openrisc: fix arbitrary kernel memory access via or1k_atomic syscallgrafted

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 <ali@iusegentoo.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>

1 files changed, 242 insertions, 0 deletions

diff --git a/drivers/misc/ocxl/trace.h b/drivers/misc/ocxl/trace.h
new file mode 100644
index 000000000..a33a5094f
--- /dev/null
+++ b/drivers/misc/ocxl/trace.h
@@ -0,0 +1,242 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+// Copyright 2017 IBM Corp.
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM ocxl
+
+#if !defined(_TRACE_OCXL_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_OCXL_H
+
+#include <linux/tracepoint.h>
+
+
+TRACE_EVENT(ocxl_mmu_notifier_range,
+	TP_PROTO(unsigned long start, unsigned long end, unsigned long pidr),
+	TP_ARGS(start, end, pidr),
+
+	TP_STRUCT__entry(
+		__field(unsigned long, start)
+		__field(unsigned long, end)
+		__field(unsigned long, pidr)
+	),
+
+	TP_fast_assign(
+		__entry->start = start;
+		__entry->end = end;
+		__entry->pidr = pidr;
+	),
+
+	TP_printk("start=0x%lx end=0x%lx pidr=0x%lx",
+		__entry->start,
+		__entry->end,
+		__entry->pidr
+	)
+);
+
+TRACE_EVENT(ocxl_init_mmu_notifier,
+	TP_PROTO(int pasid, unsigned long pidr),
+	TP_ARGS(pasid, pidr),
+
+	TP_STRUCT__entry(
+		__field(int, pasid)
+		__field(unsigned long, pidr)
+	),
+
+	TP_fast_assign(
+		__entry->pasid = pasid;
+		__entry->pidr = pidr;
+	),
+
+	TP_printk("pasid=%d, pidr=0x%lx",
+		__entry->pasid,
+		__entry->pidr
+	)
+);
+
+TRACE_EVENT(ocxl_release_mmu_notifier,
+	TP_PROTO(int pasid, unsigned long pidr),
+	TP_ARGS(pasid, pidr),
+
+	TP_STRUCT__entry(
+		__field(int, pasid)
+		__field(unsigned long, pidr)
+	),
+
+	TP_fast_assign(
+		__entry->pasid = pasid;
+		__entry->pidr = pidr;
+	),
+
+	TP_printk("pasid=%d, pidr=0x%lx",
+		__entry->pasid,
+		__entry->pidr
+	)
+);
+
+DECLARE_EVENT_CLASS(ocxl_context,
+	TP_PROTO(pid_t pid, void *spa, int pasid, u32 pidr, u32 tidr),
+	TP_ARGS(pid, spa, pasid, pidr, tidr),
+
+	TP_STRUCT__entry(
+		__field(pid_t, pid)
+		__field(void*, spa)
+		__field(int, pasid)
+		__field(u32, pidr)
+		__field(u32, tidr)
+	),
+
+	TP_fast_assign(
+		__entry->pid = pid;
+		__entry->spa = spa;
+		__entry->pasid = pasid;
+		__entry->pidr = pidr;
+		__entry->tidr = tidr;
+	),
+
+	TP_printk("linux pid=%d spa=0x%p pasid=0x%x pidr=0x%x tidr=0x%x",
+		__entry->pid,
+		__entry->spa,
+		__entry->pasid,
+		__entry->pidr,
+		__entry->tidr
+	)
+);
+
+DEFINE_EVENT(ocxl_context, ocxl_context_add,
+	TP_PROTO(pid_t pid, void *spa, int pasid, u32 pidr, u32 tidr),
+	TP_ARGS(pid, spa, pasid, pidr, tidr)
+);
+
+DEFINE_EVENT(ocxl_context, ocxl_context_remove,
+	TP_PROTO(pid_t pid, void *spa, int pasid, u32 pidr, u32 tidr),
+	TP_ARGS(pid, spa, pasid, pidr, tidr)
+);
+
+TRACE_EVENT(ocxl_terminate_pasid,
+	TP_PROTO(int pasid, int rc),
+	TP_ARGS(pasid, rc),
+
+	TP_STRUCT__entry(
+		__field(int, pasid)
+		__field(int, rc)
+	),
+
+	TP_fast_assign(
+		__entry->pasid = pasid;
+		__entry->rc = rc;
+	),
+
+	TP_printk("pasid=0x%x rc=%d",
+		__entry->pasid,
+		__entry->rc
+	)
+);
+
+DECLARE_EVENT_CLASS(ocxl_fault_handler,
+	TP_PROTO(void *spa, u64 pe, u64 dsisr, u64 dar, u64 tfc),
+	TP_ARGS(spa, pe, dsisr, dar, tfc),
+
+	TP_STRUCT__entry(
+		__field(void *, spa)
+		__field(u64, pe)
+		__field(u64, dsisr)
+		__field(u64, dar)
+		__field(u64, tfc)
+	),
+
+	TP_fast_assign(
+		__entry->spa = spa;
+		__entry->pe = pe;
+		__entry->dsisr = dsisr;
+		__entry->dar = dar;
+		__entry->tfc = tfc;
+	),
+
+	TP_printk("spa=%p pe=0x%llx dsisr=0x%llx dar=0x%llx tfc=0x%llx",
+		__entry->spa,
+		__entry->pe,
+		__entry->dsisr,
+		__entry->dar,
+		__entry->tfc
+	)
+);
+
+DEFINE_EVENT(ocxl_fault_handler, ocxl_fault,
+	TP_PROTO(void *spa, u64 pe, u64 dsisr, u64 dar, u64 tfc),
+	TP_ARGS(spa, pe, dsisr, dar, tfc)
+);
+
+DEFINE_EVENT(ocxl_fault_handler, ocxl_fault_ack,
+	TP_PROTO(void *spa, u64 pe, u64 dsisr, u64 dar, u64 tfc),
+	TP_ARGS(spa, pe, dsisr, dar, tfc)
+);
+
+TRACE_EVENT(ocxl_afu_irq_alloc,
+	TP_PROTO(int pasid, int irq_id, unsigned int virq, int hw_irq),
+	TP_ARGS(pasid, irq_id, virq, hw_irq),
+
+	TP_STRUCT__entry(
+		__field(int, pasid)
+		__field(int, irq_id)
+		__field(unsigned int, virq)
+		__field(int, hw_irq)
+	),
+
+	TP_fast_assign(
+		__entry->pasid = pasid;
+		__entry->irq_id = irq_id;
+		__entry->virq = virq;
+		__entry->hw_irq = hw_irq;
+	),
+
+	TP_printk("pasid=0x%x irq_id=%d virq=%u hw_irq=%d",
+		__entry->pasid,
+		__entry->irq_id,
+		__entry->virq,
+		__entry->hw_irq
+	)
+);
+
+TRACE_EVENT(ocxl_afu_irq_free,
+	TP_PROTO(int pasid, int irq_id),
+	TP_ARGS(pasid, irq_id),
+
+	TP_STRUCT__entry(
+		__field(int, pasid)
+		__field(int, irq_id)
+	),
+
+	TP_fast_assign(
+		__entry->pasid = pasid;
+		__entry->irq_id = irq_id;
+	),
+
+	TP_printk("pasid=0x%x irq_id=%d",
+		__entry->pasid,
+		__entry->irq_id
+	)
+);
+
+TRACE_EVENT(ocxl_afu_irq_receive,
+	TP_PROTO(int virq),
+	TP_ARGS(virq),
+
+	TP_STRUCT__entry(
+		__field(int, virq)
+	),
+
+	TP_fast_assign(
+		__entry->virq = virq;
+	),
+
+	TP_printk("virq=%d",
+		__entry->virq
+	)
+);
+
+#endif /* _TRACE_OCXL_H */
+
+/* This part must be outside protection */
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+#define TRACE_INCLUDE_FILE trace
+#include <trace/define_trace.h>