From 78004e9a87f240df03e2f73120d291763c32e0a7 Mon Sep 17 00:00:00 2001 From: Ali Ahmet Memis Date: Fri, 21 Aug 2026 01:45:27 +0000 Subject: openrisc: fix arbitrary kernel memory access via or1k_atomic syscall 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 Signed-off-by: Stafford Horne --- Documentation/admin-guide/sysctl/sunrpc.rst | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) create mode 100644 Documentation/admin-guide/sysctl/sunrpc.rst (limited to 'Documentation/admin-guide/sysctl/sunrpc.rst') diff --git a/Documentation/admin-guide/sysctl/sunrpc.rst b/Documentation/admin-guide/sysctl/sunrpc.rst new file mode 100644 index 000000000..09780a682 --- /dev/null +++ b/Documentation/admin-guide/sysctl/sunrpc.rst @@ -0,0 +1,25 @@ +=================================== +Documentation for /proc/sys/sunrpc/ +=================================== + +kernel version 2.2.10 + +Copyright (c) 1998, 1999, Rik van Riel + +For general info and legal blurb, please look in index.rst. + +------------------------------------------------------------------------------ + +This file contains the documentation for the sysctl files in +/proc/sys/sunrpc and is valid for Linux kernel version 2.2. + +The files in this directory can be used to (re)set the debug +flags of the SUN Remote Procedure Call (RPC) subsystem in +the Linux kernel. This stuff is used for NFS, KNFSD and +maybe a few other things as well. + +The files in there are used to control the debugging flags: +rpc_debug, nfs_debug, nfsd_debug and nlm_debug. + +These flags are for kernel hackers only. You should read the +source code in net/sunrpc/ for more information. -- cgit v1.3.1