[PATCH 4.9 084/191] selinux: fix double free

Sasha Levin
2020-06-29T20:23:58Z

From: Tom Rix <trix@redhat.com>

commit 65de50969a77509452ae590e9449b70a22b923bb upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
security/selinux/ss/services.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index bfc4ffa1fa1a4..6ca297821d459 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -2616,8 +2616,12 @@ int security_get_bools(int *len, char ***names, int **values)
if (*names) {
for (i = 0; i < *len; i++)
kfree((*names)[i]);
+ kfree(*names);
}
kfree(*values);
+ *len = 0;
+ *names = NULL;
+ *values = NULL;
goto out;
}

--
2.25.1