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/clocksource/clps711x-timer.c | 110 +++++++++++++++++++++++++++++++++++ 1 file changed, 110 insertions(+) create mode 100644 drivers/clocksource/clps711x-timer.c (limited to 'drivers/clocksource/clps711x-timer.c') diff --git a/drivers/clocksource/clps711x-timer.c b/drivers/clocksource/clps711x-timer.c new file mode 100644 index 000000000..bb0a44ada --- /dev/null +++ b/drivers/clocksource/clps711x-timer.c @@ -0,0 +1,110 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Cirrus Logic CLPS711X clocksource driver + * + * Copyright (C) 2014 Alexander Shiyan + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +enum { + CLPS711X_CLKSRC_CLOCKSOURCE, + CLPS711X_CLKSRC_CLOCKEVENT, +}; + +static void __iomem *tcd; + +static u64 notrace clps711x_sched_clock_read(void) +{ + return ~readw(tcd); +} + +static void __init clps711x_clksrc_init(struct clk *clock, void __iomem *base) +{ + unsigned long rate = clk_get_rate(clock); + + tcd = base; + + clocksource_mmio_init(tcd, "clps711x-clocksource", rate, 300, 16, + clocksource_mmio_readw_down); + + sched_clock_register(clps711x_sched_clock_read, 16, rate); +} + +static irqreturn_t clps711x_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = dev_id; + + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +static int __init _clps711x_clkevt_init(struct clk *clock, void __iomem *base, + unsigned int irq) +{ + struct clock_event_device *clkevt; + unsigned long rate; + + clkevt = kzalloc_obj(*clkevt); + if (!clkevt) + return -ENOMEM; + + rate = clk_get_rate(clock); + + /* Set Timer prescaler */ + writew(DIV_ROUND_CLOSEST(rate, HZ), base); + + clkevt->name = "clps711x-clockevent"; + clkevt->rating = 300; + clkevt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_C3STOP; + clkevt->cpumask = cpumask_of(0); + clockevents_config_and_register(clkevt, HZ, 0, 0); + + return request_irq(irq, clps711x_timer_interrupt, IRQF_TIMER, + "clps711x-timer", clkevt); +} + +static int __init clps711x_timer_init(struct device_node *np) +{ + unsigned int irq = irq_of_parse_and_map(np, 0); + struct clk *clock = of_clk_get(np, 0); + void __iomem *base = of_iomap(np, 0); + int ret = 0; + + if (!base) + return -ENOMEM; + if (!irq) { + ret = -EINVAL; + goto unmap_io; + } + if (IS_ERR(clock)) { + ret = PTR_ERR(clock); + goto unmap_io; + } + + switch (of_alias_get_id(np, "timer")) { + case CLPS711X_CLKSRC_CLOCKSOURCE: + clps711x_clksrc_init(clock, base); + break; + case CLPS711X_CLKSRC_CLOCKEVENT: + ret = _clps711x_clkevt_init(clock, base, irq); + break; + default: + ret = -EINVAL; + break; + } + +unmap_io: + iounmap(base); + return ret; +} +TIMER_OF_DECLARE(clps711x, "cirrus,ep7209-timer", clps711x_timer_init); -- cgit v1.3.1