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/bpf/hooks.c | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 security/bpf/hooks.c (limited to 'security/bpf/hooks.c') diff --git a/security/bpf/hooks.c b/security/bpf/hooks.c new file mode 100644 index 000000000..7b98f5d1e --- /dev/null +++ b/security/bpf/hooks.c @@ -0,0 +1,42 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Copyright (C) 2020 Google LLC. + */ +#include +#include +#include + +bool bpf_lsm_initialized __ro_after_init; + +static struct security_hook_list bpf_lsm_hooks[] __ro_after_init = { + #define LSM_HOOK(RET, DEFAULT, NAME, ...) \ + LSM_HOOK_INIT(NAME, bpf_lsm_##NAME), + #include + #undef LSM_HOOK + LSM_HOOK_INIT(inode_free_security, bpf_inode_storage_free), +}; + +static const struct lsm_id bpf_lsmid = { + .name = "bpf", + .id = LSM_ID_BPF, +}; + +static int __init bpf_lsm_init(void) +{ + security_add_hooks(bpf_lsm_hooks, ARRAY_SIZE(bpf_lsm_hooks), + &bpf_lsmid); + bpf_lsm_initialized = true; + pr_info("LSM support for eBPF active\n"); + return 0; +} + +struct lsm_blob_sizes bpf_lsm_blob_sizes __ro_after_init = { + .lbs_inode = sizeof(struct bpf_storage_blob), +}; + +DEFINE_LSM(bpf) = { + .id = &bpf_lsmid, + .init = bpf_lsm_init, + .blobs = &bpf_lsm_blob_sizes +}; -- cgit v1.3.1