openrisc: fix arbitrary kernel memory access via or1k_atomic syscallgrafted

sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user
pointers, v1 and v2, and swaps the words they point to in hand-written
assembly.

    l.lwz   r29,0(r4)
    l.lwz   r27,0(r5)
    l.sw    0(r4),r27
    l.sw    0(r5),r29

The pointers are not checked with access_ok(). The four memory
accesses also have no exception table entries.

A caller passes a kernel address as either pointer, and the syscall
reads from and writes to it directly.

This gives an unprivileged process a kernel read/write primitive. It
overwrites kernel data such as the sys_call_table, gaining code
execution in kernel context.

Check both pointers before entering the critical section. Add fixups
for the four memory accesses so faults on valid but unmapped user
addresses return -EFAULT.

[shorne@gmail.com: fix comment style]
Fixes: 9d02a4283e9c ("OpenRISC: Boot code")
Cc: stable@vger.kernel.org
Signed-off-by: Ali Ahmet Memis <ali@iusegentoo.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>

1 files changed, 134 insertions, 0 deletions

diff --git a/fs/smb/server/proc.c b/fs/smb/server/proc.c
new file mode 100644
index 000000000..101a2cc45
--- /dev/null
+++ b/fs/smb/server/proc.c
@@ -0,0 +1,134 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *   Copyright (C) 2025, LG Electronics.
+ *   Author(s): Hyunchul Lee <hyc.lee@gmail.com>
+ *   Copyright (C) 2025, Samsung Electronics.
+ *   Author(s): Vedansh Bhardwaj <v.bhardwaj@samsung.com>
+ */
+
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+
+#include "misc.h"
+#include "server.h"
+#include "stats.h"
+#include "smb_common.h"
+#include "smb2pdu.h"
+
+static struct proc_dir_entry *ksmbd_proc_fs;
+struct ksmbd_counters ksmbd_counters;
+
+struct proc_dir_entry *ksmbd_proc_create(const char *name,
+					 int (*show)(struct seq_file *m, void *v),
+						 void *v)
+{
+	return proc_create_single_data(name, 0400, ksmbd_proc_fs,
+			   show, v);
+}
+
+struct ksmbd_const_smb2_process_req {
+	unsigned int const_value;
+	const char *name;
+};
+
+static const struct ksmbd_const_smb2_process_req smb2_process_req[KSMBD_COUNTER_MAX_REQS] = {
+	{le16_to_cpu(SMB2_NEGOTIATE), "SMB2_NEGOTIATE"},
+	{le16_to_cpu(SMB2_SESSION_SETUP), "SMB2_SESSION_SETUP"},
+	{le16_to_cpu(SMB2_LOGOFF), "SMB2_LOGOFF"},
+	{le16_to_cpu(SMB2_TREE_CONNECT), "SMB2_TREE_CONNECT"},
+	{le16_to_cpu(SMB2_TREE_DISCONNECT), "SMB2_TREE_DISCONNECT"},
+	{le16_to_cpu(SMB2_CREATE), "SMB2_CREATE"},
+	{le16_to_cpu(SMB2_CLOSE), "SMB2_CLOSE"},
+	{le16_to_cpu(SMB2_FLUSH), "SMB2_FLUSH"},
+	{le16_to_cpu(SMB2_READ), "SMB2_READ"},
+	{le16_to_cpu(SMB2_WRITE), "SMB2_WRITE"},
+	{le16_to_cpu(SMB2_LOCK), "SMB2_LOCK"},
+	{le16_to_cpu(SMB2_IOCTL), "SMB2_IOCTL"},
+	{le16_to_cpu(SMB2_CANCEL), "SMB2_CANCEL"},
+	{le16_to_cpu(SMB2_ECHO), "SMB2_ECHO"},
+	{le16_to_cpu(SMB2_QUERY_DIRECTORY), "SMB2_QUERY_DIRECTORY"},
+	{le16_to_cpu(SMB2_CHANGE_NOTIFY), "SMB2_CHANGE_NOTIFY"},
+	{le16_to_cpu(SMB2_QUERY_INFO), "SMB2_QUERY_INFO"},
+	{le16_to_cpu(SMB2_SET_INFO), "SMB2_SET_INFO"},
+	{le16_to_cpu(SMB2_OPLOCK_BREAK), "SMB2_OPLOCK_BREAK"},
+};
+
+static int proc_show_ksmbd_stats(struct seq_file *m, void *v)
+{
+	int i;
+
+	seq_puts(m, "Server\n");
+	seq_printf(m, "name: %s\n", ksmbd_server_string());
+	seq_printf(m, "netbios: %s\n", ksmbd_netbios_name());
+	seq_printf(m, "work group: %s\n", ksmbd_work_group());
+	seq_printf(m, "min protocol: %s\n", ksmbd_get_protocol_string(server_conf.min_protocol));
+	seq_printf(m, "max protocol: %s\n", ksmbd_get_protocol_string(server_conf.max_protocol));
+	seq_printf(m, "flags: 0x%08x\n", server_conf.flags);
+	seq_printf(m, "share_fake_fscaps: 0x%08x\n",
+		   server_conf.share_fake_fscaps);
+	seq_printf(m, "sessions: %lld\n",
+		   ksmbd_counter_sum(KSMBD_COUNTER_SESSIONS));
+	seq_printf(m, "tree connects: %lld\n",
+		   ksmbd_counter_sum(KSMBD_COUNTER_TREE_CONNS));
+	seq_printf(m, "read bytes: %lld\n",
+		   ksmbd_counter_sum(KSMBD_COUNTER_READ_BYTES));
+	seq_printf(m, "written bytes: %lld\n",
+		   ksmbd_counter_sum(KSMBD_COUNTER_WRITE_BYTES));
+
+	seq_puts(m, "\nSMB2\n");
+	for (i = 0; i < KSMBD_COUNTER_MAX_REQS; i++)
+		seq_printf(m, "%-20s:\t%lld\n", smb2_process_req[i].name,
+			   ksmbd_counter_sum(KSMBD_COUNTER_FIRST_REQ + i));
+	return 0;
+}
+
+void ksmbd_proc_cleanup(void)
+{
+	int i;
+
+	if (!ksmbd_proc_fs)
+		return;
+
+	proc_remove(ksmbd_proc_fs);
+
+	for (i = 0; i < ARRAY_SIZE(ksmbd_counters.counters); i++)
+		percpu_counter_destroy(&ksmbd_counters.counters[i]);
+
+	ksmbd_proc_fs = NULL;
+}
+
+void ksmbd_proc_reset(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ksmbd_counters.counters); i++)
+		percpu_counter_set(&ksmbd_counters.counters[i], 0);
+}
+
+void ksmbd_proc_init(void)
+{
+	int i;
+	int retval;
+
+	ksmbd_proc_fs = proc_mkdir("fs/ksmbd", NULL);
+	if (!ksmbd_proc_fs)
+		return;
+
+	if (!proc_mkdir_mode("sessions", 0400, ksmbd_proc_fs))
+		goto err_out;
+
+	for (i = 0; i < ARRAY_SIZE(ksmbd_counters.counters); i++) {
+		retval = percpu_counter_init(&ksmbd_counters.counters[i], 0, GFP_KERNEL);
+		if (retval)
+			goto err_out;
+	}
+
+	if (!ksmbd_proc_create("server", proc_show_ksmbd_stats, NULL))
+		goto err_out;
+
+	ksmbd_proc_reset();
+	return;
+err_out:
+	ksmbd_proc_cleanup();
+}