @@ static void prefix_patches(struct patch *p)
 	if (!prefix || p->is_toplevel_relative)
 		return;
 	for ( ; p; p = p->next) {
-		if (p->new_name == p->old_name) {
-			char *prefixed = p->new_name;
-			prefix_one(&prefixed);
-			p->new_name = p->old_name = prefixed;
-		}
-		else {
-			prefix_one(&p->new_name);
-			prefix_one(&p->old_name);
-		}
+		prefix_one(&p->new_name);
+		prefix_one(&p->old_name);
 	}
 }