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, 133 insertions, 0 deletions

diff --git a/crypto/blowfish_generic.c b/crypto/blowfish_generic.c
new file mode 100644
index 000000000..f3c5f9b09
--- /dev/null
+++ b/crypto/blowfish_generic.c
@@ -0,0 +1,133 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Cryptographic API.
+ *
+ * Blowfish Cipher Algorithm, by Bruce Schneier.
+ * http://www.counterpane.com/blowfish.html
+ *
+ * Adapted from Kerneli implementation.
+ *
+ * Copyright (c) Herbert Valerio Riedel <hvr@hvrlab.org>
+ * Copyright (c) Kyle McMartin <kyle@debian.org>
+ * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
+ */
+
+#include <crypto/algapi.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/unaligned.h>
+#include <linux/types.h>
+#include <crypto/blowfish.h>
+
+/*
+ * Round loop unrolling macros, S is a pointer to a S-Box array
+ * organized in 4 unsigned longs at a row.
+ */
+#define GET32_3(x) (((x) & 0xff))
+#define GET32_2(x) (((x) >> (8)) & (0xff))
+#define GET32_1(x) (((x) >> (16)) & (0xff))
+#define GET32_0(x) (((x) >> (24)) & (0xff))
+
+#define bf_F(x) (((S[GET32_0(x)] + S[256 + GET32_1(x)]) ^ \
+		S[512 + GET32_2(x)]) + S[768 + GET32_3(x)])
+
+#define ROUND(a, b, n) ({ b ^= P[n]; a ^= bf_F(b); })
+
+static void bf_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
+{
+	struct bf_ctx *ctx = crypto_tfm_ctx(tfm);
+	const u32 *P = ctx->p;
+	const u32 *S = ctx->s;
+	u32 yl = get_unaligned_be32(src);
+	u32 yr = get_unaligned_be32(src + 4);
+
+	ROUND(yr, yl, 0);
+	ROUND(yl, yr, 1);
+	ROUND(yr, yl, 2);
+	ROUND(yl, yr, 3);
+	ROUND(yr, yl, 4);
+	ROUND(yl, yr, 5);
+	ROUND(yr, yl, 6);
+	ROUND(yl, yr, 7);
+	ROUND(yr, yl, 8);
+	ROUND(yl, yr, 9);
+	ROUND(yr, yl, 10);
+	ROUND(yl, yr, 11);
+	ROUND(yr, yl, 12);
+	ROUND(yl, yr, 13);
+	ROUND(yr, yl, 14);
+	ROUND(yl, yr, 15);
+
+	yl ^= P[16];
+	yr ^= P[17];
+
+	put_unaligned_be32(yr, dst);
+	put_unaligned_be32(yl, dst + 4);
+}
+
+static void bf_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
+{
+	struct bf_ctx *ctx = crypto_tfm_ctx(tfm);
+	const u32 *P = ctx->p;
+	const u32 *S = ctx->s;
+	u32 yl = get_unaligned_be32(src);
+	u32 yr = get_unaligned_be32(src + 4);
+
+	ROUND(yr, yl, 17);
+	ROUND(yl, yr, 16);
+	ROUND(yr, yl, 15);
+	ROUND(yl, yr, 14);
+	ROUND(yr, yl, 13);
+	ROUND(yl, yr, 12);
+	ROUND(yr, yl, 11);
+	ROUND(yl, yr, 10);
+	ROUND(yr, yl, 9);
+	ROUND(yl, yr, 8);
+	ROUND(yr, yl, 7);
+	ROUND(yl, yr, 6);
+	ROUND(yr, yl, 5);
+	ROUND(yl, yr, 4);
+	ROUND(yr, yl, 3);
+	ROUND(yl, yr, 2);
+
+	yl ^= P[1];
+	yr ^= P[0];
+
+	put_unaligned_be32(yr, dst);
+	put_unaligned_be32(yl, dst + 4);
+}
+
+static struct crypto_alg alg = {
+	.cra_name		=	"blowfish",
+	.cra_driver_name	=	"blowfish-generic",
+	.cra_priority		=	100,
+	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER,
+	.cra_blocksize		=	BF_BLOCK_SIZE,
+	.cra_ctxsize		=	sizeof(struct bf_ctx),
+	.cra_module		=	THIS_MODULE,
+	.cra_u			=	{ .cipher = {
+	.cia_min_keysize	=	BF_MIN_KEY_SIZE,
+	.cia_max_keysize	=	BF_MAX_KEY_SIZE,
+	.cia_setkey		=	blowfish_setkey,
+	.cia_encrypt		=	bf_encrypt,
+	.cia_decrypt		=	bf_decrypt } }
+};
+
+static int __init blowfish_mod_init(void)
+{
+	return crypto_register_alg(&alg);
+}
+
+static void __exit blowfish_mod_fini(void)
+{
+	crypto_unregister_alg(&alg);
+}
+
+module_init(blowfish_mod_init);
+module_exit(blowfish_mod_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Blowfish Cipher Algorithm");
+MODULE_ALIAS_CRYPTO("blowfish");
+MODULE_ALIAS_CRYPTO("blowfish-generic");