From: Lee Duncan <lduncan@suse.com>
Date: Tue, 23 Feb 2021 13:06:24 -0800
Subject: scsi: iscsi: Restrict sessions and handles to admin capabilities
Git-commit: 688e8128b7a92df982709a4137ea4588d16f24aa
References: CVE-2021-27363 CVE-2021-27364 bsc#1182716 bsc#1182717
Patch-mainline: v5.12-rc2

Protect the iSCSI transport handle, available in sysfs, by requiring
CAP_SYS_ADMIN to read it. Also protect the netlink socket by restricting
reception of messages to ones sent with CAP_SYS_ADMIN. This disables
normal users from being able to end arbitrary iSCSI sessions.

Cc: stable@vger.kernel.org
Reported-by: Adam Nichols <adam@grimm-co.com>
Reviewed-by: Chris Leech <cleech@redhat.com>
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
---
 drivers/scsi/scsi_transport_iscsi.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -128,6 +128,9 @@ show_transport_handle(struct device *dev
 		      char *buf)
 {
 	struct iscsi_internal *priv = dev_to_iscsi_internal(dev);
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EACCES;
 	return sprintf(buf, "%llu\n", (unsigned long long)iscsi_handle(priv->iscsi_transport));
 }
 static DEVICE_ATTR(handle, S_IRUGO, show_transport_handle, NULL);
@@ -3552,6 +3555,9 @@ iscsi_if_recv_msg(struct sk_buff *skb, s
 	struct iscsi_cls_conn *conn;
 	struct iscsi_endpoint *ep = NULL;
 
+	if (!netlink_capable(skb, CAP_SYS_ADMIN))
+		return -EPERM;
+
 	if (nlh->nlmsg_type == ISCSI_UEVENT_PATH_UPDATE)
 		*group = ISCSI_NL_GRP_UIP;
 	else