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/unwind.h | 85 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 85 insertions(+) create mode 100644 tools/perf/util/unwind.h (limited to 'tools/perf/util/unwind.h') diff --git a/tools/perf/util/unwind.h b/tools/perf/util/unwind.h new file mode 100644 index 000000000..a2d4af694 --- /dev/null +++ b/tools/perf/util/unwind.h @@ -0,0 +1,85 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __UNWIND_H +#define __UNWIND_H + +#include +#include +#include +#include "map_symbol.h" + +struct maps; +struct option; +struct perf_sample; +struct thread; + +struct unwind_entry { + struct map_symbol ms; + u64 ip; +}; + +typedef int (*unwind_entry_cb_t)(struct unwind_entry *entry, void *arg); + +int unwind__configure(const char *var, const char *value, void *cb); +int unwind__option(const struct option *opt, const char *arg, int unset); + +/* + * When best_effort is set, don't report errors and fail silently. This could + * be expanded in the future to be more permissive about things other than + * error messages. + */ +int unwind__get_entries(unwind_entry_cb_t cb, void *arg, + struct thread *thread, + struct perf_sample *data, int max_stack, + bool best_effort); + +#ifdef HAVE_LIBDW_SUPPORT +int libdw__get_entries(unwind_entry_cb_t cb, void *arg, + struct thread *thread, + struct perf_sample *data, int max_stack, + bool best_effort); +#else +#include "debug.h" +static inline int libdw__get_entries(unwind_entry_cb_t cb __maybe_unused, void *arg __maybe_unused, + struct thread *thread __maybe_unused, + struct perf_sample *data __maybe_unused, + int max_stack __maybe_unused, + bool best_effort __maybe_unused) +{ + pr_warning_once("Error: libdw dwarf unwinding not built into perf\n"); + return 0; +} +#endif + +#ifdef HAVE_LIBUNWIND_SUPPORT +/* libunwind specific */ +int libunwind__get_entries(unwind_entry_cb_t cb, void *arg, + struct thread *thread, + struct perf_sample *data, int max_stack, + bool best_effort); +int unwind__prepare_access(struct maps *maps, uint16_t e_machine); +void unwind__flush_access(struct maps *maps); +void unwind__finish_access(struct maps *maps); +#else +#include "debug.h" +static inline int libunwind__get_entries(unwind_entry_cb_t cb __maybe_unused, + void *arg __maybe_unused, + struct thread *thread __maybe_unused, + struct perf_sample *data __maybe_unused, + int max_stack __maybe_unused, + bool best_effort __maybe_unused) +{ + pr_warning_once("Error: libunwind dwarf unwinding not built into perf\n"); + return 0; +} + +static inline int unwind__prepare_access(struct maps *maps __maybe_unused, + uint16_t e_machine __maybe_unused) +{ + return 0; +} + +static inline void unwind__flush_access(struct maps *maps __maybe_unused) {} +static inline void unwind__finish_access(struct maps *maps __maybe_unused) {} +#endif + +#endif /* __UNWIND_H */ -- cgit v1.3.1