From 05e59e5fb0064c97a1c10921ecd549f2d4a58565 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Wed, 09 Oct 2024 06:14:40 +0000
Subject: [PATCH] add REDIRECT
---
kernel/tools/testing/selftests/x86/iopl.c | 167 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
1 files changed, 156 insertions(+), 11 deletions(-)
diff --git a/kernel/tools/testing/selftests/x86/iopl.c b/kernel/tools/testing/selftests/x86/iopl.c
index 6aa27f3..7e3e09c 100644
--- a/kernel/tools/testing/selftests/x86/iopl.c
+++ b/kernel/tools/testing/selftests/x86/iopl.c
@@ -35,6 +35,16 @@
}
+static void clearhandler(int sig)
+{
+ struct sigaction sa;
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_handler = SIG_DFL;
+ sigemptyset(&sa.sa_mask);
+ if (sigaction(sig, &sa, 0))
+ err(1, "sigaction");
+}
+
static jmp_buf jmpbuf;
static void sigsegv(int sig, siginfo_t *si, void *ctx_void)
@@ -42,24 +52,166 @@
siglongjmp(jmpbuf, 1);
}
+static bool try_outb(unsigned short port)
+{
+ sethandler(SIGSEGV, sigsegv, SA_RESETHAND);
+ if (sigsetjmp(jmpbuf, 1) != 0) {
+ return false;
+ } else {
+ asm volatile ("outb %%al, %w[port]"
+ : : [port] "Nd" (port), "a" (0));
+ return true;
+ }
+ clearhandler(SIGSEGV);
+}
+
+static void expect_ok_outb(unsigned short port)
+{
+ if (!try_outb(port)) {
+ printf("[FAIL]\toutb to 0x%02hx failed\n", port);
+ exit(1);
+ }
+
+ printf("[OK]\toutb to 0x%02hx worked\n", port);
+}
+
+static void expect_gp_outb(unsigned short port)
+{
+ if (try_outb(port)) {
+ printf("[FAIL]\toutb to 0x%02hx worked\n", port);
+ nerrs++;
+ }
+
+ printf("[OK]\toutb to 0x%02hx failed\n", port);
+}
+
+#define RET_FAULTED 0
+#define RET_FAIL 1
+#define RET_EMUL 2
+
+static int try_cli(void)
+{
+ unsigned long flags;
+
+ sethandler(SIGSEGV, sigsegv, SA_RESETHAND);
+ if (sigsetjmp(jmpbuf, 1) != 0) {
+ return RET_FAULTED;
+ } else {
+ asm volatile("cli; pushf; pop %[flags]"
+ : [flags] "=rm" (flags));
+
+ /* X86_FLAGS_IF */
+ if (!(flags & (1 << 9)))
+ return RET_FAIL;
+ else
+ return RET_EMUL;
+ }
+ clearhandler(SIGSEGV);
+}
+
+static int try_sti(bool irqs_off)
+{
+ unsigned long flags;
+
+ sethandler(SIGSEGV, sigsegv, SA_RESETHAND);
+ if (sigsetjmp(jmpbuf, 1) != 0) {
+ return RET_FAULTED;
+ } else {
+ asm volatile("sti; pushf; pop %[flags]"
+ : [flags] "=rm" (flags));
+
+ /* X86_FLAGS_IF */
+ if (irqs_off && (flags & (1 << 9)))
+ return RET_FAIL;
+ else
+ return RET_EMUL;
+ }
+ clearhandler(SIGSEGV);
+}
+
+static void expect_gp_sti(bool irqs_off)
+{
+ int ret = try_sti(irqs_off);
+
+ switch (ret) {
+ case RET_FAULTED:
+ printf("[OK]\tSTI faulted\n");
+ break;
+ case RET_EMUL:
+ printf("[OK]\tSTI NOPped\n");
+ break;
+ default:
+ printf("[FAIL]\tSTI worked\n");
+ nerrs++;
+ }
+}
+
+/*
+ * Returns whether it managed to disable interrupts.
+ */
+static bool test_cli(void)
+{
+ int ret = try_cli();
+
+ switch (ret) {
+ case RET_FAULTED:
+ printf("[OK]\tCLI faulted\n");
+ break;
+ case RET_EMUL:
+ printf("[OK]\tCLI NOPped\n");
+ break;
+ default:
+ printf("[FAIL]\tCLI worked\n");
+ nerrs++;
+ return true;
+ }
+
+ return false;
+}
+
int main(void)
{
cpu_set_t cpuset;
+
CPU_ZERO(&cpuset);
CPU_SET(0, &cpuset);
if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0)
err(1, "sched_setaffinity to CPU 0");
/* Probe for iopl support. Note that iopl(0) works even as nonroot. */
- if (iopl(3) != 0) {
+ switch(iopl(3)) {
+ case 0:
+ break;
+ case -ENOSYS:
+ printf("[OK]\tiopl() nor supported\n");
+ return 0;
+ default:
printf("[OK]\tiopl(3) failed (%d) -- try running as root\n",
errno);
return 0;
}
- /* Restore our original state prior to starting the test. */
+ /* Make sure that CLI/STI are blocked even with IOPL level 3 */
+ expect_gp_sti(test_cli());
+ expect_ok_outb(0x80);
+
+ /* Establish an I/O bitmap to test the restore */
+ if (ioperm(0x80, 1, 1) != 0)
+ err(1, "ioperm(0x80, 1, 1) failed\n");
+
+ /* Restore our original state prior to starting the fork test. */
if (iopl(0) != 0)
err(1, "iopl(0)");
+
+ /*
+ * Verify that IOPL emulation is disabled and the I/O bitmap still
+ * works.
+ */
+ expect_ok_outb(0x80);
+ expect_gp_outb(0xed);
+ /* Drop the I/O bitmap */
+ if (ioperm(0x80, 1, 0) != 0)
+ err(1, "ioperm(0x80, 1, 0) failed\n");
pid_t child = fork();
if (child == -1)
@@ -90,14 +242,8 @@
printf("[RUN]\tparent: write to 0x80 (should fail)\n");
- sethandler(SIGSEGV, sigsegv, 0);
- if (sigsetjmp(jmpbuf, 1) != 0) {
- printf("[OK]\twrite was denied\n");
- } else {
- asm volatile ("outb %%al, $0x80" : : "a" (0));
- printf("[FAIL]\twrite was allowed\n");
- nerrs++;
- }
+ expect_gp_outb(0x80);
+ expect_gp_sti(test_cli());
/* Test the capability checks. */
printf("\tiopl(3)\n");
@@ -133,4 +279,3 @@
done:
return nerrs ? 1 : 0;
}
-
--
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