From: Christian Göttsche <cgzones@xxxxxxxxxxxxxx>
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 <cgzones@xxxxxxxxxxxxxx>
---
checkpolicy/policy_define.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/checkpolicy/policy_define.c b/checkpolicy/policy_define.c
index 2f811b67..96a481f7 100644
--- a/checkpolicy/policy_define.c
+++ b/checkpolicy/policy_define.c
@@ -4437,6 +4437,7 @@ 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;
@@ -4463,7 +4464,13 @@ 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);
--
2.47.1
