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 --- include/net/fou.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) create mode 100644 include/net/fou.h (limited to 'include/net/fou.h') diff --git a/include/net/fou.h b/include/net/fou.h new file mode 100644 index 000000000..824eb4b23 --- /dev/null +++ b/include/net/fou.h @@ -0,0 +1,22 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __NET_FOU_H +#define __NET_FOU_H + +#include + +#include +#include +#include +#include + +size_t fou_encap_hlen(struct ip_tunnel_encap *e); +size_t gue_encap_hlen(struct ip_tunnel_encap *e); + +int __fou_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e, + u8 *protocol, __be16 *sport, int type); +int __gue_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e, + u8 *protocol, __be16 *sport, int type); + +int register_fou_bpf(void); + +#endif -- cgit v1.3.1