linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH v7 00/11] Retpoline: Avoid speculative indirect calls in kernel
@ 2018-01-09 14:43 David Woodhouse
  2018-01-09 14:43 ` [PATCH v7 01/11] x86/retpoline: Add initial retpoline support David Woodhouse
                   ` (10 more replies)
  0 siblings, 11 replies; 65+ messages in thread
From: David Woodhouse @ 2018-01-09 14:43 UTC (permalink / raw)
  To: Andi Kleen
  Cc: Paul Turner, LKML, Linus Torvalds, Greg Kroah-Hartman, Tim Chen,
	Dave Hansen, tglx, Kees Cook, Rik van Riel, Peter Zijlstra,
	Andy Lutomirski, Jiri Kosina, gnomes, x86

This is a mitigation for the 'variant 2' attack described in
https://googleprojectzero.blogspot.com/2018/01/reading-privileged-memory-with-side.html

Using GCC patches available from the hjl/indirect/gcc-7-branch/master
branch of https://github.com/hjl-tools/gcc/commits/hjl and by manually
patching assembler code, all vulnerable indirect branches (that occur
after userspace first runs) are eliminated from the kernel.

They are replaced with a 'retpoline' call sequence which deliberately
prevents speculation.

Fedora 27 packages of the updated compiler are available at
https://koji.fedoraproject.org/koji/taskinfo?taskID=24065739


v1: Initial post.
v2: Add CONFIG_RETPOLINE to build kernel without it.
    Change warning messages.
    Hide modpost warning message
v3: Update to the latest CET-capable retpoline version
    Reinstate ALTERNATIVE support
v4: Finish reconciling Andi's and my patch sets, bug fixes.
    Exclude objtool support for now
    Add 'noretpoline' boot option
    Add AMD retpoline alternative
v5: Silence MODVERSIONS warnings
    Use pause;jmp loop instead of lfence;jmp
    Switch to X86_FEATURE_RETPOLINE positive feature logic
    Emit thunks inline from assembler macros
    Merge AMD support into initial patch
v6: Update to latest GCC patches with no dots in symbols
    Fix MODVERSIONS properly(ish)
    Fix typo breaking 32-bit, introduced in V5
    Never set X86_FEATURE_RETPOLINE_AMD yet, pending confirmation
v7: Further bikeshedding on macro names
    Stuff RSB on kernel entry
    Implement 'spectre_v2=' command line option for IBRS/IBPB too
    Revert to precisely the asm sequences from the Google paper

Andi Kleen (3):
  x86/retpoline: Temporarily disable objtool when CONFIG_RETPOLINE=y
  x86/retpoline/irq32: Convert assembler indirect jumps
  x86/retpoline: Avoid return buffer underflows on context switch

David Woodhouse (8):
  x86/retpoline: Add initial retpoline support
  x86/spectre: Add boot time option to select Spectre v2 mitigation
  x86/retpoline/crypto: Convert crypto assembler indirect jumps
  x86/retpoline/entry: Convert entry assembler indirect jumps
  x86/retpoline/ftrace: Convert ftrace assembler indirect jumps
  x86/retpoline/hyperv: Convert assembler indirect jumps
  x86/retpoline/xen: Convert Xen hypercall indirect jumps
  x86/retpoline/checksum32: Convert assembler indirect jumps

 Documentation/admin-guide/kernel-parameters.txt |  28 +++++
 arch/x86/Kconfig                                |  17 ++-
 arch/x86/Kconfig.debug                          |   6 +-
 arch/x86/Makefile                               |  10 ++
 arch/x86/crypto/aesni-intel_asm.S               |   5 +-
 arch/x86/crypto/camellia-aesni-avx-asm_64.S     |   3 +-
 arch/x86/crypto/camellia-aesni-avx2-asm_64.S    |   3 +-
 arch/x86/crypto/crc32c-pcl-intel-asm_64.S       |   3 +-
 arch/x86/entry/entry_32.S                       |  22 +++-
 arch/x86/entry/entry_64.S                       |  29 ++++-
 arch/x86/include/asm/asm-prototypes.h           |  25 ++++
 arch/x86/include/asm/cpufeatures.h              |   2 +
 arch/x86/include/asm/mshyperv.h                 |  18 +--
 arch/x86/include/asm/nospec-branch.h            | 158 ++++++++++++++++++++++++
 arch/x86/include/asm/xen/hypercall.h            |   5 +-
 arch/x86/kernel/cpu/bugs.c                      | 122 +++++++++++++++++-
 arch/x86/kernel/ftrace_32.S                     |   6 +-
 arch/x86/kernel/ftrace_64.S                     |   8 +-
 arch/x86/kernel/irq_32.c                        |   9 +-
 arch/x86/kernel/setup.c                         |   3 +
 arch/x86/lib/Makefile                           |   1 +
 arch/x86/lib/checksum_32.S                      |   7 +-
 arch/x86/lib/retpoline.S                        |  48 +++++++
 23 files changed, 499 insertions(+), 39 deletions(-)
 create mode 100644 arch/x86/include/asm/nospec-branch.h
 create mode 100644 arch/x86/lib/retpoline.S

-- 
2.7.4

^ permalink raw reply	[flat|nested] 65+ messages in thread
* [PATCH v8 11/12] x86/retpoline/irq32: Convert assembler indirect jumps
@ 2018-01-11 21:46 David Woodhouse
  2018-01-11 23:26 ` [tip:x86/pti] " tip-bot for Andi Kleen
  0 siblings, 1 reply; 65+ messages in thread
From: David Woodhouse @ 2018-01-11 21:46 UTC (permalink / raw)
  To: Andi Kleen
  Cc: Paul Turner, LKML, Linus Torvalds, Greg Kroah-Hartman, Tim Chen,
	Dave Hansen, tglx, Kees Cook, Rik van Riel, Peter Zijlstra,
	Andy Lutomirski, Jiri Kosina, gnomes, x86, thomas.lendacky,
	Josh Poimboeuf

From: Andi Kleen <ak@linux.intel.com>

Convert all indirect jumps in 32bit irq inline asm code to use non
speculative sequences.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: gnomes@lxorguk.ukuu.org.uk
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Kees Cook <keescook@google.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linux-foundation.org>
Cc: Paul Turner <pjt@google.com>
Link: https://lkml.kernel.org/r/1515508997-6154-11-git-send-email-dwmw@amazon.co.uk
---
 arch/x86/kernel/irq_32.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index a83b334..c1bdbd3 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -20,6 +20,7 @@
 #include <linux/mm.h>
 
 #include <asm/apic.h>
+#include <asm/nospec-branch.h>
 
 #ifdef CONFIG_DEBUG_STACKOVERFLOW
 
@@ -55,11 +56,11 @@ DEFINE_PER_CPU(struct irq_stack *, softirq_stack);
 static void call_on_stack(void *func, void *stack)
 {
 	asm volatile("xchgl	%%ebx,%%esp	\n"
-		     "call	*%%edi		\n"
+		     CALL_NOSPEC
 		     "movl	%%ebx,%%esp	\n"
 		     : "=b" (stack)
 		     : "0" (stack),
-		       "D"(func)
+		       [thunk_target] "D"(func)
 		     : "memory", "cc", "edx", "ecx", "eax");
 }
 
@@ -95,11 +96,11 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 		call_on_stack(print_stack_overflow, isp);
 
 	asm volatile("xchgl	%%ebx,%%esp	\n"
-		     "call	*%%edi		\n"
+		     CALL_NOSPEC
 		     "movl	%%ebx,%%esp	\n"
 		     : "=a" (arg1), "=b" (isp)
 		     :  "0" (desc),   "1" (isp),
-			"D" (desc->handle_irq)
+			[thunk_target] "D" (desc->handle_irq)
 		     : "memory", "cc", "ecx");
 	return 1;
 }
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 65+ messages in thread

end of thread, other threads:[~2018-01-11 23:32 UTC | newest]

Thread overview: 65+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-01-09 14:43 [PATCH v7 00/11] Retpoline: Avoid speculative indirect calls in kernel David Woodhouse
2018-01-09 14:43 ` [PATCH v7 01/11] x86/retpoline: Add initial retpoline support David Woodhouse
2018-01-09 15:55   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-10 17:34   ` tip-bot for David Woodhouse
2018-01-10 18:13   ` tip-bot for David Woodhouse
2018-01-10 18:40   ` tip-bot for David Woodhouse
2018-01-09 14:43 ` [PATCH v7 02/11] x86/retpoline: Temporarily disable objtool when CONFIG_RETPOLINE=y David Woodhouse
2018-01-09 15:56   ` [tip:x86/pti] " tip-bot for Andi Kleen
2018-01-10  5:58   ` [PATCH v7 02/11] " Josh Poimboeuf
2018-01-10 10:12     ` Peter Zijlstra
2018-01-10 17:34   ` [tip:x86/pti] " tip-bot for Andi Kleen
2018-01-10 18:13   ` tip-bot for Andi Kleen
2018-01-10 18:40   ` tip-bot for Andi Kleen
2018-01-09 14:43 ` [PATCH v7 03/11] x86/spectre: Add boot time option to select Spectre v2 mitigation David Woodhouse
2018-01-09 15:56   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-10 17:35   ` tip-bot for David Woodhouse
2018-01-10 18:03     ` Tom Lendacky
2018-01-10 18:06       ` Thomas Gleixner
2018-01-10 18:10         ` Thomas Gleixner
2018-01-10 18:14   ` tip-bot for David Woodhouse
2018-01-10 18:33     ` Tom Lendacky
2018-01-10 18:35       ` Thomas Gleixner
2018-01-10 18:41   ` tip-bot for David Woodhouse
2018-01-09 14:43 ` [PATCH v7 04/11] x86/retpoline/crypto: Convert crypto assembler indirect jumps David Woodhouse
2018-01-09 15:56   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-10 17:35   ` tip-bot for David Woodhouse
2018-01-10 18:14   ` tip-bot for David Woodhouse
2018-01-10 18:41   ` tip-bot for David Woodhouse
2018-01-09 14:43 ` [PATCH v7 05/11] x86/retpoline/entry: Convert entry " David Woodhouse
2018-01-09 15:57   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-10  3:54   ` [v7, 05/11] " Andrei Vagin
2018-01-10  4:30     ` Andi Kleen
2018-01-10  4:39       ` Dave Hansen
2018-01-10  5:23         ` Andrei Vagin
2018-01-10 17:36   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-10 18:15   ` tip-bot for David Woodhouse
2018-01-10 18:41   ` tip-bot for David Woodhouse
2018-01-09 14:43 ` [PATCH v7 06/11] x86/retpoline/ftrace: Convert ftrace " David Woodhouse
2018-01-09 15:57   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-10 17:36   ` tip-bot for David Woodhouse
2018-01-10 18:15   ` tip-bot for David Woodhouse
2018-01-10 18:42   ` tip-bot for David Woodhouse
2018-01-09 14:43 ` [PATCH v7 07/11] x86/retpoline/hyperv: Convert " David Woodhouse
2018-01-09 15:58   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-10 17:37   ` tip-bot for David Woodhouse
2018-01-10 18:15   ` tip-bot for David Woodhouse
2018-01-10 18:42   ` tip-bot for David Woodhouse
2018-01-09 14:43 ` [PATCH v7 08/11] x86/retpoline/xen: Convert Xen hypercall " David Woodhouse
2018-01-09 15:58   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-10 17:37   ` tip-bot for David Woodhouse
2018-01-10 18:16   ` tip-bot for David Woodhouse
2018-01-10 18:43   ` tip-bot for David Woodhouse
2018-01-09 14:43 ` [PATCH v7 09/11] x86/retpoline/checksum32: Convert assembler " David Woodhouse
2018-01-09 15:58   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-10 17:37   ` tip-bot for David Woodhouse
2018-01-10 18:16   ` tip-bot for David Woodhouse
2018-01-10 18:43   ` tip-bot for David Woodhouse
2018-01-09 14:43 ` [PATCH v7 10/11] x86/retpoline/irq32: " David Woodhouse
2018-01-09 15:59   ` [tip:x86/pti] " tip-bot for Andi Kleen
2018-01-10 17:38   ` tip-bot for Andi Kleen
2018-01-10 18:17   ` tip-bot for Andi Kleen
2018-01-10 18:43   ` tip-bot for Andi Kleen
2018-01-09 14:43 ` [PATCH v7 11/11] x86/retpoline: Avoid return buffer underflows on context switch David Woodhouse
2018-01-09 15:59   ` [tip:x86/pti] " tip-bot for Andi Kleen
2018-01-11 21:46 [PATCH v8 11/12] x86/retpoline/irq32: Convert assembler indirect jumps David Woodhouse
2018-01-11 23:26 ` [tip:x86/pti] " tip-bot for Andi Kleen

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).