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, 196 insertions, 0 deletions

diff --git a/crypto/twofish_generic.c b/crypto/twofish_generic.c
new file mode 100644
index 000000000..368018cfa
--- /dev/null
+++ b/crypto/twofish_generic.c
@@ -0,0 +1,196 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Twofish for CryptoAPI
+ *
+ * Originally Twofish for GPG
+ * By Matthew Skala <mskala@ansuz.sooke.bc.ca>, July 26, 1998
+ * 256-bit key length added March 20, 1999
+ * Some modifications to reduce the text size by Werner Koch, April, 1998
+ * Ported to the kerneli patch by Marc Mutz <Marc@Mutz.com>
+ * Ported to CryptoAPI by Colin Slater <hoho@tacomeat.net>
+ *
+ * The original author has disclaimed all copyright interest in this
+ * code and thus put it in the public domain. The subsequent authors 
+ * have put this under the GNU General Public License.
+ *
+ * This code is a "clean room" implementation, written from the paper
+ * _Twofish: A 128-Bit Block Cipher_ by Bruce Schneier, John Kelsey,
+ * Doug Whiting, David Wagner, Chris Hall, and Niels Ferguson, available
+ * through http://www.counterpane.com/twofish.html
+ *
+ * For background information on multiplication in finite fields, used for
+ * the matrix operations in the key schedule, see the book _Contemporary
+ * Abstract Algebra_ by Joseph A. Gallian, especially chapter 22 in the
+ * Third Edition.
+ */
+
+#include <linux/unaligned.h>
+#include <crypto/algapi.h>
+#include <crypto/twofish.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/bitops.h>
+
+/* Macros to compute the g() function in the encryption and decryption
+ * rounds.  G1 is the straight g() function; G2 includes the 8-bit
+ * rotation for the high 32-bit word. */
+
+#define G1(a) \
+     (ctx->s[0][(a) & 0xFF]) ^ (ctx->s[1][((a) >> 8) & 0xFF]) \
+   ^ (ctx->s[2][((a) >> 16) & 0xFF]) ^ (ctx->s[3][(a) >> 24])
+
+#define G2(b) \
+     (ctx->s[1][(b) & 0xFF]) ^ (ctx->s[2][((b) >> 8) & 0xFF]) \
+   ^ (ctx->s[3][((b) >> 16) & 0xFF]) ^ (ctx->s[0][(b) >> 24])
+
+/* Encryption and decryption Feistel rounds.  Each one calls the two g()
+ * macros, does the PHT, and performs the XOR and the appropriate bit
+ * rotations.  The parameters are the round number (used to select subkeys),
+ * and the four 32-bit chunks of the text. */
+
+#define ENCROUND(n, a, b, c, d) \
+   x = G1 (a); y = G2 (b); \
+   x += y; y += x + ctx->k[2 * (n) + 1]; \
+   (c) ^= x + ctx->k[2 * (n)]; \
+   (c) = ror32((c), 1); \
+   (d) = rol32((d), 1) ^ y
+
+#define DECROUND(n, a, b, c, d) \
+   x = G1 (a); y = G2 (b); \
+   x += y; y += x; \
+   (d) ^= y + ctx->k[2 * (n) + 1]; \
+   (d) = ror32((d), 1); \
+   (c) = rol32((c), 1); \
+   (c) ^= (x + ctx->k[2 * (n)])
+
+/* Encryption and decryption cycles; each one is simply two Feistel rounds
+ * with the 32-bit chunks re-ordered to simulate the "swap" */
+
+#define ENCCYCLE(n) \
+   ENCROUND (2 * (n), a, b, c, d); \
+   ENCROUND (2 * (n) + 1, c, d, a, b)
+
+#define DECCYCLE(n) \
+   DECROUND (2 * (n) + 1, c, d, a, b); \
+   DECROUND (2 * (n), a, b, c, d)
+
+/* Macros to convert the input and output bytes into 32-bit words,
+ * and simultaneously perform the whitening step.  INPACK packs word
+ * number n into the variable named by x, using whitening subkey number m.
+ * OUTUNPACK unpacks word number n from the variable named by x, using
+ * whitening subkey number m. */
+
+#define INPACK(n, x, m) \
+   x = get_unaligned_le32(in + (n) * 4) ^ ctx->w[m]
+
+#define OUTUNPACK(n, x, m) \
+   x ^= ctx->w[m]; \
+   put_unaligned_le32(x, out + (n) * 4)
+
+
+
+/* Encrypt one block.  in and out may be the same. */
+static void twofish_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
+{
+	struct twofish_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	/* The four 32-bit chunks of the text. */
+	u32 a, b, c, d;
+	
+	/* Temporaries used by the round function. */
+	u32 x, y;
+
+	/* Input whitening and packing. */
+	INPACK (0, a, 0);
+	INPACK (1, b, 1);
+	INPACK (2, c, 2);
+	INPACK (3, d, 3);
+	
+	/* Encryption Feistel cycles. */
+	ENCCYCLE (0);
+	ENCCYCLE (1);
+	ENCCYCLE (2);
+	ENCCYCLE (3);
+	ENCCYCLE (4);
+	ENCCYCLE (5);
+	ENCCYCLE (6);
+	ENCCYCLE (7);
+	
+	/* Output whitening and unpacking. */
+	OUTUNPACK (0, c, 4);
+	OUTUNPACK (1, d, 5);
+	OUTUNPACK (2, a, 6);
+	OUTUNPACK (3, b, 7);
+	
+}
+
+/* Decrypt one block.  in and out may be the same. */
+static void twofish_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
+{
+	struct twofish_ctx *ctx = crypto_tfm_ctx(tfm);
+  
+	/* The four 32-bit chunks of the text. */
+	u32 a, b, c, d;
+	
+	/* Temporaries used by the round function. */
+	u32 x, y;
+	
+	/* Input whitening and packing. */
+	INPACK (0, c, 4);
+	INPACK (1, d, 5);
+	INPACK (2, a, 6);
+	INPACK (3, b, 7);
+	
+	/* Encryption Feistel cycles. */
+	DECCYCLE (7);
+	DECCYCLE (6);
+	DECCYCLE (5);
+	DECCYCLE (4);
+	DECCYCLE (3);
+	DECCYCLE (2);
+	DECCYCLE (1);
+	DECCYCLE (0);
+
+	/* Output whitening and unpacking. */
+	OUTUNPACK (0, a, 0);
+	OUTUNPACK (1, b, 1);
+	OUTUNPACK (2, c, 2);
+	OUTUNPACK (3, d, 3);
+
+}
+
+static struct crypto_alg alg = {
+	.cra_name           =   "twofish",
+	.cra_driver_name    =   "twofish-generic",
+	.cra_priority       =   100,
+	.cra_flags          =   CRYPTO_ALG_TYPE_CIPHER,
+	.cra_blocksize      =   TF_BLOCK_SIZE,
+	.cra_ctxsize        =   sizeof(struct twofish_ctx),
+	.cra_module         =   THIS_MODULE,
+	.cra_u              =   { .cipher = {
+	.cia_min_keysize    =   TF_MIN_KEY_SIZE,
+	.cia_max_keysize    =   TF_MAX_KEY_SIZE,
+	.cia_setkey         =   twofish_setkey,
+	.cia_encrypt        =   twofish_encrypt,
+	.cia_decrypt        =   twofish_decrypt } }
+};
+
+static int __init twofish_mod_init(void)
+{
+	return crypto_register_alg(&alg);
+}
+
+static void __exit twofish_mod_fini(void)
+{
+	crypto_unregister_alg(&alg);
+}
+
+module_init(twofish_mod_init);
+module_exit(twofish_mod_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION ("Twofish Cipher Algorithm");
+MODULE_ALIAS_CRYPTO("twofish");
+MODULE_ALIAS_CRYPTO("twofish-generic");