GCC is electing to instrument grub_efi_init() to give it stack smashing
protection when configuring with --enable-stack-protector on the x86_64-efi
target. In the function prologue, the canary at the top of the stack frame
is set to the value of the stack guard. And in the epilogue, the canary is
checked to verify if it is equal to the guard and if not to call the stack
check fail function. The issue is that grub_efi_init() sets up the guard
by initializing it with random bytes, if the firmware supports the RNG
protocol. So in its prologue the canary will be set with the value of the
uninitialized guard, likely NUL bytes. Then the guard is initialized, and
finally the epilogue checks the canary against the guard, which will almost
certainly be different. This causes the code path for a smashed stack to be
taken, causing the machine to print out a message that stack smashing was
detected, wait 5 seconds, and then reboot. Disable grub_efi_init()
instrumentation so there is no stack smashing false positive generated.
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The sector size in bytes is added to each line and it is allowed to be
6 decimal digits long, which covers the most common cases of 512 and 4096
byte sectors with space for two additional digits as future-proofing. The
size allocation is updated to reflect this additional field. Also make
clearer the size allocation calculation.
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Use the return value of grub_snprintf() to move the string pointer forward,
instead of incrementing the string pointer iteratively until a NULL byte is
reached. Move the space out of the format string argument, a small
optimization, but also makes the spacing clearer. Also, use the new
PRIxGRUB_OFFSET instead of PRIuGRUB_UINT64_T to accurately reflect the
format string for this type.
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
A large enough argument to the --port option could cause a string buffer
to be not NULL terminated because grub_strncpy() does not guarantee NULL
termination if copied string is longer than max characters to copy.
Fixes: 712309eaae04 (term/serial: Use grub_strncpy() instead of grub_snprintf() when only copying string)
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
E.g. 2.10 instead of 00020064 and 2.3.1 instead of 0002001f.
See UEFI 2.10 specification, chapter 4.2.1 EFI_TABLE_HEADER.
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Move some calls used to access NTFS attribute header fields into
functions with human-readable names.
Suggested-by: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: Maxim Suhanov <dfirblog@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This fix introduces checks to ensure that an NTFS volume label is always
read from the corresponding file record segment.
The current NTFS code allows the volume label string to be read from an
arbitrary, attacker-chosen memory location. However, the bytes read are
always treated as UTF-16LE. So, the final string displayed is mostly
unreadable and it can't be easily converted back to raw bytes.
The lack of this check is a minor issue, likely not causing a significant
data leak.
Reported-by: Maxim Suhanov <dfirblog@gmail.com>
Signed-off-by: Maxim Suhanov <dfirblog@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This fix introduces checks to ensure that bitmaps for directory indices
are never read beyond their actual sizes.
The lack of this check is a minor issue, likely not exploitable in any way.
Reported-by: Maxim Suhanov <dfirblog@gmail.com>
Signed-off-by: Maxim Suhanov <dfirblog@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This fix introduces checks to ensure that index entries are never read
beyond the corresponding directory index.
The lack of this check is a minor issue, likely not exploitable in any way.
Reported-by: Maxim Suhanov <dfirblog@gmail.com>
Signed-off-by: Maxim Suhanov <dfirblog@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
When reading a file containing resident data, i.e., the file data is stored in
the $DATA attribute within the NTFS file record, not in external clusters,
there are no checks that this resident data actually fits the corresponding
file record segment.
When parsing a specially-crafted file system image, the current NTFS code will
read the file data from an arbitrary, attacker-chosen memory offset and of
arbitrary, attacker-chosen length.
This allows an attacker to display arbitrary chunks of memory, which could
contain sensitive information like password hashes or even plain-text,
obfuscated passwords from BS EFI variables.
This fix implements a check to ensure that resident data is read from the
corresponding file record segment only.
Fixes: CVE-2023-4693
Reported-by: Maxim Suhanov <dfirblog@gmail.com>
Signed-off-by: Maxim Suhanov <dfirblog@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
When parsing an extremely fragmented $MFT file, i.e., the file described
using the $ATTRIBUTE_LIST attribute, current NTFS code will reuse a buffer
containing bytes read from the underlying drive to store sector numbers,
which are consumed later to read data from these sectors into another buffer.
These sectors numbers, two 32-bit integers, are always stored at predefined
offsets, 0x10 and 0x14, relative to first byte of the selected entry within
the $ATTRIBUTE_LIST attribute. Usually, this won't cause any problem.
However, when parsing a specially-crafted file system image, this may cause
the NTFS code to write these integers beyond the buffer boundary, likely
causing the GRUB memory allocator to misbehave or fail. These integers contain
values which are controlled by on-disk structures of the NTFS file system.
Such modification and resulting misbehavior may touch a memory range not
assigned to the GRUB and owned by firmware or another EFI application/driver.
This fix introduces checks to ensure that these sector numbers are never
written beyond the boundary.
Fixes: CVE-2023-4692
Reported-by: Maxim Suhanov <dfirblog@gmail.com>
Signed-off-by: Maxim Suhanov <dfirblog@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
During attempts to configure a serial console, a Page Fault Exception
and system reset were encountered, specifically on release 2.12~rc1.
This issue was not present in prior versions and seemed to affect only
a specific machine, potentially pointing to hardware or firmware flaw.
After investigation, it was discovered that the invalid page access
occurred during the discovery of serial MMIO ports as specified by
ACPI's SPCR table [1]. The recent change uncovered an issue in GRUB's
ACPI driver.
In certain cases, the XSDT/RSDT root table might contain a NULL entry as
a terminator, depending on how the tables are assembled. GRUB cannot
blindly trust the address in the root table to be valid and should
perform a sanity check for NULL entries. This patch introduces this
simple check.
This fix is also inspired by a related Linux kernel fix [2].
[1] 7b192ec4c term/ns8250: Use ACPI SPCR table when available to configure serial
[2] 0f929fbf0 ACPICA: Tables: Add new mechanism to skip NULL entries in RSDT and XSDT.
Signed-off-by: Michael Chang <mchang@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
When grub-install is run with the verbose option, it will print a log
message indicating the grub-mkimage command and arguments used.
GRUB no longer calls the grub-mkimage binary internally, however the
command logged is a command that if run should effectively be what
grub-install used. However, as this has changed some of the newer
options have been incorrectly added so that the printed command fails
when run separately. This change makes the displayed command run as
intended.
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This is a preparatory patch to make the following patch less cluttered. The
only visible change made here is to not print extra spaces when either or
both --note or --disable-shim-lock are not given and to not print an extra
space at the end of the command. The latter is done by constructing the
trailing argument string with spaces in front of each argument rather than
trailing. The allocation of the argument string is made precise, which has
the benefit of saving a few bytes, but more importantly self-documenting
what the needed allocated bytes are. Also, unneeded braces are removed from
an if block.
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The commit 80948f532d (lib/i386/relocator64: Build fixes for i386) has
broken 64-bit FreeBSD boot on BIOS. This patch fixes the issue.
Fixes: 80948f532d (lib/i386/relocator64: Build fixes for i386)
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
It turns out that setting $xen_version in linux_entry_xsm() override
$xen_version in the loop over $reverse_sorted_xen_list. This means
that only one entry per Xen version is going to enable XSM, but all
further entries are going to have "(XSM enabled)" in their titles
without enabling XSM.
When a "xenpolicy-$xen_version" file was found for the current
$xen_version, it would overwrite $xen_version to add "(XSM enabled)" to
the menu entry title. Once updated, the next call to linux_entry_xsm()
would also have this modified $xen_version and would look for the file
"xenpolicy-*(XSM enabled)" and fail.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
In the configure phase, the "-mcmodel=large" CFLAGS passed the test, but
because it has not been implemented in gcc, the following warning will
appear when compiling:
gcc: warning: 'large' is not supported, now cmodel is set to 'normal'
Signed-off-by: Xiaotian Wu <wuxiaotian@loongson.cn>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The backtrace module is written assuming that the frame pointer is in %ebp.
By default, -Os optimization level is used, which enables the gcc option
-fomit-frame-pointer. This breaks the backtrace functionality. Enabling
this may cause an unnoticeable performance cost and virtually no size increase.
The backtrace command on x86_64 and probably i386 is broken due to the
above rationale. I've not verified, but presumably the backtrace that used
to be printed for an unhandled CPU exception is also broken. Do any distros
handle this?
Considering that, to my knowledge, no one has complained about this in the
over 13 years that -Os has been used, has this code actually been useful?
Is it worth disabling -fomit-frame-pointer? Though, I don't see much downside
right now in disabling it. Alternatively, we could disable/remove the
backtrace code. I think it would be nice to keep it and have it working.
Nowadays, presumably QEMU makes the GDB stub rarely used as I imagine most
are developing in a virtual machines. Also, the GDB stub does not work in UEFI.
So, if anyone is using it on real hardware, they are doing so on pretty old
machines. The lack of a GDB stub does not seem to be a pain point because
no one has got it working on UEFI.
This patch gets the backtrace command working on x86_64-efi in QEMU for me.
However, it hangs when run on my laptop. Not sure what's going on there.
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Recent mixed-mode Linux kernels, i.e., v4.0 or newer, can access EFI
runtime services at OS runtime even when the OS was not entered via the
EFI stub. This is because, instead of reverting back to the firmware's
segment selectors, GDTs and IDTs, the 64-bit kernel simply calls 32-bit
runtime services using compatibility mode, i.e., the same mode used for
32-bit user space, without taking down all interrupt handling, exception
handling, etc.
This means that GRUB's legacy x86 boot mode is sufficient to make use of
this: 32-bit i686 builds of GRUB can already boot 64-bit kernels in EFI
enlightened mode, but without going via the EFI stub, and provide all
the metadata that the OS needs to map the EFI runtime regions and call
EFI runtime services successfully.
It does mean that GRUB should not attempt to invoke the firmware's
LoadImage()/StartImage() methods on kernel builds that it knows cannot
be started natively. So, add a check for this in the native EFI boot
path and fall back to legacy x86 mode in such cases.
Note that in the general case, booting non-native images of the same
native word size, e.g., x64 EFI apps on arm64 firmware, might be
supported by means of emulation. So, let's only disallow images that use
a non-native word size. This will also permit booting i686 kernels on
x86_64 builds, although without access to runtime services, as this is
not supported by Linux.
This change on top of 2.12-rc1 is sufficient to boot ordinary Linux
mixed mode builds and get full access to the EFI runtime services.
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: Steve McIntyre <steve@einval.com>
Cc: Julian Andres Klode <julian.klode@canonical.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Dimitri John Ledkov <dimitri.ledkov@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The x86_64 Linux kernel can be booted in 32-bit mode, in which case the
startup code creates a set of preliminary page tables that map the first
4 GiB of physical memory 1:1 and enables paging. This is a prerequisite
for 64-bit execution and can therefore only be implemented in 32-bit code.
The x86_64 Linux kernel can also be booted in 64-bit mode directly: this
implies that paging is already enabled and it is the responsibility of
the bootloader to ensure that the active page tables cover the entire
loaded image, including its BSS space, the size of which is described in
the image's setup header.
Given that the EFI spec mandates execution in long mode for x86_64 and
stipulates that all system memory is mapped 1:1, the Linux/x86
requirements for 64-bit entry can be met trivially when booting on
x86_64 via EFI. So, enter via the 64-bit entry point in this case.
This involves inspecting the xloadflags field in the setup header to
check whether the 64-bit entry point is supported. This field was
introduced in Linux version v3.8 (early 2013).
This change ensures that all EFI firmware tables and other assets passed
by the firmware or bootloader in memory remain mapped and accessible
throughout the early startup code.
Avoiding the drop out of long mode will also be needed to support
upcoming CPU designs that no longer implement 32-bit mode at all
(as recently announced by Intel [0]).
[0] https://www.intel.com/content/www/us/en/developer/articles/technical/envisioning-future-simplified-architecture.html
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: Julian Andres Klode <julian.klode@canonical.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Some dnodes are shared with properties zap. This is used
e.g. for quotas. Then dnode type is 0xc4 and GRUB stumbles on
this. Check bonus type and if it's ok then ignore dnode type mismatch
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Reading them is harmless but useless as they are empty by definition
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
We ended up comparing over unset values as we had dnode_phys on one side
and dnode on another
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This is a speedup used in some ZFS version. This trips GRUB and makes it
unable to access directories. Just skip it for now and revisit
if we ever need this speedup.
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
If the EFI graphics pixel format is PixelBltOnly, we cannot write directly
to the frame buffer. We need the shadow frame buffer which we copy via
the BitBlt operation to the hardware.
If the pixel format is PixelBltOnly and allocation of the shadow frame
buffer fails, we must raise an error to signal that the EFI GOP protocol
is not usable.
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
It has been reported that makeinfo version 4.13a complains and returns
error when menus for chapter structuring commands are not present. It
is also known that newer makeinfos, such as version 6.7, will create
default menus when needed. Since the menu will be created regardless,
explicitly create it to support older makeinfo versions. This also
enables building to be successful when an older makeinfo is installed
because in that case info files are attempted to be generated with the
"all" target.
Reported-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Olaf Hering <olaf@aepfle.de>
The @xref command is meant to be used at the beginning of a sentence
because its expansion creates a "See " prefix on all output formats, and
on older makeinfo versions is strict about enforcing a "." or "," after
the command. The @ref command has no such restriction and is just the
link, which allows more control over output. This also fixes an issue
where there was a repeated "see" in the output.
Reported-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Olaf Hering <olaf@aepfle.de>
Allow using the envvar GRUB_SHELL_LUKS_TIMEOUT to change the default
timeout. If not specified, use value of GRUB_SHELL_DEFAULT_TIMEOUT. And
if that is not specified, fallback to original 600s timeout.
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This was causing the cryptomount command to return failure even though
the crypto device was successfully added. Of course, this meant that any
script using the return code would behave unexpectedly.
Fixes: 3cf2e848bc03 (disk/cryptodisk: Allows UUIDs to be compared in a dash-insensitive manner)
Suggested-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Patrich Steinhardt <ps@pks.im>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
To comply with C99 and POSIX standards, snprintf() should return the
number of bytes that would be written to the string (excluding the
terminating NUL byte) if the buffer size was big enough. Before this
change, the return value was the minimum of the standard return and the
length of the buffer. Rarely is the return value of grub_snprintf() or
grub_vsnprintf() used with current code, and the few places where it is
used do not need to be changed.
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This test is meant to test output via various serial devices. Currently,
only the PCI serial device is tested.
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
While here, move "-qemu=*" case to be next to the "--qemu-opts=*" case.
This causes no change in logic, but is more logically located.
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
In long list mode, if the file can not be opened, the file is not printed.
Instead, print the file but print the size as "????????????".
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
For each non-directory path argument to the ls command, the full path was
being sent to the print functions, instead of the dirname. The long output
print function expected dirname to be the directory containing the file
and so could not open the file to get the file size because the generated
path was incorrect. This caused the output to be a blank line.
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Specifically, return GRUB_ERR_BAD_FILE_TYPE because this is what is
expected by the ls command when it is given a path to a non-directory.
This fixes a bug where calling ls with a list of non-directory paths
outputs a blank line for each such argument.
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The videoinfo command will initialize all non-active video adapters. Video
drivers tend to zero out the global framebuffer object on initialization.
This is not a problem when there is no active video adapter. However, when
there is, then outputting to the video adapter will cause a crash because
methods in the framebuffer object are reinitialized. For example, this
command sequence will cause a crash.
terminal_output --append gfxterm; videoinfo
When running in a QEMU headless with GRUB built for the x86_64-efi target,
the first command initializes the Bochs video adapter, which, among
other things, sets the set_page() member function. Then when videoinfo is
run, all non-Bochs video adapters will be initialized, each one wiping
the framebuffer and thus setting set_page to NULL. Soon after the videoinfo
command finishes there will be a call to grub_refresh(), which will
ultimately call the framebuffer's set_page which will be NULL and cause
a crash when called.
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
A list of improvements:
* Remove reference to "initial ramdisk" and replace with "initrd". This
then covers the case of ramdisk and ramfs, which is the usual method
with kernels 2.6 and newer.
* Add sentence with URL to initrd documentation Linux kernel.
* Add a section documenting how to have the initrd command generate
a new-style initrd via a specially crafted argument and include an example.
* Update initrd16 to refer to the initrd section and make note that
initrd16 is only on the pc platform.
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Oskari Pirhonen <xxc3ncoredxx@gmail.com>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
According to commit 0231d00082 (ACPI: SPCR: Make SPCR available to x86)
to the Linux kernel, "On x86, many systems have a valid SPCR table but the
table version is not 2 so the table version check must be a warning."
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The cat command should not be used to print binary data because it can
show bytes not in the binary data and not show bytes that are in the data,
which can lead to confusion. This happens because cat does some processing
of the data stream, namely trying to decode substrings as UTF-8.
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Oskari Pirhonen <xxc3ncoredxx@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
During configuration of SDL2, variable enable_grub_emu_sdl2 is checked
whether to throw an error message. However, error could not happen
because two unequal strings were compared. Fix this by referencing
value of enable_grub_emu_sdl2, not name.
Fixes: 17d6ac1a7 (emu: Add SDL2 support)
Signed-off-by: Michał Grzelak <mchl.grzlk@gmail.com>
Reviewed-by: Julian Andres Klode <julian.klode@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Also reword a prior sentence to be more clear.
Fixes: 5a3d2b4742df (docs: Add debugging chapter to development documentation)
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Oskari Pirhonen <xxc3ncoredxx@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
On an unmerged-usr system, grub-mkconfig errors out with the following
error due to /usr/bin/sh not existing:
/usr/sbin/grub-mkconfig: /etc/grub.d/25_bli: /usr/bin/sh: bad interpreter: No such file or directory
Use a /bin/sh shebang to fix the error as well as match the other
existing files.
Fixes: 158a6583e (util/grub.d/25_bli.in: Activate bli module on EFI)
Signed-off-by: Oskari Pirhonen <xxc3ncoredxx@gmail.com>
Reviewed-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Oliver Steffen <osteffen@redhat.com>
This allows an invocation of grub-shell to set the value of debug regardless
of the global default environment variable GRUB_SHELL_DEFAULT_DEBUG.
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
