Merge tag 'selinux-pr-20191007' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
Pull selinuxfix from Paul Moore:
"One patch to ensure we don't copy bad memory up into userspace"
* tag 'selinux-pr-20191007' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
selinux: fix context string corruption in convert_context()
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 3a29e7c..a5813c7 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -1946,7 +1946,14 @@
rc = string_to_context_struct(args->newp, NULL, s,
newc, SECSID_NULL);
if (rc == -EINVAL) {
- /* Retain string representation for later mapping. */
+ /*
+ * Retain string representation for later mapping.
+ *
+ * IMPORTANT: We need to copy the contents of oldc->str
+ * back into s again because string_to_context_struct()
+ * may have garbled it.
+ */
+ memcpy(s, oldc->str, oldc->len);
context_init(newc);
newc->str = s;
newc->len = oldc->len;
