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, 395 insertions, 0 deletions

diff --git a/drivers/crypto/padlock-sha.c b/drivers/crypto/padlock-sha.c
new file mode 100644
index 000000000..9214bbfc8
--- /dev/null
+++ b/drivers/crypto/padlock-sha.c
@@ -0,0 +1,395 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Cryptographic API.
+ *
+ * Support for VIA PadLock hardware crypto engine.
+ *
+ * Copyright (c) 2006  Michal Ludvig <michal@logix.cz>
+ */
+
+#include <asm/cpu_device_id.h>
+#include <crypto/internal/hash.h>
+#include <crypto/padlock.h>
+#include <crypto/sha1.h>
+#include <crypto/sha2.h>
+#include <linux/cpufeature.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+#define PADLOCK_SHA_DESCSIZE (128 + ((PADLOCK_ALIGNMENT - 1) & \
+				     ~(CRYPTO_MINALIGN - 1)))
+
+struct padlock_sha_ctx {
+	struct crypto_ahash *fallback;
+};
+
+static inline void *padlock_shash_desc_ctx(struct shash_desc *desc)
+{
+	return PTR_ALIGN(shash_desc_ctx(desc), PADLOCK_ALIGNMENT);
+}
+
+static int padlock_sha1_init(struct shash_desc *desc)
+{
+	struct sha1_state *sctx = padlock_shash_desc_ctx(desc);
+
+	*sctx = (struct sha1_state){
+		.state = { SHA1_H0, SHA1_H1, SHA1_H2, SHA1_H3, SHA1_H4 },
+	};
+
+	return 0;
+}
+
+static int padlock_sha256_init(struct shash_desc *desc)
+{
+	struct crypto_sha256_state *sctx = padlock_shash_desc_ctx(desc);
+
+	sha256_block_init(sctx);
+	return 0;
+}
+
+static int padlock_sha_update(struct shash_desc *desc,
+			      const u8 *data, unsigned int length)
+{
+	u8 *state = padlock_shash_desc_ctx(desc);
+	struct crypto_shash *tfm = desc->tfm;
+	int err, remain;
+
+	remain = length - round_down(length, crypto_shash_blocksize(tfm));
+	{
+		struct padlock_sha_ctx *ctx = crypto_shash_ctx(tfm);
+		HASH_REQUEST_ON_STACK(req, ctx->fallback);
+
+		ahash_request_set_callback(req, 0, NULL, NULL);
+		ahash_request_set_virt(req, data, NULL, length - remain);
+		err = crypto_ahash_import_core(req, state) ?:
+		      crypto_ahash_update(req) ?:
+		      crypto_ahash_export_core(req, state);
+		HASH_REQUEST_ZERO(req);
+	}
+
+	return err ?: remain;
+}
+
+static int padlock_sha_export(struct shash_desc *desc, void *out)
+{
+	memcpy(out, padlock_shash_desc_ctx(desc),
+	       crypto_shash_coresize(desc->tfm));
+	return 0;
+}
+
+static int padlock_sha_import(struct shash_desc *desc, const void *in)
+{
+	unsigned int bs = crypto_shash_blocksize(desc->tfm);
+	unsigned int ss = crypto_shash_coresize(desc->tfm);
+	u64 *state = padlock_shash_desc_ctx(desc);
+
+	memcpy(state, in, ss);
+
+	/* Stop evil imports from generating a fault. */
+	state[ss / 8 - 1] &= ~(bs - 1);
+
+	return 0;
+}
+
+static inline void padlock_output_block(uint32_t *src,
+		 	uint32_t *dst, size_t count)
+{
+	while (count--)
+		*dst++ = swab32(*src++);
+}
+
+static int padlock_sha_finup(struct shash_desc *desc, const u8 *in,
+			     unsigned int count, u8 *out)
+{
+	struct padlock_sha_ctx *ctx = crypto_shash_ctx(desc->tfm);
+	HASH_REQUEST_ON_STACK(req, ctx->fallback);
+
+	ahash_request_set_callback(req, 0, NULL, NULL);
+	ahash_request_set_virt(req, in, out, count);
+	return crypto_ahash_import_core(req, padlock_shash_desc_ctx(desc)) ?:
+	       crypto_ahash_finup(req);
+}
+
+static int padlock_sha1_finup(struct shash_desc *desc, const u8 *in,
+			      unsigned int count, u8 *out)
+{
+	/* We can't store directly to *out as it may be unaligned. */
+	/* BTW Don't reduce the buffer size below 128 Bytes!
+	 *     PadLock microcode needs it that big. */
+	struct sha1_state *state = padlock_shash_desc_ctx(desc);
+	u64 start = state->count;
+
+	if (start + count > ULONG_MAX)
+		return padlock_sha_finup(desc, in, count, out);
+
+	asm volatile (".byte 0xf3,0x0f,0xa6,0xc8" /* rep xsha1 */
+		      : \
+		      : "c"((unsigned long)start + count), \
+			"a"((unsigned long)start), \
+			"S"(in), "D"(state));
+
+	padlock_output_block(state->state, (uint32_t *)out, 5);
+	return 0;
+}
+
+static int padlock_sha256_finup(struct shash_desc *desc, const u8 *in,
+				unsigned int count, u8 *out)
+{
+	/* We can't store directly to *out as it may be unaligned. */
+	/* BTW Don't reduce the buffer size below 128 Bytes!
+	 *     PadLock microcode needs it that big. */
+	struct sha256_state *state = padlock_shash_desc_ctx(desc);
+	u64 start = state->count;
+
+	if (start + count > ULONG_MAX)
+		return padlock_sha_finup(desc, in, count, out);
+
+	asm volatile (".byte 0xf3,0x0f,0xa6,0xd0" /* rep xsha256 */
+		      : \
+		      : "c"((unsigned long)start + count), \
+			"a"((unsigned long)start), \
+			"S"(in), "D"(state));
+
+	padlock_output_block(state->state, (uint32_t *)out, 8);
+	return 0;
+}
+
+static int padlock_init_tfm(struct crypto_shash *hash)
+{
+	const char *fallback_driver_name = crypto_shash_alg_name(hash);
+	struct padlock_sha_ctx *ctx = crypto_shash_ctx(hash);
+	struct crypto_ahash *fallback_tfm;
+
+	/* Allocate a fallback and abort if it failed. */
+	fallback_tfm = crypto_alloc_ahash(fallback_driver_name, 0,
+					  CRYPTO_ALG_NEED_FALLBACK |
+					  CRYPTO_ALG_ASYNC);
+	if (IS_ERR(fallback_tfm)) {
+		printk(KERN_WARNING PFX "Fallback driver '%s' could not be loaded!\n",
+		       fallback_driver_name);
+		return PTR_ERR(fallback_tfm);
+	}
+
+	if (crypto_shash_statesize(hash) !=
+	    crypto_ahash_statesize(fallback_tfm)) {
+		crypto_free_ahash(fallback_tfm);
+		return -EINVAL;
+	}
+
+	ctx->fallback = fallback_tfm;
+
+	return 0;
+}
+
+static void padlock_exit_tfm(struct crypto_shash *hash)
+{
+	struct padlock_sha_ctx *ctx = crypto_shash_ctx(hash);
+
+	crypto_free_ahash(ctx->fallback);
+}
+
+static struct shash_alg sha1_alg = {
+	.digestsize	=	SHA1_DIGEST_SIZE,
+	.init   	= 	padlock_sha1_init,
+	.update 	=	padlock_sha_update,
+	.finup  	=	padlock_sha1_finup,
+	.export		=	padlock_sha_export,
+	.import		=	padlock_sha_import,
+	.init_tfm	=	padlock_init_tfm,
+	.exit_tfm	=	padlock_exit_tfm,
+	.descsize	=	PADLOCK_SHA_DESCSIZE,
+	.statesize	=	SHA1_STATE_SIZE,
+	.base		=	{
+		.cra_name		=	"sha1",
+		.cra_driver_name	=	"sha1-padlock",
+		.cra_priority		=	PADLOCK_CRA_PRIORITY,
+		.cra_flags		=	CRYPTO_ALG_NEED_FALLBACK |
+						CRYPTO_AHASH_ALG_BLOCK_ONLY |
+						CRYPTO_AHASH_ALG_FINUP_MAX,
+		.cra_blocksize		=	SHA1_BLOCK_SIZE,
+		.cra_ctxsize		=	sizeof(struct padlock_sha_ctx),
+		.cra_module		=	THIS_MODULE,
+	}
+};
+
+static struct shash_alg sha256_alg = {
+	.digestsize	=	SHA256_DIGEST_SIZE,
+	.init   	= 	padlock_sha256_init,
+	.update 	=	padlock_sha_update,
+	.finup  	=	padlock_sha256_finup,
+	.init_tfm	=	padlock_init_tfm,
+	.export		=	padlock_sha_export,
+	.import		=	padlock_sha_import,
+	.exit_tfm	=	padlock_exit_tfm,
+	.descsize	=	PADLOCK_SHA_DESCSIZE,
+	.statesize	=	sizeof(struct crypto_sha256_state),
+	.base		=	{
+		.cra_name		=	"sha256",
+		.cra_driver_name	=	"sha256-padlock",
+		.cra_priority		=	PADLOCK_CRA_PRIORITY,
+		.cra_flags		=	CRYPTO_ALG_NEED_FALLBACK |
+						CRYPTO_AHASH_ALG_BLOCK_ONLY |
+						CRYPTO_AHASH_ALG_FINUP_MAX,
+		.cra_blocksize		=	SHA256_BLOCK_SIZE,
+		.cra_ctxsize		=	sizeof(struct padlock_sha_ctx),
+		.cra_module		=	THIS_MODULE,
+	}
+};
+
+/* Add two shash_alg instance for hardware-implemented *
+* multiple-parts hash supported by VIA Nano Processor.*/
+
+static int padlock_sha1_update_nano(struct shash_desc *desc,
+				    const u8 *src, unsigned int len)
+{
+	/*The PHE require the out buffer must 128 bytes and 16-bytes aligned*/
+	struct sha1_state *state = padlock_shash_desc_ctx(desc);
+	int blocks = len / SHA1_BLOCK_SIZE;
+
+	len -= blocks * SHA1_BLOCK_SIZE;
+	state->count += blocks * SHA1_BLOCK_SIZE;
+
+	/* Process the left bytes from the input data */
+	asm volatile (".byte 0xf3,0x0f,0xa6,0xc8"
+		      : "+S"(src), "+D"(state)
+		      : "a"((long)-1),
+			"c"((unsigned long)blocks));
+	return len;
+}
+
+static int padlock_sha256_update_nano(struct shash_desc *desc, const u8 *src,
+			  unsigned int len)
+{
+	/*The PHE require the out buffer must 128 bytes and 16-bytes aligned*/
+	struct crypto_sha256_state *state = padlock_shash_desc_ctx(desc);
+	int blocks = len / SHA256_BLOCK_SIZE;
+
+	len -= blocks * SHA256_BLOCK_SIZE;
+	state->count += blocks * SHA256_BLOCK_SIZE;
+
+	/* Process the left bytes from input data*/
+	asm volatile (".byte 0xf3,0x0f,0xa6,0xd0"
+		      : "+S"(src), "+D"(state)
+		      : "a"((long)-1),
+		      "c"((unsigned long)blocks));
+	return len;
+}
+
+static struct shash_alg sha1_alg_nano = {
+	.digestsize	=	SHA1_DIGEST_SIZE,
+	.init		=	padlock_sha1_init,
+	.update		=	padlock_sha1_update_nano,
+	.finup  	=	padlock_sha1_finup,
+	.export		=	padlock_sha_export,
+	.import		=	padlock_sha_import,
+	.descsize	=	PADLOCK_SHA_DESCSIZE,
+	.statesize	=	SHA1_STATE_SIZE,
+	.base		=	{
+		.cra_name		=	"sha1",
+		.cra_driver_name	=	"sha1-padlock-nano",
+		.cra_priority		=	PADLOCK_CRA_PRIORITY,
+		.cra_flags		=	CRYPTO_AHASH_ALG_BLOCK_ONLY |
+						CRYPTO_AHASH_ALG_FINUP_MAX,
+		.cra_blocksize		=	SHA1_BLOCK_SIZE,
+		.cra_module		=	THIS_MODULE,
+	}
+};
+
+static struct shash_alg sha256_alg_nano = {
+	.digestsize	=	SHA256_DIGEST_SIZE,
+	.init		=	padlock_sha256_init,
+	.update		=	padlock_sha256_update_nano,
+	.finup		=	padlock_sha256_finup,
+	.export		=	padlock_sha_export,
+	.import		=	padlock_sha_import,
+	.descsize	=	PADLOCK_SHA_DESCSIZE,
+	.statesize	=	sizeof(struct crypto_sha256_state),
+	.base		=	{
+		.cra_name		=	"sha256",
+		.cra_driver_name	=	"sha256-padlock-nano",
+		.cra_priority		=	PADLOCK_CRA_PRIORITY,
+		.cra_flags		=	CRYPTO_AHASH_ALG_BLOCK_ONLY |
+						CRYPTO_AHASH_ALG_FINUP_MAX,
+		.cra_blocksize		=	SHA256_BLOCK_SIZE,
+		.cra_module		=	THIS_MODULE,
+	}
+};
+
+static const struct x86_cpu_id padlock_sha_ids[] = {
+	X86_MATCH_FEATURE(X86_FEATURE_PHE, NULL),
+	{}
+};
+MODULE_DEVICE_TABLE(x86cpu, padlock_sha_ids);
+
+static int __init padlock_init(void)
+{
+	int rc = -ENODEV;
+	struct cpuinfo_x86 *c = &cpu_data(0);
+	struct shash_alg *sha1;
+	struct shash_alg *sha256;
+
+	if (!x86_match_cpu(padlock_sha_ids) || !boot_cpu_has(X86_FEATURE_PHE_EN))
+		return -ENODEV;
+
+	/*
+	 * Skip family 0x07 and newer used by Zhaoxin processors,
+	 * as the driver's self-tests fail on these CPUs.
+	 */
+	if (c->x86 >= 0x07)
+		return -ENODEV;
+
+	/* Register the newly added algorithm module if on *
+	* VIA Nano processor, or else just do as before */
+	if (c->x86_model < 0x0f) {
+		sha1 = &sha1_alg;
+		sha256 = &sha256_alg;
+	} else {
+		sha1 = &sha1_alg_nano;
+		sha256 = &sha256_alg_nano;
+	}
+
+	rc = crypto_register_shash(sha1);
+	if (rc)
+		goto out;
+
+	rc = crypto_register_shash(sha256);
+	if (rc)
+		goto out_unreg1;
+
+	printk(KERN_NOTICE PFX "Using VIA PadLock ACE for SHA1/SHA256 algorithms.\n");
+
+	return 0;
+
+out_unreg1:
+	crypto_unregister_shash(sha1);
+
+out:
+	printk(KERN_ERR PFX "VIA PadLock SHA1/SHA256 initialization failed.\n");
+	return rc;
+}
+
+static void __exit padlock_fini(void)
+{
+	struct cpuinfo_x86 *c = &cpu_data(0);
+
+	if (c->x86_model >= 0x0f) {
+		crypto_unregister_shash(&sha1_alg_nano);
+		crypto_unregister_shash(&sha256_alg_nano);
+	} else {
+		crypto_unregister_shash(&sha1_alg);
+		crypto_unregister_shash(&sha256_alg);
+	}
+}
+
+module_init(padlock_init);
+module_exit(padlock_fini);
+
+MODULE_DESCRIPTION("VIA PadLock SHA1/SHA256 algorithms support.");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Michal Ludvig");
+
+MODULE_ALIAS_CRYPTO("sha1-all");
+MODULE_ALIAS_CRYPTO("sha256-all");
+MODULE_ALIAS_CRYPTO("sha1-padlock");
+MODULE_ALIAS_CRYPTO("sha256-padlock");