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/tracepoint.c | 52 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 tools/perf/util/tracepoint.c (limited to 'tools/perf/util/tracepoint.c') diff --git a/tools/perf/util/tracepoint.c b/tools/perf/util/tracepoint.c new file mode 100644 index 000000000..95377ed5d --- /dev/null +++ b/tools/perf/util/tracepoint.c @@ -0,0 +1,52 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "tracepoint.h" + +#include +#include +#include +#include +#include +#include + +#include +#include "fncache.h" + +int tp_event_has_id(const char *dir_path, struct dirent *evt_dir) +{ + char evt_path[MAXPATHLEN]; + int fd; + + snprintf(evt_path, MAXPATHLEN, "%s/%s/id", dir_path, evt_dir->d_name); + fd = open(evt_path, O_RDONLY); + if (fd < 0) + return -EINVAL; + close(fd); + + return 0; +} + +/* + * Check whether event is in /tracing/events + */ +bool is_valid_tracepoint(const char *event_string) +{ + char *dst, *path = malloc(strlen(event_string) + 4); /* Space for "/id\0". */ + bool have_file = false; /* Conservatively return false if memory allocation failed. */ + const char *src; + + if (!path) + return false; + + /* Copy event_string replacing the ':' with '/'. */ + for (src = event_string, dst = path; *src; src++, dst++) + *dst = (*src == ':') ? '/' : *src; + /* Add "/id\0". */ + memcpy(dst, "/id", 4); + + dst = get_events_file(path); + if (dst) + have_file = file_available(dst); + free(dst); + free(path); + return have_file; +} -- cgit v1.3.1