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 --- security/keys/sysctl.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 76 insertions(+) create mode 100644 security/keys/sysctl.c (limited to 'security/keys/sysctl.c') diff --git a/security/keys/sysctl.c b/security/keys/sysctl.c new file mode 100644 index 000000000..cde08c478 --- /dev/null +++ b/security/keys/sysctl.c @@ -0,0 +1,76 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Key management controls + * + * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include +#include +#include "internal.h" + +static const struct ctl_table key_sysctls[] = { + { + .procname = "maxkeys", + .data = &key_quota_maxkeys, + .maxlen = sizeof(unsigned), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = (void *) SYSCTL_ONE, + .extra2 = (void *) SYSCTL_INT_MAX, + }, + { + .procname = "maxbytes", + .data = &key_quota_maxbytes, + .maxlen = sizeof(unsigned), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = (void *) SYSCTL_ONE, + .extra2 = (void *) SYSCTL_INT_MAX, + }, + { + .procname = "root_maxkeys", + .data = &key_quota_root_maxkeys, + .maxlen = sizeof(unsigned), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = (void *) SYSCTL_ONE, + .extra2 = (void *) SYSCTL_INT_MAX, + }, + { + .procname = "root_maxbytes", + .data = &key_quota_root_maxbytes, + .maxlen = sizeof(unsigned), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = (void *) SYSCTL_ONE, + .extra2 = (void *) SYSCTL_INT_MAX, + }, + { + .procname = "gc_delay", + .data = &key_gc_delay, + .maxlen = sizeof(unsigned), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = (void *) SYSCTL_ZERO, + .extra2 = (void *) SYSCTL_INT_MAX, + }, +#ifdef CONFIG_PERSISTENT_KEYRINGS + { + .procname = "persistent_keyring_expiry", + .data = &persistent_keyring_expiry, + .maxlen = sizeof(unsigned), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = (void *) SYSCTL_ZERO, + .extra2 = (void *) SYSCTL_INT_MAX, + }, +#endif +}; + +static int __init init_security_keys_sysctls(void) +{ + register_sysctl_init("kernel/keys", key_sysctls); + return 0; +} +early_initcall(init_security_keys_sysctls); -- cgit v1.3.1