From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: x86@kernel.org, Stephen Hemminger <stephen@networkplumber.org>,
Willy Tarreau <w@1wt.eu>, Juergen Gross <jgross@suse.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: [patch 9/9] selftests/x86/iopl: Verify that CLI/STI result in #GP
Date: Wed, 06 Nov 2019 20:35:08 +0100 [thread overview]
Message-ID: <20191106202806.611930277@linutronix.de> (raw)
In-Reply-To: 20191106193459.581614484@linutronix.de
Add tests that the now emulated iopl() functionality does not longer
allow user space to disable interrupts.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
tools/testing/selftests/x86/iopl.c | 104 +++++++++++++++++++++++++++++++++----
1 file changed, 93 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)
@@ -42,22 +52,100 @@ 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_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();
+
+ /* Restore our original state prior to starting the fork test. */
if (iopl(0) != 0)
err(1, "iopl(0)");
@@ -90,14 +178,9 @@ 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 +216,3 @@ int main(void)
done:
return nerrs ? 1 : 0;
}
-
next prev parent reply other threads:[~2019-11-06 20:57 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-06 19:34 [patch 0/9] x86/iopl: Prevent user space from using CLI/STI with iopl(3) Thomas Gleixner
2019-11-06 19:35 ` [patch 1/9] x86/ptrace: Prevent truncation of bitmap size Thomas Gleixner
2019-11-07 7:31 ` Ingo Molnar
2019-11-06 19:35 ` [patch 2/9] x86/process: Unify copy_thread_tls() Thomas Gleixner
2019-11-08 22:31 ` Andy Lutomirski
2019-11-08 23:43 ` Thomas Gleixner
2019-11-10 12:36 ` Thomas Gleixner
2019-11-10 16:56 ` Andy Lutomirski
2019-11-11 8:52 ` Peter Zijlstra
2019-11-06 19:35 ` [patch 3/9] x86/cpu: Unify cpu_init() Thomas Gleixner
2019-11-08 22:34 ` Andy Lutomirski
2019-11-06 19:35 ` [patch 4/9] x86/io: Speedup schedule out of I/O bitmap user Thomas Gleixner
2019-11-07 9:12 ` Peter Zijlstra
2019-11-07 14:04 ` Thomas Gleixner
2019-11-07 14:08 ` Thomas Gleixner
2019-11-08 22:41 ` Andy Lutomirski
2019-11-08 23:45 ` Thomas Gleixner
2019-11-09 3:32 ` Andy Lutomirski
2019-11-10 12:43 ` Thomas Gleixner
2019-11-09 0:24 ` Andy Lutomirski
2019-11-06 19:35 ` [patch 5/9] x86/ioport: Reduce ioperm impact for sane usage further Thomas Gleixner
2019-11-07 1:11 ` Linus Torvalds
2019-11-07 7:44 ` Thomas Gleixner
2019-11-07 8:25 ` Ingo Molnar
2019-11-07 9:17 ` Willy Tarreau
2019-11-07 10:00 ` Thomas Gleixner
2019-11-07 10:13 ` Willy Tarreau
2019-11-07 10:19 ` hpa
2019-11-07 10:27 ` Willy Tarreau
2019-11-07 10:50 ` hpa
2019-11-07 12:56 ` Willy Tarreau
2019-11-07 16:45 ` Eric W. Biederman
2019-11-07 16:53 ` Linus Torvalds
2019-11-07 16:57 ` Willy Tarreau
2019-11-10 17:17 ` Andy Lutomirski
2019-11-07 7:37 ` Ingo Molnar
2019-11-07 7:45 ` Thomas Gleixner
2019-11-07 8:16 ` Ingo Molnar
2019-11-07 18:02 ` Thomas Gleixner
2019-11-07 19:24 ` Brian Gerst
2019-11-07 19:54 ` Linus Torvalds
2019-11-07 21:00 ` Brian Gerst
2019-11-07 21:32 ` Thomas Gleixner
2019-11-07 23:20 ` hpa
2019-11-07 21:44 ` Linus Torvalds
2019-11-08 1:12 ` H. Peter Anvin
2019-11-08 2:12 ` Brian Gerst
2019-11-10 17:21 ` Andy Lutomirski
2019-11-06 19:35 ` [patch 6/9] x86/iopl: Fixup misleading comment Thomas Gleixner
2019-11-06 19:35 ` [patch 7/9] x86/iopl: Restrict iopl() permission scope Thomas Gleixner
2019-11-07 9:09 ` Peter Zijlstra
2019-11-10 17:26 ` Andy Lutomirski
2019-11-10 20:31 ` Thomas Gleixner
2019-11-10 21:05 ` Andy Lutomirski
2019-11-10 21:21 ` Thomas Gleixner
2019-11-06 19:35 ` [patch 8/9] x86/iopl: Remove legacy IOPL option Thomas Gleixner
2019-11-07 6:11 ` Jürgen Groß
2019-11-07 6:26 ` hpa
2019-11-07 16:44 ` Stephen Hemminger
2019-11-07 9:13 ` Peter Zijlstra
2019-11-06 19:35 ` Thomas Gleixner [this message]
2019-11-07 7:28 ` [patch] x86/iopl: Remove unused local variable, update comments in ksys_ioperm() Ingo Molnar
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