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, 32 insertions, 0 deletions

diff --git a/fs/ntfs/dir.h b/fs/ntfs/dir.h
new file mode 100644
index 000000000..a38c6b071
--- /dev/null
+++ b/fs/ntfs/dir.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Defines for directory handling in NTFS Linux kernel driver.
+ *
+ * Copyright (c) 2002-2004 Anton Altaparmakov
+ */
+
+#ifndef _LINUX_NTFS_DIR_H
+#define _LINUX_NTFS_DIR_H
+
+#include "inode.h"
+
+/*
+ * ntfs_name is used to return the file name to the caller of
+ * ntfs_lookup_inode_by_name() in order for the caller (namei.c::ntfs_lookup())
+ * to be able to deal with dcache aliasing issues.
+ */
+struct ntfs_name {
+	u64 mref;
+	u8 type;
+	u8 len;
+	__le16 name[];
+} __packed;
+
+/* The little endian Unicode string $I30 as a global constant. */
+extern __le16 I30[5];
+
+u64 ntfs_lookup_inode_by_name(struct ntfs_inode *dir_ni,
+		const __le16 *uname, const int uname_len, struct ntfs_name **res);
+int ntfs_check_empty_dir(struct ntfs_inode *ni, struct mft_record *ni_mrec);
+
+#endif /* _LINUX_NTFS_FS_DIR_H */