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/trace/events/rseq.h | 62 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) create mode 100644 include/trace/events/rseq.h (limited to 'include/trace/events/rseq.h') diff --git a/include/trace/events/rseq.h b/include/trace/events/rseq.h new file mode 100644 index 000000000..ce85d650b --- /dev/null +++ b/include/trace/events/rseq.h @@ -0,0 +1,62 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM rseq + +#if !defined(_TRACE_RSEQ_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_RSEQ_H + +#include +#include + +TRACE_EVENT(rseq_update, + + TP_PROTO(struct task_struct *t), + + TP_ARGS(t), + + TP_STRUCT__entry( + __field(s32, cpu_id) + __field(s32, node_id) + __field(s32, mm_cid) + ), + + TP_fast_assign( + __entry->cpu_id = t->rseq.ids.cpu_id; + __entry->node_id = cpu_to_node(__entry->cpu_id); + __entry->mm_cid = t->rseq.ids.mm_cid; + ), + + TP_printk("cpu_id=%d node_id=%d mm_cid=%d", __entry->cpu_id, + __entry->node_id, __entry->mm_cid) +); + +TRACE_EVENT(rseq_ip_fixup, + + TP_PROTO(unsigned long regs_ip, unsigned long start_ip, + unsigned long post_commit_offset, unsigned long abort_ip), + + TP_ARGS(regs_ip, start_ip, post_commit_offset, abort_ip), + + TP_STRUCT__entry( + __field(unsigned long, regs_ip) + __field(unsigned long, start_ip) + __field(unsigned long, post_commit_offset) + __field(unsigned long, abort_ip) + ), + + TP_fast_assign( + __entry->regs_ip = regs_ip; + __entry->start_ip = start_ip; + __entry->post_commit_offset = post_commit_offset; + __entry->abort_ip = abort_ip; + ), + + TP_printk("regs_ip=0x%lx start_ip=0x%lx post_commit_offset=%lu abort_ip=0x%lx", + __entry->regs_ip, __entry->start_ip, + __entry->post_commit_offset, __entry->abort_ip) +); + +#endif /* _TRACE_SOCK_H */ + +/* This part must be outside protection */ +#include -- cgit v1.3.1