lib-storage: Fix NUL handling in mail_get_first_header*(), mail_get_h…

…eaders*()

These functions return NUL-terminated values, so they got truncated whenever
a header value contained a NUL. Fix this by converting NULs to unicode
replacement characters in the output.

src/lib-storage/index/index-mail-headers.c

@@ -613,8 +613,9 @@ index_mail_get_parsed_header(struct index_mail *mail, unsigned int field_idx)
 		if (skip_header(&value_start, value_end - value_start)) {
 			if (value_start != value_end && value_end[-1] == '\n')
 				value_end--;
-			value = p_strndup(mail->mail.data_pool, value_start,
-					  value_end - value_start);
+			value = message_header_strdup(mail->mail.data_pool,
+						      value_start,
+						      value_end - value_start);
 			array_append(&header_values, &value, 1);
 		}
 	}
@@ -630,7 +631,7 @@ index_mail_get_raw_headers(struct index_mail *mail, const char *field,
 	struct mail *_mail = &mail->mail.mail;
 	const char *headers[2], *value;
 	struct mailbox_header_lookup_ctx *headers_ctx;
-	unsigned char *data;
+	const unsigned char *data;
 	unsigned int field_idx;
 	string_t *dest;
 	size_t i, len, len2;
@@ -642,7 +643,7 @@ index_mail_get_raw_headers(struct index_mail *mail, const char *field,
 	field_idx = get_header_field_idx(_mail->box, field,
 					 MAIL_CACHE_DECISION_TEMP);
 
-	dest = str_new(mail->mail.data_pool, 128);
+	dest = t_str_new(128);
 	if (mail_cache_lookup_headers(_mail->transaction->cache_view, dest,
 				      _mail->seq, &field_idx, 1) <= 0) {
 		/* not in cache / error - first see if it's already parsed */
@@ -679,7 +680,7 @@ index_mail_get_raw_headers(struct index_mail *mail, const char *field,
 		return 0;
 	}
 	_mail->transaction->stats.cache_hit_count++;
-	data = buffer_get_modifiable_data(dest, &len);
+	data = buffer_get_data(dest, &len);
 
 	if (len == 0) {
 		/* cached as nonexistent. */
@@ -697,8 +698,8 @@ index_mail_get_raw_headers(struct index_mail *mail, const char *field,
 
 			/* @UNSAFE */
 			len2 = get_header_size(dest, i);
-			data[i + len2] = '\0';
-			value = (const char *)data + i;
+			value = message_header_strdup(mail->mail.data_pool,
+						     data + i, len2);
 			i += len2 + 1;
 
 			array_append(&header_values, &value, 1);