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 --- arch/arm/mach-s3c/dev-uart.c | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 arch/arm/mach-s3c/dev-uart.c (limited to 'arch/arm/mach-s3c/dev-uart.c') diff --git a/arch/arm/mach-s3c/dev-uart.c b/arch/arm/mach-s3c/dev-uart.c new file mode 100644 index 000000000..3d1f7f2fd --- /dev/null +++ b/arch/arm/mach-s3c/dev-uart.c @@ -0,0 +1,41 @@ +// SPDX-License-Identifier: GPL-2.0 +// +// originally from arch/arm/plat-s3c24xx/devs.c +// +// Copyright (c) 2004 Simtec Electronics +// Ben Dooks +// +// Base S3C24XX platform device definitions + +#include +#include + +#include "devs.h" + +/* uart devices */ + +static struct platform_device s3c24xx_uart_device0 = { + .id = 0, +}; + +static struct platform_device s3c24xx_uart_device1 = { + .id = 1, +}; + +static struct platform_device s3c24xx_uart_device2 = { + .id = 2, +}; + +static struct platform_device s3c24xx_uart_device3 = { + .id = 3, +}; + +struct platform_device *s3c24xx_uart_src[4] = { + &s3c24xx_uart_device0, + &s3c24xx_uart_device1, + &s3c24xx_uart_device2, + &s3c24xx_uart_device3, +}; + +struct platform_device *s3c24xx_uart_devs[4] = { +}; -- cgit v1.3.1