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, 61 insertions, 0 deletions

diff --git a/security/apparmor/crypto.c b/security/apparmor/crypto.c
new file mode 100644
index 000000000..d8a7bde94
--- /dev/null
+++ b/security/apparmor/crypto.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AppArmor security module
+ *
+ * This file contains AppArmor policy loading interface function definitions.
+ *
+ * Copyright 2013 Canonical Ltd.
+ *
+ * Fns to provide a checksum of policy that has been loaded this can be
+ * compared to userspace policy compiles to check loaded policy is what
+ * it should be.
+ */
+
+#include <crypto/sha2.h>
+
+#include "include/apparmor.h"
+#include "include/crypto.h"
+
+unsigned int aa_hash_size(void)
+{
+	return SHA256_DIGEST_SIZE;
+}
+
+char *aa_calc_hash(void *data, size_t len)
+{
+	char *hash;
+
+	hash = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL);
+	if (!hash)
+		return ERR_PTR(-ENOMEM);
+
+	sha256(data, len, hash);
+	return hash;
+}
+
+int aa_calc_profile_hash(struct aa_profile *profile, u32 version, void *start,
+			 size_t len)
+{
+	struct sha256_ctx sctx;
+	__le32 le32_version = cpu_to_le32(version);
+
+	if (!aa_g_hash_policy)
+		return 0;
+
+	profile->hash = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL);
+	if (!profile->hash)
+		return -ENOMEM;
+
+	sha256_init(&sctx);
+	sha256_update(&sctx, (u8 *)&le32_version, 4);
+	sha256_update(&sctx, (u8 *)start, len);
+	sha256_final(&sctx, profile->hash);
+	return 0;
+}
+
+int __init init_profile_hash(void)
+{
+	if (apparmor_initialized)
+		aa_info_message("AppArmor sha256 policy hashing enabled");
+	return 0;
+}