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 --- lib/trace_readwrite.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 lib/trace_readwrite.c (limited to 'lib/trace_readwrite.c') diff --git a/lib/trace_readwrite.c b/lib/trace_readwrite.c new file mode 100644 index 000000000..a94cd56a1 --- /dev/null +++ b/lib/trace_readwrite.c @@ -0,0 +1,47 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Register read and write tracepoints + * + * Copyright (c) 2021-2022 Qualcomm Innovation Center, Inc. All rights reserved. + */ + +#include +#include +#include + +#define CREATE_TRACE_POINTS +#include + +#ifdef CONFIG_TRACE_MMIO_ACCESS +void log_write_mmio(u64 val, u8 width, volatile void __iomem *addr, + unsigned long caller_addr, unsigned long caller_addr0) +{ + trace_rwmmio_write(caller_addr, caller_addr0, val, width, addr); +} +EXPORT_SYMBOL_GPL(log_write_mmio); +EXPORT_TRACEPOINT_SYMBOL_GPL(rwmmio_write); + +void log_post_write_mmio(u64 val, u8 width, volatile void __iomem *addr, + unsigned long caller_addr, unsigned long caller_addr0) +{ + trace_rwmmio_post_write(caller_addr, caller_addr0, val, width, addr); +} +EXPORT_SYMBOL_GPL(log_post_write_mmio); +EXPORT_TRACEPOINT_SYMBOL_GPL(rwmmio_post_write); + +void log_read_mmio(u8 width, const volatile void __iomem *addr, + unsigned long caller_addr, unsigned long caller_addr0) +{ + trace_rwmmio_read(caller_addr, caller_addr0, width, addr); +} +EXPORT_SYMBOL_GPL(log_read_mmio); +EXPORT_TRACEPOINT_SYMBOL_GPL(rwmmio_read); + +void log_post_read_mmio(u64 val, u8 width, const volatile void __iomem *addr, + unsigned long caller_addr, unsigned long caller_addr0) +{ + trace_rwmmio_post_read(caller_addr, caller_addr0, val, width, addr); +} +EXPORT_SYMBOL_GPL(log_post_read_mmio); +EXPORT_TRACEPOINT_SYMBOL_GPL(rwmmio_post_read); +#endif /* CONFIG_TRACE_MMIO_ACCESS */ -- cgit v1.3.1