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, 83 insertions, 0 deletions

diff --git a/fs/smb/client/smbencrypt.c b/fs/smb/client/smbencrypt.c
new file mode 100644
index 000000000..094b8296d
--- /dev/null
+++ b/fs/smb/client/smbencrypt.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+   Unix SMB/Netbios implementation.
+   Version 1.9.
+   SMB parameters and setup
+   Copyright (C) Andrew Tridgell 1992-2000
+   Copyright (C) Luke Kenneth Casson Leighton 1996-2000
+   Modified by Jeremy Allison 1995.
+   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2002-2003
+   Modified by Steve French (sfrench@us.ibm.com) 2002-2003
+
+*/
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/fips.h>
+#include <linux/fs.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/random.h>
+#include "cifs_fs_sb.h"
+#include "cifs_unicode.h"
+#include "cifsglob.h"
+#include "cifs_debug.h"
+#include "cifsproto.h"
+#include "../common/md4.h"
+
+/* following came from the other byteorder.h to avoid include conflicts */
+#define CVAL(buf,pos) (((unsigned char *)(buf))[pos])
+#define SSVALX(buf,pos,val) (CVAL(buf,pos)=(val)&0xFF,CVAL(buf,pos+1)=(val)>>8)
+#define SSVAL(buf,pos,val) SSVALX((buf),(pos),((__u16)(val)))
+
+/* produce a md4 message digest from data of length n bytes */
+static int
+mdfour(unsigned char *md4_hash, unsigned char *link_str, int link_len)
+{
+	int rc;
+	struct md4_ctx mctx;
+
+	rc = cifs_md4_init(&mctx);
+	if (rc) {
+		cifs_dbg(VFS, "%s: Could not init MD4\n", __func__);
+		goto mdfour_err;
+	}
+	rc = cifs_md4_update(&mctx, link_str, link_len);
+	if (rc) {
+		cifs_dbg(VFS, "%s: Could not update MD4\n", __func__);
+		goto mdfour_err;
+	}
+	rc = cifs_md4_final(&mctx, md4_hash);
+	if (rc)
+		cifs_dbg(VFS, "%s: Could not finalize MD4\n", __func__);
+
+
+mdfour_err:
+	return rc;
+}
+
+/*
+ * Creates the MD4 Hash of the users password in NT UNICODE.
+ */
+
+int
+E_md4hash(const unsigned char *passwd, unsigned char *p16,
+	const struct nls_table *codepage)
+{
+	int rc;
+	int len;
+	__le16 wpwd[129];
+
+	/* Password cannot be longer than 128 characters */
+	if (passwd) /* Password must be converted to NT unicode */
+		len = cifs_strtoUTF16(wpwd, passwd, 128, codepage);
+	else {
+		len = 0;
+		*wpwd = 0; /* Ensure string is null terminated */
+	}
+
+	rc = mdfour(p16, (unsigned char *) wpwd, len * sizeof(__le16));
+	memzero_explicit(wpwd, sizeof(wpwd));
+
+	return rc;
+}