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, 137 insertions, 0 deletions

diff --git a/drivers/crypto/ccp/psp-dev.h b/drivers/crypto/ccp/psp-dev.h
new file mode 100644
index 000000000..4e370e76b
--- /dev/null
+++ b/drivers/crypto/ccp/psp-dev.h
@@ -0,0 +1,137 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * AMD Platform Security Processor (PSP) interface driver
+ *
+ * Copyright (C) 2017-2019 Advanced Micro Devices, Inc.
+ *
+ * Author: Brijesh Singh <brijesh.singh@amd.com>
+ */
+
+#ifndef __PSP_DEV_H__
+#define __PSP_DEV_H__
+
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/bits.h>
+#include <linux/interrupt.h>
+#include <linux/mutex.h>
+#include <linux/psp.h>
+#include <linux/psp-platform-access.h>
+
+#include "sp-dev.h"
+
+#define MAX_PSP_NAME_LEN		16
+
+extern struct psp_device *psp_master;
+
+typedef void (*psp_irq_handler_t)(int, void *, unsigned int);
+
+union psp_cap_register {
+	unsigned int raw;
+	struct {
+		unsigned int sev			:1,
+			     tee			:1,
+			     dbc_thru_ext		:1,
+			     sfs			:1,
+			     rsvd1			:3,
+			     security_reporting		:1,
+			     fused_part			:1,
+			     boot_integrity		:1,
+			     debug_lock_on		:1,
+			     rsvd3			:2,
+			     tsme_status		:1,
+			     rsvd4			:1,
+			     anti_rollback_status	:1,
+			     rpmc_production_enabled	:1,
+			     rpmc_spirom_available	:1,
+			     hsp_tpm_available		:1,
+			     rom_armor_enforced		:1,
+			     rsvd5			:12;
+	};
+};
+
+struct psp_device {
+	struct list_head entry;
+
+	struct psp_vdata *vdata;
+	char name[MAX_PSP_NAME_LEN];
+
+	struct device *dev;
+	struct sp_device *sp;
+
+	void __iomem *io_regs;
+	struct mutex mailbox_mutex;
+
+	psp_irq_handler_t sev_irq_handler;
+	void *sev_irq_data;
+
+	void *sev_data;
+	void *tee_data;
+	void *platform_access_data;
+	void *dbc_data;
+	void *sfs_data;
+
+	union psp_cap_register capability;
+};
+
+void psp_set_sev_irq_handler(struct psp_device *psp, psp_irq_handler_t handler,
+			     void *data);
+void psp_clear_sev_irq_handler(struct psp_device *psp);
+
+struct psp_device *psp_get_master_device(void);
+
+/**
+ * enum psp_cmd - PSP mailbox commands
+ * @PSP_CMD_TEE_RING_INIT:	Initialize TEE ring buffer
+ * @PSP_CMD_TEE_RING_DESTROY:	Destroy TEE ring buffer
+ * @PSP_CMD_TEE_EXTENDED_CMD:	Extended command
+ * @PSP_CMD_MAX:		Maximum command id
+ */
+enum psp_cmd {
+	PSP_CMD_TEE_RING_INIT		= 1,
+	PSP_CMD_TEE_RING_DESTROY	= 2,
+	PSP_CMD_TEE_EXTENDED_CMD	= 14,
+	PSP_CMD_MAX			= 15,
+};
+
+int psp_mailbox_command(struct psp_device *psp, enum psp_cmd cmd, void *cmdbuff,
+			unsigned int timeout_msecs, unsigned int *cmdresp);
+
+/**
+ * struct psp_ext_req_buffer_hdr - Structure of the extended command header
+ * @payload_size: total payload size
+ * @sub_cmd_id: extended command ID
+ * @status: status of command execution (out)
+ */
+struct psp_ext_req_buffer_hdr {
+	u32 payload_size;
+	u32 sub_cmd_id;
+	u32 status;
+} __packed;
+
+struct psp_ext_request {
+	struct psp_ext_req_buffer_hdr header;
+	void *buf;
+} __packed;
+
+/**
+ * enum psp_sub_cmd - PSP mailbox sub commands
+ * @PSP_SUB_CMD_DBC_GET_NONCE:		Get nonce from DBC
+ * @PSP_SUB_CMD_DBC_SET_UID:		Set UID for DBC
+ * @PSP_SUB_CMD_DBC_GET_PARAMETER:	Get parameter from DBC
+ * @PSP_SUB_CMD_DBC_SET_PARAMETER:	Set parameter for DBC
+ * @PSP_SUB_CMD_SFS_GET_FW_VERS:	Get firmware versions for ASP and other MP
+ * @PSP_SUB_CMD_SFS_UPDATE:		Command to load, verify and execute SFS package
+ */
+enum psp_sub_cmd {
+	PSP_SUB_CMD_DBC_GET_NONCE	= PSP_DYNAMIC_BOOST_GET_NONCE,
+	PSP_SUB_CMD_DBC_SET_UID		= PSP_DYNAMIC_BOOST_SET_UID,
+	PSP_SUB_CMD_DBC_GET_PARAMETER	= PSP_DYNAMIC_BOOST_GET_PARAMETER,
+	PSP_SUB_CMD_DBC_SET_PARAMETER	= PSP_DYNAMIC_BOOST_SET_PARAMETER,
+	PSP_SUB_CMD_SFS_GET_FW_VERS	= PSP_SFS_GET_FW_VERSIONS,
+	PSP_SUB_CMD_SFS_UPDATE		= PSP_SFS_UPDATE,
+};
+
+int psp_extended_mailbox_cmd(struct psp_device *psp, unsigned int timeout_msecs,
+			     struct psp_ext_request *req);
+#endif /* __PSP_DEV_H */