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, 477 insertions, 0 deletions

diff --git a/crypto/xts.c b/crypto/xts.c
new file mode 100644
index 000000000..1dc948745
--- /dev/null
+++ b/crypto/xts.c
@@ -0,0 +1,477 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* XTS: as defined in IEEE1619/D16
+ *	http://grouper.ieee.org/groups/1619/email/pdf00086.pdf
+ *
+ * Copyright (c) 2007 Rik Snel <rsnel@cube.dyndns.org>
+ *
+ * Based on ecb.c
+ * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
+ */
+#include <crypto/internal/cipher.h>
+#include <crypto/internal/skcipher.h>
+#include <crypto/scatterwalk.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/scatterlist.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+
+#include <crypto/xts.h>
+#include <crypto/b128ops.h>
+#include <crypto/gf128mul.h>
+
+struct xts_tfm_ctx {
+	struct crypto_skcipher *child;
+	struct crypto_cipher *tweak;
+};
+
+struct xts_instance_ctx {
+	struct crypto_skcipher_spawn spawn;
+	struct crypto_cipher_spawn tweak_spawn;
+};
+
+struct xts_request_ctx {
+	le128 t;
+	struct scatterlist *tail;
+	struct scatterlist sg[2];
+	struct skcipher_request subreq;
+};
+
+static int xts_setkey(struct crypto_skcipher *parent, const u8 *key,
+		      unsigned int keylen)
+{
+	struct xts_tfm_ctx *ctx = crypto_skcipher_ctx(parent);
+	struct crypto_skcipher *child;
+	struct crypto_cipher *tweak;
+	int err;
+
+	err = xts_verify_key(parent, key, keylen);
+	if (err)
+		return err;
+
+	keylen /= 2;
+
+	/* we need two cipher instances: one to compute the initial 'tweak'
+	 * by encrypting the IV (usually the 'plain' iv) and the other
+	 * one to encrypt and decrypt the data */
+
+	/* tweak cipher, uses Key2 i.e. the second half of *key */
+	tweak = ctx->tweak;
+	crypto_cipher_clear_flags(tweak, CRYPTO_TFM_REQ_MASK);
+	crypto_cipher_set_flags(tweak, crypto_skcipher_get_flags(parent) &
+				       CRYPTO_TFM_REQ_MASK);
+	err = crypto_cipher_setkey(tweak, key + keylen, keylen);
+	if (err)
+		return err;
+
+	/* data cipher, uses Key1 i.e. the first half of *key */
+	child = ctx->child;
+	crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
+	crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &
+					 CRYPTO_TFM_REQ_MASK);
+	return crypto_skcipher_setkey(child, key, keylen);
+}
+
+/*
+ * We compute the tweak masks twice (both before and after the ECB encryption or
+ * decryption) to avoid having to allocate a temporary buffer and/or make
+ * multiple calls to the 'ecb(..)' instance, which usually would be slower than
+ * just doing the gf128mul_x_ble() calls again.
+ */
+static int xts_xor_tweak(struct skcipher_request *req, bool second_pass,
+			 bool enc)
+{
+	struct xts_request_ctx *rctx = skcipher_request_ctx(req);
+	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+	const bool cts = (req->cryptlen % XTS_BLOCK_SIZE);
+	const int bs = XTS_BLOCK_SIZE;
+	struct skcipher_walk w;
+	le128 t = rctx->t;
+	int err;
+
+	if (second_pass) {
+		req = &rctx->subreq;
+		/* set to our TFM to enforce correct alignment: */
+		skcipher_request_set_tfm(req, tfm);
+	}
+	err = skcipher_walk_virt(&w, req, false);
+
+	while (w.nbytes) {
+		unsigned int avail = w.nbytes;
+		const le128 *wsrc;
+		le128 *wdst;
+
+		wsrc = w.src.virt.addr;
+		wdst = w.dst.virt.addr;
+
+		do {
+			if (unlikely(cts) &&
+			    w.total - w.nbytes + avail < 2 * XTS_BLOCK_SIZE) {
+				if (!enc) {
+					if (second_pass)
+						rctx->t = t;
+					gf128mul_x_ble(&t, &t);
+				}
+				le128_xor(wdst, &t, wsrc);
+				if (enc && second_pass)
+					gf128mul_x_ble(&rctx->t, &t);
+				skcipher_walk_done(&w, avail - bs);
+				return 0;
+			}
+
+			le128_xor(wdst++, &t, wsrc++);
+			gf128mul_x_ble(&t, &t);
+		} while ((avail -= bs) >= bs);
+
+		err = skcipher_walk_done(&w, avail);
+	}
+
+	return err;
+}
+
+static int xts_xor_tweak_pre(struct skcipher_request *req, bool enc)
+{
+	return xts_xor_tweak(req, false, enc);
+}
+
+static int xts_xor_tweak_post(struct skcipher_request *req, bool enc)
+{
+	return xts_xor_tweak(req, true, enc);
+}
+
+static void xts_cts_done(void *data, int err)
+{
+	struct skcipher_request *req = data;
+	le128 b;
+
+	if (!err) {
+		struct xts_request_ctx *rctx = skcipher_request_ctx(req);
+
+		scatterwalk_map_and_copy(&b, rctx->tail, 0, XTS_BLOCK_SIZE, 0);
+		le128_xor(&b, &rctx->t, &b);
+		scatterwalk_map_and_copy(&b, rctx->tail, 0, XTS_BLOCK_SIZE, 1);
+	}
+
+	skcipher_request_complete(req, err);
+}
+
+static int xts_cts_final(struct skcipher_request *req,
+			 int (*crypt)(struct skcipher_request *req))
+{
+	const struct xts_tfm_ctx *ctx =
+		crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
+	int offset = req->cryptlen & ~(XTS_BLOCK_SIZE - 1);
+	struct xts_request_ctx *rctx = skcipher_request_ctx(req);
+	struct skcipher_request *subreq = &rctx->subreq;
+	int tail = req->cryptlen % XTS_BLOCK_SIZE;
+	le128 b[2];
+	int err;
+
+	rctx->tail = scatterwalk_ffwd(rctx->sg, req->dst,
+				      offset - XTS_BLOCK_SIZE);
+
+	scatterwalk_map_and_copy(b, rctx->tail, 0, XTS_BLOCK_SIZE, 0);
+	b[1] = b[0];
+	scatterwalk_map_and_copy(b, req->src, offset, tail, 0);
+
+	le128_xor(b, &rctx->t, b);
+
+	scatterwalk_map_and_copy(b, rctx->tail, 0, XTS_BLOCK_SIZE + tail, 1);
+
+	skcipher_request_set_tfm(subreq, ctx->child);
+	skcipher_request_set_callback(subreq, req->base.flags, xts_cts_done,
+				      req);
+	skcipher_request_set_crypt(subreq, rctx->tail, rctx->tail,
+				   XTS_BLOCK_SIZE, NULL);
+
+	err = crypt(subreq);
+	if (err)
+		return err;
+
+	scatterwalk_map_and_copy(b, rctx->tail, 0, XTS_BLOCK_SIZE, 0);
+	le128_xor(b, &rctx->t, b);
+	scatterwalk_map_and_copy(b, rctx->tail, 0, XTS_BLOCK_SIZE, 1);
+
+	return 0;
+}
+
+static void xts_encrypt_done(void *data, int err)
+{
+	struct skcipher_request *req = data;
+
+	if (!err) {
+		struct xts_request_ctx *rctx = skcipher_request_ctx(req);
+
+		rctx->subreq.base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;
+		err = xts_xor_tweak_post(req, true);
+
+		if (!err && unlikely(req->cryptlen % XTS_BLOCK_SIZE)) {
+			err = xts_cts_final(req, crypto_skcipher_encrypt);
+			if (err == -EINPROGRESS || err == -EBUSY)
+				return;
+		}
+	}
+
+	skcipher_request_complete(req, err);
+}
+
+static void xts_decrypt_done(void *data, int err)
+{
+	struct skcipher_request *req = data;
+
+	if (!err) {
+		struct xts_request_ctx *rctx = skcipher_request_ctx(req);
+
+		rctx->subreq.base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;
+		err = xts_xor_tweak_post(req, false);
+
+		if (!err && unlikely(req->cryptlen % XTS_BLOCK_SIZE)) {
+			err = xts_cts_final(req, crypto_skcipher_decrypt);
+			if (err == -EINPROGRESS || err == -EBUSY)
+				return;
+		}
+	}
+
+	skcipher_request_complete(req, err);
+}
+
+static int xts_init_crypt(struct skcipher_request *req,
+			  crypto_completion_t compl)
+{
+	const struct xts_tfm_ctx *ctx =
+		crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
+	struct xts_request_ctx *rctx = skcipher_request_ctx(req);
+	struct skcipher_request *subreq = &rctx->subreq;
+
+	if (req->cryptlen < XTS_BLOCK_SIZE)
+		return -EINVAL;
+
+	skcipher_request_set_tfm(subreq, ctx->child);
+	skcipher_request_set_callback(subreq, req->base.flags, compl, req);
+	skcipher_request_set_crypt(subreq, req->dst, req->dst,
+				   req->cryptlen & ~(XTS_BLOCK_SIZE - 1), NULL);
+
+	/* calculate first value of T */
+	crypto_cipher_encrypt_one(ctx->tweak, (u8 *)&rctx->t, req->iv);
+
+	return 0;
+}
+
+static int xts_encrypt(struct skcipher_request *req)
+{
+	struct xts_request_ctx *rctx = skcipher_request_ctx(req);
+	struct skcipher_request *subreq = &rctx->subreq;
+	int err;
+
+	err = xts_init_crypt(req, xts_encrypt_done) ?:
+	      xts_xor_tweak_pre(req, true) ?:
+	      crypto_skcipher_encrypt(subreq) ?:
+	      xts_xor_tweak_post(req, true);
+
+	if (err || likely((req->cryptlen % XTS_BLOCK_SIZE) == 0))
+		return err;
+
+	return xts_cts_final(req, crypto_skcipher_encrypt);
+}
+
+static int xts_decrypt(struct skcipher_request *req)
+{
+	struct xts_request_ctx *rctx = skcipher_request_ctx(req);
+	struct skcipher_request *subreq = &rctx->subreq;
+	int err;
+
+	err = xts_init_crypt(req, xts_decrypt_done) ?:
+	      xts_xor_tweak_pre(req, false) ?:
+	      crypto_skcipher_decrypt(subreq) ?:
+	      xts_xor_tweak_post(req, false);
+
+	if (err || likely((req->cryptlen % XTS_BLOCK_SIZE) == 0))
+		return err;
+
+	return xts_cts_final(req, crypto_skcipher_decrypt);
+}
+
+static int xts_init_tfm(struct crypto_skcipher *tfm)
+{
+	struct skcipher_instance *inst = skcipher_alg_instance(tfm);
+	struct xts_instance_ctx *ictx = skcipher_instance_ctx(inst);
+	struct xts_tfm_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct crypto_skcipher *child;
+	struct crypto_cipher *tweak;
+
+	child = crypto_spawn_skcipher(&ictx->spawn);
+	if (IS_ERR(child))
+		return PTR_ERR(child);
+
+	ctx->child = child;
+
+	tweak = crypto_spawn_cipher(&ictx->tweak_spawn);
+	if (IS_ERR(tweak)) {
+		crypto_free_skcipher(ctx->child);
+		return PTR_ERR(tweak);
+	}
+
+	ctx->tweak = tweak;
+
+	crypto_skcipher_set_reqsize(tfm, crypto_skcipher_reqsize(child) +
+					 sizeof(struct xts_request_ctx));
+
+	return 0;
+}
+
+static void xts_exit_tfm(struct crypto_skcipher *tfm)
+{
+	struct xts_tfm_ctx *ctx = crypto_skcipher_ctx(tfm);
+
+	crypto_free_skcipher(ctx->child);
+	crypto_free_cipher(ctx->tweak);
+}
+
+static void xts_free_instance(struct skcipher_instance *inst)
+{
+	struct xts_instance_ctx *ictx = skcipher_instance_ctx(inst);
+
+	crypto_drop_skcipher(&ictx->spawn);
+	crypto_drop_cipher(&ictx->tweak_spawn);
+	kfree(inst);
+}
+
+static int xts_create(struct crypto_template *tmpl, struct rtattr **tb)
+{
+	struct skcipher_alg_common *alg;
+	char name[CRYPTO_MAX_ALG_NAME];
+	struct skcipher_instance *inst;
+	struct xts_instance_ctx *ctx;
+	const char *cipher_name;
+	u32 mask;
+	int err;
+
+	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SKCIPHER, &mask);
+	if (err)
+		return err;
+
+	cipher_name = crypto_attr_alg_name(tb[1]);
+	if (IS_ERR(cipher_name))
+		return PTR_ERR(cipher_name);
+
+	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
+	if (!inst)
+		return -ENOMEM;
+
+	ctx = skcipher_instance_ctx(inst);
+
+	err = crypto_grab_skcipher(&ctx->spawn, skcipher_crypto_instance(inst),
+				   cipher_name, 0, mask);
+	if (err == -ENOENT && memcmp(cipher_name, "ecb(", 4)) {
+		err = -ENAMETOOLONG;
+		if (snprintf(name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
+			     cipher_name) >= CRYPTO_MAX_ALG_NAME)
+			goto err_free_inst;
+
+		err = crypto_grab_skcipher(&ctx->spawn,
+					   skcipher_crypto_instance(inst),
+					   name, 0, mask);
+	}
+
+	if (err)
+		goto err_free_inst;
+
+	alg = crypto_spawn_skcipher_alg_common(&ctx->spawn);
+
+	err = -EINVAL;
+	if (alg->base.cra_blocksize != XTS_BLOCK_SIZE)
+		goto err_free_inst;
+
+	if (alg->ivsize)
+		goto err_free_inst;
+
+	err = crypto_inst_setname(skcipher_crypto_instance(inst), "xts",
+				  &alg->base);
+	if (err)
+		goto err_free_inst;
+
+	err = -EINVAL;
+	cipher_name = alg->base.cra_name;
+
+	/* Alas we screwed up the naming so we have to mangle the
+	 * cipher name.
+	 */
+	if (!memcmp(cipher_name, "ecb(", 4)) {
+		int len;
+
+		len = strscpy(name, cipher_name + 4);
+		if (len < 2)
+			goto err_free_inst;
+
+		if (name[len - 1] != ')')
+			goto err_free_inst;
+
+		name[len - 1] = 0;
+
+		if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
+			     "xts(%s)", name) >= CRYPTO_MAX_ALG_NAME) {
+			err = -ENAMETOOLONG;
+			goto err_free_inst;
+		}
+	} else
+		goto err_free_inst;
+
+	err = crypto_grab_cipher(&ctx->tweak_spawn,
+				 skcipher_crypto_instance(inst), name, 0, mask);
+	if (err)
+		goto err_free_inst;
+
+	inst->alg.base.cra_priority = alg->base.cra_priority;
+	inst->alg.base.cra_blocksize = XTS_BLOCK_SIZE;
+	inst->alg.base.cra_alignmask = alg->base.cra_alignmask |
+				       (__alignof__(u64) - 1);
+
+	inst->alg.ivsize = XTS_BLOCK_SIZE;
+	inst->alg.min_keysize = alg->min_keysize * 2;
+	inst->alg.max_keysize = alg->max_keysize * 2;
+
+	inst->alg.base.cra_ctxsize = sizeof(struct xts_tfm_ctx);
+
+	inst->alg.init = xts_init_tfm;
+	inst->alg.exit = xts_exit_tfm;
+
+	inst->alg.setkey = xts_setkey;
+	inst->alg.encrypt = xts_encrypt;
+	inst->alg.decrypt = xts_decrypt;
+
+	inst->free = xts_free_instance;
+
+	err = skcipher_register_instance(tmpl, inst);
+	if (err) {
+err_free_inst:
+		xts_free_instance(inst);
+	}
+	return err;
+}
+
+static struct crypto_template xts_tmpl = {
+	.name = "xts",
+	.create = xts_create,
+	.module = THIS_MODULE,
+};
+
+static int __init xts_module_init(void)
+{
+	return crypto_register_template(&xts_tmpl);
+}
+
+static void __exit xts_module_exit(void)
+{
+	crypto_unregister_template(&xts_tmpl);
+}
+
+module_init(xts_module_init);
+module_exit(xts_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("XTS block cipher mode");
+MODULE_ALIAS_CRYPTO("xts");
+MODULE_IMPORT_NS("CRYPTO_INTERNAL");
+MODULE_SOFTDEP("pre: ecb");