This is a note to let you know that I've just added the patch titled
efi/x86: use naked RET on mixed mode call wrapper
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
efi-x86-use-naked-ret-on-mixed-mode-call-wrapper.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 51a6fa0732d6be6a44e0032752ad2ac10d67c796 Mon Sep 17 00:00:00 2001
From: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxx>
Date: Fri, 15 Jul 2022 16:45:50 -0300
Subject: efi/x86: use naked RET on mixed mode call wrapper
From: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxx>
commit 51a6fa0732d6be6a44e0032752ad2ac10d67c796 upstream.
When running with return thunks enabled under 32-bit EFI, the system
crashes with:
kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
BUG: unable to handle page fault for address: 000000005bc02900
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0011) - permissions violation
PGD 18f7063 P4D 18f7063 PUD 18ff063 PMD 190e063 PTE 800000005bc02063
Oops: 0011 [#1] PREEMPT SMP PTI
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.19.0-rc6+ #166
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
RIP: 0010:0x5bc02900
Code: Unable to access opcode bytes at RIP 0x5bc028d6.
RSP: 0018:ffffffffb3203e10 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000048
RDX: 000000000190dfac RSI: 0000000000001710 RDI: 000000007eae823b
RBP: ffffffffb3203e70 R08: 0000000001970000 R09: ffffffffb3203e28
R10: 747563657865206c R11: 6c6977203a696665 R12: 0000000000001710
R13: 0000000000000030 R14: 0000000001970000 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8e013ca00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0018 ES: 0018 CR0: 0000000080050033
CR2: 000000005bc02900 CR3: 0000000001930000 CR4: 00000000000006f0
Call Trace:
? efi_set_virtual_address_map+0x9c/0x175
efi_enter_virtual_mode+0x4a6/0x53e
start_kernel+0x67c/0x71e
x86_64_start_reservations+0x24/0x2a
x86_64_start_kernel+0xe9/0xf4
secondary_startup_64_no_verify+0xe5/0xeb
That's because it cannot jump to the return thunk from the 32-bit code.
Using a naked RET and marking it as safe allows the system to proceed
booting.
Fixes: aa3d480315ba ("x86: Use return-thunk in asm code")
Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxx>
Cc: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/platform/efi/efi_thunk_64.S | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/arch/x86/platform/efi/efi_thunk_64.S
+++ b/arch/x86/platform/efi/efi_thunk_64.S
@@ -22,6 +22,7 @@
#include <linux/linkage.h>
#include <asm/page_types.h>
#include <asm/segment.h>
+#include <asm/nospec-branch.h>
.text
.code64
@@ -63,7 +64,9 @@ SYM_CODE_START(__efi64_thunk)
1: movq 24(%rsp), %rsp
pop %rbx
pop %rbp
- RET
+ ANNOTATE_UNRET_SAFE
+ ret
+ int3
.code32
2: pushl $__KERNEL_CS
Patches currently in stable-queue which might be from cascardo@xxxxxxxxxxxxx are
queue-5.15/x86-bugs-add-amd-retbleed-boot-parameter.patch
queue-5.15/x86-bpf-use-alternative-ret-encoding.patch
queue-5.15/objtool-default-ignore-int3-for-unreachable.patch
queue-5.15/x86-retpoline-cleanup-some-ifdefery.patch
queue-5.15/x86-bugs-enable-stibp-for-jmp2ret.patch
queue-5.15/x86-speculation-fill-rsb-on-vmexit-for-ibrs.patch
queue-5.15/x86-retpoline-create-a-retpoline-thunk-array.patch
queue-5.15/x86-speculation-fix-firmware-entry-spec_ctrl-handling.patch
queue-5.15/x86-ftrace-use-alternative-ret-encoding.patch
queue-5.15/x86-retpoline-swizzle-retpoline-thunk.patch
queue-5.15/kvm-vmx-flatten-__vmx_vcpu_run.patch
queue-5.15/x86-speculation-add-spectre_v2-ibrs-option-to-support-kernel-ibrs.patch
queue-5.15/x86-alternative-implement-.retpoline_sites-support.patch
queue-5.15/x86-entry-move-push_and_clear_regs-back-into-error_entry.patch
queue-5.15/objtool-re-add-unwind_hint_-save_restore.patch
queue-5.15/x86-retpoline-move-the-retpoline-thunk-declarations-to-nospec-branch.h.patch
queue-5.15/x86-speculation-remove-x86_spec_ctrl_mask.patch
queue-5.15/x86-bugs-add-retbleed-ibpb.patch
queue-5.15/x86-asm-fixup-odd-gen-for-each-reg.h-usage.patch
queue-5.15/x86-alternative-handle-jcc-__x86_indirect_thunk_-reg.patch
queue-5.15/objtool-classify-symbols.patch
queue-5.15/x86-cpu-amd-enumerate-btc_no.patch
queue-5.15/x86-asm-fix-register-order.patch
queue-5.15/objtool-skip-non-text-sections-when-adding-return-thunk-sites.patch
queue-5.15/x86-speculation-disable-rrsba-behavior.patch
queue-5.15/intel_idle-disable-ibrs-during-long-idle.patch
queue-5.15/objtool-update-retpoline-validation.patch
queue-5.15/kvm-vmx-fix-ibrs-handling-after-vmexit.patch
queue-5.15/objtool-shrink-struct-instruction.patch
queue-5.15/x86-bugs-optimize-spec_ctrl-msr-writes.patch
queue-5.15/x86-objtool-create-.return_sites.patch
queue-5.15/x86-kvm-fix-fastop_size-when-return-thunks-are-enabled.patch
queue-5.15/x86-xen-add-untrain_ret.patch
queue-5.15/x86-retpoline-use-mfunction-return.patch
queue-5.15/x86-bugs-keep-a-per-cpu-ia32_spec_ctrl-value.patch
queue-5.15/objtool-treat-.text.__x86.-as-noinstr.patch
queue-5.15/x86-retpoline-remove-unused-replacement-symbols.patch
queue-5.15/x86-kexec-disable-ret-on-kexec.patch
queue-5.15/x86-add-magic-amd-return-thunk.patch
queue-5.15/x86-xen-rename-sys-entry-points.patch
queue-5.15/kvm-vmx-prevent-guest-rsb-poisoning-attacks-with-eibrs.patch
queue-5.15/x86-kvm-fix-setcc-emulation-for-return-thunks.patch
queue-5.15/x86-speculation-fix-spec_ctrl-write-on-smt-state-change.patch
queue-5.15/x86-use-return-thunk-in-asm-code.patch
queue-5.15/x86-bugs-do-ibpb-fallback-check-only-once.patch
queue-5.15/x86-bugs-do-not-enable-ibpb-on-entry-when-ibpb-is-not-supported.patch
queue-5.15/x86-bugs-split-spectre_v2_select_mitigation-and-spectre_v2_user_select_mitigation.patch
queue-5.15/x86-static_call-use-alternative-ret-encoding.patch
queue-5.15/objtool-explicitly-avoid-self-modifying-code-in-.altinstr_replacement.patch
queue-5.15/x86-cpu-amd-add-spectral-chicken.patch
queue-5.15/x86-cpufeatures-move-retpoline-flags-to-word-11.patch
queue-5.15/x86-entry-avoid-very-early-ret.patch
queue-5.15/x86-vsyscall_emu-64-don-t-use-ret-in-vsyscall-emulation.patch
queue-5.15/x86-entry-move-push_and_clear_regs-out-of-error_entry.patch
queue-5.15/x86-speculation-use-cached-host-spec_ctrl-value-for-guest-entry-exit.patch
queue-5.15/x86-bugs-report-amd-retbleed-vulnerability.patch
queue-5.15/efi-x86-use-naked-ret-on-mixed-mode-call-wrapper.patch
queue-5.15/objtool-x86-replace-alternatives-with-.retpoline_sites.patch
queue-5.15/x86-entry-switch-the-stack-after-error_entry-returns.patch
queue-5.15/x86-sev-avoid-using-__x86_return_thunk.patch
queue-5.15/x86-speculation-fix-rsb-filling-with-config_retpoline-n.patch
queue-5.15/x86-entry-remove-skip_r11rcx.patch
queue-5.15/x86-undo-return-thunk-damage.patch
queue-5.15/bpf-x86-respect-x86_feature_retpoline.patch
queue-5.15/objtool-introduce-cfi-hash.patch
queue-5.15/x86-common-stamp-out-the-stepping-madness.patch
queue-5.15/x86-bugs-report-intel-retbleed-vulnerability.patch
queue-5.15/x86-entry-don-t-call-error_entry-for-xenpv.patch
queue-5.15/bpf-x86-simplify-computing-label-offsets.patch
queue-5.15/x86-traps-use-pt_regs-directly-in-fixup_bad_iret.patch
queue-5.15/x86-alternative-try-inline-spectre_v2-retpoline-amd.patch
queue-5.15/x86-realmode-build-with-d__disable_exports.patch
queue-5.15/x86-bugs-add-cannon-lake-to-retbleed-affected-cpu-list.patch
queue-5.15/x86-kvm-vmx-make-noinstr-clean.patch
queue-5.15/x86-retbleed-add-fine-grained-kconfig-knobs.patch
queue-5.15/x86-alternative-add-debug-prints-to-apply_retpolines.patch
queue-5.15/kvm-vmx-convert-launched-argument-to-flags.patch
queue-5.15/x86-entry-add-kernel-ibrs-implementation.patch
queue-5.15/objtool-add-entry-unret-validation.patch
