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, 178 insertions, 0 deletions

diff --git a/crypto/seqiv.c b/crypto/seqiv.c
new file mode 100644
index 000000000..678bb4145
--- /dev/null
+++ b/crypto/seqiv.c
@@ -0,0 +1,178 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * seqiv: Sequence Number IV Generator
+ *
+ * This generator generates an IV based on a sequence number by xoring it
+ * with a salt.  This algorithm is mainly useful for CTR and similar modes.
+ *
+ * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
+ */
+
+#include <crypto/internal/geniv.h>
+#include <crypto/scatterwalk.h>
+#include <crypto/skcipher.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+
+static void seqiv_aead_encrypt_complete2(struct aead_request *req, int err)
+{
+	struct aead_request *subreq = aead_request_ctx(req);
+	struct crypto_aead *geniv;
+
+	if (err == -EINPROGRESS || err == -EBUSY)
+		return;
+
+	if (err)
+		goto out;
+
+	geniv = crypto_aead_reqtfm(req);
+	memcpy(req->iv, subreq->iv, crypto_aead_ivsize(geniv));
+
+out:
+	kfree_sensitive(subreq->iv);
+}
+
+static void seqiv_aead_encrypt_complete(void *data, int err)
+{
+	struct aead_request *req = data;
+
+	seqiv_aead_encrypt_complete2(req, err);
+	aead_request_complete(req, err);
+}
+
+static int seqiv_aead_encrypt(struct aead_request *req)
+{
+	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
+	struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv);
+	struct aead_request *subreq = aead_request_ctx(req);
+	crypto_completion_t compl;
+	bool unaligned_info;
+	void *data;
+	u8 *info;
+	unsigned int ivsize = 8;
+	int err;
+
+	if (req->cryptlen < ivsize)
+		return -EINVAL;
+
+	aead_request_set_tfm(subreq, ctx->child);
+
+	compl = req->base.complete;
+	data = req->base.data;
+	info = req->iv;
+
+	if (req->src != req->dst)
+		memcpy_sglist(req->dst, req->src,
+			      req->assoclen + req->cryptlen);
+
+	unaligned_info = !IS_ALIGNED((unsigned long)info,
+				     crypto_aead_alignmask(geniv) + 1);
+	if (unlikely(unaligned_info)) {
+		info = kmemdup(req->iv, ivsize, req->base.flags &
+			       CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL :
+			       GFP_ATOMIC);
+		if (!info)
+			return -ENOMEM;
+
+		compl = seqiv_aead_encrypt_complete;
+		data = req;
+	}
+
+	aead_request_set_callback(subreq, req->base.flags, compl, data);
+	aead_request_set_crypt(subreq, req->dst, req->dst,
+			       req->cryptlen - ivsize, info);
+	aead_request_set_ad(subreq, req->assoclen + ivsize);
+
+	crypto_xor(info, ctx->salt, ivsize);
+	scatterwalk_map_and_copy(info, req->dst, req->assoclen, ivsize, 1);
+
+	err = crypto_aead_encrypt(subreq);
+	if (unlikely(unaligned_info))
+		seqiv_aead_encrypt_complete2(req, err);
+	return err;
+}
+
+static int seqiv_aead_decrypt(struct aead_request *req)
+{
+	struct crypto_aead *geniv = crypto_aead_reqtfm(req);
+	struct aead_geniv_ctx *ctx = crypto_aead_ctx(geniv);
+	struct aead_request *subreq = aead_request_ctx(req);
+	crypto_completion_t compl;
+	void *data;
+	unsigned int ivsize = 8;
+
+	if (req->cryptlen < ivsize + crypto_aead_authsize(geniv))
+		return -EINVAL;
+
+	aead_request_set_tfm(subreq, ctx->child);
+
+	compl = req->base.complete;
+	data = req->base.data;
+
+	aead_request_set_callback(subreq, req->base.flags, compl, data);
+	aead_request_set_crypt(subreq, req->src, req->dst,
+			       req->cryptlen - ivsize, req->iv);
+	aead_request_set_ad(subreq, req->assoclen + ivsize);
+
+	scatterwalk_map_and_copy(req->iv, req->src, req->assoclen, ivsize, 0);
+
+	return crypto_aead_decrypt(subreq);
+}
+
+static int seqiv_aead_create(struct crypto_template *tmpl, struct rtattr **tb)
+{
+	struct aead_instance *inst;
+	int err;
+
+	inst = aead_geniv_alloc(tmpl, tb);
+
+	if (IS_ERR(inst))
+		return PTR_ERR(inst);
+
+	err = -EINVAL;
+	if (inst->alg.ivsize != sizeof(u64))
+		goto free_inst;
+
+	inst->alg.encrypt = seqiv_aead_encrypt;
+	inst->alg.decrypt = seqiv_aead_decrypt;
+
+	inst->alg.init = aead_init_geniv;
+	inst->alg.exit = aead_exit_geniv;
+
+	inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx);
+	inst->alg.base.cra_ctxsize += inst->alg.ivsize;
+
+	err = aead_register_instance(tmpl, inst);
+	if (err) {
+free_inst:
+		inst->free(inst);
+	}
+	return err;
+}
+
+static struct crypto_template seqiv_tmpl = {
+	.name = "seqiv",
+	.create = seqiv_aead_create,
+	.module = THIS_MODULE,
+};
+
+static int __init seqiv_module_init(void)
+{
+	return crypto_register_template(&seqiv_tmpl);
+}
+
+static void __exit seqiv_module_exit(void)
+{
+	crypto_unregister_template(&seqiv_tmpl);
+}
+
+module_init(seqiv_module_init);
+module_exit(seqiv_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Sequence Number IV Generator");
+MODULE_ALIAS_CRYPTO("seqiv");