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/ntfs/sysctl.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 fs/ntfs/sysctl.c (limited to 'fs/ntfs/sysctl.c') diff --git a/fs/ntfs/sysctl.c b/fs/ntfs/sysctl.c new file mode 100644 index 000000000..8c5c1b7cd --- /dev/null +++ b/fs/ntfs/sysctl.c @@ -0,0 +1,54 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Code for sysctl handling in NTFS Linux kernel driver. + * + * Copyright (C) 1997 Martin von Löwis, Régis Duchesne + * Copyright (c) 2002-2005 Anton Altaparmakov + */ + +#ifdef DEBUG + +#include + +#ifdef CONFIG_SYSCTL + +#include +#include + +#include "sysctl.h" +#include "debug.h" + +/* Definition of the ntfs sysctl. */ +static const struct ctl_table ntfs_sysctls[] = { + { + .procname = "ntfs-debug", + .data = &debug_msgs, /* Data pointer and size. */ + .maxlen = sizeof(debug_msgs), + .mode = 0644, /* Mode, proc handler. */ + .proc_handler = proc_dointvec + }, +}; + +/* Storage for the sysctls header. */ +static struct ctl_table_header *sysctls_root_table; + +/* + * ntfs_sysctl - add or remove the debug sysctl + * @add: add (1) or remove (0) the sysctl + * + * Add or remove the debug sysctl. Return 0 on success or -errno on error. + */ +int ntfs_sysctl(int add) +{ + if (add) { + sysctls_root_table = register_sysctl("fs/ntfs", ntfs_sysctls); + if (!sysctls_root_table) + return -ENOMEM; + } else { + unregister_sysctl_table(sysctls_root_table); + sysctls_root_table = NULL; + } + return 0; +} +#endif /* CONFIG_SYSCTL */ +#endif /* DEBUG */ -- cgit v1.3.1