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 --- drivers/gpu/host1x/debug.h | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 drivers/gpu/host1x/debug.h (limited to 'drivers/gpu/host1x/debug.h') diff --git a/drivers/gpu/host1x/debug.h b/drivers/gpu/host1x/debug.h new file mode 100644 index 000000000..c43c61d87 --- /dev/null +++ b/drivers/gpu/host1x/debug.h @@ -0,0 +1,45 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Tegra host1x Debug + * + * Copyright (c) 2011-2013 NVIDIA Corporation. + */ +#ifndef __HOST1X_DEBUG_H +#define __HOST1X_DEBUG_H + +#include +#include + +struct host1x; + +struct output { + void (*fn)(void *ctx, const char *str, size_t len, bool cont); + void *ctx; + char buf[256]; +}; + +static inline void write_to_seqfile(void *ctx, const char *str, size_t len, + bool cont) +{ + seq_write((struct seq_file *)ctx, str, len); +} + +static inline void write_to_printk(void *ctx, const char *str, size_t len, + bool cont) +{ + if (cont) + pr_cont("%s", str); + else + pr_info("%s", str); +} + +void __printf(2, 3) host1x_debug_output(struct output *o, const char *fmt, ...); +void __printf(2, 3) host1x_debug_cont(struct output *o, const char *fmt, ...); + +extern unsigned int host1x_debug_trace_cmdbuf; + +void host1x_debug_init(struct host1x *host1x); +void host1x_debug_deinit(struct host1x *host1x); +void host1x_debug_dump(struct host1x *host1x); + +#endif -- cgit v1.3.1