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/mips/bcm63xx/dev-uart.c | 77 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 77 insertions(+) create mode 100644 arch/mips/bcm63xx/dev-uart.c (limited to 'arch/mips/bcm63xx/dev-uart.c') diff --git a/arch/mips/bcm63xx/dev-uart.c b/arch/mips/bcm63xx/dev-uart.c new file mode 100644 index 000000000..5d6bf0445 --- /dev/null +++ b/arch/mips/bcm63xx/dev-uart.c @@ -0,0 +1,77 @@ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 2008 Maxime Bizon + */ + +#include +#include +#include +#include +#include + +static struct resource uart0_resources[] = { + { + /* start & end filled at runtime */ + .flags = IORESOURCE_MEM, + }, + { + /* start filled at runtime */ + .flags = IORESOURCE_IRQ, + }, +}; + +static struct resource uart1_resources[] = { + { + /* start & end filled at runtime */ + .flags = IORESOURCE_MEM, + }, + { + /* start filled at runtime */ + .flags = IORESOURCE_IRQ, + }, +}; + +static struct platform_device bcm63xx_uart_devices[] = { + { + .name = "bcm63xx_uart", + .id = 0, + .num_resources = ARRAY_SIZE(uart0_resources), + .resource = uart0_resources, + }, + + { + .name = "bcm63xx_uart", + .id = 1, + .num_resources = ARRAY_SIZE(uart1_resources), + .resource = uart1_resources, + } +}; + +int __init bcm63xx_uart_register(unsigned int id) +{ + if (id >= ARRAY_SIZE(bcm63xx_uart_devices)) + return -ENODEV; + + if (id == 1 && (!BCMCPU_IS_3368() && !BCMCPU_IS_6358() && + !BCMCPU_IS_6368())) + return -ENODEV; + + if (id == 0) { + uart0_resources[0].start = bcm63xx_regset_address(RSET_UART0); + uart0_resources[0].end = uart0_resources[0].start + + RSET_UART_SIZE - 1; + uart0_resources[1].start = bcm63xx_get_irq_number(IRQ_UART0); + } + + if (id == 1) { + uart1_resources[0].start = bcm63xx_regset_address(RSET_UART1); + uart1_resources[0].end = uart1_resources[0].start + + RSET_UART_SIZE - 1; + uart1_resources[1].start = bcm63xx_get_irq_number(IRQ_UART1); + } + + return platform_device_register(&bcm63xx_uart_devices[id]); +} -- cgit v1.3.1