openrisc: fix arbitrary kernel memory access via or1k_atomic syscallgrafted

sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user
pointers, v1 and v2, and swaps the words they point to in hand-written
assembly.

    l.lwz   r29,0(r4)
    l.lwz   r27,0(r5)
    l.sw    0(r4),r27
    l.sw    0(r5),r29

The pointers are not checked with access_ok(). The four memory
accesses also have no exception table entries.

A caller passes a kernel address as either pointer, and the syscall
reads from and writes to it directly.

This gives an unprivileged process a kernel read/write primitive. It
overwrites kernel data such as the sys_call_table, gaining code
execution in kernel context.

Check both pointers before entering the critical section. Add fixups
for the four memory accesses so faults on valid but unmapped user
addresses return -EFAULT.

[shorne@gmail.com: fix comment style]
Fixes: 9d02a4283e9c ("OpenRISC: Boot code")
Cc: stable@vger.kernel.org
Signed-off-by: Ali Ahmet Memis <ali@iusegentoo.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>

1 files changed, 100 insertions, 0 deletions

diff --git a/drivers/usb/chipidea/udc.h b/drivers/usb/chipidea/udc.h
new file mode 100644
index 000000000..c8a47389a
--- /dev/null
+++ b/drivers/usb/chipidea/udc.h
@@ -0,0 +1,100 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * udc.h - ChipIdea UDC structures
+ *
+ * Copyright (C) 2008 Chipidea - MIPS Technologies, Inc. All rights reserved.
+ *
+ * Author: David Lopo
+ */
+
+#ifndef __DRIVERS_USB_CHIPIDEA_UDC_H
+#define __DRIVERS_USB_CHIPIDEA_UDC_H
+
+#include <linux/list.h>
+
+#define CTRL_PAYLOAD_MAX   64
+#define RX        0  /* similar to USB_DIR_OUT but can be used as an index */
+#define TX        1  /* similar to USB_DIR_IN  but can be used as an index */
+
+/* DMA layout of transfer descriptors */
+struct ci_hw_td {
+	/* 0 */
+	__le32 next;
+#define TD_TERMINATE          BIT(0)
+#define TD_ADDR_MASK          (0xFFFFFFEUL << 5)
+	/* 1 */
+	__le32 token;
+#define TD_STATUS             (0x00FFUL <<  0)
+#define TD_STATUS_TR_ERR      BIT(3)
+#define TD_STATUS_DT_ERR      BIT(5)
+#define TD_STATUS_HALTED      BIT(6)
+#define TD_STATUS_ACTIVE      BIT(7)
+#define TD_MULTO              (0x0003UL << 10)
+#define TD_IOC                BIT(15)
+#define TD_TOTAL_BYTES        (0x7FFFUL << 16)
+	/* 2 */
+	__le32 page[5];
+#define TD_CURR_OFFSET        (0x0FFFUL <<  0)
+#define TD_FRAME_NUM          (0x07FFUL <<  0)
+#define TD_RESERVED_MASK      (0x0FFFUL <<  0)
+} __attribute__ ((packed, aligned(4)));
+
+/* DMA layout of queue heads */
+struct ci_hw_qh {
+	/* 0 */
+	__le32 cap;
+#define QH_IOS                BIT(15)
+#define QH_MAX_PKT            (0x07FFUL << 16)
+#define QH_ZLT                BIT(29)
+#define QH_MULT               (0x0003UL << 30)
+#define QH_ISO_MULT(x)		((x >> 11) & 0x03)
+	/* 1 */
+	__le32 curr;
+	/* 2 - 8 */
+	struct ci_hw_td		td;
+	/* 9 */
+	__le32 RESERVED;
+	struct usb_ctrlrequest   setup;
+} __attribute__ ((packed, aligned(4)));
+
+struct td_node {
+	struct list_head	td;
+	dma_addr_t		dma;
+	struct ci_hw_td		*ptr;
+	int			td_remaining_size;
+};
+
+/**
+ * struct ci_hw_req - usb request representation
+ * @req: request structure for gadget drivers
+ * @queue: link to QH list
+ * @tds: link to TD list
+ * @sgt: hold original sglist when bounce sglist
+ */
+struct ci_hw_req {
+	struct usb_request	req;
+	struct list_head	queue;
+	struct list_head	tds;
+	struct sg_table		sgt;
+};
+
+#ifdef CONFIG_USB_CHIPIDEA_UDC
+
+int ci_hdrc_gadget_init(struct ci_hdrc *ci);
+void ci_hdrc_gadget_destroy(struct ci_hdrc *ci);
+
+#else
+
+static inline int ci_hdrc_gadget_init(struct ci_hdrc *ci)
+{
+	return -ENXIO;
+}
+
+static inline void ci_hdrc_gadget_destroy(struct ci_hdrc *ci)
+{
+
+}
+
+#endif
+
+#endif /* __DRIVERS_USB_CHIPIDEA_UDC_H */