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/timer-sp.h | 63 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) create mode 100644 drivers/clocksource/timer-sp.h (limited to 'drivers/clocksource/timer-sp.h') diff --git a/drivers/clocksource/timer-sp.h b/drivers/clocksource/timer-sp.h new file mode 100644 index 000000000..811f840be --- /dev/null +++ b/drivers/clocksource/timer-sp.h @@ -0,0 +1,63 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * ARM timer implementation, found in Integrator, Versatile and Realview + * platforms. Not all platforms support all registers and bits in these + * registers, so we mark them with A for Integrator AP, C for Integrator + * CP, V for Versatile and R for Realview. + * + * Integrator AP has 16-bit timers, Integrator CP, Versatile and Realview + * can have 16-bit or 32-bit selectable via a bit in the control register. + * + * Every SP804 contains two identical timers. + */ +#define NR_TIMERS 2 +#define TIMER_1_BASE 0x00 +#define TIMER_2_BASE 0x20 + +#define TIMER_LOAD 0x00 /* ACVR rw */ +#define TIMER_VALUE 0x04 /* ACVR ro */ +#define TIMER_CTRL 0x08 /* ACVR rw */ +#define TIMER_CTRL_ONESHOT (1 << 0) /* CVR */ +#define TIMER_CTRL_32BIT (1 << 1) /* CVR */ +#define TIMER_CTRL_DIV1 (0 << 2) /* ACVR */ +#define TIMER_CTRL_DIV16 (1 << 2) /* ACVR */ +#define TIMER_CTRL_DIV256 (2 << 2) /* ACVR */ +#define TIMER_CTRL_IE (1 << 5) /* VR */ +#define TIMER_CTRL_PERIODIC (1 << 6) /* ACVR */ +#define TIMER_CTRL_ENABLE (1 << 7) /* ACVR */ + +#define TIMER_INTCLR 0x0c /* ACVR wo */ +#define TIMER_RIS 0x10 /* CVR ro */ +#define TIMER_MIS 0x14 /* CVR ro */ +#define TIMER_BGLOAD 0x18 /* CVR rw */ + +struct sp804_timer { + int load; + int load_h; + int value; + int value_h; + int ctrl; + int intclr; + int ris; + int mis; + int bgload; + int bgload_h; + int timer_base[NR_TIMERS]; + int width; +}; + +struct sp804_clkevt { + void __iomem *base; + void __iomem *load; + void __iomem *load_h; + void __iomem *value; + void __iomem *value_h; + void __iomem *ctrl; + void __iomem *intclr; + void __iomem *ris; + void __iomem *mis; + void __iomem *bgload; + void __iomem *bgload_h; + unsigned long reload; + int width; +}; -- cgit v1.3.1