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, 74 insertions, 0 deletions

diff --git a/include/scsi/scsi_status.h b/include/scsi/scsi_status.h
new file mode 100644
index 000000000..9cb85262d
--- /dev/null
+++ b/include/scsi/scsi_status.h
@@ -0,0 +1,74 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _SCSI_SCSI_STATUS_H
+#define _SCSI_SCSI_STATUS_H
+
+#include <linux/types.h>
+#include <scsi/scsi_proto.h>
+
+/* Message codes. */
+enum scsi_msg_byte {
+	COMMAND_COMPLETE	= 0x00,
+	EXTENDED_MESSAGE	= 0x01,
+	SAVE_POINTERS		= 0x02,
+	RESTORE_POINTERS	= 0x03,
+	DISCONNECT		= 0x04,
+	INITIATOR_ERROR		= 0x05,
+	ABORT_TASK_SET		= 0x06,
+	MESSAGE_REJECT		= 0x07,
+	NOP			= 0x08,
+	MSG_PARITY_ERROR	= 0x09,
+	LINKED_CMD_COMPLETE	= 0x0a,
+	LINKED_FLG_CMD_COMPLETE	= 0x0b,
+	TARGET_RESET		= 0x0c,
+	ABORT_TASK		= 0x0d,
+	CLEAR_TASK_SET		= 0x0e,
+	INITIATE_RECOVERY	= 0x0f,            /* SCSI-II only */
+	RELEASE_RECOVERY	= 0x10,            /* SCSI-II only */
+	TERMINATE_IO_PROC	= 0x11,            /* SCSI-II only */
+	CLEAR_ACA		= 0x16,
+	LOGICAL_UNIT_RESET	= 0x17,
+	SIMPLE_QUEUE_TAG	= 0x20,
+	HEAD_OF_QUEUE_TAG	= 0x21,
+	ORDERED_QUEUE_TAG	= 0x22,
+	IGNORE_WIDE_RESIDUE	= 0x23,
+	ACA			= 0x24,
+	QAS_REQUEST		= 0x55,
+
+	/* Old SCSI2 names, don't use in new code */
+	BUS_DEVICE_RESET	= TARGET_RESET,
+	ABORT			= ABORT_TASK_SET,
+};
+
+/* Host byte codes. */
+enum scsi_host_status {
+	DID_OK		= 0x00,	/* NO error                                */
+	DID_NO_CONNECT	= 0x01,	/* Couldn't connect before timeout period  */
+	DID_BUS_BUSY	= 0x02,	/* BUS stayed busy through time out period */
+	DID_TIME_OUT	= 0x03,	/* TIMED OUT for other reason              */
+	DID_BAD_TARGET	= 0x04,	/* BAD target.                             */
+	DID_ABORT	= 0x05,	/* Told to abort for some other reason     */
+	DID_PARITY	= 0x06,	/* Parity error                            */
+	DID_ERROR	= 0x07,	/* Internal error                          */
+	DID_RESET	= 0x08,	/* Reset by somebody.                      */
+	DID_BAD_INTR	= 0x09,	/* Got an interrupt we weren't expecting.  */
+	DID_PASSTHROUGH	= 0x0a,	/* Force command past mid-layer            */
+	DID_SOFT_ERROR	= 0x0b,	/* The low level driver just wish a retry  */
+	DID_IMM_RETRY	= 0x0c,	/* Retry without decrementing retry count  */
+	DID_REQUEUE	= 0x0d,	/* Requeue command (no immediate retry) also
+				 * without decrementing the retry count	   */
+	DID_TRANSPORT_DISRUPTED = 0x0e, /* Transport error disrupted execution
+					 * and the driver blocked the port to
+					 * recover the link. Transport class will
+					 * retry or fail IO */
+	DID_TRANSPORT_FAILFAST = 0x0f, /* Transport class fastfailed the io */
+	/*
+	 * We used to have DID_TARGET_FAILURE, DID_NEXUS_FAILURE,
+	 * DID_ALLOC_FAILURE and DID_MEDIUM_ERROR at 0x10 - 0x13. For compat
+	 * with userspace apps that parse the host byte for SG IO, we leave
+	 * that block of codes unused and start at 0x14 below.
+	 */
+	DID_TRANSPORT_MARGINAL = 0x14, /* Transport marginal errors */
+};
+
+#endif /* _SCSI_SCSI_STATUS_H */