When the Linux kernel is being used with no initrd, iPXE will still
provide a zero-length initrd.magic file within the virtual filesystem.
As of commit 6a004be ("[efi] Support the initrd autodetection
mechanism in newer Linux kernels"), this zero-length file will also be
exposed via an EFI_LOAD_FILE2_PROTOCOL instance on a handle with a
fixed device path.
The correct handling of zero-length files via EFI_LOAD_FILE2_PROTOCOL
is unfortunately not well defined.
Linux expects the first call to LoadFile() to always fail with
EFI_BUFFER_TOO_SMALL. When the initrd is genuinely zero-length, iPXE
will return success since the buffer is not too small to hold the
(zero-length) file. This causes Linux to immediately report a
spurious EFI_LOAD_ERROR boot failure.
We could change the logic in iPXE's efi_file_load() to always return
EFI_BUFFER_TOO_SMALL if Buffer is NULL on entry. Since the correct
behaviour of LoadFile() in the corner case of a zero-length file is
left undefined by the UEFI specification, this would be permissible.
Unfortunately this approach would not fix the problem. If we return
EFI_BUFFER_TOO_SMALL and set the file length to zero, then Linux will
call the boot services AllocatePages() method with a zero length. In
at least the EDK2 implementation, this combination of parameters will
cause AllocatePages() to return EFI_OUT_OF_RESOURCES, and Linux will
again report a boot failure.
Another approach would be to install the initrd device path handle
only if we have a non-empty initrd to offer. Unfortunately this would
lead to a failure in yet another corner case: if a previous bootloader
has installed an initrd device path handle (e.g. to pass a boot script
to iPXE) then we must not leave that initrd in place, since then our
loaded kernel would end up seeing the wrong initrd content.
The cleanest fix seems to be to ensure that the initrd device path
handle is installed with the EFI_DEVICE_PATH_PROTOCOL instance present
but with the EFI_LOAD_FILE2_PROTOCOL instance absent (and forcibly
uninstalled if necessary), matching the state in which we leave the
handle after uninstalling our virtual filesystem. Linux will then not
find any handle that supports EFI_LOAD_FILE2_PROTOCOL within the fixed
device path, and so will fall through to trying other mechanisms to
locate the initrd.
Reported-by: Chris Bradshaw <cwbshaw@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Commit 7ca801d ("[efi] Use the EFI_RNG_PROTOCOL as an entropy source
if available") added EFI_RNG_PROTOCOL as an alternative entropy source
via an ad-hoc mechanism specific to efi_entropy.c.
Split out EFI_RNG_PROTOCOL to a separate entropy source, and allow the
entropy core to handle the selection of RDRAND, EFI_RNG_PROTOCOL, or
timer ticks as the active source.
The fault detection logic added in commit a87537d ("[efi] Detect and
disable seriously broken EFI_RNG_PROTOCOL implementations") may be
removed completely, since the failure will already be detected by the
generic ANS X9.82-mandated repetition count test and will now be
handled gracefully by the entropy core.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
As noted in commit 3c83843 ("[rng] Check for several functioning RTC
interrupts"), experimentation shows that Hyper-V cannot be trusted to
reliably generate RTC interrupts. (As noted in commit f3ba0fb
("[hyperv] Provide timer based on the 10MHz time reference count
MSR"), Hyper-V appears to suffer from a general problem in reliably
generating any legacy interrupts.) An alternative entropy source is
therefore required for an image that may be used in a Hyper-V Gen1
virtual machine.
The x86 RDRAND instruction provides a suitable alternative entropy
source, but may not be supported by all CPUs. We must therefore allow
for multiple entropy sources to be compiled in, with the single active
entropy source selected only at runtime.
Restructure the internal entropy API to allow a working entropy source
to be detected and chosen at runtime.
Enable the RDRAND entropy source for all x86 builds, since it is
likely to be substantially faster than any other source.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Linux 5.7 added the ability to autodetect an initrd by searching for a
handle via a fixed vendor-specific "Linux initrd device path" and then
locating and using the EFI_LOAD_FILE2_PROTOCOL instance on that
handle.
This maps quite naturally onto our existing concept of a "magic
initrd" as introduced for EFI in commit e5f0255 ("[efi] Provide an
"initrd.magic" file for use by UEFI kernels").
Add an EFI_LOAD_FILE2_PROTOCOL instance to our EFI virtual files
(backed by simply calling the existing EFI_SIMPLE_FILE_SYSTEM_PROTOCOL
method to read from the file), and install the protocol instance for
the "initrd.magic" virtual file onto a new device handle that also
provides the Linux initrd device path.
The design choice in Linux of using a single fixed device path makes
this unfortunately messy to support, since device paths must be unique
within a system. When multiple bootloaders are used (e.g. GRUB
loading iPXE loading Linux) then only one bootloader can ever install
the device path onto a handle. Subsequent bootloaders must locate the
existing handle and replace the load file protocol instance with their
own.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Show the requested range when a caller reads from a virtual file via
the EFI_SIMPLE_FILE_SYSTEM_PROTOCOL interface.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The "bridge" driver introduced in 3aa6b79 ("[pci] Add minimal PCI
bridge driver") is required only for BIOS builds using the ENA driver,
where experimentation shows that we cannot rely on the BIOS to fully
assign MMIO addresses.
Since the driver is a valid PCI driver, it will end up binding to all
PCI bridge devices even on a UEFI platform, where the firmware is
likely to have completed MMIO address assignment correctly. This has
no impact on most systems since there is generally no UEFI driver for
PCI bridges: the enumeration of the whole PCI bus is handled by the
PciBusDxe driver bound to the root bridge.
Experimentation shows that at least one laptop will freeze at the
point that iPXE attempts to bind to the bridge device. No deeper
investigation has been carried out to find the root cause.
Fix by causing efipci_supported() to return an error unless the
configuration space header type indicates a non-bridge device.
Reported-by: Marcel Petersen <mp@sbe.de>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Try loading the autoexec.ipxe script first from the directory
containing the iPXE binary (based on the relative file path provided
to us via EFI_LOADED_IMAGE_PROTOCOL), then fall back to trying the
root directory.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Treat a command line passed to iPXE via UEFI LoadOptions as an image
to be registered at startup, as is already done for the .lkrn, .pxe,
and .exe BIOS images.
Originally-implemented-by: Ladi Prosek <lprosek@redhat.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Extend the functionality of efi_locate_device() to allow callers to
find instances of the protocol that may exist further up the device
path.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
When chainloading iPXE from an EFI VLAN device, configure the
corresponding iPXE VLAN device to be created automatically.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
When chainloading iPXE from a VLAN device, the MAC address of the
loaded image's device handle will match the MAC address of the trunk
device created by iPXE, and the autoboot process will then erroneously
consider the trunk device to be an autoboot device.
Fix by recording the VLAN tag along with the MAC address, and treating
the VLAN tag as part of the filter used to match the MAC address
against candidate network devices.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The network device index currently serves two purposes: acting as a
sequential index for network device names ("net0", "net1", etc), and
acting as an opaque unique integer identifier used in socket address
scope IDs.
There is no particular need for these usages to be linked, and it can
lead to situations in which devices are named unexpectedly. For
example: if a system has two network devices "net0" and "net1", a VLAN
is created as "net1-42", and then a USB NIC is connected, then the USB
NIC will be named "net3" rather than the expected "net2" since the
VLAN device "net1-42" will have consumed an index.
Separate the usages: rename the "index" field to "scope_id" (matching
its one and only use case), and assign the name without reference to
the scope ID by finding the first unused name. For consistency,
assign the scope ID by similarly finding the first unused scope ID.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
When chainloading iPXE from a VLAN device, the MAC address within the
cached DHCPACK will match the MAC address of the trunk device created
by iPXE, and the cached DHCPACK will then end up being erroneously
applied to the trunk device. This tends to break outbound IPv4
routing, since both the trunk and VLAN devices will have the same
assigned IPv4 address.
Fix by recording the VLAN tag along with the cached DHCPACK, and
treating the VLAN tag as part of the filter used to match the cached
DHCPACK against candidate network devices.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
EFI provides no API for determining the VLAN tag (if any) for a
specified device handle. There is the EFI_VLAN_CONFIG_PROTOCOL, but
that exists only on the trunk device handle (not on the VLAN device
handle), and provides no way to match VLAN tags against the trunk
device's child device handles.
The EDK2 codebase seems to rely solely on the device path to determine
the VLAN tag for a specified device handle: both NetLibGetVlanId() and
BmGetNetworkDescription() will parse the device path to search for a
VLAN_DEVICE_PATH component.
Add efi_path_vlan() which uses the same device path parsing logic to
determine the VLAN tag.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Provide a single central implementation of the logic for stepping
through elements of an EFI device path.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
UEFI implements VLAN support within the Managed Network Protocol (MNP)
driver, which may create child VLAN devices automatically based on
stored UEFI variables. These child devices do not themselves provide
a raw-packet interface via EFI_SIMPLE_NETWORK_PROTOCOL, and may be
consumed only via the EFI_MANAGED_NETWORK_PROTOCOL interface.
The device paths constructed for these child devices may conflict with
those for the EFI_SIMPLE_NETWORK_PROTOCOL instances that iPXE attempts
to install for its own VLAN devices. The upshot is that creating an
iPXE VLAN device (e.g. via the "vcreate" command) will fail if the
UEFI Managed Network Protocol has already created a device for the
same VLAN tag.
Fix by providing our own EFI_VLAN_CONFIG_PROTOCOL instance on the same
device handle as EFI_SIMPLE_NETWORK_PROTOCOL. This causes the MNP
driver to treat iPXE's device as supporting hardware VLAN offload, and
it will therefore not attempt to install its own instance of the
protocol.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The DMA mapping is performed implicitly as part of the call to
dma_alloc(). The current implementation creates the IOMMU mapping for
the allocated and potentially uninitialised data before returning to
the caller (which will immediately zero out or otherwise initialise
the buffer). This leaves a small window within which a malicious PCI
device could potentially attempt to retrieve firmware-owned secrets
present in the uninitialised buffer. (Note that the hypothetically
malicious PCI device has no viable way to know the address of the
buffer from which to attempt a DMA read, rendering the attack
extremely implausible.)
Guard against any such hypothetical attacks by zeroing out the
allocated buffer prior to creating the coherent DMA mapping.
Suggested-by: Mateusz Siwiec <Mateusz.Siwiec@ioactive.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow pci_find_next() to discover devices beyond the first PCI
segment, by generalising pci_num_bus() (which implicitly assumes that
there is only a single PCI segment) with pci_discover() (which has the
ability to return an arbitrary contiguous chunk of PCI bus:dev.fn
address space).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Extend the glyph cache to include a number of dynamic entries that are
populated on demand whenever a non-ASCII character needs to be drawn.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Accumulate UTF-8 characters in fbcon_putchar(), and require the frame
buffer console's .glyph() method to accept Unicode character values.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Several keyboard layouts define ASCII characters as accessible only
via the AltGr modifier. Add support for this modifier to ensure that
all ASCII characters are accessible.
Experiments suggest that the BIOS console is likely to fail to
generate ASCII characters when the AltGr key is pressed. Work around
this limitation by accepting LShift+RShift (which will definitely
produce an ASCII character) as a synonym for AltGr.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Handle Ctrl and CapsLock key modifiers within key_remap(), to provide
consistent behaviour across different console types.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Attempt to fetch the autoexec.ipxe script via TFTP using the PXE base
code protocol installed on the loaded image's device handle, if
present.
This provides a generic alternative to the use of an embedded script
for chainloaded binaries, which is particularly useful in a UEFI
Secure Boot environment since it allows the script to be modified
without the need to sign a new binary.
As a side effect, this also provides a third method for breaking the
PXE chainloading loop (as an alternative to requiring an embedded
script or custom DHCP server configuration).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The RFC4122 specification defines UUIDs as being in network byte
order, but an unfortunately significant amount of (mostly Microsoft)
software treats them as having the first three fields in little-endian
byte order.
In an ideal world, any server-side software that compares UUIDs for
equality would perform an endian-insensitive comparison (analogous to
comparing strings for equality using a case-insensitive comparison),
and would therefore not care about byte order differences.
Define a setting type name ":guid" to allow a UUID setting to be
formatted in little-endian order, to simplify interoperability with
server-side software that expects such a formatting.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The UEFI specification mandates that the EFI watchdog timer should be
disabled by the platform firmware as part of the ExitBootServices()
call, but some platforms (e.g. Hyper-V) are observed to occasionally
forget to do so, resulting in a reboot approximately five minutes
after starting the operating system.
Work around these firmware bugs by disabling the watchdog timer
ourselves.
Requested-by: Andreas Hammarskjöld <junior@2PintSoftware.com>
Tested-by: Andreas Hammarskjöld <junior@2PintSoftware.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
On some systems (observed with the Thunderbolt ports on a ThinkPad X1
Extreme Gen3 and a ThinkPad P53), if the IOMMU is enabled then the
system firmware will install an ExitBootServices notification event
that disables bus mastering on the Thunderbolt xHCI controller and all
PCI bridges, and destroys any extant IOMMU mappings. This leaves the
xHCI controller unable to perform any DMA operations.
As described in commit 236299b ("[xhci] Avoid DMA during shutdown if
firmware has disabled bus mastering"), any subsequent DMA operation
attempted by the xHCI controller will end up completing after the
operating system kernel has reenabled bus mastering, resulting in a
DMA operation to an area of memory that the hardware is no longer
permitted to access and, on Windows with the Driver Verifier enabled,
a STOP 0xE6 (DRIVER_VERIFIER_DMA_VIOLATION).
That commit avoids triggering any DMA attempts during the shutdown of
the xHCI controller itself. However, this is not a complete solution
since any attached and opened USB device (e.g. a USB NIC) may
asynchronously trigger DMA attempts that happen to occur after bus
mastering has been disabled but before we reset the xHCI controller.
Avoid this problem by installing our own ExitBootServices notification
event at TPL_NOTIFY, thereby causing it to be invoked before the
firmware's own ExitBootServices notification event that disables bus
mastering.
This unsurprisingly causes the shutdown hook itself to be invoked at
TPL_NOTIFY, which causes a fatal error when later code attempts to
raise the TPL to TPL_CALLBACK (which is a lower TPL). Work around
this problem by redefining the "internal" iPXE TPL to be variable, and
set this internal TPL to TPL_NOTIFY when the shutdown hook is invoked.
Avoid calling into an underlying SNP protocol instance from within our
shutdown hook at TPL_NOTIFY, since the underlying SNP driver may
attempt to raise the TPL to TPL_CALLBACK (which would cause a fatal
error). Failing to shut down the underlying SNP device is safe to do
since the underlying device must, in any case, have installed its own
ExitBootServices hook if any shutdown actions are required.
Reported-by: Andreas Hammarskjöld <junior@2PintSoftware.com>
Tested-by: Andreas Hammarskjöld <junior@2PintSoftware.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The efi_unload() function is currently missing the calls to raise and
restore the TPL. This has the side effect of causing iPXE to return
from the driver unload entry point at TPL_CALLBACK, which will cause
unexpected behaviour (typically a system lockup) shortly afterwards.
Fix by adding the missing calls to raise and restore the TPL.
Debugged-by: Petr Borsodi <petr.borsodi@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The EFI loaded image protocol allows an image to be provided with a
custom system table, and we currently use this mechanism to wrap any
boot services calls made by the loaded image in order to provide
strace-like debugging via DEBUG=efi_wrap.
The ExitBootServices() call will modify the global system table,
leaving the loaded image using a system table that is no longer
current. When DEBUG=efi_wrap is used, this generally results in the
machine locking up at the point that the loaded operating system calls
ExitBootServices().
Fix by modifying the global EFI system table to point to our wrapper
functions, instead of providing a custom system table via the loaded
image protocol.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
A successful call to ExitBootServices() will result in the EFI console
becoming unusable. Ensure that the EFI wrapper produces a complete
line of debug output before calling the wrapped ExitBootServices()
method, and attempt subsequent debug output only if the call fails.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Commit cd3de55 ("[efi] Record cached DHCPACK from loaded image's
device handle, if present") added the ability for a chainloaded UEFI
iPXE to reuse an IPv4 address and DHCP options previously obtained by
a built-in PXE stack, without needing to perform a second DHCP
request.
Extend this to also record the cached ProxyDHCPOFFER and PXEBSACK
obtained from the EFI_PXE_BASE_CODE_PROTOCOL instance installed on the
loaded image's device handle, if present.
This allows a chainloaded UEFI iPXE to reuse a boot filename or other
options that were provided via a ProxyDHCP or PXE boot server
mechanism, rather than by standard DHCP.
Tested-by: Andreas Hammarskjöld <junior@2PintSoftware.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The Ip4ConfigDxe driver bug that was observed on Dell systems in
commit 64b4452 ("[efi] Blacklist the Dell Ip4ConfigDxe driver") has
also been observed on systems with a manufacturer name of "Itautec
S.A.". The symptoms of the bug are identical: an attempt to call
DisconnectController() on the LOM device handle will lock up the
system.
Fix by extending the veto to cover the Ip4ConfigDxe driver for this
manufacturer.
Debugged-by: Celso Viana <celso.vianna@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Provide a file "initrd.magic" via the EFI_SIMPLE_FILE_SYSTEM_PROTOCOL
that contains the initrd file as constructed for BIOS bzImage kernels
(including injected files with CPIO headers constructed by iPXE).
This allows BIOS and UEFI kernels to obtain the exact same initramfs
image, by adding "initrd=initrd.magic" to the kernel command line.
For example:
#!ipxe
kernel boot/vmlinuz initrd=initrd.magic
initrd boot/initrd.img
initrd boot/modules/e1000.ko /lib/modules/e1000.ko
initrd boot/modules/af_packet.ko /lib/modules/af_packet.ko
boot
Do not include the "initrd.magic" file within the root directory
listing, since doing so would break software such as wimboot that
processes all files within the root directory.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Restructure the EFI_SIMPLE_FILE_SYSTEM_PROTOCOL implementation to
allow for the existence of virtual files that are not simply backed by
a single underlying image.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The EFI PCI API takes a page count as the input to AllocateBuffer()
but a byte count as the input to Map(). There is nothing in the UEFI
specification that requires us to map exactly the allocated length,
and no systems have yet been observed that will fail if the map length
does not exactly match the allocated length. However, it is plausible
that some implementations may fail if asked to map a length that does
not match the length of the corresponding allocation.
Avoid potential future problems by always mapping the full allocated
length.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The iPXE build system is constructed for a standalone codebase with no
external dependencies, and does not have any equivalent of the
standard userspace ./configure script. We currently check for the
ability to include slirp/libslirp.h and conditionalise portions of
linux_api.c on its presence. The actual slirp driver code is built
unconditionally, as with all iPXE drivers.
This currently leads to a silent runtime failure if attempting to use
slirp.linux built on a system that was missing slirp/libslirp.h.
Convert this to a link-time failure by deliberately omitting the
relevant symbols from linux_api.c when slirp/libslirp.h is not
present. This allows other builds (e.g. tap.linux or tests.linux) to
succeed: the link-time failure will occur only if the slirp driver is
included within the build target.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Linux kernel 3.12 and earlier report a zero size via stat() for all
ACPI table files in sysfs. There is no way to determine the file size
other than by reading the file until EOF.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Consumers of acpi_find() will assume that returned structures include
a valid table header and that the length in the table header is
correct. These assumptions are necessary when dealing with raw ACPI
tables, since there exists no independent source of length
information.
Ensure that these assumptions are also valid for ACPI tables read from
sysfs.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The statx() system call has a clean header file and a consistent
layout, but was unfortunately added only in kernel 4.11.
Using stat() or fstat() directly is extremely messy since glibc does
not necessarily use the kernel native data structures. However, as
the only current use case is to obtain the length of an open file, we
can merely provide a wrapper that does precisely this.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Michael Brown