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kumquat-buildroot/boot/grub2/0017-relocator-Protect-grub_relocator_alloc_chunk_align-m.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

342 lines
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From 0cfbbca3ccd84d36ffb1bcd6644ada7c73b19fc0 Mon Sep 17 00:00:00 2001
From: Alexey Makhalov <amakhalov@vmware.com>
Date: Wed, 8 Jul 2020 01:44:38 +0000
Subject: [PATCH] relocator: Protect grub_relocator_alloc_chunk_align()
max_addr against integer underflow
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
This commit introduces integer underflow mitigation in max_addr calculation
in grub_relocator_alloc_chunk_align() invocation.
It consists of 2 fixes:
1. Introduced grub_relocator_alloc_chunk_align_safe() wrapper function to perform
sanity check for min/max and size values, and to make safe invocation of
grub_relocator_alloc_chunk_align() with validated max_addr value. Replace all
invocations such as grub_relocator_alloc_chunk_align(..., min_addr, max_addr - size, size, ...)
by grub_relocator_alloc_chunk_align_safe(..., min_addr, max_addr, size, ...).
2. Introduced UP_TO_TOP32(s) macro for the cases where max_addr is 32-bit top
address (0xffffffff - size + 1) or similar.
Signed-off-by: Alexey Makhalov <amakhalov@vmware.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com>
---
grub-core/lib/i386/relocator.c | 28 ++++++++++----------------
grub-core/lib/mips/relocator.c | 6 ++----
grub-core/lib/powerpc/relocator.c | 6 ++----
grub-core/lib/x86_64/efi/relocator.c | 7 +++----
grub-core/loader/i386/linux.c | 5 ++---
grub-core/loader/i386/multiboot_mbi.c | 7 +++----
grub-core/loader/i386/pc/linux.c | 6 ++----
grub-core/loader/mips/linux.c | 9 +++------
grub-core/loader/multiboot.c | 2 +-
grub-core/loader/multiboot_elfxx.c | 10 ++++-----
grub-core/loader/multiboot_mbi2.c | 10 ++++-----
grub-core/loader/xnu_resume.c | 2 +-
include/grub/relocator.h | 29 +++++++++++++++++++++++++++
13 files changed, 69 insertions(+), 58 deletions(-)
diff --git a/grub-core/lib/i386/relocator.c b/grub-core/lib/i386/relocator.c
index 71dd4f0ab..34cbe834f 100644
--- a/grub-core/lib/i386/relocator.c
+++ b/grub-core/lib/i386/relocator.c
@@ -83,11 +83,10 @@ grub_relocator32_boot (struct grub_relocator *rel,
/* Specific memory range due to Global Descriptor Table for use by payload
that we will store in returned chunk. The address range and preference
are based on "THE LINUX/x86 BOOT PROTOCOL" specification. */
- err = grub_relocator_alloc_chunk_align (rel, &ch, 0x1000,
- 0x9a000 - RELOCATOR_SIZEOF (32),
- RELOCATOR_SIZEOF (32), 16,
- GRUB_RELOCATOR_PREFERENCE_LOW,
- avoid_efi_bootservices);
+ err = grub_relocator_alloc_chunk_align_safe (rel, &ch, 0x1000, 0x9a000,
+ RELOCATOR_SIZEOF (32), 16,
+ GRUB_RELOCATOR_PREFERENCE_LOW,
+ avoid_efi_bootservices);
if (err)
return err;
@@ -125,13 +124,10 @@ grub_relocator16_boot (struct grub_relocator *rel,
grub_relocator_chunk_t ch;
/* Put it higher than the byte it checks for A20 check. */
- err = grub_relocator_alloc_chunk_align (rel, &ch, 0x8010,
- 0xa0000 - RELOCATOR_SIZEOF (16)
- - GRUB_RELOCATOR16_STACK_SIZE,
- RELOCATOR_SIZEOF (16)
- + GRUB_RELOCATOR16_STACK_SIZE, 16,
- GRUB_RELOCATOR_PREFERENCE_NONE,
- 0);
+ err = grub_relocator_alloc_chunk_align_safe (rel, &ch, 0x8010, 0xa0000,
+ RELOCATOR_SIZEOF (16) +
+ GRUB_RELOCATOR16_STACK_SIZE, 16,
+ GRUB_RELOCATOR_PREFERENCE_NONE, 0);
if (err)
return err;
@@ -183,11 +179,9 @@ grub_relocator64_boot (struct grub_relocator *rel,
void *relst;
grub_relocator_chunk_t ch;
- err = grub_relocator_alloc_chunk_align (rel, &ch, min_addr,
- max_addr - RELOCATOR_SIZEOF (64),
- RELOCATOR_SIZEOF (64), 16,
- GRUB_RELOCATOR_PREFERENCE_NONE,
- 0);
+ err = grub_relocator_alloc_chunk_align_safe (rel, &ch, min_addr, max_addr,
+ RELOCATOR_SIZEOF (64), 16,
+ GRUB_RELOCATOR_PREFERENCE_NONE, 0);
if (err)
return err;
diff --git a/grub-core/lib/mips/relocator.c b/grub-core/lib/mips/relocator.c
index 9d5f49cb9..743b213e6 100644
--- a/grub-core/lib/mips/relocator.c
+++ b/grub-core/lib/mips/relocator.c
@@ -120,10 +120,8 @@ grub_relocator32_boot (struct grub_relocator *rel,
unsigned i;
grub_addr_t vtarget;
- err = grub_relocator_alloc_chunk_align (rel, &ch, 0,
- (0xffffffff - stateset_size)
- + 1, stateset_size,
- sizeof (grub_uint32_t),
+ err = grub_relocator_alloc_chunk_align (rel, &ch, 0, UP_TO_TOP32 (stateset_size),
+ stateset_size, sizeof (grub_uint32_t),
GRUB_RELOCATOR_PREFERENCE_NONE, 0);
if (err)
return err;
diff --git a/grub-core/lib/powerpc/relocator.c b/grub-core/lib/powerpc/relocator.c
index bdf2b111b..8ffb8b686 100644
--- a/grub-core/lib/powerpc/relocator.c
+++ b/grub-core/lib/powerpc/relocator.c
@@ -115,10 +115,8 @@ grub_relocator32_boot (struct grub_relocator *rel,
unsigned i;
grub_relocator_chunk_t ch;
- err = grub_relocator_alloc_chunk_align (rel, &ch, 0,
- (0xffffffff - stateset_size)
- + 1, stateset_size,
- sizeof (grub_uint32_t),
+ err = grub_relocator_alloc_chunk_align (rel, &ch, 0, UP_TO_TOP32 (stateset_size),
+ stateset_size, sizeof (grub_uint32_t),
GRUB_RELOCATOR_PREFERENCE_NONE, 0);
if (err)
return err;
diff --git a/grub-core/lib/x86_64/efi/relocator.c b/grub-core/lib/x86_64/efi/relocator.c
index 3caef7a40..7d200a125 100644
--- a/grub-core/lib/x86_64/efi/relocator.c
+++ b/grub-core/lib/x86_64/efi/relocator.c
@@ -50,10 +50,9 @@ grub_relocator64_efi_boot (struct grub_relocator *rel,
* 64-bit relocator code may live above 4 GiB quite well.
* However, I do not want ask for problems. Just in case.
*/
- err = grub_relocator_alloc_chunk_align (rel, &ch, 0,
- 0x100000000 - RELOCATOR_SIZEOF (64_efi),
- RELOCATOR_SIZEOF (64_efi), 16,
- GRUB_RELOCATOR_PREFERENCE_NONE, 1);
+ err = grub_relocator_alloc_chunk_align_safe (rel, &ch, 0, 0x100000000,
+ RELOCATOR_SIZEOF (64_efi), 16,
+ GRUB_RELOCATOR_PREFERENCE_NONE, 1);
if (err)
return err;
diff --git a/grub-core/loader/i386/linux.c b/grub-core/loader/i386/linux.c
index 02a73463a..efbb99307 100644
--- a/grub-core/loader/i386/linux.c
+++ b/grub-core/loader/i386/linux.c
@@ -181,9 +181,8 @@ allocate_pages (grub_size_t prot_size, grub_size_t *align,
for (; err && *align + 1 > min_align; (*align)--)
{
grub_errno = GRUB_ERR_NONE;
- err = grub_relocator_alloc_chunk_align (relocator, &ch,
- 0x1000000,
- 0xffffffff & ~prot_size,
+ err = grub_relocator_alloc_chunk_align (relocator, &ch, 0x1000000,
+ UP_TO_TOP32 (prot_size),
prot_size, 1 << *align,
GRUB_RELOCATOR_PREFERENCE_LOW,
1);
diff --git a/grub-core/loader/i386/multiboot_mbi.c b/grub-core/loader/i386/multiboot_mbi.c
index ad3cc292f..a67d9d0a8 100644
--- a/grub-core/loader/i386/multiboot_mbi.c
+++ b/grub-core/loader/i386/multiboot_mbi.c
@@ -466,10 +466,9 @@ grub_multiboot_make_mbi (grub_uint32_t *target)
bufsize = grub_multiboot_get_mbi_size ();
- err = grub_relocator_alloc_chunk_align (grub_multiboot_relocator, &ch,
- 0x10000, 0xa0000 - bufsize,
- bufsize, 4,
- GRUB_RELOCATOR_PREFERENCE_NONE, 0);
+ err = grub_relocator_alloc_chunk_align_safe (grub_multiboot_relocator, &ch,
+ 0x10000, 0xa0000, bufsize, 4,
+ GRUB_RELOCATOR_PREFERENCE_NONE, 0);
if (err)
return err;
ptrorig = get_virtual_current_address (ch);
diff --git a/grub-core/loader/i386/pc/linux.c b/grub-core/loader/i386/pc/linux.c
index 31f09922b..5fed5ffdf 100644
--- a/grub-core/loader/i386/pc/linux.c
+++ b/grub-core/loader/i386/pc/linux.c
@@ -453,10 +453,8 @@ grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),
{
grub_relocator_chunk_t ch;
- err = grub_relocator_alloc_chunk_align (relocator, &ch,
- addr_min, addr_max - size,
- size, 0x1000,
- GRUB_RELOCATOR_PREFERENCE_HIGH, 0);
+ err = grub_relocator_alloc_chunk_align_safe (relocator, &ch, addr_min, addr_max, size,
+ 0x1000, GRUB_RELOCATOR_PREFERENCE_HIGH, 0);
if (err)
return err;
initrd_chunk = get_virtual_current_address (ch);
diff --git a/grub-core/loader/mips/linux.c b/grub-core/loader/mips/linux.c
index 7b723bf18..e4ed95921 100644
--- a/grub-core/loader/mips/linux.c
+++ b/grub-core/loader/mips/linux.c
@@ -442,12 +442,9 @@ grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),
{
grub_relocator_chunk_t ch;
- err = grub_relocator_alloc_chunk_align (relocator, &ch,
- (target_addr & 0x1fffffff)
- + linux_size + 0x10000,
- (0x10000000 - size),
- size, 0x10000,
- GRUB_RELOCATOR_PREFERENCE_NONE, 0);
+ err = grub_relocator_alloc_chunk_align_safe (relocator, &ch, (target_addr & 0x1fffffff) +
+ linux_size + 0x10000, 0x10000000, size,
+ 0x10000, GRUB_RELOCATOR_PREFERENCE_NONE, 0);
if (err)
goto fail;
diff --git a/grub-core/loader/multiboot.c b/grub-core/loader/multiboot.c
index 4a98d7082..facb13f3d 100644
--- a/grub-core/loader/multiboot.c
+++ b/grub-core/loader/multiboot.c
@@ -403,7 +403,7 @@ grub_cmd_module (grub_command_t cmd __attribute__ ((unused)),
{
grub_relocator_chunk_t ch;
err = grub_relocator_alloc_chunk_align (GRUB_MULTIBOOT (relocator), &ch,
- lowest_addr, (0xffffffff - size) + 1,
+ lowest_addr, UP_TO_TOP32 (size),
size, MULTIBOOT_MOD_ALIGN,
GRUB_RELOCATOR_PREFERENCE_NONE, 1);
if (err)
diff --git a/grub-core/loader/multiboot_elfxx.c b/grub-core/loader/multiboot_elfxx.c
index cc6853692..f2318e0d1 100644
--- a/grub-core/loader/multiboot_elfxx.c
+++ b/grub-core/loader/multiboot_elfxx.c
@@ -109,10 +109,10 @@ CONCAT(grub_multiboot_load_elf, XX) (mbi_load_data_t *mld)
if (load_size > mld->max_addr || mld->min_addr > mld->max_addr - load_size)
return grub_error (GRUB_ERR_BAD_OS, "invalid min/max address and/or load size");
- err = grub_relocator_alloc_chunk_align (GRUB_MULTIBOOT (relocator), &ch,
- mld->min_addr, mld->max_addr - load_size,
- load_size, mld->align ? mld->align : 1,
- mld->preference, mld->avoid_efi_boot_services);
+ err = grub_relocator_alloc_chunk_align_safe (GRUB_MULTIBOOT (relocator), &ch,
+ mld->min_addr, mld->max_addr,
+ load_size, mld->align ? mld->align : 1,
+ mld->preference, mld->avoid_efi_boot_services);
if (err)
{
@@ -256,7 +256,7 @@ CONCAT(grub_multiboot_load_elf, XX) (mbi_load_data_t *mld)
continue;
err = grub_relocator_alloc_chunk_align (GRUB_MULTIBOOT (relocator), &ch, 0,
- (0xffffffff - sh->sh_size) + 1,
+ UP_TO_TOP32 (sh->sh_size),
sh->sh_size, sh->sh_addralign,
GRUB_RELOCATOR_PREFERENCE_NONE,
mld->avoid_efi_boot_services);
diff --git a/grub-core/loader/multiboot_mbi2.c b/grub-core/loader/multiboot_mbi2.c
index 0efc66062..03967839c 100644
--- a/grub-core/loader/multiboot_mbi2.c
+++ b/grub-core/loader/multiboot_mbi2.c
@@ -295,10 +295,10 @@ grub_multiboot2_load (grub_file_t file, const char *filename)
return grub_error (GRUB_ERR_BAD_OS, "invalid min/max address and/or load size");
}
- err = grub_relocator_alloc_chunk_align (grub_multiboot2_relocator, &ch,
- mld.min_addr, mld.max_addr - code_size,
- code_size, mld.align ? mld.align : 1,
- mld.preference, keep_bs);
+ err = grub_relocator_alloc_chunk_align_safe (grub_multiboot2_relocator, &ch,
+ mld.min_addr, mld.max_addr,
+ code_size, mld.align ? mld.align : 1,
+ mld.preference, keep_bs);
}
else
err = grub_relocator_alloc_chunk_addr (grub_multiboot2_relocator,
@@ -708,7 +708,7 @@ grub_multiboot2_make_mbi (grub_uint32_t *target)
COMPILE_TIME_ASSERT (MULTIBOOT_TAG_ALIGN % sizeof (grub_properly_aligned_t) == 0);
err = grub_relocator_alloc_chunk_align (grub_multiboot2_relocator, &ch,
- 0, 0xffffffff - bufsize,
+ 0, UP_TO_TOP32 (bufsize),
bufsize, MULTIBOOT_TAG_ALIGN,
GRUB_RELOCATOR_PREFERENCE_NONE, 1);
if (err)
diff --git a/grub-core/loader/xnu_resume.c b/grub-core/loader/xnu_resume.c
index 8089804d4..d648ef0cd 100644
--- a/grub-core/loader/xnu_resume.c
+++ b/grub-core/loader/xnu_resume.c
@@ -129,7 +129,7 @@ grub_xnu_resume (char *imagename)
{
grub_relocator_chunk_t ch;
err = grub_relocator_alloc_chunk_align (grub_xnu_relocator, &ch, 0,
- (0xffffffff - hibhead.image_size) + 1,
+ UP_TO_TOP32 (hibhead.image_size),
hibhead.image_size,
GRUB_XNU_PAGESIZE,
GRUB_RELOCATOR_PREFERENCE_NONE, 0);
diff --git a/include/grub/relocator.h b/include/grub/relocator.h
index 24d8672d2..1b3bdd92a 100644
--- a/include/grub/relocator.h
+++ b/include/grub/relocator.h
@@ -49,6 +49,35 @@ grub_relocator_alloc_chunk_align (struct grub_relocator *rel,
int preference,
int avoid_efi_boot_services);
+/*
+ * Wrapper for grub_relocator_alloc_chunk_align() with purpose of
+ * protecting against integer underflow.
+ *
+ * Compare to its callee, max_addr has different meaning here.
+ * It covers entire chunk and not just start address of the chunk.
+ */
+static inline grub_err_t
+grub_relocator_alloc_chunk_align_safe (struct grub_relocator *rel,
+ grub_relocator_chunk_t *out,
+ grub_phys_addr_t min_addr,
+ grub_phys_addr_t max_addr,
+ grub_size_t size, grub_size_t align,
+ int preference,
+ int avoid_efi_boot_services)
+{
+ /* Sanity check and ensure following equation (max_addr - size) is safe. */
+ if (max_addr < size || (max_addr - size) < min_addr)
+ return GRUB_ERR_OUT_OF_RANGE;
+
+ return grub_relocator_alloc_chunk_align (rel, out, min_addr,
+ max_addr - size,
+ size, align, preference,
+ avoid_efi_boot_services);
+}
+
+/* Top 32-bit address minus s bytes and plus 1 byte. */
+#define UP_TO_TOP32(s) ((~(s) & 0xffffffff) + 1)
+
#define GRUB_RELOCATOR_PREFERENCE_NONE 0
#define GRUB_RELOCATOR_PREFERENCE_LOW 1
#define GRUB_RELOCATOR_PREFERENCE_HIGH 2
--
2.26.2
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