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, 161 insertions, 0 deletions

diff --git a/crypto/ecdsa-p1363.c b/crypto/ecdsa-p1363.c
new file mode 100644
index 000000000..e0c55c647
--- /dev/null
+++ b/crypto/ecdsa-p1363.c
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ECDSA P1363 signature encoding
+ *
+ * Copyright (c) 2024 Intel Corporation
+ */
+
+#include <linux/err.h>
+#include <linux/module.h>
+#include <crypto/algapi.h>
+#include <crypto/sig.h>
+#include <crypto/internal/ecc.h>
+#include <crypto/internal/sig.h>
+
+struct ecdsa_p1363_ctx {
+	struct crypto_sig *child;
+};
+
+static int ecdsa_p1363_verify(struct crypto_sig *tfm,
+			      const void *src, unsigned int slen,
+			      const void *digest, unsigned int dlen)
+{
+	struct ecdsa_p1363_ctx *ctx = crypto_sig_ctx(tfm);
+	unsigned int keylen = DIV_ROUND_UP_POW2(crypto_sig_keysize(ctx->child),
+						BITS_PER_BYTE);
+	unsigned int ndigits = DIV_ROUND_UP_POW2(keylen, sizeof(u64));
+	struct ecdsa_raw_sig sig;
+
+	if (slen != 2 * keylen)
+		return -EINVAL;
+
+	ecc_digits_from_bytes(src, keylen, sig.r, ndigits);
+	ecc_digits_from_bytes(src + keylen, keylen, sig.s, ndigits);
+
+	return crypto_sig_verify(ctx->child, &sig, sizeof(sig), digest, dlen);
+}
+
+static unsigned int ecdsa_p1363_key_size(struct crypto_sig *tfm)
+{
+	struct ecdsa_p1363_ctx *ctx = crypto_sig_ctx(tfm);
+
+	return crypto_sig_keysize(ctx->child);
+}
+
+static unsigned int ecdsa_p1363_max_size(struct crypto_sig *tfm)
+{
+	struct ecdsa_p1363_ctx *ctx = crypto_sig_ctx(tfm);
+
+	return 2 * DIV_ROUND_UP_POW2(crypto_sig_keysize(ctx->child),
+				     BITS_PER_BYTE);
+}
+
+static unsigned int ecdsa_p1363_digest_size(struct crypto_sig *tfm)
+{
+	struct ecdsa_p1363_ctx *ctx = crypto_sig_ctx(tfm);
+
+	return crypto_sig_digestsize(ctx->child);
+}
+
+static int ecdsa_p1363_set_pub_key(struct crypto_sig *tfm,
+				   const void *key, unsigned int keylen)
+{
+	struct ecdsa_p1363_ctx *ctx = crypto_sig_ctx(tfm);
+
+	return crypto_sig_set_pubkey(ctx->child, key, keylen);
+}
+
+static int ecdsa_p1363_init_tfm(struct crypto_sig *tfm)
+{
+	struct sig_instance *inst = sig_alg_instance(tfm);
+	struct crypto_sig_spawn *spawn = sig_instance_ctx(inst);
+	struct ecdsa_p1363_ctx *ctx = crypto_sig_ctx(tfm);
+	struct crypto_sig *child_tfm;
+
+	child_tfm = crypto_spawn_sig(spawn);
+	if (IS_ERR(child_tfm))
+		return PTR_ERR(child_tfm);
+
+	ctx->child = child_tfm;
+
+	return 0;
+}
+
+static void ecdsa_p1363_exit_tfm(struct crypto_sig *tfm)
+{
+	struct ecdsa_p1363_ctx *ctx = crypto_sig_ctx(tfm);
+
+	crypto_free_sig(ctx->child);
+}
+
+static void ecdsa_p1363_free(struct sig_instance *inst)
+{
+	struct crypto_sig_spawn *spawn = sig_instance_ctx(inst);
+
+	crypto_drop_sig(spawn);
+	kfree(inst);
+}
+
+static int ecdsa_p1363_create(struct crypto_template *tmpl, struct rtattr **tb)
+{
+	struct crypto_sig_spawn *spawn;
+	struct sig_instance *inst;
+	struct sig_alg *ecdsa_alg;
+	u32 mask;
+	int err;
+
+	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SIG, &mask);
+	if (err)
+		return err;
+
+	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
+	if (!inst)
+		return -ENOMEM;
+
+	spawn = sig_instance_ctx(inst);
+
+	err = crypto_grab_sig(spawn, sig_crypto_instance(inst),
+			      crypto_attr_alg_name(tb[1]), 0, mask);
+	if (err)
+		goto err_free_inst;
+
+	ecdsa_alg = crypto_spawn_sig_alg(spawn);
+
+	err = -EINVAL;
+	if (strncmp(ecdsa_alg->base.cra_name, "ecdsa", 5) != 0)
+		goto err_free_inst;
+
+	err = crypto_inst_setname(sig_crypto_instance(inst), tmpl->name,
+				  &ecdsa_alg->base);
+	if (err)
+		goto err_free_inst;
+
+	inst->alg.base.cra_priority = ecdsa_alg->base.cra_priority;
+	inst->alg.base.cra_ctxsize = sizeof(struct ecdsa_p1363_ctx);
+
+	inst->alg.init = ecdsa_p1363_init_tfm;
+	inst->alg.exit = ecdsa_p1363_exit_tfm;
+
+	inst->alg.verify = ecdsa_p1363_verify;
+	inst->alg.key_size = ecdsa_p1363_key_size;
+	inst->alg.max_size = ecdsa_p1363_max_size;
+	inst->alg.digest_size = ecdsa_p1363_digest_size;
+	inst->alg.set_pub_key = ecdsa_p1363_set_pub_key;
+
+	inst->free = ecdsa_p1363_free;
+
+	err = sig_register_instance(tmpl, inst);
+	if (err) {
+err_free_inst:
+		ecdsa_p1363_free(inst);
+	}
+	return err;
+}
+
+struct crypto_template ecdsa_p1363_tmpl = {
+	.name = "p1363",
+	.create = ecdsa_p1363_create,
+	.module = THIS_MODULE,
+};
+
+MODULE_ALIAS_CRYPTO("p1363");