From b447378e121713faa4c63e8c93a8ebf25218fc40 Mon Sep 17 00:00:00 2001 From: Thomas Huth Date: Fri, 17 Nov 2023 12:44:57 +0100 Subject: [PATCH] qom/object: Limit type names to alphanumerical and some few special characters MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit QOM names currently don't have any enforced naming rules. This can be problematic, e.g. when they are used on the command line for the "-device" option (where the comma is used to separate properties). To avoid that such problematic type names come in again, let's restrict the set of acceptable characters during the type registration. Ideally, we'd apply here the same rules as for QAPI, i.e. all type names should begin with a letter, and contain only ASCII letters, digits, hyphen, and underscore. However, we already have so many pre-existing types like: 486-x86_64-cpu cfi.pflash01 power5+_v2.1-spapr-cpu-core virt-2.6-machine pc-i440fx-3.0-machine ... so that we have to allow "." and "+" for now, too. While the dot is used in a lot of places, the "+" can fortunately be limited to two classes of legacy names ("power" and "Sun-UltraSparc" CPUs). We also cannot enforce the rule that names must start with a letter yet, since there are lot of types that start with a digit. Still, at least limiting the first characters to the alphanumerical range should be way better than nothing. Reviewed-by: Philippe Mathieu-Daudé Message-ID: <20231117114457.177308-6-thuth@redhat.com> Reviewed-by: Alistair Francis Signed-off-by: Thomas Huth --- qom/object.c | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) diff --git a/qom/object.c b/qom/object.c index 95c0dc8285..654e1afaf2 100644 --- a/qom/object.c +++ b/qom/object.c @@ -138,9 +138,50 @@ static TypeImpl *type_new(const TypeInfo *info) return ti; } +static bool type_name_is_valid(const char *name) +{ + const int slen = strlen(name); + int plen; + + g_assert(slen > 1); + + /* + * Ideally, the name should start with a letter - however, we've got + * too many names starting with a digit already, so allow digits here, + * too (except '0' which is not used yet) + */ + if (!g_ascii_isalnum(name[0]) || name[0] == '0') { + return false; + } + + plen = strspn(name, "abcdefghijklmnopqrstuvwxyz" + "ABCDEFGHIJKLMNOPQRSTUVWXYZ" + "0123456789-_."); + + /* Allow some legacy names with '+' in it for compatibility reasons */ + if (name[plen] == '+') { + if (plen == 6 && g_str_has_prefix(name, "power")) { + /* Allow "power5+" and "power7+" CPU names*/ + return true; + } + if (plen >= 17 && g_str_has_prefix(name, "Sun-UltraSparc-I")) { + /* Allow "Sun-UltraSparc-IV+" and "Sun-UltraSparc-IIIi+" */ + return true; + } + } + + return plen == slen; +} + static TypeImpl *type_register_internal(const TypeInfo *info) { TypeImpl *ti; + + if (!type_name_is_valid(info->name)) { + fprintf(stderr, "Registering '%s' with illegal type name\n", info->name); + abort(); + } + ti = type_new(info); type_table_add(ti);