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- From 6ef121f444bab6ac294e1eda62eb727ee639c6d7 Mon Sep 17 00:00:00 2001
- From: Josh Poimboeuf <[email protected]>
- Date: Mon, 18 Sep 2017 21:43:37 -0500
- Subject: [PATCH 059/231] x86/head: Add unwind hint annotations
- MIME-Version: 1.0
- Content-Type: text/plain; charset=UTF-8
- Content-Transfer-Encoding: 8bit
- CVE-2017-5754
- Jiri Slaby reported an ORC issue when unwinding from an idle task. The
- stack was:
- ffffffff811083c2 do_idle+0x142/0x1e0
- ffffffff8110861d cpu_startup_entry+0x5d/0x60
- ffffffff82715f58 start_kernel+0x3ff/0x407
- ffffffff827153e8 x86_64_start_kernel+0x14e/0x15d
- ffffffff810001bf secondary_startup_64+0x9f/0xa0
- The ORC unwinder errored out at secondary_startup_64 because the head
- code isn't annotated yet so there wasn't a corresponding ORC entry.
- Fix that and any other head-related unwinding issues by adding unwind
- hints to the head code.
- Reported-by: Jiri Slaby <[email protected]>
- Tested-by: Jiri Slaby <[email protected]>
- Signed-off-by: Josh Poimboeuf <[email protected]>
- Cc: Andy Lutomirski <[email protected]>
- Cc: Boris Ostrovsky <[email protected]>
- Cc: Juergen Gross <[email protected]>
- Cc: Linus Torvalds <[email protected]>
- Cc: Peter Zijlstra <[email protected]>
- Cc: Thomas Gleixner <[email protected]>
- Link: http://lkml.kernel.org/r/78ef000a2f68f545d6eef44ee912edceaad82ccf.1505764066.git.jpoimboe@redhat.com
- Signed-off-by: Ingo Molnar <[email protected]>
- (cherry picked from commit 2704fbb672d0d9a19414907fda7949283dcef6a1)
- Signed-off-by: Andy Whitcroft <[email protected]>
- Signed-off-by: Kleber Sacilotto de Souza <[email protected]>
- (cherry picked from commit b63a868e404e64172afefea553c6a40963a151db)
- Signed-off-by: Fabian Grünbichler <[email protected]>
- ---
- arch/x86/kernel/Makefile | 1 -
- arch/x86/kernel/head_64.S | 14 ++++++++++++--
- 2 files changed, 12 insertions(+), 3 deletions(-)
- diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
- index 287eac7d207f..e2315aecc441 100644
- --- a/arch/x86/kernel/Makefile
- +++ b/arch/x86/kernel/Makefile
- @@ -26,7 +26,6 @@ KASAN_SANITIZE_dumpstack.o := n
- KASAN_SANITIZE_dumpstack_$(BITS).o := n
- KASAN_SANITIZE_stacktrace.o := n
-
- -OBJECT_FILES_NON_STANDARD_head_$(BITS).o := y
- OBJECT_FILES_NON_STANDARD_relocate_kernel_$(BITS).o := y
- OBJECT_FILES_NON_STANDARD_ftrace_$(BITS).o := y
- OBJECT_FILES_NON_STANDARD_test_nx.o := y
- diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
- index 45b18b1a6417..d081bc7a027d 100644
- --- a/arch/x86/kernel/head_64.S
- +++ b/arch/x86/kernel/head_64.S
- @@ -49,6 +49,7 @@ L3_START_KERNEL = pud_index(__START_KERNEL_map)
- .code64
- .globl startup_64
- startup_64:
- + UNWIND_HINT_EMPTY
- /*
- * At this point the CPU runs in 64bit mode CS.L = 1 CS.D = 0,
- * and someone has loaded an identity mapped page table
- @@ -81,6 +82,7 @@ startup_64:
- movq $(early_top_pgt - __START_KERNEL_map), %rax
- jmp 1f
- ENTRY(secondary_startup_64)
- + UNWIND_HINT_EMPTY
- /*
- * At this point the CPU runs in 64bit mode CS.L = 1 CS.D = 0,
- * and someone has loaded a mapped page table.
- @@ -116,6 +118,7 @@ ENTRY(secondary_startup_64)
- movq $1f, %rax
- jmp *%rax
- 1:
- + UNWIND_HINT_EMPTY
-
- /* Check if nx is implemented */
- movl $0x80000001, %eax
- @@ -230,6 +233,7 @@ END(secondary_startup_64)
- */
- ENTRY(start_cpu0)
- movq initial_stack(%rip), %rsp
- + UNWIND_HINT_EMPTY
- jmp .Ljump_to_C_code
- ENDPROC(start_cpu0)
- #endif
- @@ -254,13 +258,18 @@ ENTRY(early_idt_handler_array)
- i = 0
- .rept NUM_EXCEPTION_VECTORS
- .ifeq (EXCEPTION_ERRCODE_MASK >> i) & 1
- - pushq $0 # Dummy error code, to make stack frame uniform
- + UNWIND_HINT_IRET_REGS
- + pushq $0 # Dummy error code, to make stack frame uniform
- + .else
- + UNWIND_HINT_IRET_REGS offset=8
- .endif
- pushq $i # 72(%rsp) Vector number
- jmp early_idt_handler_common
- + UNWIND_HINT_IRET_REGS
- i = i + 1
- .fill early_idt_handler_array + i*EARLY_IDT_HANDLER_SIZE - ., 1, 0xcc
- .endr
- + UNWIND_HINT_IRET_REGS offset=16
- END(early_idt_handler_array)
-
- early_idt_handler_common:
- @@ -289,6 +298,7 @@ early_idt_handler_common:
- pushq %r13 /* pt_regs->r13 */
- pushq %r14 /* pt_regs->r14 */
- pushq %r15 /* pt_regs->r15 */
- + UNWIND_HINT_REGS
-
- cmpq $14,%rsi /* Page fault? */
- jnz 10f
- @@ -411,7 +421,7 @@ ENTRY(phys_base)
- EXPORT_SYMBOL(phys_base)
-
- #include "../../x86/xen/xen-head.S"
- -
- +
- __PAGE_ALIGNED_BSS
- NEXT_PAGE(empty_zero_page)
- .skip PAGE_SIZE
- --
- 2.14.2
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