selinux: fix double free

Clang's static analysis tool reports these double free memory errors.

security/selinux/ss/services.c:2987:4: warning: Attempt to free released memory [unix.Malloc]
                        kfree(bnames[i]);
                        ^~~~~~~~~~~~~~~~
security/selinux/ss/services.c:2990:2: warning: Attempt to free released memory [unix.Malloc]
        kfree(bvalues);
        ^~~~~~~~~~~~~~

So improve the security_get_bools error handling by freeing these variables
and setting their return pointers to NULL and the return len to 0

Cc: stable@vger.kernel.org
Signed-off-by: Tom Rix <trix@redhat.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 313919b..ef0afd8 100644 (file)
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -2888,8 +2888,12 @@ err:
        if (*names) {
                for (i = 0; i < *len; i++)
                        kfree((*names)[i]);
+               kfree(*names);
        }
        kfree(*values);
+       *len = 0;
+       *names = NULL;
+       *values = NULL;
        goto out;
 }