diff options
| author | Dan Williams | 2018-02-06 02:18:11 +0100 |
|---|---|---|
| committer | Ingo Molnar | 2018-02-06 11:47:44 +0100 |
| commit | 3ac6d8c787b835b997eb23e43e09aa0895ef7d58 (patch) | |
| tree | e08f3c4bc1d80afd184a31f4836a759e014c16e3 /arch/x86/entry/entry_64.S | |
| parent | x86/entry/64: Clear extra registers beyond syscall arguments, to reduce specu... (diff) | |
| download | kernel-qcow2-linux-3ac6d8c787b835b997eb23e43e09aa0895ef7d58.tar.gz kernel-qcow2-linux-3ac6d8c787b835b997eb23e43e09aa0895ef7d58.tar.xz kernel-qcow2-linux-3ac6d8c787b835b997eb23e43e09aa0895ef7d58.zip | |
x86/entry/64: Clear registers for exceptions/interrupts, to reduce speculation attack surface
Clear the 'extra' registers on entering the 64-bit kernel for exceptions
and interrupts. The common registers are not cleared since they are
likely clobbered well before they can be exploited in a speculative
execution attack.
Originally-From: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Cc: <stable@vger.kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/151787989146.7847.15749181712358213254.stgit@dwillia2-desk3.amr.corp.intel.com
[ Made small improvements to the changelog and the code comments. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/entry/entry_64.S')
| -rw-r--r-- | arch/x86/entry/entry_64.S | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 065a71b90808..9e48002b953b 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -575,6 +575,7 @@ END(irq_entries_start) ALLOC_PT_GPREGS_ON_STACK SAVE_C_REGS SAVE_EXTRA_REGS + CLEAR_REGS_NOSPEC ENCODE_FRAME_POINTER testb $3, CS(%rsp) @@ -1133,6 +1134,7 @@ ENTRY(xen_failsafe_callback) ALLOC_PT_GPREGS_ON_STACK SAVE_C_REGS SAVE_EXTRA_REGS + CLEAR_REGS_NOSPEC ENCODE_FRAME_POINTER jmp error_exit END(xen_failsafe_callback) @@ -1178,6 +1180,7 @@ ENTRY(paranoid_entry) cld SAVE_C_REGS 8 SAVE_EXTRA_REGS 8 + CLEAR_REGS_NOSPEC ENCODE_FRAME_POINTER 8 movl $1, %ebx movl $MSR_GS_BASE, %ecx @@ -1230,8 +1233,8 @@ ENTRY(error_entry) cld SAVE_C_REGS 8 SAVE_EXTRA_REGS 8 + CLEAR_REGS_NOSPEC ENCODE_FRAME_POINTER 8 - xorl %ebx, %ebx testb $3, CS+8(%rsp) jz .Lerror_kernelspace @@ -1428,6 +1431,7 @@ ENTRY(nmi) pushq %r14 /* pt_regs->r14 */ pushq %r15 /* pt_regs->r15 */ UNWIND_HINT_REGS + CLEAR_REGS_NOSPEC ENCODE_FRAME_POINTER /* |