62 lines
1.9 KiB
Diff
62 lines
1.9 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: Thu, 2 Nov 2017 00:59:03 -0700
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Subject: [PATCH] x86/entry/64: Use pop instead of movq in
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syscall_return_via_sysret
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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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Saves 64 bytes.
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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/6609b7f74ab31c36604ad746e019ea8495aec76c.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 4fbb39108f972437c44e5ffa781b56635d496826)
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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 1e9a9d5ef9f65eeb26eb8f0974dd3e693894baf1)
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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 | 14 +++++++++++---
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1 file changed, 11 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 6995f7e08aa1..33a416c7df2d 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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@@ -315,10 +315,18 @@ 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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+ POP_EXTRA_REGS
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+ popq %rsi /* skip r11 */
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+ popq %r10
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+ popq %r9
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+ popq %r8
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+ popq %rax
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+ popq %rsi /* skip rcx */
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+ popq %rdx
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+ popq %rsi
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+ popq %rdi
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+ movq RSP-ORIG_RAX(%rsp), %rsp
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USERGS_SYSRET64
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END(entry_SYSCALL_64)
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--
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2.14.2
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