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 --- net/phonet/sysctl.c | 95 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 95 insertions(+) create mode 100644 net/phonet/sysctl.c (limited to 'net/phonet/sysctl.c') diff --git a/net/phonet/sysctl.c b/net/phonet/sysctl.c new file mode 100644 index 000000000..463a74a27 --- /dev/null +++ b/net/phonet/sysctl.c @@ -0,0 +1,95 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * File: sysctl.c + * + * Phonet /proc/sys/net/phonet interface implementation + * + * Copyright (C) 2008 Nokia Corporation. + * + * Author: Rémi Denis-Courmont + */ + +#include +#include +#include +#include + +#include +#include +#include + +#define DYNAMIC_PORT_MIN 0x40 +#define DYNAMIC_PORT_MAX 0x7f + +static DEFINE_SEQLOCK(local_port_range_lock); +static int local_port_range_min[2] = {0, 0}; +static int local_port_range_max[2] = {1023, 1023}; +static int local_port_range[2] = {DYNAMIC_PORT_MIN, DYNAMIC_PORT_MAX}; +static struct ctl_table_header *phonet_table_hrd; + +static void set_local_port_range(int range[2]) +{ + write_seqlock(&local_port_range_lock); + local_port_range[0] = range[0]; + local_port_range[1] = range[1]; + write_sequnlock(&local_port_range_lock); +} + +void phonet_get_local_port_range(int *min, int *max) +{ + unsigned int seq; + + do { + seq = read_seqbegin(&local_port_range_lock); + if (min) + *min = local_port_range[0]; + if (max) + *max = local_port_range[1]; + } while (read_seqretry(&local_port_range_lock, seq)); +} + +static int proc_local_port_range(const struct ctl_table *table, int write, + void *buffer, size_t *lenp, loff_t *ppos) +{ + int ret; + int range[2] = {local_port_range[0], local_port_range[1]}; + struct ctl_table tmp = { + .data = &range, + .maxlen = sizeof(range), + .mode = table->mode, + .extra1 = &local_port_range_min, + .extra2 = &local_port_range_max, + }; + + ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos); + + if (write && ret == 0) { + if (range[1] < range[0]) + ret = -EINVAL; + else + set_local_port_range(range); + } + + return ret; +} + +static struct ctl_table phonet_table[] = { + { + .procname = "local_port_range", + .data = &local_port_range, + .maxlen = sizeof(local_port_range), + .mode = 0644, + .proc_handler = proc_local_port_range, + }, +}; + +int __init phonet_sysctl_init(void) +{ + phonet_table_hrd = register_net_sysctl(&init_net, "net/phonet", phonet_table); + return phonet_table_hrd == NULL ? -ENOMEM : 0; +} + +void phonet_sysctl_exit(void) +{ + unregister_net_sysctl_table(phonet_table_hrd); +} -- cgit v1.3.1