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, 36 insertions, 0 deletions

diff --git a/fs/ntfs/collate.h b/fs/ntfs/collate.h
new file mode 100644
index 000000000..8ad1f04be
--- /dev/null
+++ b/fs/ntfs/collate.h
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Defines for NTFS kernel collation handling.
+ *
+ * Copyright (c) 2004 Anton Altaparmakov
+ *
+ * Part of this file is based on code from the NTFS-3G.
+ * and is copyrighted by the respective authors below:
+ * Copyright (c) 2004 Anton Altaparmakov
+ * Copyright (c) 2005 Yura Pakhuchiy
+ */
+
+#ifndef _LINUX_NTFS_COLLATE_H
+#define _LINUX_NTFS_COLLATE_H
+
+#include "volume.h"
+
+static inline bool ntfs_is_collation_rule_supported(__le32 cr)
+{
+	int i;
+
+	if (unlikely(cr != COLLATION_BINARY && cr != COLLATION_NTOFS_ULONG &&
+		     cr != COLLATION_FILE_NAME) && cr != COLLATION_NTOFS_ULONGS)
+		return false;
+	i = le32_to_cpu(cr);
+	if (likely(((i >= 0) && (i <= 0x02)) ||
+			((i >= 0x10) && (i <= 0x13))))
+		return true;
+	return false;
+}
+
+int ntfs_collate(struct ntfs_volume *vol, __le32 cr,
+		const void *data1, const u32 data1_len,
+		const void *data2, const u32 data2_len);
+
+#endif /* _LINUX_NTFS_COLLATE_H */