2018-01-06 17:13:39 +03:00
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From befef5ef70f959cd51694298c4370557e5d846cf Mon Sep 17 00:00:00 2001
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From: Andy Lutomirski <luto@kernel.org>
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Date: Thu, 2 Nov 2017 00:58:58 -0700
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2018-01-08 13:50:09 +03:00
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Subject: [PATCH 086/242] x86/entry/64: Remove the restore_c_regs_and_iret
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2018-01-06 17:13:39 +03:00
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label
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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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The only user was the 64-bit opportunistic SYSRET failure path, and
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that path didn't really need it. This change makes the
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opportunistic SYSRET code a bit more straightforward and gets rid of
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the label.
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Signed-off-by: Andy Lutomirski <luto@kernel.org>
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Reviewed-by: Borislav Petkov <bp@suse.de>
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Cc: Borislav Petkov <bpetkov@suse.de>
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Cc: Brian Gerst <brgerst@gmail.com>
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Cc: Dave Hansen <dave.hansen@intel.com>
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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/be3006a7ad3326e3458cf1cc55d416252cbe1986.1509609304.git.luto@kernel.org
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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(cherry picked from commit 9da78ba6b47b46428cfdfc0851511ab29c869798)
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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 629c8b858cbe72e88e7f44a8f10e1b434ab80721)
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Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
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---
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arch/x86/entry/entry_64.S | 5 ++---
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1 file changed, 2 insertions(+), 3 deletions(-)
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diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
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index 34adfe0221d2..fac354ddf056 100644
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--- a/arch/x86/entry/entry_64.S
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+++ b/arch/x86/entry/entry_64.S
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@@ -245,7 +245,6 @@ entry_SYSCALL64_slow_path:
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call do_syscall_64 /* returns with IRQs disabled */
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return_from_SYSCALL_64:
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- RESTORE_EXTRA_REGS
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TRACE_IRQS_IRETQ /* we're about to change IF */
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/*
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@@ -314,6 +313,7 @@ return_from_SYSCALL_64:
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*/
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syscall_return_via_sysret:
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/* rcx and r11 are already restored (see code above) */
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+ RESTORE_EXTRA_REGS
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RESTORE_C_REGS_EXCEPT_RCX_R11
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movq RSP(%rsp), %rsp
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UNWIND_HINT_EMPTY
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@@ -321,7 +321,7 @@ syscall_return_via_sysret:
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opportunistic_sysret_failed:
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SWAPGS
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- jmp restore_c_regs_and_iret
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+ jmp restore_regs_and_iret
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END(entry_SYSCALL_64)
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ENTRY(stub_ptregs_64)
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@@ -638,7 +638,6 @@ retint_kernel:
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*/
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GLOBAL(restore_regs_and_iret)
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RESTORE_EXTRA_REGS
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-restore_c_regs_and_iret:
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RESTORE_C_REGS
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REMOVE_PT_GPREGS_FROM_STACK 8
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INTERRUPT_RETURN
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--
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2.14.2
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