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, 190 insertions, 0 deletions

diff --git a/drivers/crypto/ccp/sp-dev.h b/drivers/crypto/ccp/sp-dev.h
new file mode 100644
index 000000000..a83751cfd
--- /dev/null
+++ b/drivers/crypto/ccp/sp-dev.h
@@ -0,0 +1,190 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * AMD Secure Processor driver
+ *
+ * Copyright (C) 2017-2019 Advanced Micro Devices, Inc.
+ *
+ * Author: Tom Lendacky <thomas.lendacky@amd.com>
+ * Author: Gary R Hook <gary.hook@amd.com>
+ * Author: Brijesh Singh <brijesh.singh@amd.com>
+ */
+
+#ifndef __SP_DEV_H__
+#define __SP_DEV_H__
+
+#include <linux/device.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+#include <linux/list.h>
+#include <linux/wait.h>
+#include <linux/dmapool.h>
+#include <linux/hw_random.h>
+#include <linux/bitops.h>
+#include <linux/interrupt.h>
+#include <linux/irqreturn.h>
+
+#define SP_MAX_NAME_LEN		32
+
+#define CACHE_NONE			0x00
+#define CACHE_WB_NO_ALLOC		0xb7
+
+#define PLATFORM_FEATURE_DBC		0x1
+#define PLATFORM_FEATURE_HSTI		0x2
+
+#define PSP_FEATURE(psp, feat)	(psp->vdata && psp->vdata->platform_features & PLATFORM_FEATURE_##feat)
+
+/* Structure to hold CCP device data */
+struct ccp_device;
+struct ccp_vdata {
+	const unsigned int version;
+	const unsigned int dma_chan_attr;
+	void (*setup)(struct ccp_device *);
+	const struct ccp_actions *perform;
+	const unsigned int offset;
+	const unsigned int rsamax;
+};
+
+struct sev_vdata {
+	const unsigned int cmdresp_reg;
+	const unsigned int cmdbuff_addr_lo_reg;
+	const unsigned int cmdbuff_addr_hi_reg;
+};
+
+struct tee_vdata {
+	const unsigned int cmdresp_reg;
+	const unsigned int cmdbuff_addr_lo_reg;
+	const unsigned int cmdbuff_addr_hi_reg;
+	const unsigned int ring_wptr_reg;
+	const unsigned int ring_rptr_reg;
+	const unsigned int info_reg;
+};
+
+struct platform_access_vdata {
+	const unsigned int cmdresp_reg;
+	const unsigned int cmdbuff_addr_lo_reg;
+	const unsigned int cmdbuff_addr_hi_reg;
+	const unsigned int doorbell_button_reg;
+	const unsigned int doorbell_cmd_reg;
+
+};
+
+struct psp_vdata {
+	const struct sev_vdata *sev;
+	const struct tee_vdata *tee;
+	const struct platform_access_vdata *platform_access;
+	const unsigned int cmdresp_reg;
+	const unsigned int cmdbuff_addr_lo_reg;
+	const unsigned int cmdbuff_addr_hi_reg;
+	const unsigned int feature_reg;
+	const unsigned int inten_reg;
+	const unsigned int intsts_reg;
+	const unsigned int bootloader_info_reg;
+	const unsigned int platform_features;
+};
+
+/* Structure to hold SP device data */
+struct sp_dev_vdata {
+	const unsigned int bar;
+
+	const struct ccp_vdata *ccp_vdata;
+	const struct psp_vdata *psp_vdata;
+};
+
+struct sp_device {
+	struct list_head entry;
+
+	struct device *dev;
+
+	const struct sp_dev_vdata *dev_vdata;
+	unsigned int ord;
+	char name[SP_MAX_NAME_LEN];
+
+	/* Bus specific device information */
+	void *dev_specific;
+
+	/* I/O area used for device communication. */
+	void __iomem *io_map;
+
+	/* DMA caching attribute support */
+	unsigned int axcache;
+
+	/* get and set master device */
+	struct sp_device*(*get_psp_master_device)(void);
+	void (*set_psp_master_device)(struct sp_device *);
+	void (*clear_psp_master_device)(struct sp_device *);
+
+	bool irq_registered;
+	bool use_tasklet;
+
+	unsigned int ccp_irq;
+	irq_handler_t ccp_irq_handler;
+	void *ccp_irq_data;
+
+	unsigned int psp_irq;
+	irq_handler_t psp_irq_handler;
+	void *psp_irq_data;
+
+	void *ccp_data;
+	void *psp_data;
+};
+
+int sp_pci_init(void);
+void sp_pci_exit(void);
+
+int sp_platform_init(void);
+void sp_platform_exit(void);
+
+struct sp_device *sp_alloc_struct(struct device *dev);
+
+int sp_init(struct sp_device *sp);
+void sp_destroy(struct sp_device *sp);
+
+int sp_suspend(struct sp_device *sp);
+int sp_resume(struct sp_device *sp);
+int sp_restore(struct sp_device *sp);
+int sp_request_ccp_irq(struct sp_device *sp, irq_handler_t handler,
+		       const char *name, void *data);
+void sp_free_ccp_irq(struct sp_device *sp, void *data);
+int sp_request_psp_irq(struct sp_device *sp, irq_handler_t handler,
+		       const char *name, void *data);
+void sp_free_psp_irq(struct sp_device *sp, void *data);
+struct sp_device *sp_get_psp_master_device(void);
+
+#ifdef CONFIG_CRYPTO_DEV_SP_CCP
+
+int ccp_dev_init(struct sp_device *sp);
+void ccp_dev_destroy(struct sp_device *sp);
+
+void ccp_dev_suspend(struct sp_device *sp);
+void ccp_dev_resume(struct sp_device *sp);
+
+#else	/* !CONFIG_CRYPTO_DEV_SP_CCP */
+
+static inline int ccp_dev_init(struct sp_device *sp)
+{
+	return 0;
+}
+static inline void ccp_dev_destroy(struct sp_device *sp) { }
+static inline void ccp_dev_suspend(struct sp_device *sp) { }
+static inline void ccp_dev_resume(struct sp_device *sp) { }
+#endif	/* CONFIG_CRYPTO_DEV_SP_CCP */
+
+#ifdef CONFIG_CRYPTO_DEV_SP_PSP
+
+int psp_dev_init(struct sp_device *sp);
+void psp_pci_init(void);
+void psp_dev_destroy(struct sp_device *sp);
+void psp_pci_exit(void);
+int psp_restore(struct sp_device *sp);
+
+#else /* !CONFIG_CRYPTO_DEV_SP_PSP */
+
+static inline int psp_dev_init(struct sp_device *sp) { return 0; }
+static inline void psp_pci_init(void) { }
+static inline void psp_dev_destroy(struct sp_device *sp) { }
+static inline void psp_pci_exit(void) { }
+static inline int psp_restore(struct sp_device *sp) { return 0; }
+
+#endif /* CONFIG_CRYPTO_DEV_SP_PSP */
+
+#endif