From 158fb95ef28af13ccc8a6f1474aaa2e69620afd0 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Christian=20G=C3=B6ttsche?= Date: Wed, 15 Jan 2025 14:13:25 +0100 Subject: [PATCH] checkpolicy: check identifier before copying MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Avoid calling strdup(3) with a NULL pointer, which can happen with an invalid policy context, e.g.: class C sid S class C { P } ; user U roles j; sid S s:l:q:q:q Fixes: 6f2b689f ("checkpolicy: Fix MLS users in optional blocks") Reported-by: oss-fuzz (issue 390004173) Signed-off-by: Christian Göttsche --- policy_define.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/policy_define.c b/policy_define.c index 2f811b67..96a481f7 100644 --- a/policy_define.c +++ b/policy_define.c @@ -4411,6 +4411,7 @@ static int parse_semantic_categories(char *id, level_datum_t * levdatum __attrib int define_user(void) { + const char *username; char *id; user_datum_t *usrdatum, *usr_global; level_datum_t *levdatum; @@ -4437,7 +4438,13 @@ int define_user(void) return 0; } - id = strdup(queue_head(id_queue)); + username = queue_head(id_queue); + if (!username) { + yyerror("no user name"); + return -1; + } + + id = strdup(username); if ((usrdatum = declare_user()) == NULL) { free(id); -- 2.33.0