powerpc/pseries/dlpar: Fix a missing check in dlpar_parse_cc_property()

mainline inclusion
from mainline-v5.2-rc6
commit efa9ace68e487ddd29c2b4d6dd23242158f1f607
category: bugfix
bugzilla: 13690
CVE: CVE-2019-12614

-------------------------------------------------

In dlpar_parse_cc_property(), 'prop->name' is allocated by kstrdup().
kstrdup() may return NULL, so it should be checked and handle error.
And prop should be freed if 'prop->name' is NULL.
Signed-off-by: NGen Zhang <blackgod016574@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

arch/powerpc/platforms/pseries/dlpar.c

@@ -63,6 +63,10 @@ static struct property *dlpar_parse_cc_property(struct cc_workarea *ccwa)
 
 	name = (char *)ccwa + be32_to_cpu(ccwa->name_offset);
 	prop->name = kstrdup(name, GFP_KERNEL);
+	if (!prop->name) {
+		dlpar_free_cc_property(prop);
+		return NULL;
+	}
 
 	prop->length = be32_to_cpu(ccwa->prop_length);
 	value = (char *)ccwa + be32_to_cpu(ccwa->prop_offset);