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, 186 insertions, 0 deletions

diff --git a/crypto/rsa_helper.c b/crypto/rsa_helper.c
new file mode 100644
index 000000000..94266f290
--- /dev/null
+++ b/crypto/rsa_helper.c
@@ -0,0 +1,186 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * RSA key extract helper
+ *
+ * Copyright (c) 2015, Intel Corporation
+ * Authors: Tadeusz Struk <tadeusz.struk@intel.com>
+ */
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/err.h>
+#include <linux/fips.h>
+#include <crypto/internal/rsa.h>
+#include "rsapubkey.asn1.h"
+#include "rsaprivkey.asn1.h"
+
+int rsa_get_n(void *context, size_t hdrlen, unsigned char tag,
+	      const void *value, size_t vlen)
+{
+	struct rsa_key *key = context;
+	const u8 *ptr = value;
+	size_t n_sz = vlen;
+
+	/* invalid key provided */
+	if (!value || !vlen)
+		return -EINVAL;
+
+	if (fips_enabled) {
+		while (n_sz && !*ptr) {
+			ptr++;
+			n_sz--;
+		}
+
+		/* In FIPS mode only allow key size 2K and higher */
+		if (n_sz < 256) {
+			pr_err("RSA: key size not allowed in FIPS mode\n");
+			return -EINVAL;
+		}
+	}
+
+	key->n = value;
+	key->n_sz = vlen;
+
+	return 0;
+}
+
+int rsa_get_e(void *context, size_t hdrlen, unsigned char tag,
+	      const void *value, size_t vlen)
+{
+	struct rsa_key *key = context;
+
+	/* invalid key provided */
+	if (!value || !key->n_sz || !vlen || vlen > key->n_sz)
+		return -EINVAL;
+
+	key->e = value;
+	key->e_sz = vlen;
+
+	return 0;
+}
+
+int rsa_get_d(void *context, size_t hdrlen, unsigned char tag,
+	      const void *value, size_t vlen)
+{
+	struct rsa_key *key = context;
+
+	/* invalid key provided */
+	if (!value || !key->n_sz || !vlen || vlen > key->n_sz)
+		return -EINVAL;
+
+	key->d = value;
+	key->d_sz = vlen;
+
+	return 0;
+}
+
+int rsa_get_p(void *context, size_t hdrlen, unsigned char tag,
+	      const void *value, size_t vlen)
+{
+	struct rsa_key *key = context;
+
+	/* invalid key provided */
+	if (!value || !vlen || vlen > key->n_sz)
+		return -EINVAL;
+
+	key->p = value;
+	key->p_sz = vlen;
+
+	return 0;
+}
+
+int rsa_get_q(void *context, size_t hdrlen, unsigned char tag,
+	      const void *value, size_t vlen)
+{
+	struct rsa_key *key = context;
+
+	/* invalid key provided */
+	if (!value || !vlen || vlen > key->n_sz)
+		return -EINVAL;
+
+	key->q = value;
+	key->q_sz = vlen;
+
+	return 0;
+}
+
+int rsa_get_dp(void *context, size_t hdrlen, unsigned char tag,
+	       const void *value, size_t vlen)
+{
+	struct rsa_key *key = context;
+
+	/* invalid key provided */
+	if (!value || !vlen || vlen > key->n_sz)
+		return -EINVAL;
+
+	key->dp = value;
+	key->dp_sz = vlen;
+
+	return 0;
+}
+
+int rsa_get_dq(void *context, size_t hdrlen, unsigned char tag,
+	       const void *value, size_t vlen)
+{
+	struct rsa_key *key = context;
+
+	/* invalid key provided */
+	if (!value || !vlen || vlen > key->n_sz)
+		return -EINVAL;
+
+	key->dq = value;
+	key->dq_sz = vlen;
+
+	return 0;
+}
+
+int rsa_get_qinv(void *context, size_t hdrlen, unsigned char tag,
+		 const void *value, size_t vlen)
+{
+	struct rsa_key *key = context;
+
+	/* invalid key provided */
+	if (!value || !vlen || vlen > key->n_sz)
+		return -EINVAL;
+
+	key->qinv = value;
+	key->qinv_sz = vlen;
+
+	return 0;
+}
+
+/**
+ * rsa_parse_pub_key() - decodes the BER encoded buffer and stores in the
+ *                       provided struct rsa_key, pointers to the raw key as is,
+ *                       so that the caller can copy it or MPI parse it, etc.
+ *
+ * @rsa_key:	struct rsa_key key representation
+ * @key:	key in BER format
+ * @key_len:	length of key
+ *
+ * Return:	0 on success or error code in case of error
+ */
+int rsa_parse_pub_key(struct rsa_key *rsa_key, const void *key,
+		      unsigned int key_len)
+{
+	return asn1_ber_decoder(&rsapubkey_decoder, rsa_key, key, key_len);
+}
+EXPORT_SYMBOL_GPL(rsa_parse_pub_key);
+
+/**
+ * rsa_parse_priv_key() - decodes the BER encoded buffer and stores in the
+ *                        provided struct rsa_key, pointers to the raw key
+ *                        as is, so that the caller can copy it or MPI parse it,
+ *                        etc.
+ *
+ * @rsa_key:	struct rsa_key key representation
+ * @key:	key in BER format
+ * @key_len:	length of key
+ *
+ * Return:	0 on success or error code in case of error
+ */
+int rsa_parse_priv_key(struct rsa_key *rsa_key, const void *key,
+		       unsigned int key_len)
+{
+	return asn1_ber_decoder(&rsaprivkey_decoder, rsa_key, key, key_len);
+}
+EXPORT_SYMBOL_GPL(rsa_parse_priv_key);