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/lockd/netlink.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 fs/lockd/netlink.c (limited to 'fs/lockd/netlink.c') diff --git a/fs/lockd/netlink.c b/fs/lockd/netlink.c new file mode 100644 index 000000000..880c42b4f --- /dev/null +++ b/fs/lockd/netlink.c @@ -0,0 +1,45 @@ +// SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) +/* Do not edit directly, auto-generated from: */ +/* Documentation/netlink/specs/lockd.yaml */ +/* YNL-GEN kernel source */ +/* To regenerate run: tools/net/ynl/ynl-regen.sh */ + +#include +#include + +#include "netlink.h" + +#include + +/* LOCKD_CMD_SERVER_SET - do */ +static const struct nla_policy lockd_server_set_nl_policy[LOCKD_A_SERVER_UDP_PORT + 1] = { + [LOCKD_A_SERVER_GRACETIME] = { .type = NLA_U32, }, + [LOCKD_A_SERVER_TCP_PORT] = { .type = NLA_U16, }, + [LOCKD_A_SERVER_UDP_PORT] = { .type = NLA_U16, }, +}; + +/* Ops table for lockd */ +static const struct genl_split_ops lockd_nl_ops[] = { + { + .cmd = LOCKD_CMD_SERVER_SET, + .doit = lockd_nl_server_set_doit, + .policy = lockd_server_set_nl_policy, + .maxattr = LOCKD_A_SERVER_UDP_PORT, + .flags = GENL_ADMIN_PERM | GENL_CMD_CAP_DO, + }, + { + .cmd = LOCKD_CMD_SERVER_GET, + .doit = lockd_nl_server_get_doit, + .flags = GENL_CMD_CAP_DO, + }, +}; + +struct genl_family lockd_nl_family __ro_after_init = { + .name = LOCKD_FAMILY_NAME, + .version = LOCKD_FAMILY_VERSION, + .netnsok = true, + .parallel_ops = true, + .module = THIS_MODULE, + .split_ops = lockd_nl_ops, + .n_split_ops = ARRAY_SIZE(lockd_nl_ops), +}; -- cgit v1.3.1