2f7a8021b5
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>
129 lines
4.5 KiB
Diff
129 lines
4.5 KiB
Diff
From 782a4580a5e347793443aa8e9152db1bf4a0fff8 Mon Sep 17 00:00:00 2001
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From: Peter Jones <pjones@redhat.com>
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Date: Mon, 15 Jun 2020 10:58:42 -0400
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Subject: [PATCH] safemath: Add some arithmetic primitives that check for
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overflow
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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This adds a new header, include/grub/safemath.h, that includes easy to
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use wrappers for __builtin_{add,sub,mul}_overflow() declared like:
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bool OP(a, b, res)
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where OP is grub_add, grub_sub or grub_mul. OP() returns true in the
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case where the operation would overflow and res is not modified.
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Otherwise, false is returned and the operation is executed.
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These arithmetic primitives require newer compiler versions. So, bump
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these requirements in the INSTALL file too.
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Signed-off-by: Peter Jones <pjones@redhat.com>
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Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
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Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com>
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---
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INSTALL | 22 ++--------------------
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include/grub/compiler.h | 8 ++++++++
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include/grub/safemath.h | 37 +++++++++++++++++++++++++++++++++++++
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3 files changed, 47 insertions(+), 20 deletions(-)
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create mode 100644 include/grub/safemath.h
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diff --git a/INSTALL b/INSTALL
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index 8acb40902..dcb9b7d7b 100644
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--- a/INSTALL
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+++ b/INSTALL
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@@ -11,27 +11,9 @@ GRUB depends on some software packages installed into your system. If
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you don't have any of them, please obtain and install them before
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configuring the GRUB.
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-* GCC 4.1.3 or later
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- Note: older versions may work but support is limited
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-
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- Experimental support for clang 3.3 or later (results in much bigger binaries)
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+* GCC 5.1.0 or later
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+ Experimental support for clang 3.8.0 or later (results in much bigger binaries)
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for i386, x86_64, arm (including thumb), arm64, mips(el), powerpc, sparc64
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- Note: clang 3.2 or later works for i386 and x86_64 targets but results in
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- much bigger binaries.
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- earlier versions not tested
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- Note: clang 3.2 or later works for arm
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- earlier versions not tested
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- Note: clang on arm64 is not supported due to
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- https://llvm.org/bugs/show_bug.cgi?id=26030
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- Note: clang 3.3 or later works for mips(el)
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- earlier versions fail to generate .reginfo and hence gprel relocations
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- fail.
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- Note: clang 3.2 or later works for powerpc
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- earlier versions not tested
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- Note: clang 3.5 or later works for sparc64
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- earlier versions return "error: unable to interface with target machine"
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- Note: clang has no support for ia64 and hence you can't compile GRUB
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- for ia64 with clang
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* GNU Make
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* GNU Bison 2.3 or later
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* GNU gettext 0.17 or later
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diff --git a/include/grub/compiler.h b/include/grub/compiler.h
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index c9e1d7a73..8f3be3ae7 100644
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--- a/include/grub/compiler.h
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+++ b/include/grub/compiler.h
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@@ -48,4 +48,12 @@
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# define WARN_UNUSED_RESULT
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#endif
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+#if defined(__clang__) && defined(__clang_major__) && defined(__clang_minor__)
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+# define CLANG_PREREQ(maj,min) \
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+ ((__clang_major__ > (maj)) || \
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+ (__clang_major__ == (maj) && __clang_minor__ >= (min)))
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+#else
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+# define CLANG_PREREQ(maj,min) 0
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+#endif
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+
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#endif /* ! GRUB_COMPILER_HEADER */
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diff --git a/include/grub/safemath.h b/include/grub/safemath.h
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new file mode 100644
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index 000000000..c17b89bba
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--- /dev/null
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+++ b/include/grub/safemath.h
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@@ -0,0 +1,37 @@
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+/*
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+ * GRUB -- GRand Unified Bootloader
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+ * Copyright (C) 2020 Free Software Foundation, Inc.
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+ *
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+ * GRUB is free software: you can redistribute it and/or modify
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+ * it under the terms of the GNU General Public License as published by
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+ * the Free Software Foundation, either version 3 of the License, or
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+ * (at your option) any later version.
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+ *
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+ * GRUB is distributed in the hope that it will be useful,
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+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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+ * GNU General Public License for more details.
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+ *
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+ * You should have received a copy of the GNU General Public License
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+ * along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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+ *
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+ * Arithmetic operations that protect against overflow.
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+ */
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+
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+#ifndef GRUB_SAFEMATH_H
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+#define GRUB_SAFEMATH_H 1
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+
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+#include <grub/compiler.h>
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+
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+/* These appear in gcc 5.1 and clang 3.8. */
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+#if GNUC_PREREQ(5, 1) || CLANG_PREREQ(3, 8)
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+
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+#define grub_add(a, b, res) __builtin_add_overflow(a, b, res)
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+#define grub_sub(a, b, res) __builtin_sub_overflow(a, b, res)
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+#define grub_mul(a, b, res) __builtin_mul_overflow(a, b, res)
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+
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+#else
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+#error gcc 5.1 or newer or clang 3.8 or newer is required
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+#endif
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+
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+#endif /* GRUB_SAFEMATH_H */
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--
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2.26.2
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