ftrace: Synchronize the initialization of ftrace_opsgrafted

There's some internal state that ftrace_ops needs to have set, but since
it can be declared outside of the ftrace.c code, it calls
ftrace_ops_init() on the ops in every global function. The issue is that
if two tasks call it on the same ops at the same time it is possible to
have the initialization of one corrupt the initialization of the other
call.

Create a ops_mutex to use to synchronize every initialization of the
ftrace_ops. The mutex is taken within checking the ftrace_ops flag that
states it was initializied but the flag is checked again after the mutex
has been taken. Checking first outside the mutex allows it to shortcut
having to take the mutex. But then the check needs to be done again after
the mute is taken in case of races.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home
Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock")
Reported-by: sashiko-bot@kernel.org
Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 252 insertions, 0 deletions

diff --git a/crypto/akcipher.c b/crypto/akcipher.c
new file mode 100644
index 000000000..630bb1973
--- /dev/null
+++ b/crypto/akcipher.c
@@ -0,0 +1,252 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Public Key Encryption
+ *
+ * Copyright (c) 2015, Intel Corporation
+ * Authors: Tadeusz Struk <tadeusz.struk@intel.com>
+ */
+#include <crypto/internal/akcipher.h>
+#include <linux/cryptouser.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/scatterlist.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <net/netlink.h>
+
+#include "internal.h"
+
+#define CRYPTO_ALG_TYPE_AHASH_MASK	0x0000000e
+
+struct crypto_akcipher_sync_data {
+	struct crypto_akcipher *tfm;
+	const void *src;
+	void *dst;
+	unsigned int slen;
+	unsigned int dlen;
+
+	struct akcipher_request *req;
+	struct crypto_wait cwait;
+	struct scatterlist sg;
+	u8 *buf;
+};
+
+static int __maybe_unused crypto_akcipher_report(
+	struct sk_buff *skb, struct crypto_alg *alg)
+{
+	struct crypto_report_akcipher rakcipher = {
+		.type = "akcipher",
+	};
+
+	return nla_put(skb, CRYPTOCFGA_REPORT_AKCIPHER,
+		       sizeof(rakcipher), &rakcipher);
+}
+
+static void __maybe_unused crypto_akcipher_show(struct seq_file *m,
+						struct crypto_alg *alg)
+{
+	seq_puts(m, "type         : akcipher\n");
+}
+
+static void crypto_akcipher_exit_tfm(struct crypto_tfm *tfm)
+{
+	struct crypto_akcipher *akcipher = __crypto_akcipher_tfm(tfm);
+	struct akcipher_alg *alg = crypto_akcipher_alg(akcipher);
+
+	alg->exit(akcipher);
+}
+
+static int crypto_akcipher_init_tfm(struct crypto_tfm *tfm)
+{
+	struct crypto_akcipher *akcipher = __crypto_akcipher_tfm(tfm);
+	struct akcipher_alg *alg = crypto_akcipher_alg(akcipher);
+
+	if (alg->exit)
+		akcipher->base.exit = crypto_akcipher_exit_tfm;
+
+	if (alg->init)
+		return alg->init(akcipher);
+
+	return 0;
+}
+
+static void crypto_akcipher_free_instance(struct crypto_instance *inst)
+{
+	struct akcipher_instance *akcipher = akcipher_instance(inst);
+
+	akcipher->free(akcipher);
+}
+
+static const struct crypto_type crypto_akcipher_type = {
+	.extsize = crypto_alg_extsize,
+	.init_tfm = crypto_akcipher_init_tfm,
+	.free = crypto_akcipher_free_instance,
+#ifdef CONFIG_PROC_FS
+	.show = crypto_akcipher_show,
+#endif
+#if IS_ENABLED(CONFIG_CRYPTO_USER)
+	.report = crypto_akcipher_report,
+#endif
+	.maskclear = ~CRYPTO_ALG_TYPE_MASK,
+	.maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
+	.type = CRYPTO_ALG_TYPE_AKCIPHER,
+	.tfmsize = offsetof(struct crypto_akcipher, base),
+	.algsize = offsetof(struct akcipher_alg, base),
+};
+
+int crypto_grab_akcipher(struct crypto_akcipher_spawn *spawn,
+			 struct crypto_instance *inst,
+			 const char *name, u32 type, u32 mask)
+{
+	spawn->base.frontend = &crypto_akcipher_type;
+	return crypto_grab_spawn(&spawn->base, inst, name, type, mask);
+}
+EXPORT_SYMBOL_GPL(crypto_grab_akcipher);
+
+struct crypto_akcipher *crypto_alloc_akcipher(const char *alg_name, u32 type,
+					      u32 mask)
+{
+	return crypto_alloc_tfm(alg_name, &crypto_akcipher_type, type, mask);
+}
+EXPORT_SYMBOL_GPL(crypto_alloc_akcipher);
+
+static void akcipher_prepare_alg(struct akcipher_alg *alg)
+{
+	struct crypto_alg *base = &alg->base;
+
+	base->cra_type = &crypto_akcipher_type;
+	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
+	base->cra_flags |= CRYPTO_ALG_TYPE_AKCIPHER;
+}
+
+static int akcipher_default_op(struct akcipher_request *req)
+{
+	return -ENOSYS;
+}
+
+static int akcipher_default_set_key(struct crypto_akcipher *tfm,
+				     const void *key, unsigned int keylen)
+{
+	return -ENOSYS;
+}
+
+int crypto_register_akcipher(struct akcipher_alg *alg)
+{
+	struct crypto_alg *base = &alg->base;
+
+	if (!alg->encrypt)
+		alg->encrypt = akcipher_default_op;
+	if (!alg->decrypt)
+		alg->decrypt = akcipher_default_op;
+	if (!alg->set_priv_key)
+		alg->set_priv_key = akcipher_default_set_key;
+
+	akcipher_prepare_alg(alg);
+	return crypto_register_alg(base);
+}
+EXPORT_SYMBOL_GPL(crypto_register_akcipher);
+
+void crypto_unregister_akcipher(struct akcipher_alg *alg)
+{
+	crypto_unregister_alg(&alg->base);
+}
+EXPORT_SYMBOL_GPL(crypto_unregister_akcipher);
+
+int akcipher_register_instance(struct crypto_template *tmpl,
+			       struct akcipher_instance *inst)
+{
+	if (WARN_ON(!inst->free))
+		return -EINVAL;
+	akcipher_prepare_alg(&inst->alg);
+	return crypto_register_instance(tmpl, akcipher_crypto_instance(inst));
+}
+EXPORT_SYMBOL_GPL(akcipher_register_instance);
+
+static int crypto_akcipher_sync_prep(struct crypto_akcipher_sync_data *data)
+{
+	unsigned int reqsize = crypto_akcipher_reqsize(data->tfm);
+	struct akcipher_request *req;
+	struct scatterlist *sg;
+	unsigned int mlen;
+	unsigned int len;
+	u8 *buf;
+
+	mlen = max(data->slen, data->dlen);
+
+	len = sizeof(*req) + reqsize + mlen;
+	if (len < mlen)
+		return -EOVERFLOW;
+
+	req = kzalloc(len, GFP_KERNEL);
+	if (!req)
+		return -ENOMEM;
+
+	data->req = req;
+	akcipher_request_set_tfm(req, data->tfm);
+
+	buf = (u8 *)(req + 1) + reqsize;
+	data->buf = buf;
+	memcpy(buf, data->src, data->slen);
+
+	sg = &data->sg;
+	sg_init_one(sg, buf, mlen);
+	akcipher_request_set_crypt(req, sg, sg, data->slen, data->dlen);
+
+	crypto_init_wait(&data->cwait);
+	akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
+				      crypto_req_done, &data->cwait);
+
+	return 0;
+}
+
+static int crypto_akcipher_sync_post(struct crypto_akcipher_sync_data *data,
+				     int err)
+{
+	err = crypto_wait_req(err, &data->cwait);
+	memcpy(data->dst, data->buf, data->dlen);
+	data->dlen = data->req->dst_len;
+	kfree_sensitive(data->req);
+	return err;
+}
+
+int crypto_akcipher_sync_encrypt(struct crypto_akcipher *tfm,
+				 const void *src, unsigned int slen,
+				 void *dst, unsigned int dlen)
+{
+	struct crypto_akcipher_sync_data data = {
+		.tfm = tfm,
+		.src = src,
+		.dst = dst,
+		.slen = slen,
+		.dlen = dlen,
+	};
+
+	return crypto_akcipher_sync_prep(&data) ?:
+	       crypto_akcipher_sync_post(&data,
+					 crypto_akcipher_encrypt(data.req));
+}
+EXPORT_SYMBOL_GPL(crypto_akcipher_sync_encrypt);
+
+int crypto_akcipher_sync_decrypt(struct crypto_akcipher *tfm,
+				 const void *src, unsigned int slen,
+				 void *dst, unsigned int dlen)
+{
+	struct crypto_akcipher_sync_data data = {
+		.tfm = tfm,
+		.src = src,
+		.dst = dst,
+		.slen = slen,
+		.dlen = dlen,
+	};
+
+	return crypto_akcipher_sync_prep(&data) ?:
+	       crypto_akcipher_sync_post(&data,
+					 crypto_akcipher_decrypt(data.req)) ?:
+	       data.dlen;
+}
+EXPORT_SYMBOL_GPL(crypto_akcipher_sync_decrypt);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Generic public key cipher type");