183 lines
6.6 KiB
Diff
183 lines
6.6 KiB
Diff
From c8756c2077aba1a33ec603766211fdb1dad34577 Mon Sep 17 00:00:00 2001
|
|
From: Andy Lutomirski <luto@kernel.org>
|
|
Date: Mon, 4 Dec 2017 15:07:12 +0100
|
|
Subject: [PATCH 142/233] x86/entry/64: Allocate and enable the SYSENTER stack
|
|
MIME-Version: 1.0
|
|
Content-Type: text/plain; charset=UTF-8
|
|
Content-Transfer-Encoding: 8bit
|
|
|
|
CVE-2017-5754
|
|
|
|
This will simplify future changes that want scratch variables early in
|
|
the SYSENTER handler -- they'll be able to spill registers to the
|
|
stack. It also lets us get rid of a SWAPGS_UNSAFE_STACK user.
|
|
|
|
This does not depend on CONFIG_IA32_EMULATION=y because we'll want the
|
|
stack space even without IA32 emulation.
|
|
|
|
As far as I can tell, the reason that this wasn't done from day 1 is
|
|
that we use IST for #DB and #BP, which is IMO rather nasty and causes
|
|
a lot more problems than it solves. But, since #DB uses IST, we don't
|
|
actually need a real stack for SYSENTER (because SYSENTER with TF set
|
|
will invoke #DB on the IST stack rather than the SYSENTER stack).
|
|
|
|
I want to remove IST usage from these vectors some day, and this patch
|
|
is a prerequisite for that as well.
|
|
|
|
Signed-off-by: Andy Lutomirski <luto@kernel.org>
|
|
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
|
|
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
|
|
Reviewed-by: Borislav Petkov <bp@suse.de>
|
|
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
|
|
Cc: Borislav Petkov <bp@alien8.de>
|
|
Cc: Borislav Petkov <bpetkov@suse.de>
|
|
Cc: Brian Gerst <brgerst@gmail.com>
|
|
Cc: Dave Hansen <dave.hansen@intel.com>
|
|
Cc: Dave Hansen <dave.hansen@linux.intel.com>
|
|
Cc: David Laight <David.Laight@aculab.com>
|
|
Cc: Denys Vlasenko <dvlasenk@redhat.com>
|
|
Cc: Eduardo Valentin <eduval@amazon.com>
|
|
Cc: Greg KH <gregkh@linuxfoundation.org>
|
|
Cc: H. Peter Anvin <hpa@zytor.com>
|
|
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
|
|
Cc: Juergen Gross <jgross@suse.com>
|
|
Cc: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Cc: Peter Zijlstra <peterz@infradead.org>
|
|
Cc: Rik van Riel <riel@redhat.com>
|
|
Cc: Will Deacon <will.deacon@arm.com>
|
|
Cc: aliguori@amazon.com
|
|
Cc: daniel.gruss@iaik.tugraz.at
|
|
Cc: hughd@google.com
|
|
Cc: keescook@google.com
|
|
Link: https://lkml.kernel.org/r/20171204150605.312726423@linutronix.de
|
|
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
(cherry picked from commit 1a79797b58cddfa948420a7553241c79c013e3ca)
|
|
Signed-off-by: Andy Whitcroft <apw@canonical.com>
|
|
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
|
|
(cherry picked from commit 8e621515fa8d1649b031f34b9d498dcd865db1c3)
|
|
Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
|
|
---
|
|
arch/x86/include/asm/processor.h | 3 ---
|
|
arch/x86/kernel/asm-offsets.c | 5 +++++
|
|
arch/x86/kernel/asm-offsets_32.c | 5 -----
|
|
arch/x86/kernel/cpu/common.c | 4 +++-
|
|
arch/x86/kernel/process.c | 2 --
|
|
arch/x86/kernel/traps.c | 3 +--
|
|
arch/x86/entry/entry_64_compat.S | 2 +-
|
|
7 files changed, 10 insertions(+), 14 deletions(-)
|
|
|
|
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
|
|
index 79739e5f939a..5225917f9760 100644
|
|
--- a/arch/x86/include/asm/processor.h
|
|
+++ b/arch/x86/include/asm/processor.h
|
|
@@ -333,14 +333,11 @@ struct tss_struct {
|
|
*/
|
|
unsigned long io_bitmap[IO_BITMAP_LONGS + 1];
|
|
|
|
-#ifdef CONFIG_X86_32
|
|
/*
|
|
* Space for the temporary SYSENTER stack.
|
|
*/
|
|
unsigned long SYSENTER_stack_canary;
|
|
unsigned long SYSENTER_stack[64];
|
|
-#endif
|
|
-
|
|
} ____cacheline_aligned;
|
|
|
|
DECLARE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss);
|
|
diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c
|
|
index de827d6ac8c2..031bd35bd911 100644
|
|
--- a/arch/x86/kernel/asm-offsets.c
|
|
+++ b/arch/x86/kernel/asm-offsets.c
|
|
@@ -92,4 +92,9 @@ void common(void) {
|
|
|
|
BLANK();
|
|
DEFINE(PTREGS_SIZE, sizeof(struct pt_regs));
|
|
+
|
|
+ /* Offset from cpu_tss to SYSENTER_stack */
|
|
+ OFFSET(CPU_TSS_SYSENTER_stack, tss_struct, SYSENTER_stack);
|
|
+ /* Size of SYSENTER_stack */
|
|
+ DEFINE(SIZEOF_SYSENTER_stack, sizeof(((struct tss_struct *)0)->SYSENTER_stack));
|
|
}
|
|
diff --git a/arch/x86/kernel/asm-offsets_32.c b/arch/x86/kernel/asm-offsets_32.c
|
|
index 880aa093268d..d09b161a3bd0 100644
|
|
--- a/arch/x86/kernel/asm-offsets_32.c
|
|
+++ b/arch/x86/kernel/asm-offsets_32.c
|
|
@@ -52,11 +52,6 @@ void foo(void)
|
|
DEFINE(TSS_sysenter_sp0, offsetof(struct tss_struct, x86_tss.sp0) -
|
|
offsetofend(struct tss_struct, SYSENTER_stack));
|
|
|
|
- /* Offset from cpu_tss to SYSENTER_stack */
|
|
- OFFSET(CPU_TSS_SYSENTER_stack, tss_struct, SYSENTER_stack);
|
|
- /* Size of SYSENTER_stack */
|
|
- DEFINE(SIZEOF_SYSENTER_stack, sizeof(((struct tss_struct *)0)->SYSENTER_stack));
|
|
-
|
|
#ifdef CONFIG_CC_STACKPROTECTOR
|
|
BLANK();
|
|
OFFSET(stack_canary_offset, stack_canary, canary);
|
|
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
|
|
index 121fe3570d6f..aa97e4cd3a33 100644
|
|
--- a/arch/x86/kernel/cpu/common.c
|
|
+++ b/arch/x86/kernel/cpu/common.c
|
|
@@ -1362,7 +1362,9 @@ void syscall_init(void)
|
|
* AMD doesn't allow SYSENTER in long mode (either 32- or 64-bit).
|
|
*/
|
|
wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)__KERNEL_CS);
|
|
- wrmsrl_safe(MSR_IA32_SYSENTER_ESP, 0ULL);
|
|
+ wrmsrl_safe(MSR_IA32_SYSENTER_ESP,
|
|
+ (unsigned long)this_cpu_ptr(&cpu_tss) +
|
|
+ offsetofend(struct tss_struct, SYSENTER_stack));
|
|
wrmsrl_safe(MSR_IA32_SYSENTER_EIP, (u64)entry_SYSENTER_compat);
|
|
#else
|
|
wrmsrl(MSR_CSTAR, (unsigned long)ignore_sysret);
|
|
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
|
|
index ccf3a4f4ef68..aa86e810fb54 100644
|
|
--- a/arch/x86/kernel/process.c
|
|
+++ b/arch/x86/kernel/process.c
|
|
@@ -70,9 +70,7 @@ __visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss) = {
|
|
*/
|
|
.io_bitmap = { [0 ... IO_BITMAP_LONGS] = ~0 },
|
|
#endif
|
|
-#ifdef CONFIG_X86_32
|
|
.SYSENTER_stack_canary = STACK_END_MAGIC,
|
|
-#endif
|
|
};
|
|
EXPORT_PER_CPU_SYMBOL(cpu_tss);
|
|
|
|
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
|
|
index 3a46cab2696e..7b1d0df624cf 100644
|
|
--- a/arch/x86/kernel/traps.c
|
|
+++ b/arch/x86/kernel/traps.c
|
|
@@ -806,14 +806,13 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
|
|
debug_stack_usage_dec();
|
|
|
|
exit:
|
|
-#if defined(CONFIG_X86_32)
|
|
/*
|
|
* This is the most likely code path that involves non-trivial use
|
|
* of the SYSENTER stack. Check that we haven't overrun it.
|
|
*/
|
|
WARN(this_cpu_read(cpu_tss.SYSENTER_stack_canary) != STACK_END_MAGIC,
|
|
"Overran or corrupted SYSENTER stack\n");
|
|
-#endif
|
|
+
|
|
ist_exit(regs);
|
|
}
|
|
NOKPROBE_SYMBOL(do_debug);
|
|
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S
|
|
index be745b7a3e3e..1f76b66518ee 100644
|
|
--- a/arch/x86/entry/entry_64_compat.S
|
|
+++ b/arch/x86/entry/entry_64_compat.S
|
|
@@ -47,7 +47,7 @@
|
|
*/
|
|
ENTRY(entry_SYSENTER_compat)
|
|
/* Interrupts are off on entry. */
|
|
- SWAPGS_UNSAFE_STACK
|
|
+ SWAPGS
|
|
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
|
|
|
|
/*
|
|
--
|
|
2.14.2
|
|
|