From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: x86@kernel.org, Andy Lutomirski <luto@kernel.org>,
Linus Torvalds <torvalds@linuxfoundation.org>,
Stephen Hemminger <stephen@networkplumber.org>,
Willy Tarreau <w@1wt.eu>, Juergen Gross <jgross@suse.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: [patch V3 20/20] selftests/x86/iopl: Extend test to cover IOPL emulation
Date: Wed, 13 Nov 2019 21:43:00 +0100 [thread overview]
Message-ID: <20191113210105.671132359@linutronix.de> (raw)
In-Reply-To: 20191113204240.767922595@linutronix.de
From: Thomas Gleixner <tglx@linutronix.de>
Add tests that the now emulated iopl() functionality:
- does not longer allow user space to disable interrupts.
- does restore a I/O bitmap when IOPL is dropped
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
tools/testing/selftests/x86/iopl.c | 129 +++++++++++++++++++++++++++++++++----
1 file changed, 118 insertions(+), 11 deletions(-)
--- a/tools/testing/selftests/x86/iopl.c
+++ b/tools/testing/selftests/x86/iopl.c
@@ -35,6 +35,16 @@ static void sethandler(int sig, void (*h
}
+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)
@@ -42,25 +52,128 @@ static void sigsegv(int sig, siginfo_t *
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);
+}
+
+static bool try_cli(void)
+{
+ sethandler(SIGSEGV, sigsegv, SA_RESETHAND);
+ if (sigsetjmp(jmpbuf, 1) != 0) {
+ return false;
+ } else {
+ asm volatile ("cli");
+ return true;
+ }
+ clearhandler(SIGSEGV);
+}
+
+static bool try_sti(void)
+{
+ sethandler(SIGSEGV, sigsegv, SA_RESETHAND);
+ if (sigsetjmp(jmpbuf, 1) != 0) {
+ return false;
+ } else {
+ asm volatile ("sti");
+ return true;
+ }
+ clearhandler(SIGSEGV);
+}
+
+static void expect_gp_sti(void)
+{
+ if (try_sti()) {
+ printf("[FAIL]\tSTI worked\n");
+ nerrs++;
+ } else {
+ printf("[OK]\tSTI faulted\n");
+ }
+}
+
+static void expect_gp_cli(void)
+{
+ if (try_cli()) {
+ printf("[FAIL]\tCLI worked\n");
+ nerrs++;
+ } else {
+ printf("[OK]\tCLI faulted\n");
+ }
+}
+
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_cli();
+ expect_gp_sti();
+ 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)
err(1, "fork");
@@ -90,14 +203,9 @@ int main(void)
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_cli();
+ expect_gp_sti();
/* Test the capability checks. */
printf("\tiopl(3)\n");
@@ -133,4 +241,3 @@ int main(void)
done:
return nerrs ? 1 : 0;
}
-
next prev parent reply other threads:[~2019-11-13 21:02 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-13 20:42 [patch V3 00/20] x86/iopl: Prevent user space from using CLI/STI with iopl(3) Thomas Gleixner
2019-11-13 20:42 ` [patch V3 01/20] x86/ptrace: Prevent truncation of bitmap size Thomas Gleixner
2019-11-15 21:12 ` [tip: x86/iopl] " tip-bot2 for Thomas Gleixner
2019-11-13 20:42 ` [patch V3 02/20] x86/process: Unify copy_thread_tls() Thomas Gleixner
2019-11-13 21:10 ` Linus Torvalds
2019-11-13 21:41 ` Thomas Gleixner
2019-11-13 22:10 ` Linus Torvalds
2019-11-13 22:33 ` Thomas Gleixner
2019-11-13 21:44 ` Brian Gerst
2019-11-15 21:12 ` [tip: x86/iopl] " tip-bot2 for Thomas Gleixner
2019-11-13 20:42 ` [patch V3 03/20] x86/cpu: Unify cpu_init() Thomas Gleixner
2019-11-15 21:12 ` [tip: x86/iopl] " tip-bot2 for Thomas Gleixner
2019-11-13 20:42 ` [patch V3 04/20] x86/tss: Fix and move VMX BUILD_BUG_ON() Thomas Gleixner
2019-11-15 21:12 ` [tip: x86/iopl] " tip-bot2 for Thomas Gleixner
2019-11-13 20:42 ` [patch V3 05/20] x86/iopl: Cleanup include maze Thomas Gleixner
2019-11-15 21:12 ` [tip: x86/iopl] " tip-bot2 for Thomas Gleixner
2019-11-13 20:42 ` [patch V3 06/20] x86/ioperm: Simplify first ioperm() invocation logic Thomas Gleixner
2019-11-15 21:12 ` [tip: x86/iopl] " tip-bot2 for Thomas Gleixner
2019-11-13 20:42 ` [patch V3 07/20] x86/ioperm: Avoid bitmap allocation if no permissions are set Thomas Gleixner
2019-11-15 21:12 ` [tip: x86/iopl] " tip-bot2 for Thomas Gleixner
2019-11-13 20:42 ` [patch V3 08/20] x86/io: Speedup schedule out of I/O bitmap user Thomas Gleixner
2019-11-15 21:12 ` [tip: x86/iopl] " tip-bot2 for Thomas Gleixner
2019-11-13 20:42 ` [patch V3 09/20] x86/tss: Move I/O bitmap data into a seperate struct Thomas Gleixner
2019-11-15 21:12 ` [tip: x86/iopl] " tip-bot2 for Thomas Gleixner
2019-11-13 20:42 ` [patch V3 10/20] x86/ioperm: Move iobitmap data into a struct Thomas Gleixner
2019-11-15 21:12 ` [tip: x86/iopl] " tip-bot2 for Thomas Gleixner
2019-11-13 20:42 ` [patch V3 11/20] x86/ioperm: Add bitmap sequence number Thomas Gleixner
2019-11-15 21:12 ` [tip: x86/iopl] " tip-bot2 for Thomas Gleixner
2019-11-13 20:42 ` [patch V3 12/20] x86/ioperm: Move TSS bitmap update to exit to user work Thomas Gleixner
2019-11-13 21:19 ` Linus Torvalds
2019-11-13 21:21 ` Linus Torvalds
2019-11-13 21:44 ` Thomas Gleixner
2019-11-15 21:12 ` [tip: x86/iopl] " tip-bot2 for Thomas Gleixner
2019-11-13 20:42 ` [patch V3 13/20] x86/ioperm: Remove bitmap if all permissions dropped Thomas Gleixner
2019-11-15 21:12 ` [tip: x86/iopl] " tip-bot2 for Thomas Gleixner
2019-11-13 20:42 ` [patch V3 14/20] x86/ioperm: Share I/O bitmap if identical Thomas Gleixner
2019-11-15 21:12 ` [tip: x86/iopl] " tip-bot2 for Thomas Gleixner
2019-11-13 20:42 ` [patch V3 15/20] selftests/x86/ioperm: Extend testing so the shared bitmap is exercised Thomas Gleixner
2019-11-15 21:12 ` [tip: x86/iopl] " tip-bot2 for Thomas Gleixner
2019-11-13 20:42 ` [patch V3 16/20] x86/iopl: Fixup misleading comment Thomas Gleixner
2019-11-15 21:12 ` [tip: x86/iopl] " tip-bot2 for Thomas Gleixner
2019-11-13 20:42 ` [patch V3 17/20] x86/iopl: Restrict iopl() permission scope Thomas Gleixner
2019-11-14 18:13 ` Borislav Petkov
2019-11-14 18:39 ` Thomas Gleixner
2019-11-15 21:12 ` [tip: x86/iopl] " tip-bot2 for Thomas Gleixner
2019-11-13 20:42 ` [patch V3 18/20] x86/iopl: Remove legacy IOPL option Thomas Gleixner
2019-11-15 21:12 ` [tip: x86/iopl] " tip-bot2 for Thomas Gleixner
2019-11-13 20:42 ` [patch V3 19/20] x86/ioperm: Extend IOPL config to control ioperm() as well Thomas Gleixner
2019-11-15 21:12 ` [tip: x86/iopl] " tip-bot2 for Thomas Gleixner
2019-11-13 20:43 ` Thomas Gleixner [this message]
2019-11-15 21:12 ` [tip: x86/iopl] selftests/x86/iopl: Extend test to cover IOPL emulation tip-bot2 for Thomas Gleixner
2019-11-14 8:43 ` [patch V3 00/20] x86/iopl: Prevent user space from using CLI/STI with iopl(3) Peter Zijlstra
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