114 lines
3.6 KiB
Diff
114 lines
3.6 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Andy Lutomirski <luto@kernel.org>
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Date: Sat, 4 Nov 2017 04:19:50 -0700
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Subject: [PATCH] selftests/x86/ldt_gdt: Add infrastructure to test
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set_thread_area()
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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CVE-2017-5754
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Much of the test design could apply to set_thread_area() (i.e. GDT),
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not just modify_ldt(). Add set_thread_area() to the
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install_valid_mode() helper.
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Signed-off-by: Andy Lutomirski <luto@kernel.org>
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Cc: Borislav Petkov <bpetkov@suse.de>
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Cc: Linus Torvalds <torvalds@linux-foundation.org>
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Cc: Peter Zijlstra <peterz@infradead.org>
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Cc: Thomas Gleixner <tglx@linutronix.de>
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Link: http://lkml.kernel.org/r/02c23f8fba5547007f741dc24c3926e5284ede02.1509794321.git.luto@kernel.org
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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(cherry picked from commit d744dcad39094c9187075e274d1cdef79c57c8b5)
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Signed-off-by: Andy Whitcroft <apw@canonical.com>
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Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
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(cherry picked from commit d6ae7ac5849304e520538a6ce3111f372f809596)
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Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
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---
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tools/testing/selftests/x86/ldt_gdt.c | 53 ++++++++++++++++++++++++-----------
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1 file changed, 37 insertions(+), 16 deletions(-)
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diff --git a/tools/testing/selftests/x86/ldt_gdt.c b/tools/testing/selftests/x86/ldt_gdt.c
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index b2c54f4673f2..337f217d0ae9 100644
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--- a/tools/testing/selftests/x86/ldt_gdt.c
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+++ b/tools/testing/selftests/x86/ldt_gdt.c
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@@ -136,30 +136,51 @@ static void check_valid_segment(uint16_t index, int ldt,
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}
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}
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-static bool install_valid_mode(const struct user_desc *desc, uint32_t ar,
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- bool oldmode)
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+static bool install_valid_mode(const struct user_desc *d, uint32_t ar,
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+ bool oldmode, bool ldt)
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{
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- int ret = syscall(SYS_modify_ldt, oldmode ? 1 : 0x11,
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- desc, sizeof(*desc));
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- if (ret < -1)
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- errno = -ret;
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+ struct user_desc desc = *d;
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+ int ret;
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+
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+ if (!ldt) {
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+#ifndef __i386__
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+ /* No point testing set_thread_area in a 64-bit build */
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+ return false;
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+#endif
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+ if (!gdt_entry_num)
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+ return false;
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+ desc.entry_number = gdt_entry_num;
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+
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+ ret = syscall(SYS_set_thread_area, &desc);
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+ } else {
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+ ret = syscall(SYS_modify_ldt, oldmode ? 1 : 0x11,
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+ &desc, sizeof(desc));
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+
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+ if (ret < -1)
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+ errno = -ret;
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+
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+ if (ret != 0 && errno == ENOSYS) {
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+ printf("[OK]\tmodify_ldt returned -ENOSYS\n");
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+ return false;
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+ }
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+ }
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+
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if (ret == 0) {
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- uint32_t limit = desc->limit;
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- if (desc->limit_in_pages)
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+ uint32_t limit = desc.limit;
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+ if (desc.limit_in_pages)
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limit = (limit << 12) + 4095;
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- check_valid_segment(desc->entry_number, 1, ar, limit, true);
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+ check_valid_segment(desc.entry_number, ldt, ar, limit, true);
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return true;
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- } else if (errno == ENOSYS) {
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- printf("[OK]\tmodify_ldt returned -ENOSYS\n");
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- return false;
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} else {
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- if (desc->seg_32bit) {
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- printf("[FAIL]\tUnexpected modify_ldt failure %d\n",
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+ if (desc.seg_32bit) {
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+ printf("[FAIL]\tUnexpected %s failure %d\n",
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+ ldt ? "modify_ldt" : "set_thread_area",
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errno);
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nerrs++;
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return false;
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} else {
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- printf("[OK]\tmodify_ldt rejected 16 bit segment\n");
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+ printf("[OK]\t%s rejected 16 bit segment\n",
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+ ldt ? "modify_ldt" : "set_thread_area");
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return false;
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}
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}
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@@ -167,7 +188,7 @@ static bool install_valid_mode(const struct user_desc *desc, uint32_t ar,
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static bool install_valid(const struct user_desc *desc, uint32_t ar)
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{
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- return install_valid_mode(desc, ar, false);
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+ return install_valid_mode(desc, ar, false, true);
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}
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static void install_invalid(const struct user_desc *desc, bool oldmode)
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--
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2.14.2
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