This is a note to let you know that I've just added the patch titled
efi: Fix boot panic because of invalid BGRT image address
to the 4.11-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-fix-boot-panic-because-of-invalid-bgrt-image-address.patch
and it can be found in the queue-4.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 792ef14df5c585c19b2831673a077504a09e5203 Mon Sep 17 00:00:00 2001
From: Dave Young <dyoung@xxxxxxxxxx>
Date: Fri, 9 Jun 2017 08:45:58 +0000
Subject: efi: Fix boot panic because of invalid BGRT image address
From: Dave Young <dyoung@xxxxxxxxxx>
commit 792ef14df5c585c19b2831673a077504a09e5203 upstream.
Maniaxx reported a kernel boot crash in the EFI code, which I emulated
by using same invalid phys addr in code:
BUG: unable to handle kernel paging request at ffffffffff280001
IP: efi_bgrt_init+0xfb/0x153
...
Call Trace:
? bgrt_init+0xbc/0xbc
acpi_parse_bgrt+0xe/0x12
acpi_table_parse+0x89/0xb8
acpi_boot_init+0x445/0x4e2
? acpi_parse_x2apic+0x79/0x79
? dmi_ignore_irq0_timer_override+0x33/0x33
setup_arch+0xb63/0xc82
? early_idt_handler_array+0x120/0x120
start_kernel+0xb7/0x443
? early_idt_handler_array+0x120/0x120
x86_64_start_reservations+0x29/0x2b
x86_64_start_kernel+0x154/0x177
secondary_startup_64+0x9f/0x9f
There is also a similar bug filed in bugzilla.kernel.org:
https://bugzilla.kernel.org/show_bug.cgi?id=195633
The crash is caused by this commit:
7b0a911478c7 efi/x86: Move the EFI BGRT init code to early init code
The root cause is the firmware on those machines provides invalid BGRT
image addresses.
In a kernel before above commit BGRT initializes late and uses ioremap()
to map the image address. Ioremap validates the address, if it is not a
valid physical address ioremap() just fails and returns. However in current
kernel EFI BGRT initializes early and uses early_memremap() which does not
validate the image address, and kernel panic happens.
According to ACPI spec the BGRT image address should fall into
EFI_BOOT_SERVICES_DATA, see the section 5.2.22.4 of below document:
http://www.uefi.org/sites/default/files/resources/ACPI_6_1.pdf
Fix this issue by validating the image address in efi_bgrt_init(). If the
image address does not fall into any EFI_BOOT_SERVICES_DATA areas we just
bail out with a warning message.
Reported-by: Maniaxx <tripleshiftone@xxxxxxxxx>
Signed-off-by: Dave Young <dyoung@xxxxxxxxxx>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-efi@xxxxxxxxxxxxxxx
Fixes: 7b0a911478c7 ("efi/x86: Move the EFI BGRT init code to early init code")
Link: http://lkml.kernel.org/r/20170609084558.26766-2-ard.biesheuvel@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/platform/efi/efi-bgrt.c | 26 +++++++++++++++++++++++++-
1 file changed, 25 insertions(+), 1 deletion(-)
--- a/arch/x86/platform/efi/efi-bgrt.c
+++ b/arch/x86/platform/efi/efi-bgrt.c
@@ -27,6 +27,26 @@ struct bmp_header {
u32 size;
} __packed;
+static bool efi_bgrt_addr_valid(u64 addr)
+{
+ efi_memory_desc_t *md;
+
+ for_each_efi_memory_desc(md) {
+ u64 size;
+ u64 end;
+
+ if (md->type != EFI_BOOT_SERVICES_DATA)
+ continue;
+
+ size = md->num_pages << EFI_PAGE_SHIFT;
+ end = md->phys_addr + size;
+ if (addr >= md->phys_addr && addr < end)
+ return true;
+ }
+
+ return false;
+}
+
void __init efi_bgrt_init(struct acpi_table_header *table)
{
void *image;
@@ -36,7 +56,7 @@ void __init efi_bgrt_init(struct acpi_ta
if (acpi_disabled)
return;
- if (!efi_enabled(EFI_BOOT))
+ if (!efi_enabled(EFI_MEMMAP))
return;
if (table->length < sizeof(bgrt_tab)) {
@@ -65,6 +85,10 @@ void __init efi_bgrt_init(struct acpi_ta
goto out;
}
+ if (!efi_bgrt_addr_valid(bgrt->image_address)) {
+ pr_notice("Ignoring BGRT: invalid image address\n");
+ goto out;
+ }
image = early_memremap(bgrt->image_address, sizeof(bmp_header));
if (!image) {
pr_notice("Ignoring BGRT: failed to map image header memory\n");
Patches currently in stable-queue which might be from dyoung@xxxxxxxxxx are
queue-4.11/efi-fix-boot-panic-because-of-invalid-bgrt-image-address.patch