From d8fdea47d7fc1177aa0843a49dc89422ac6f4fea Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Thu, 2 Nov 2017 00:59:02 -0700 Subject: [PATCH 090/242] x86/entry/64: Shrink paranoid_exit_restore and make labels local MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit CVE-2017-5754 paranoid_exit_restore was a copy of restore_regs_and_return_to_kernel. Merge them and make the paranoid_exit internal labels local. Keeping .Lparanoid_exit makes the code a bit shorter because it allows a 2-byte jnz instead of a 5-byte jnz. Saves 96 bytes of text. ( This is still a bit suboptimal in a non-CONFIG_TRACE_IRQFLAGS kernel, but fixing that would make the code rather messy. ) Signed-off-by: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/510d66a1895cda9473c84b1086f0bb974f22de6a.1509609304.git.luto@kernel.org Signed-off-by: Ingo Molnar (cherry picked from commit e53178328c9b96fbdbc719e78c93b5687ee007c3) Signed-off-by: Andy Whitcroft Signed-off-by: Kleber Sacilotto de Souza (cherry picked from commit fb53fe10add935c3d0eb63199e43426eaf3b4299) Signed-off-by: Fabian Grünbichler --- arch/x86/entry/entry_64.S | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index a1a86e782a0e..6995f7e08aa1 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -1136,17 +1136,14 @@ ENTRY(paranoid_exit) DISABLE_INTERRUPTS(CLBR_ANY) TRACE_IRQS_OFF_DEBUG testl %ebx, %ebx /* swapgs needed? */ - jnz paranoid_exit_no_swapgs + jnz .Lparanoid_exit_no_swapgs TRACE_IRQS_IRETQ SWAPGS_UNSAFE_STACK - jmp paranoid_exit_restore -paranoid_exit_no_swapgs: + jmp .Lparanoid_exit_restore +.Lparanoid_exit_no_swapgs: TRACE_IRQS_IRETQ_DEBUG -paranoid_exit_restore: - RESTORE_EXTRA_REGS - RESTORE_C_REGS - REMOVE_PT_GPREGS_FROM_STACK 8 - INTERRUPT_RETURN +.Lparanoid_exit_restore: + jmp restore_regs_and_return_to_kernel END(paranoid_exit) /* -- 2.14.2