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, 313 insertions, 0 deletions

diff --git a/security/keys/dh.c b/security/keys/dh.c
new file mode 100644
index 000000000..da64c3584
--- /dev/null
+++ b/security/keys/dh.c
@@ -0,0 +1,313 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Crypto operations using stored keys
+ *
+ * Copyright (c) 2016, Intel Corporation
+ */
+
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/scatterlist.h>
+#include <linux/crypto.h>
+#include <crypto/hash.h>
+#include <crypto/kpp.h>
+#include <crypto/dh.h>
+#include <crypto/kdf_sp800108.h>
+#include <keys/user-type.h>
+#include "internal.h"
+
+static ssize_t dh_data_from_key(key_serial_t keyid, const void **data)
+{
+	struct key *key;
+	key_ref_t key_ref;
+	long status;
+	ssize_t ret;
+
+	key_ref = lookup_user_key(keyid, 0, KEY_NEED_READ);
+	if (IS_ERR(key_ref)) {
+		ret = -ENOKEY;
+		goto error;
+	}
+
+	key = key_ref_to_ptr(key_ref);
+
+	ret = -EOPNOTSUPP;
+	if (key->type == &key_type_user) {
+		down_read(&key->sem);
+		status = key_validate(key);
+		if (status == 0) {
+			const struct user_key_payload *payload;
+			uint8_t *duplicate;
+
+			payload = user_key_payload_locked(key);
+
+			duplicate = kmemdup(payload->data, payload->datalen,
+					    GFP_KERNEL);
+			if (duplicate) {
+				*data = duplicate;
+				ret = payload->datalen;
+			} else {
+				ret = -ENOMEM;
+			}
+		}
+		up_read(&key->sem);
+	}
+
+	key_put(key);
+error:
+	return ret;
+}
+
+static void dh_free_data(struct dh *dh)
+{
+	kfree_sensitive(dh->key);
+	kfree_sensitive(dh->p);
+	kfree_sensitive(dh->g);
+}
+
+static int kdf_alloc(struct crypto_shash **hash, char *hashname)
+{
+	struct crypto_shash *tfm;
+
+	/* allocate synchronous hash */
+	tfm = crypto_alloc_shash(hashname, 0, 0);
+	if (IS_ERR(tfm)) {
+		pr_info("could not allocate digest TFM handle %s\n", hashname);
+		return PTR_ERR(tfm);
+	}
+
+	if (crypto_shash_digestsize(tfm) == 0) {
+		crypto_free_shash(tfm);
+		return -EINVAL;
+	}
+
+	*hash = tfm;
+
+	return 0;
+}
+
+static void kdf_dealloc(struct crypto_shash *hash)
+{
+	if (hash)
+		crypto_free_shash(hash);
+}
+
+static int keyctl_dh_compute_kdf(struct crypto_shash *hash,
+				 char __user *buffer, size_t buflen,
+				 uint8_t *kbuf, size_t kbuflen)
+{
+	struct kvec kbuf_iov = { .iov_base = kbuf, .iov_len = kbuflen };
+	uint8_t *outbuf = NULL;
+	int ret;
+	size_t outbuf_len = roundup(buflen, crypto_shash_digestsize(hash));
+
+	outbuf = kmalloc(outbuf_len, GFP_KERNEL);
+	if (!outbuf) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	ret = crypto_kdf108_ctr_generate(hash, &kbuf_iov, 1, outbuf, outbuf_len);
+	if (ret)
+		goto err;
+
+	ret = buflen;
+	if (copy_to_user(buffer, outbuf, buflen) != 0)
+		ret = -EFAULT;
+
+err:
+	kfree_sensitive(outbuf);
+	return ret;
+}
+
+long __keyctl_dh_compute(struct keyctl_dh_params __user *params,
+			 char __user *buffer, size_t buflen,
+			 struct keyctl_kdf_params *kdfcopy)
+{
+	long ret;
+	ssize_t dlen;
+	int secretlen;
+	int outlen;
+	struct keyctl_dh_params pcopy;
+	struct dh dh_inputs;
+	struct scatterlist outsg;
+	DECLARE_CRYPTO_WAIT(compl);
+	struct crypto_kpp *tfm;
+	struct kpp_request *req;
+	uint8_t *secret;
+	uint8_t *outbuf;
+	struct crypto_shash *hash = NULL;
+
+	if (!params || (!buffer && buflen)) {
+		ret = -EINVAL;
+		goto out1;
+	}
+	if (copy_from_user(&pcopy, params, sizeof(pcopy)) != 0) {
+		ret = -EFAULT;
+		goto out1;
+	}
+
+	if (kdfcopy) {
+		char *hashname;
+
+		if (memchr_inv(kdfcopy->__spare, 0, sizeof(kdfcopy->__spare))) {
+			ret = -EINVAL;
+			goto out1;
+		}
+
+		if (buflen > KEYCTL_KDF_MAX_OUTPUT_LEN ||
+		    kdfcopy->otherinfolen > KEYCTL_KDF_MAX_OI_LEN) {
+			ret = -EMSGSIZE;
+			goto out1;
+		}
+
+		/* get KDF name string */
+		hashname = strndup_user(kdfcopy->hashname, CRYPTO_MAX_ALG_NAME);
+		if (IS_ERR(hashname)) {
+			ret = PTR_ERR(hashname);
+			goto out1;
+		}
+
+		/* allocate KDF from the kernel crypto API */
+		ret = kdf_alloc(&hash, hashname);
+		kfree(hashname);
+		if (ret)
+			goto out1;
+	}
+
+	memset(&dh_inputs, 0, sizeof(dh_inputs));
+
+	dlen = dh_data_from_key(pcopy.prime, &dh_inputs.p);
+	if (dlen < 0) {
+		ret = dlen;
+		goto out1;
+	}
+	dh_inputs.p_size = dlen;
+
+	dlen = dh_data_from_key(pcopy.base, &dh_inputs.g);
+	if (dlen < 0) {
+		ret = dlen;
+		goto out2;
+	}
+	dh_inputs.g_size = dlen;
+
+	dlen = dh_data_from_key(pcopy.private, &dh_inputs.key);
+	if (dlen < 0) {
+		ret = dlen;
+		goto out2;
+	}
+	dh_inputs.key_size = dlen;
+
+	secretlen = crypto_dh_key_len(&dh_inputs);
+	secret = kmalloc(secretlen, GFP_KERNEL);
+	if (!secret) {
+		ret = -ENOMEM;
+		goto out2;
+	}
+	ret = crypto_dh_encode_key(secret, secretlen, &dh_inputs);
+	if (ret)
+		goto out3;
+
+	tfm = crypto_alloc_kpp("dh", 0, 0);
+	if (IS_ERR(tfm)) {
+		ret = PTR_ERR(tfm);
+		goto out3;
+	}
+
+	ret = crypto_kpp_set_secret(tfm, secret, secretlen);
+	if (ret)
+		goto out4;
+
+	outlen = crypto_kpp_maxsize(tfm);
+
+	if (!kdfcopy) {
+		/*
+		 * When not using a KDF, buflen 0 is used to read the
+		 * required buffer length
+		 */
+		if (buflen == 0) {
+			ret = outlen;
+			goto out4;
+		} else if (outlen > buflen) {
+			ret = -EOVERFLOW;
+			goto out4;
+		}
+	}
+
+	outbuf = kzalloc(kdfcopy ? (outlen + kdfcopy->otherinfolen) : outlen,
+			 GFP_KERNEL);
+	if (!outbuf) {
+		ret = -ENOMEM;
+		goto out4;
+	}
+
+	sg_init_one(&outsg, outbuf, outlen);
+
+	req = kpp_request_alloc(tfm, GFP_KERNEL);
+	if (!req) {
+		ret = -ENOMEM;
+		goto out5;
+	}
+
+	kpp_request_set_input(req, NULL, 0);
+	kpp_request_set_output(req, &outsg, outlen);
+	kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
+				 CRYPTO_TFM_REQ_MAY_SLEEP,
+				 crypto_req_done, &compl);
+
+	/*
+	 * For DH, generate_public_key and generate_shared_secret are
+	 * the same calculation
+	 */
+	ret = crypto_kpp_generate_public_key(req);
+	ret = crypto_wait_req(ret, &compl);
+	if (ret)
+		goto out6;
+
+	if (kdfcopy) {
+		/*
+		 * Concatenate SP800-56A otherinfo past DH shared secret -- the
+		 * input to the KDF is (DH shared secret || otherinfo)
+		 */
+		if (copy_from_user(outbuf + req->dst_len, kdfcopy->otherinfo,
+				   kdfcopy->otherinfolen) != 0) {
+			ret = -EFAULT;
+			goto out6;
+		}
+
+		ret = keyctl_dh_compute_kdf(hash, buffer, buflen, outbuf,
+					    req->dst_len + kdfcopy->otherinfolen);
+	} else if (copy_to_user(buffer, outbuf, req->dst_len) == 0) {
+		ret = req->dst_len;
+	} else {
+		ret = -EFAULT;
+	}
+
+out6:
+	kpp_request_free(req);
+out5:
+	kfree_sensitive(outbuf);
+out4:
+	crypto_free_kpp(tfm);
+out3:
+	kfree_sensitive(secret);
+out2:
+	dh_free_data(&dh_inputs);
+out1:
+	kdf_dealloc(hash);
+	return ret;
+}
+
+long keyctl_dh_compute(struct keyctl_dh_params __user *params,
+		       char __user *buffer, size_t buflen,
+		       struct keyctl_kdf_params __user *kdf)
+{
+	struct keyctl_kdf_params kdfcopy;
+
+	if (!kdf)
+		return __keyctl_dh_compute(params, buffer, buflen, NULL);
+
+	if (copy_from_user(&kdfcopy, kdf, sizeof(kdfcopy)) != 0)
+		return -EFAULT;
+
+	return __keyctl_dh_compute(params, buffer, buflen, &kdfcopy);
+}