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 --- tools/perf/util/trigger.h | 95 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 95 insertions(+) create mode 100644 tools/perf/util/trigger.h (limited to 'tools/perf/util/trigger.h') diff --git a/tools/perf/util/trigger.h b/tools/perf/util/trigger.h new file mode 100644 index 000000000..33e997f9c --- /dev/null +++ b/tools/perf/util/trigger.h @@ -0,0 +1,95 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __TRIGGER_H_ +#define __TRIGGER_H_ 1 + +#include "asm/bug.h" + +/* + * Use trigger to model operations which need to be executed when + * an event (a signal, for example) is observed. + * + * States and transits: + * + * + * OFF--> ON --> READY --(hit)--> HIT + * ^ | + * | (ready) + * | | + * \_____________/ + * + * is_hit and is_ready are two key functions to query the state of + * a trigger. is_hit means the event already happen; is_ready means the + * trigger is waiting for the event. + */ + +struct trigger { + volatile enum { + TRIGGER_ERROR = -2, + TRIGGER_OFF = -1, + TRIGGER_ON = 0, + TRIGGER_READY = 1, + TRIGGER_HIT = 2, + } state; + const char *name; +}; + +#define TRIGGER_WARN_ONCE(t, exp) \ + WARN_ONCE(t->state != exp, "trigger '%s' state transist error: %d in %s()\n", \ + t->name, t->state, __func__) + +static inline bool trigger_is_available(struct trigger *t) +{ + return t->state >= 0; +} + +static inline bool trigger_is_error(struct trigger *t) +{ + return t->state <= TRIGGER_ERROR; +} + +static inline void trigger_on(struct trigger *t) +{ + TRIGGER_WARN_ONCE(t, TRIGGER_OFF); + t->state = TRIGGER_ON; +} + +static inline void trigger_ready(struct trigger *t) +{ + if (!trigger_is_available(t)) + return; + t->state = TRIGGER_READY; +} + +static inline void trigger_hit(struct trigger *t) +{ + if (!trigger_is_available(t)) + return; + TRIGGER_WARN_ONCE(t, TRIGGER_READY); + t->state = TRIGGER_HIT; +} + +static inline void trigger_off(struct trigger *t) +{ + if (!trigger_is_available(t)) + return; + t->state = TRIGGER_OFF; +} + +static inline void trigger_error(struct trigger *t) +{ + t->state = TRIGGER_ERROR; +} + +static inline bool trigger_is_ready(struct trigger *t) +{ + return t->state == TRIGGER_READY; +} + +static inline bool trigger_is_hit(struct trigger *t) +{ + return t->state == TRIGGER_HIT; +} + +#define DEFINE_TRIGGER(n) \ +struct trigger n = {.state = TRIGGER_OFF, .name = #n} +#endif -- cgit v1.3.1