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/evswitch.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) create mode 100644 tools/perf/util/evswitch.c (limited to 'tools/perf/util/evswitch.c') diff --git a/tools/perf/util/evswitch.c b/tools/perf/util/evswitch.c new file mode 100644 index 000000000..d4c06a3f8 --- /dev/null +++ b/tools/perf/util/evswitch.c @@ -0,0 +1,62 @@ +// SPDX-License-Identifier: GPL-2.0-only +// Copyright (C) 2019, Red Hat Inc, Arnaldo Carvalho de Melo + +#include +#include "evswitch.h" +#include "evlist.h" + +bool evswitch__discard(struct evswitch *evswitch, struct evsel *evsel) +{ + if (evswitch->on && evswitch->discarding) { + if (evswitch->on != evsel) + return true; + + evswitch->discarding = false; + + if (!evswitch->show_on_off_events) + return true; + + return false; + } + + if (evswitch->off && !evswitch->discarding) { + if (evswitch->off != evsel) + return false; + + evswitch->discarding = true; + + if (!evswitch->show_on_off_events) + return true; + } + + return false; +} + +static int evswitch__fprintf_enoent(FILE *fp, const char *evtype, const char *evname) +{ + int printed = fprintf(fp, "ERROR: switch-%s event not found (%s)\n", evtype, evname); + + return printed += fprintf(fp, "HINT: use 'perf evlist' to see the available event names\n"); +} + +int evswitch__init(struct evswitch *evswitch, struct evlist *evlist, FILE *fp) +{ + if (evswitch->on_name) { + evswitch->on = evlist__find_evsel_by_str(evlist, evswitch->on_name); + if (evswitch->on == NULL) { + evswitch__fprintf_enoent(fp, "on", evswitch->on_name); + return -ENOENT; + } + evswitch->discarding = true; + } + + if (evswitch->off_name) { + evswitch->off = evlist__find_evsel_by_str(evlist, evswitch->off_name); + if (evswitch->off == NULL) { + evswitch__fprintf_enoent(fp, "off", evswitch->off_name); + return -ENOENT; + } + } + + return 0; +} -- cgit v1.3.1