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, 157 insertions, 0 deletions

diff --git a/crypto/kdf_sp800108.c b/crypto/kdf_sp800108.c
new file mode 100644
index 000000000..b7a6bf9da
--- /dev/null
+++ b/crypto/kdf_sp800108.c
@@ -0,0 +1,157 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * SP800-108 Key-derivation function
+ *
+ * Copyright (C) 2021, Stephan Mueller <smueller@chronox.de>
+ */
+
+#include <linux/fips.h>
+#include <linux/module.h>
+#include <crypto/kdf_sp800108.h>
+#include <crypto/internal/kdf_selftest.h>
+
+/*
+ * SP800-108 CTR KDF implementation
+ */
+int crypto_kdf108_ctr_generate(struct crypto_shash *kmd,
+			       const struct kvec *info, unsigned int info_nvec,
+			       u8 *dst, unsigned int dlen)
+{
+	SHASH_DESC_ON_STACK(desc, kmd);
+	__be32 counter = cpu_to_be32(1);
+	const unsigned int h = crypto_shash_digestsize(kmd), dlen_orig = dlen;
+	unsigned int i;
+	int err = 0;
+	u8 *dst_orig = dst;
+
+	desc->tfm = kmd;
+
+	while (dlen) {
+		err = crypto_shash_init(desc);
+		if (err)
+			goto out;
+
+		err = crypto_shash_update(desc, (u8 *)&counter, sizeof(__be32));
+		if (err)
+			goto out;
+
+		for (i = 0; i < info_nvec; i++) {
+			err = crypto_shash_update(desc, info[i].iov_base,
+						  info[i].iov_len);
+			if (err)
+				goto out;
+		}
+
+		if (dlen < h) {
+			u8 tmpbuffer[HASH_MAX_DIGESTSIZE];
+
+			err = crypto_shash_final(desc, tmpbuffer);
+			if (err)
+				goto out;
+			memcpy(dst, tmpbuffer, dlen);
+			memzero_explicit(tmpbuffer, h);
+			goto out;
+		}
+
+		err = crypto_shash_final(desc, dst);
+		if (err)
+			goto out;
+
+		dlen -= h;
+		dst += h;
+		counter = cpu_to_be32(be32_to_cpu(counter) + 1);
+	}
+
+out:
+	if (err)
+		memzero_explicit(dst_orig, dlen_orig);
+	shash_desc_zero(desc);
+	return err;
+}
+EXPORT_SYMBOL(crypto_kdf108_ctr_generate);
+
+/*
+ * The seeding of the KDF
+ */
+int crypto_kdf108_setkey(struct crypto_shash *kmd,
+			 const u8 *key, size_t keylen,
+			 const u8 *ikm, size_t ikmlen)
+{
+	unsigned int ds = crypto_shash_digestsize(kmd);
+
+	/* SP800-108 does not support IKM */
+	if (ikm || ikmlen)
+		return -EINVAL;
+
+	/* Check according to SP800-108 section 7.2 */
+	if (ds > keylen)
+		return -EINVAL;
+
+	/* Set the key for the MAC used for the KDF. */
+	return crypto_shash_setkey(kmd, key, keylen);
+}
+EXPORT_SYMBOL(crypto_kdf108_setkey);
+
+/*
+ * Test vector obtained from
+ * http://csrc.nist.gov/groups/STM/cavp/documents/KBKDF800-108/CounterMode.zip
+ */
+static const struct kdf_testvec kdf_ctr_hmac_sha256_tv_template[] = {
+	{
+		.key = "\xdd\x1d\x91\xb7\xd9\x0b\x2b\xd3"
+		       "\x13\x85\x33\xce\x92\xb2\x72\xfb"
+		       "\xf8\xa3\x69\x31\x6a\xef\xe2\x42"
+		       "\xe6\x59\xcc\x0a\xe2\x38\xaf\xe0",
+		.keylen = 32,
+		.ikm = NULL,
+		.ikmlen = 0,
+		.info = {
+			.iov_base = "\x01\x32\x2b\x96\xb3\x0a\xcd\x19"
+				    "\x79\x79\x44\x4e\x46\x8e\x1c\x5c"
+				    "\x68\x59\xbf\x1b\x1c\xf9\x51\xb7"
+				    "\xe7\x25\x30\x3e\x23\x7e\x46\xb8"
+				    "\x64\xa1\x45\xfa\xb2\x5e\x51\x7b"
+				    "\x08\xf8\x68\x3d\x03\x15\xbb\x29"
+				    "\x11\xd8\x0a\x0e\x8a\xba\x17\xf3"
+				    "\xb4\x13\xfa\xac",
+			.iov_len  = 60
+		},
+		.expected	  = "\x10\x62\x13\x42\xbf\xb0\xfd\x40"
+				    "\x04\x6c\x0e\x29\xf2\xcf\xdb\xf0",
+		.expectedlen	  = 16
+	}
+};
+
+static int __init crypto_kdf108_init(void)
+{
+	int ret;
+
+	if (!IS_ENABLED(CONFIG_CRYPTO_SELFTESTS))
+		return 0;
+
+	ret = kdf_test(&kdf_ctr_hmac_sha256_tv_template[0], "hmac(sha256)",
+		       crypto_kdf108_setkey, crypto_kdf108_ctr_generate);
+	if (ret) {
+		if (fips_enabled)
+			panic("alg: self-tests for CTR-KDF (hmac(sha256)) failed (rc=%d)\n",
+			      ret);
+
+		WARN(1,
+		     "alg: self-tests for CTR-KDF (hmac(sha256)) failed (rc=%d)\n",
+		     ret);
+	} else if (fips_enabled) {
+		pr_info("alg: self-tests for CTR-KDF (hmac(sha256)) passed\n");
+	}
+
+	return ret;
+}
+
+static void __exit crypto_kdf108_exit(void) { }
+
+module_init(crypto_kdf108_init);
+module_exit(crypto_kdf108_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
+MODULE_DESCRIPTION("Key Derivation Function conformant to SP800-108");