x86/kprobes: Fix crash when probing CS CALL instructionsgrafted

When using eBPF to probe CS CALL instructions within a function,
a crash can be triggered.

The eBPF tool probes offset 257 of the __hrtimer_run_queues()
function:

<__hrtimer_run_queues+249>:  nopl   0x0(%rax,%rax,1)
<__hrtimer_run_queues+254>:  mov    %r14,%rdi
<__hrtimer_run_queues+257>:  cs call <__x86_indirect_thunk_r12>
<__hrtimer_run_queues+263>:  mov    %eax,%r12d
<__hrtimer_run_queues+266>:  xchg   %ax,%ax
<__hrtimer_run_queues+268>:  mov    %r13,%rdi

Which triggers this crash:

  BUG: unable to handle page fault for address: 00000000000f41c9
  #PF: supervisor write access in kernel mode
  #PF: error_code(0x0002) - not-present page
  PGD 0 P4D 0
  Oops: 0002 [#1] SMP NOPTI
  CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P
  RIP: 0010:__hrtimer_run_queues+0x106/0x230

Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is
at the 6th byte of the above CS CALL instruction. Since the CS CALL
instruction occupies 6 bytes, the exception occurred in the middle of that
call instruction.

The root cause is that when using eBPF tools to probe in the middle of a
function, a kprobe with INT3 is used as the underlying implementation.

During single-step emulation of the original CALL instruction,
int3_emulate_call() assumes that the probed CALL instruction is 5 bytes
long. However, the actual CS-prefixed CALL instruction occupies 6 bytes,
so it constructs an incorrect exception return address. When the CPU
returns from the kprobe handler, the next instruction to be executed is at
the address of the last byte of that CS CALL instruction. Coincidentally,
starting from that address, the CPU fetches and decodes a completely
different instruction, which ultimately triggers a kernel crash.

Fix the issue by using the actual instruction length obtained from
the instruction decoder when constructing the exception return
address, rather than relying on the hardcoded CALL_INSN_SIZE macro.

[ mingo: Refined the changelog ]

Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step")
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jinke Han <jinkehan@didiglobal.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000

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 */