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 --- fs/proc/version.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) create mode 100644 fs/proc/version.c (limited to 'fs/proc/version.c') diff --git a/fs/proc/version.c b/fs/proc/version.c new file mode 100644 index 000000000..02e3c3cd4 --- /dev/null +++ b/fs/proc/version.c @@ -0,0 +1,27 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include +#include +#include "internal.h" + +static int version_proc_show(struct seq_file *m, void *v) +{ + seq_printf(m, linux_proc_banner, + utsname()->sysname, + utsname()->release, + utsname()->version); + return 0; +} + +static int __init proc_version_init(void) +{ + struct proc_dir_entry *pde; + + pde = proc_create_single("version", 0, NULL, version_proc_show); + pde_make_permanent(pde); + return 0; +} +fs_initcall(proc_version_init); -- cgit v1.3.1