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kumquat-buildroot/boot/grub2/0026-efi-Fix-use-after-free-in-halt-reboot-path.patch
Stefan Sørensen 2f7a8021b5 boot/grub2: Backport Boothole securify fixes 
Details: https://lists.gnu.org/archive/html/grub-devel/2020-07/msg00034.html

Fixes the following security issues:

 * CVE-2020-10713
   A flaw was found in grub2, prior to version 2.06. An attacker may
   use the GRUB 2 flaw to hijack and tamper the GRUB verification
   process. This flaw also allows the bypass of Secure Boot
   protections. In order to load an untrusted or modified kernel, an
   attacker would first need to establish access to the system such as
   gaining physical access, obtain the ability to alter a pxe-boot
   network, or have remote access to a networked system with root
   access. With this access, an attacker could then craft a string to
   cause a buffer overflow by injecting a malicious payload that leads
   to arbitrary code execution within GRUB. The highest threat from
   this vulnerability is to data confidentiality and integrity as well
   as system availability.

 * CVE-2020-14308
   In grub2 versions before 2.06 the grub memory allocator doesn't
   check for possible arithmetic overflows on the requested allocation
   size. This leads the function to return invalid memory allocations
   which can be further used to cause possible integrity,
   confidentiality and availability impacts during the boot process.

 * CVE-2020-14309
   There's an issue with grub2 in all versions before 2.06 when
   handling squashfs filesystems containing a symbolic link with name
   length of UINT32 bytes in size. The name size leads to an
   arithmetic overflow leading to a zero-size allocation further
   causing a heap-based buffer overflow with attacker controlled data.

 * CVE-2020-14310
   An integer overflow in read_section_from_string may lead to a heap
   based buffer overflow.

 * CVE-2020-14311
   An integer overflow in grub_ext2_read_link may lead to a heap-based
   buffer overflow.

 * CVE-2020-15706
   GRUB2 contains a race condition in grub_script_function_create()
   leading to a use-after-free vulnerability which can be triggered by
   redefining a function whilst the same function is already
   executing, leading to arbitrary code execution and secure boot
   restriction bypass

 * CVE-2020-15707
   Integer overflows were discovered in the functions grub_cmd_initrd
   and grub_initrd_init in the efilinux component of GRUB2, as shipped
   in Debian, Red Hat, and Ubuntu (the functionality is not included
   in GRUB2 upstream), leading to a heap-based buffer overflow. These
   could be triggered by an extremely large number of arguments to the
   initrd command on 32-bit architectures, or a crafted filesystem
   with very large files on any architecture. An attacker could use
   this to execute arbitrary code and bypass UEFI Secure Boot
   restrictions. This issue affects GRUB2 version 2.04 and prior
   versions.

Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
2020-08-03 13:38:49 +02:00

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From 8a6d6299efcffd14c1130942195e6c0d9b50cacd Mon Sep 17 00:00:00 2001
From: Alexey Makhalov <amakhalov@vmware.com>
Date: Mon, 20 Jul 2020 23:03:05 +0000
Subject: [PATCH] efi: Fix use-after-free in halt/reboot path
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
commit 92bfc33db984 ("efi: Free malloc regions on exit")
introduced memory freeing in grub_efi_fini(), which is
used not only by exit path but by halt/reboot one as well.
As result of memory freeing, code and data regions used by
modules, such as halt, reboot, acpi (used by halt) also got
freed. After return to module code, CPU executes, filled
by UEFI firmware (tested with edk2), 0xAFAFAFAF pattern as
a code. Which leads to #UD exception later.
grub> halt
!!!! X64 Exception Type - 06(#UD - Invalid Opcode) CPU Apic ID - 00000000 !!!!
RIP - 0000000003F4EC28, CS - 0000000000000038, RFLAGS - 0000000000200246
RAX - 0000000000000000, RCX - 00000000061DA188, RDX - 0A74C0854DC35D41
RBX - 0000000003E10E08, RSP - 0000000007F0F860, RBP - 0000000000000000
RSI - 00000000064DB768, RDI - 000000000832C5C3
R8 - 0000000000000002, R9 - 0000000000000000, R10 - 00000000061E2E52
R11 - 0000000000000020, R12 - 0000000003EE5C1F, R13 - 00000000061E0FF4
R14 - 0000000003E10D80, R15 - 00000000061E2F60
DS - 0000000000000030, ES - 0000000000000030, FS - 0000000000000030
GS - 0000000000000030, SS - 0000000000000030
CR0 - 0000000080010033, CR2 - 0000000000000000, CR3 - 0000000007C01000
CR4 - 0000000000000668, CR8 - 0000000000000000
DR0 - 0000000000000000, DR1 - 0000000000000000, DR2 - 0000000000000000
DR3 - 0000000000000000, DR6 - 00000000FFFF0FF0, DR7 - 0000000000000400
GDTR - 00000000079EEA98 0000000000000047, LDTR - 0000000000000000
IDTR - 0000000007598018 0000000000000FFF, TR - 0000000000000000
FXSAVE_STATE - 0000000007F0F4C0
Proposal here is to continue to free allocated memory for
exit boot services path but keep it for halt/reboot path
as it won't be much security concern here.
Introduced GRUB_LOADER_FLAG_EFI_KEEP_ALLOCATED_MEMORY
loader flag to be used by efi halt/reboot path.
Signed-off-by: Alexey Makhalov <amakhalov@vmware.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com>
---
grub-core/kern/arm/efi/init.c | 3 +++
grub-core/kern/arm64/efi/init.c | 3 +++
grub-core/kern/efi/efi.c | 3 ++-
grub-core/kern/efi/init.c | 1 -
grub-core/kern/i386/efi/init.c | 9 +++++++--
grub-core/kern/ia64/efi/init.c | 9 +++++++--
grub-core/kern/riscv/efi/init.c | 3 +++
grub-core/lib/efi/halt.c | 3 ++-
include/grub/loader.h | 1 +
9 files changed, 28 insertions(+), 7 deletions(-)
diff --git a/grub-core/kern/arm/efi/init.c b/grub-core/kern/arm/efi/init.c
index 06df60e2f..40c3b467f 100644
--- a/grub-core/kern/arm/efi/init.c
+++ b/grub-core/kern/arm/efi/init.c
@@ -71,4 +71,7 @@ grub_machine_fini (int flags)
efi_call_1 (b->close_event, tmr_evt);
grub_efi_fini ();
+
+ if (!(flags & GRUB_LOADER_FLAG_EFI_KEEP_ALLOCATED_MEMORY))
+ grub_efi_memory_fini ();
}
diff --git a/grub-core/kern/arm64/efi/init.c b/grub-core/kern/arm64/efi/init.c
index 6224999ec..5010caefd 100644
--- a/grub-core/kern/arm64/efi/init.c
+++ b/grub-core/kern/arm64/efi/init.c
@@ -57,4 +57,7 @@ grub_machine_fini (int flags)
return;
grub_efi_fini ();
+
+ if (!(flags & GRUB_LOADER_FLAG_EFI_KEEP_ALLOCATED_MEMORY))
+ grub_efi_memory_fini ();
}
diff --git a/grub-core/kern/efi/efi.c b/grub-core/kern/efi/efi.c
index c97969a65..9cfd88d77 100644
--- a/grub-core/kern/efi/efi.c
+++ b/grub-core/kern/efi/efi.c
@@ -157,7 +157,8 @@ grub_efi_get_loaded_image (grub_efi_handle_t image_handle)
void
grub_reboot (void)
{
- grub_machine_fini (GRUB_LOADER_FLAG_NORETURN);
+ grub_machine_fini (GRUB_LOADER_FLAG_NORETURN |
+ GRUB_LOADER_FLAG_EFI_KEEP_ALLOCATED_MEMORY);
efi_call_4 (grub_efi_system_table->runtime_services->reset_system,
GRUB_EFI_RESET_COLD, GRUB_EFI_SUCCESS, 0, NULL);
for (;;) ;
diff --git a/grub-core/kern/efi/init.c b/grub-core/kern/efi/init.c
index 3dfdf2d22..2c31847bf 100644
--- a/grub-core/kern/efi/init.c
+++ b/grub-core/kern/efi/init.c
@@ -80,5 +80,4 @@ grub_efi_fini (void)
{
grub_efidisk_fini ();
grub_console_fini ();
- grub_efi_memory_fini ();
}
diff --git a/grub-core/kern/i386/efi/init.c b/grub-core/kern/i386/efi/init.c
index da499aba0..deb2eacd8 100644
--- a/grub-core/kern/i386/efi/init.c
+++ b/grub-core/kern/i386/efi/init.c
@@ -39,6 +39,11 @@ grub_machine_init (void)
void
grub_machine_fini (int flags)
{
- if (flags & GRUB_LOADER_FLAG_NORETURN)
- grub_efi_fini ();
+ if (!(flags & GRUB_LOADER_FLAG_NORETURN))
+ return;
+
+ grub_efi_fini ();
+
+ if (!(flags & GRUB_LOADER_FLAG_EFI_KEEP_ALLOCATED_MEMORY))
+ grub_efi_memory_fini ();
}
diff --git a/grub-core/kern/ia64/efi/init.c b/grub-core/kern/ia64/efi/init.c
index b5ecbd091..f1965571b 100644
--- a/grub-core/kern/ia64/efi/init.c
+++ b/grub-core/kern/ia64/efi/init.c
@@ -70,6 +70,11 @@ grub_machine_init (void)
void
grub_machine_fini (int flags)
{
- if (flags & GRUB_LOADER_FLAG_NORETURN)
- grub_efi_fini ();
+ if (!(flags & GRUB_LOADER_FLAG_NORETURN))
+ return;
+
+ grub_efi_fini ();
+
+ if (!(flags & GRUB_LOADER_FLAG_EFI_KEEP_ALLOCATED_MEMORY))
+ grub_efi_memory_fini ();
}
diff --git a/grub-core/kern/riscv/efi/init.c b/grub-core/kern/riscv/efi/init.c
index 7eb1969d0..38795fe67 100644
--- a/grub-core/kern/riscv/efi/init.c
+++ b/grub-core/kern/riscv/efi/init.c
@@ -73,4 +73,7 @@ grub_machine_fini (int flags)
return;
grub_efi_fini ();
+
+ if (!(flags & GRUB_LOADER_FLAG_EFI_KEEP_ALLOCATED_MEMORY))
+ grub_efi_memory_fini ();
}
diff --git a/grub-core/lib/efi/halt.c b/grub-core/lib/efi/halt.c
index 5859f0498..29d413641 100644
--- a/grub-core/lib/efi/halt.c
+++ b/grub-core/lib/efi/halt.c
@@ -28,7 +28,8 @@
void
grub_halt (void)
{
- grub_machine_fini (GRUB_LOADER_FLAG_NORETURN);
+ grub_machine_fini (GRUB_LOADER_FLAG_NORETURN |
+ GRUB_LOADER_FLAG_EFI_KEEP_ALLOCATED_MEMORY);
#if !defined(__ia64__) && !defined(__arm__) && !defined(__aarch64__) && \
!defined(__riscv)
grub_acpi_halt ();
diff --git a/include/grub/loader.h b/include/grub/loader.h
index 7f82a499f..b20864282 100644
--- a/include/grub/loader.h
+++ b/include/grub/loader.h
@@ -33,6 +33,7 @@ enum
{
GRUB_LOADER_FLAG_NORETURN = 1,
GRUB_LOADER_FLAG_PXE_NOT_UNLOAD = 2,
+ GRUB_LOADER_FLAG_EFI_KEEP_ALLOCATED_MEMORY = 4,
};
void EXPORT_FUNC (grub_loader_set) (grub_err_t (*boot) (void),
--
2.26.2
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