[PATCH v2 1/1] selinux: fix double free

From: trix
Date: Wed Jun 10 2020 - 17:57:33 EST


From: Tom Rix <trix@xxxxxxxxxx>

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

Signed-off-by: Tom Rix <trix@xxxxxxxxxx>
---
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 313919bd42f8..ef0afd878bfc 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -2888,8 +2888,12 @@ int security_get_bools(struct selinux_state *state,
if (*names) {
for (i = 0; i < *len; i++)
kfree((*names)[i]);
+ kfree(*names);
}
kfree(*values);
+ *len = 0;
+ *names = NULL;
+ *values = NULL;
goto out;
}

--
2.18.1