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, 54 insertions, 0 deletions

diff --git a/Documentation/doc-guide/checktransupdate.rst b/Documentation/doc-guide/checktransupdate.rst
new file mode 100644
index 000000000..7b25375cc
--- /dev/null
+++ b/Documentation/doc-guide/checktransupdate.rst
@@ -0,0 +1,54 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Checking for needed translation updates
+=======================================
+
+This script helps track the translation status of the documentation in
+different locales, i.e., whether the documentation is up-to-date with
+the English counterpart.
+
+How it works
+------------
+
+It uses ``git log`` command to track the latest English commit from the
+translation commit (order by author date) and the latest English commits
+from HEAD. If any differences occur, the file is considered as out-of-date,
+then commits that need to be updated will be collected and reported.
+
+Features implemented
+
+-  check all files in a certain locale
+-  check a single file or a set of files
+-  provide options to change output format
+-  track the translation status of files that have no translation
+
+Usage
+-----
+
+::
+
+   tools/docs/checktransupdate.py --help
+
+Please refer to the output of argument parser for usage details.
+
+Samples
+
+-  ``tools/docs/checktransupdate.py -l zh_CN``
+   This will print all the files that need to be updated in the zh_CN locale.
+-  ``tools/docs/checktransupdate.py Documentation/translations/zh_CN/dev-tools/testing-overview.rst``
+   This will only print the status of the specified file.
+
+Then the output is something like:
+
+::
+
+    Documentation/dev-tools/kfence.rst
+    No translation in the locale of zh_CN
+
+    Documentation/translations/zh_CN/dev-tools/testing-overview.rst
+    commit 42fb9cfd5b18 ("Documentation: dev-tools: Add link to RV docs")
+    1 commits needs resolving in total
+
+Features to be implemented
+
+- files can be a folder instead of only a file