linux-kernel - [PATCH AUTOSEL 4.4 20/26] x86/kexec: Don't setup EFI info if EFI runtime is not enabled

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Message-Id: <20190223211047.202725-20-sashal@kernel.org>
Date:   Sat, 23 Feb 2019 16:10:41 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Kairui Song <kasong@...hat.com>, Borislav Petkov <bp@...e.de>,
        AKASHI Takahiro <takahiro.akashi@...aro.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>, bhe@...hat.com,
        David Howells <dhowells@...hat.com>, erik.schmauss@...el.com,
        fanc.fnst@...fujitsu.com, "H. Peter Anvin" <hpa@...or.com>,
        Ingo Molnar <mingo@...hat.com>, kexec@...ts.infradead.org,
        lenb@...nel.org, linux-acpi@...r.kernel.org,
        Philipp Rudo <prudo@...ux.vnet.ibm.com>,
        rafael.j.wysocki@...el.com, robert.moore@...el.com,
        Thomas Gleixner <tglx@...utronix.de>, x86-ml <x86@...nel.org>,
        Yannik Sembritzki <yannik@...britzki.me>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 4.4 20/26] x86/kexec: Don't setup EFI info if EFI runtime is not enabled

From: Kairui Song <kasong@...hat.com>

[ Upstream commit 2aa958c99c7fd3162b089a1a56a34a0cdb778de1 ]

Kexec-ing a kernel with "efi=noruntime" on the first kernel's command
line causes the following null pointer dereference:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
  #PF error: [normal kernel read fault]
  Call Trace:
   efi_runtime_map_copy+0x28/0x30
   bzImage64_load+0x688/0x872
   arch_kexec_kernel_image_load+0x6d/0x70
   kimage_file_alloc_init+0x13e/0x220
   __x64_sys_kexec_file_load+0x144/0x290
   do_syscall_64+0x55/0x1a0
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

Just skip the EFI info setup if EFI runtime services are not enabled.

 [ bp: Massage commit message. ]

Suggested-by: Dave Young <dyoung@...hat.com>
Signed-off-by: Kairui Song <kasong@...hat.com>
Signed-off-by: Borislav Petkov <bp@...e.de>
Acked-by: Dave Young <dyoung@...hat.com>
Cc: AKASHI Takahiro <takahiro.akashi@...aro.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Ard Biesheuvel <ard.biesheuvel@...aro.org>
Cc: bhe@...hat.com
Cc: David Howells <dhowells@...hat.com>
Cc: erik.schmauss@...el.com
Cc: fanc.fnst@...fujitsu.com
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: kexec@...ts.infradead.org
Cc: lenb@...nel.org
Cc: linux-acpi@...r.kernel.org
Cc: Philipp Rudo <prudo@...ux.vnet.ibm.com>
Cc: rafael.j.wysocki@...el.com
Cc: robert.moore@...el.com
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: x86-ml <x86@...nel.org>
Cc: Yannik Sembritzki <yannik@...britzki.me>
Link: https://lkml.kernel.org/r/20190118111310.29589-2-kasong@redhat.com
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/x86/kernel/kexec-bzimage64.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index 0f8a6bbaaa443..0bf17576dd2af 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -168,6 +168,9 @@ setup_efi_state(struct boot_params *params, unsigned long params_load_addr,
 	struct efi_info *current_ei = &boot_params.efi_info;
 	struct efi_info *ei = &params->efi_info;
 
+	if (!efi_enabled(EFI_RUNTIME_SERVICES))
+		return 0;
+
 	if (!current_ei->efi_memmap_size)
 		return 0;
 
-- 
2.19.1