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, 219 insertions, 0 deletions

diff --git a/drivers/crypto/omap-aes.h b/drivers/crypto/omap-aes.h
new file mode 100644
index 000000000..6aa70bde3
--- /dev/null
+++ b/drivers/crypto/omap-aes.h
@@ -0,0 +1,219 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Cryptographic API.
+ *
+ * Support for OMAP AES HW ACCELERATOR defines
+ *
+ * Copyright (c) 2015 Texas Instruments Incorporated
+ */
+#ifndef __OMAP_AES_H__
+#define __OMAP_AES_H__
+
+#include <crypto/aes.h>
+
+#define DST_MAXBURST			4
+#define DMA_MIN				(DST_MAXBURST * sizeof(u32))
+
+/*
+ * OMAP TRM gives bitfields as start:end, where start is the higher bit
+ * number. For example 7:0
+ */
+#define FLD_MASK(start, end)	(((1 << ((start) - (end) + 1)) - 1) << (end))
+#define FLD_VAL(val, start, end) (((val) << (end)) & FLD_MASK(start, end))
+
+#define AES_REG_KEY(dd, x)		((dd)->pdata->key_ofs - \
+						(((x) ^ 0x01) * 0x04))
+#define AES_REG_IV(dd, x)		((dd)->pdata->iv_ofs + ((x) * 0x04))
+
+#define AES_REG_CTRL(dd)		((dd)->pdata->ctrl_ofs)
+#define AES_REG_CTRL_CONTEXT_READY	BIT(31)
+#define AES_REG_CTRL_CTR_WIDTH_MASK	GENMASK(8, 7)
+#define AES_REG_CTRL_CTR_WIDTH_32	0
+#define AES_REG_CTRL_CTR_WIDTH_64	BIT(7)
+#define AES_REG_CTRL_CTR_WIDTH_96	BIT(8)
+#define AES_REG_CTRL_CTR_WIDTH_128	GENMASK(8, 7)
+#define AES_REG_CTRL_GCM		GENMASK(17, 16)
+#define AES_REG_CTRL_CTR		BIT(6)
+#define AES_REG_CTRL_CBC		BIT(5)
+#define AES_REG_CTRL_KEY_SIZE		GENMASK(4, 3)
+#define AES_REG_CTRL_DIRECTION		BIT(2)
+#define AES_REG_CTRL_INPUT_READY	BIT(1)
+#define AES_REG_CTRL_OUTPUT_READY	BIT(0)
+#define AES_REG_CTRL_MASK		GENMASK(24, 2)
+
+#define AES_REG_C_LEN_0			0x54
+#define AES_REG_C_LEN_1			0x58
+#define AES_REG_A_LEN			0x5C
+
+#define AES_REG_DATA_N(dd, x)		((dd)->pdata->data_ofs + ((x) * 0x04))
+#define AES_REG_TAG_N(dd, x)		(0x70 + ((x) * 0x04))
+
+#define AES_REG_REV(dd)			((dd)->pdata->rev_ofs)
+
+#define AES_REG_MASK(dd)		((dd)->pdata->mask_ofs)
+#define AES_REG_MASK_SIDLE		BIT(6)
+#define AES_REG_MASK_START		BIT(5)
+#define AES_REG_MASK_DMA_OUT_EN		BIT(3)
+#define AES_REG_MASK_DMA_IN_EN		BIT(2)
+#define AES_REG_MASK_SOFTRESET		BIT(1)
+#define AES_REG_AUTOIDLE		BIT(0)
+
+#define AES_REG_LENGTH_N(x)		(0x54 + ((x) * 0x04))
+
+#define AES_REG_IRQ_STATUS(dd)         ((dd)->pdata->irq_status_ofs)
+#define AES_REG_IRQ_ENABLE(dd)         ((dd)->pdata->irq_enable_ofs)
+#define AES_REG_IRQ_DATA_IN            BIT(1)
+#define AES_REG_IRQ_DATA_OUT           BIT(2)
+#define DEFAULT_TIMEOUT		(5 * HZ)
+
+#define DEFAULT_AUTOSUSPEND_DELAY	1000
+
+#define FLAGS_MODE_MASK		0x001f
+#define FLAGS_ENCRYPT		BIT(0)
+#define FLAGS_CBC		BIT(1)
+#define FLAGS_CTR		BIT(2)
+#define FLAGS_GCM		BIT(3)
+#define FLAGS_RFC4106_GCM	BIT(4)
+
+#define FLAGS_INIT		BIT(5)
+#define FLAGS_FAST		BIT(6)
+
+#define FLAGS_IN_DATA_ST_SHIFT	8
+#define FLAGS_OUT_DATA_ST_SHIFT	10
+#define FLAGS_ASSOC_DATA_ST_SHIFT	12
+
+#define AES_BLOCK_WORDS		(AES_BLOCK_SIZE >> 2)
+
+struct omap_aes_gcm_result {
+	struct completion completion;
+	int err;
+};
+
+struct omap_aes_ctx {
+	int		keylen;
+	u32		key[AES_KEYSIZE_256 / sizeof(u32)];
+	u8		nonce[4];
+	struct crypto_skcipher	*fallback;
+};
+
+struct omap_aes_gcm_ctx {
+	struct omap_aes_ctx	octx;
+	struct aes_enckey	akey;
+};
+
+struct omap_aes_reqctx {
+	struct omap_aes_dev *dd;
+	unsigned long mode;
+	u8 iv[AES_BLOCK_SIZE];
+	u32 auth_tag[AES_BLOCK_SIZE / sizeof(u32)];
+	struct skcipher_request fallback_req;	// keep at the end
+};
+
+#define OMAP_AES_QUEUE_LENGTH	1
+#define OMAP_AES_CACHE_SIZE	0
+
+struct omap_aes_algs_info {
+	struct skcipher_engine_alg	*algs_list;
+	unsigned int			size;
+	unsigned int			registered;
+};
+
+struct omap_aes_aead_algs {
+	struct aead_engine_alg		*algs_list;
+	unsigned int			size;
+	unsigned int			registered;
+};
+
+struct omap_aes_pdata {
+	struct omap_aes_algs_info	*algs_info;
+	unsigned int	algs_info_size;
+	struct omap_aes_aead_algs	*aead_algs_info;
+
+	void		(*trigger)(struct omap_aes_dev *dd, int length);
+
+	u32		key_ofs;
+	u32		iv_ofs;
+	u32		ctrl_ofs;
+	u32		data_ofs;
+	u32		rev_ofs;
+	u32		mask_ofs;
+	u32             irq_enable_ofs;
+	u32             irq_status_ofs;
+
+	u32		dma_enable_in;
+	u32		dma_enable_out;
+	u32		dma_start;
+
+	u32		major_mask;
+	u32		major_shift;
+	u32		minor_mask;
+	u32		minor_shift;
+};
+
+struct omap_aes_dev {
+	struct list_head	list;
+	unsigned long		phys_base;
+	void __iomem		*io_base;
+	struct omap_aes_ctx	*ctx;
+	struct device		*dev;
+	unsigned long		flags;
+	int			err;
+
+	struct work_struct	done_task;
+	struct aead_queue	aead_queue;
+	spinlock_t		lock;
+
+	struct skcipher_request		*req;
+	struct aead_request		*aead_req;
+	struct crypto_engine		*engine;
+
+	/*
+	 * total is used by PIO mode for book keeping so introduce
+	 * variable total_save as need it to calc page_order
+	 */
+	size_t				total;
+	size_t				total_save;
+	size_t				assoc_len;
+	size_t				authsize;
+
+	struct scatterlist		*in_sg;
+	struct scatterlist		*out_sg;
+
+	/* Buffers for copying for unaligned cases */
+	struct scatterlist		in_sgl[2];
+	struct scatterlist		out_sgl;
+	struct scatterlist		*orig_out;
+
+	unsigned int		in_sg_offset;
+	unsigned int		out_sg_offset;
+	struct dma_chan		*dma_lch_in;
+	struct dma_chan		*dma_lch_out;
+	int			in_sg_len;
+	int			out_sg_len;
+	int			pio_only;
+	const struct omap_aes_pdata	*pdata;
+};
+
+u32 omap_aes_read(struct omap_aes_dev *dd, u32 offset);
+void omap_aes_write(struct omap_aes_dev *dd, u32 offset, u32 value);
+struct omap_aes_dev *omap_aes_find_dev(struct omap_aes_reqctx *rctx);
+int omap_aes_gcm_setkey(struct crypto_aead *tfm, const u8 *key,
+			unsigned int keylen);
+int omap_aes_4106gcm_setkey(struct crypto_aead *tfm, const u8 *key,
+			    unsigned int keylen);
+int omap_aes_gcm_encrypt(struct aead_request *req);
+int omap_aes_gcm_decrypt(struct aead_request *req);
+int omap_aes_gcm_setauthsize(struct crypto_aead *tfm, unsigned int authsize);
+int omap_aes_4106gcm_encrypt(struct aead_request *req);
+int omap_aes_4106gcm_decrypt(struct aead_request *req);
+int omap_aes_4106gcm_setauthsize(struct crypto_aead *parent,
+				 unsigned int authsize);
+int omap_aes_gcm_cra_init(struct crypto_aead *tfm);
+int omap_aes_write_ctrl(struct omap_aes_dev *dd);
+int omap_aes_crypt_dma_start(struct omap_aes_dev *dd);
+int omap_aes_crypt_dma_stop(struct omap_aes_dev *dd);
+void omap_aes_gcm_dma_out_callback(void *data);
+void omap_aes_clear_copy_flags(struct omap_aes_dev *dd);
+int omap_aes_gcm_crypt_req(struct crypto_engine *engine, void *areq);
+
+#endif