diff --git a/range-diff.c b/range-diff.c
index 5f01605550..bbb0952264 100644
--- a/range-diff.c
+++ b/range-diff.c
@@ -450,8 +450,10 @@ static void output_pair_header(struct diff_options *diffopt,
 }
 
 static struct userdiff_driver section_headers = {
-	.funcname = { "^ ## (.*) ##$\n"
-		      "^.?@@ (.*)$", REG_EXTENDED }
+	.funcname = {
+		.pattern = "^ ## (.*) ##$\n^.?@@ (.*)$",
+		.cflags = REG_EXTENDED,
+	},
 };
 
 static struct diff_filespec *get_filespec(const char *name, const char *p)
diff --git a/t/t4018-diff-funcname.sh b/t/t4018-diff-funcname.sh
index e026fac1f4..8128c30e7f 100755
--- a/t/t4018-diff-funcname.sh
+++ b/t/t4018-diff-funcname.sh
@@ -5,6 +5,7 @@
 
 test_description='Test custom diff function name patterns'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup' '
diff --git a/t/t4042-diff-textconv-caching.sh b/t/t4042-diff-textconv-caching.sh
index 8ebfa3c1be..a179205394 100755
--- a/t/t4042-diff-textconv-caching.sh
+++ b/t/t4042-diff-textconv-caching.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='test textconv caching'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 cat >helper <<'EOF'
diff --git a/t/t4048-diff-combined-binary.sh b/t/t4048-diff-combined-binary.sh
index 0260cf64f5..f399484bce 100755
--- a/t/t4048-diff-combined-binary.sh
+++ b/t/t4048-diff-combined-binary.sh
@@ -4,6 +4,7 @@ test_description='combined and merge diff handle binary files and textconv'
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup binary merge conflict' '
diff --git a/t/t4209-log-pickaxe.sh b/t/t4209-log-pickaxe.sh
index 64e1623733..b42fdc54fc 100755
--- a/t/t4209-log-pickaxe.sh
+++ b/t/t4209-log-pickaxe.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='log --grep/--author/--regexp-ignore-case/-S/-G'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_log () {
diff --git a/userdiff.c b/userdiff.c
index c4ebb9ff73..989629149f 100644
--- a/userdiff.c
+++ b/userdiff.c
@@ -399,8 +399,11 @@ static struct userdiff_driver *userdiff_find_by_namelen(const char *name, size_t
 static int parse_funcname(struct userdiff_funcname *f, const char *k,
 		const char *v, int cflags)
 {
-	if (git_config_string((char **) &f->pattern, k, v) < 0)
+	f->pattern = NULL;
+	FREE_AND_NULL(f->pattern_owned);
+	if (git_config_string(&f->pattern_owned, k, v) < 0)
 		return -1;
+	f->pattern = f->pattern_owned;
 	f->cflags = cflags;
 	return 0;
 }
@@ -444,20 +447,37 @@ int userdiff_config(const char *k, const char *v)
 		return parse_funcname(&drv->funcname, k, v, REG_EXTENDED);
 	if (!strcmp(type, "binary"))
 		return parse_tristate(&drv->binary, k, v);
-	if (!strcmp(type, "command"))
-		return git_config_string((char **) &drv->external.cmd, k, v);
+	if (!strcmp(type, "command")) {
+		FREE_AND_NULL(drv->external.cmd);
+		return git_config_string(&drv->external.cmd, k, v);
+	}
 	if (!strcmp(type, "trustexitcode")) {
 		drv->external.trust_exit_code = git_config_bool(k, v);
 		return 0;
 	}
-	if (!strcmp(type, "textconv"))
-		return git_config_string((char **) &drv->textconv, k, v);
+	if (!strcmp(type, "textconv")) {
+		int ret;
+		FREE_AND_NULL(drv->textconv_owned);
+		ret = git_config_string(&drv->textconv_owned, k, v);
+		drv->textconv = drv->textconv_owned;
+		return ret;
+	}
 	if (!strcmp(type, "cachetextconv"))
 		return parse_bool(&drv->textconv_want_cache, k, v);
-	if (!strcmp(type, "wordregex"))
-		return git_config_string((char **) &drv->word_regex, k, v);
-	if (!strcmp(type, "algorithm"))
-		return git_config_string((char **) &drv->algorithm, k, v);
+	if (!strcmp(type, "wordregex")) {
+		int ret;
+		FREE_AND_NULL(drv->word_regex_owned);
+		ret = git_config_string(&drv->word_regex_owned, k, v);
+		drv->word_regex = drv->word_regex_owned;
+		return ret;
+	}
+	if (!strcmp(type, "algorithm")) {
+		int ret;
+		FREE_AND_NULL(drv->algorithm_owned);
+		ret = git_config_string(&drv->algorithm_owned, k, v);
+		drv->algorithm = drv->algorithm_owned;
+		return ret;
+	}
 
 	return 0;
 }
diff --git a/userdiff.h b/userdiff.h
index 7565930337..827361b0bc 100644
--- a/userdiff.h
+++ b/userdiff.h
@@ -8,6 +8,7 @@ struct repository;
 
 struct userdiff_funcname {
 	const char *pattern;
+	char *pattern_owned;
 	int cflags;
 };
 
@@ -20,11 +21,14 @@ struct userdiff_driver {
 	const char *name;
 	struct external_diff external;
 	const char *algorithm;
+	char *algorithm_owned;
 	int binary;
 	struct userdiff_funcname funcname;
 	const char *word_regex;
+	char *word_regex_owned;
 	const char *word_regex_multi_byte;
 	const char *textconv;
+	char *textconv_owned;
 	struct notes_cache *textconv_cache;
 	int textconv_want_cache;
 };