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, 100 insertions, 0 deletions

diff --git a/fs/ntfs/bitmap.h b/fs/ntfs/bitmap.h
new file mode 100644
index 000000000..31177fe61
--- /dev/null
+++ b/fs/ntfs/bitmap.h
@@ -0,0 +1,100 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Defines for NTFS kernel bitmap handling.
+ *
+ * Copyright (c) 2004 Anton Altaparmakov
+ */
+
+#ifndef _LINUX_NTFS_BITMAP_H
+#define _LINUX_NTFS_BITMAP_H
+
+#include <linux/fs.h>
+
+#include "volume.h"
+
+int ntfs_trim_fs(struct ntfs_volume *vol, struct fstrim_range *range);
+int __ntfs_bitmap_set_bits_in_run(struct inode *vi, const s64 start_bit,
+		const s64 count, const u8 value, const bool is_rollback);
+
+/*
+ * ntfs_bitmap_set_bits_in_run - set a run of bits in a bitmap to a value
+ * @vi:			vfs inode describing the bitmap
+ * @start_bit:		first bit to set
+ * @count:		number of bits to set
+ * @value:		value to set the bits to (i.e. 0 or 1)
+ *
+ * Set @count bits starting at bit @start_bit in the bitmap described by the
+ * vfs inode @vi to @value, where @value is either 0 or 1.
+ *
+ * Return 0 on success and -errno on error.
+ */
+static inline int ntfs_bitmap_set_bits_in_run(struct inode *vi,
+		const s64 start_bit, const s64 count, const u8 value)
+{
+	return __ntfs_bitmap_set_bits_in_run(vi, start_bit, count, value,
+			false);
+}
+
+/*
+ * ntfs_bitmap_set_run - set a run of bits in a bitmap
+ * @vi:		vfs inode describing the bitmap
+ * @start_bit:	first bit to set
+ * @count:	number of bits to set
+ *
+ * Set @count bits starting at bit @start_bit in the bitmap described by the
+ * vfs inode @vi.
+ *
+ * Return 0 on success and -errno on error.
+ */
+static inline int ntfs_bitmap_set_run(struct inode *vi, const s64 start_bit,
+		const s64 count)
+{
+	return ntfs_bitmap_set_bits_in_run(vi, start_bit, count, 1);
+}
+
+/*
+ * ntfs_bitmap_clear_run - clear a run of bits in a bitmap
+ * @vi:		vfs inode describing the bitmap
+ * @start_bit:	first bit to clear
+ * @count:	number of bits to clear
+ *
+ * Clear @count bits starting at bit @start_bit in the bitmap described by the
+ * vfs inode @vi.
+ *
+ * Return 0 on success and -errno on error.
+ */
+static inline int ntfs_bitmap_clear_run(struct inode *vi, const s64 start_bit,
+		const s64 count)
+{
+	return ntfs_bitmap_set_bits_in_run(vi, start_bit, count, 0);
+}
+
+/*
+ * ntfs_bitmap_set_bit - set a bit in a bitmap
+ * @vi:		vfs inode describing the bitmap
+ * @bit:	bit to set
+ *
+ * Set bit @bit in the bitmap described by the vfs inode @vi.
+ *
+ * Return 0 on success and -errno on error.
+ */
+static inline int ntfs_bitmap_set_bit(struct inode *vi, const s64 bit)
+{
+	return ntfs_bitmap_set_run(vi, bit, 1);
+}
+
+/*
+ * ntfs_bitmap_clear_bit - clear a bit in a bitmap
+ * @vi:		vfs inode describing the bitmap
+ * @bit:	bit to clear
+ *
+ * Clear bit @bit in the bitmap described by the vfs inode @vi.
+ *
+ * Return 0 on success and -errno on error.
+ */
+static inline int ntfs_bitmap_clear_bit(struct inode *vi, const s64 bit)
+{
+	return ntfs_bitmap_clear_run(vi, bit, 1);
+}
+
+#endif /* defined _LINUX_NTFS_BITMAP_H */