Commit Graph

6598 Commits (77b07ea4fdc259d7253c6f9df2beda6e6c7a9d85)
 

Author SHA1 Message Date
Michael Brown 77b07ea4fd [cloud] Add utility script to read iPXE output from INT13CON partition
Some AWS instance types still do not support serial console output or
screenshots.  For these instance types, the only viable way to extract
debugging information is to use the INT13 console (which is already
enabled via CONFIG=cloud for all AWS images).

Obtaining the INT13 console output can be very cumbersome, since there
is no direct way to read from an AWS volume.  The simplest current
approach is to stop the instance under test, detach its root volume,
and reattach the volume to a Linux instance in the same region.

Add a utility script aws-int13con to retrieve the INT13 console output
by creating a temporary snapshot, reading the first block from the
snapshot, and extracting the INT13 console partition content.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-11-07 18:05:45 +00:00
Michael Brown d8f9c221ed [cloud] Add ability to overwrite existing AMI images
AMI names must be unique within a region.  Add a --overwrite option
that allows an existing AMI of the same name to be deregistered (and
its underlying snapshot deleted).

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-11-07 15:57:13 +00:00
Michael Brown 595b1796f6 [eapol] Limit number of EAPoL-Start packets transmitted per attempt
Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-11-07 13:51:16 +00:00
Michael Brown 1bd01b761f [eapol] Delay EAPoL-Start while waiting for EAP to complete
EAP exchanges may take a long time to reach a final status, especially
when relying upon MAC Authentication Bypass (MAB).  Our current
behaviour of sending EAPoL-Start every few seconds until a final
status is obtained can prevent these exchanges from ever completing.

Fix by redefining the EAP supplicant state to allow EAPoL-Start to be
suppressed: either temporarily (while waiting for a full EAP exchange
to complete, in which case we need to eventually resend EAPoL-Start if
the final Success or Failure packet is lost), or permanently (while
waiting for the potentially very long MAC Authentication Bypass
timeout period).

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-11-07 13:31:20 +00:00
Michael Brown 5524bb9832 [pci] Require discovery of a PCI device when determining usable PCI APIs
The PCI cloud API (PCIAPI_CLOUD) currently selects the first PCI API
that successfully discovers a PCI device address range.  The ECAM API
may discover an address range but subsequently be unable to map the
configuration space region, which would result in the selected PCI API
being unusable.

Fix by instead selecting the first PCI API that can be successfully
used to discover a PCI device.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-11-02 16:11:38 +00:00
Michael Brown 36e1a559a2 [pci] Check that ECAM configuration space is within reachable memory
Some machines (observed with an AWS EC2 m7a.large instance) will place
the ECAM configuration space window above 4GB, thereby making it
unreachable from non-paged 32-bit code.  This problem is currently
ignored by iPXE, since the address is silently truncated in the call
to ioremap().  (Note that other uses of ioremap() are not affected
since the PCI core will already have checked for unreachable 64-bit
BARs when retrieving the physical address to be mapped.)

Fix by adding an explicit check that the region to be mapped starts
within the reachable memory address space.  (Assume that no machines
will be sufficiently peverse to provide a region that straddles the
4GB boundary.)

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-11-02 15:38:08 +00:00
Michael Brown 1f3a37e342 [pci] Cache ECAM mapping errors
When an error occurs during ECAM configuration space mapping, preserve
the error within the existing cached mapping (instead of invalidating
the cached mapping) in order to avoid flooding the debug log with
repeated identical mapping errors.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-11-02 15:20:27 +00:00
Michael Brown 74ec00a9f3 [pci] Handle non-zero starting bus in ECAM allocations
The base address provided in the PCI ECAM allocation within the ACPI
MCFG table is the base address for the segment as a whole, not for the
starting bus within that allocation.  On machines that provide ECAM
allocations with a non-zero starting bus number (observed with an AWS
EC2 m7a.large instance), this will result in iPXE accessing the wrong
memory addresses within the ECAM region.

Fix by adding the appropriate starting bus offset to the base address.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-11-02 15:05:15 +00:00
Michael Brown f883203132 [pci] Force completion of ECAM configuration space writes
The PCIe specification requires that "processor and host bridge
implementations must ensure that a method exists for the software to
determine when the write using the ECAM is completed by the completer"
but does not specify any particular method to be used.  Some platforms
might treat writes to the ECAM region as non-posted, others might
require reading back from a dedicated (and implementation-specific)
completion register to determine when the configuration space write
has completed.

Since PCI configuration space writes will never be used for any
performance-critical datapath operations (on any sane hardware), a
simple and platform-independent solution is to always read back from
the written register in order to guarantee that the write must have
completed.  This is safe to do, since the PCIe specification defines a
limited set of configuration register types, none of which have read
side effects.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-11-01 22:32:21 +00:00
Michael Brown 115707c0ed [iphone] Add missing va_start()/va_end() around reused argument list
The ipair_tx() function uses a va_list twice (first to calculate the
formatted string length before allocation, then to construct the
string in the allocated buffer) but is missing the va_start() and
va_end() around the second usage.  This is undefined behaviour that
happens to work on some build platforms.

Fix by adding the missing va_start() and va_end() around the second
usage of the variadic argument list.

Reported-by: Andreas Hammarskjöld <andreas@2PintSoftware.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-10-24 11:43:56 +01:00
Michael Brown ff0f860483 [libc] Use wall clock time as seed for the (non-cryptographic) RNG
We currently use the number of timer ticks since power-on as a seed
for the non-cryptographic RNG implemented by random().  Since iPXE is
often executed directly after power-on, and since the timer tick
resolution is generally low, this can often result in identical seed
values being used on each cold boot attempt.

As of commit 41f786c ("[settings] Add "unixtime" builtin setting to
expose the current time"), the current wall-clock time is always
available within the default build of iPXE.  Use this time instead, to
introduce variability between cold boot attempts on the same host.
(Note that variability between different hosts is obtained by using
the MAC address as an additional seed value.)

This has no effect on the separate DRBG used by cryptographic code.

Suggested-by: Heiko <heik0@xs4all.nl>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-10-06 12:50:43 +01:00
Michael Brown 8b14652e50 [eapol] Send EAPoL-Start packets to trigger EAP authentication
We have no way to force a link-layer restart in iPXE, and therefore no
way to explicitly trigger a restart of EAP authentication.  If an iPXE
script has performed some action that requires such a restart
(e.g. registering a device such that the port VLAN assignment will be
changed), then the only means currently available to effect the
restart is to reboot the whole system.  If iPXE is taking over a
physical link already used by a preceding bootloader, then even a
reboot may not work.

In the EAP model, the supplicant is a pure responder and never
initiates transmissions.  EAPoL extends this to include an EAPoL-Start
packet type that may be sent by the supplicant to (re)trigger EAP.

Add support for sending EAPoL-Start packets at two-second intervals on
links that are open and have reached physical link-up, but for which
EAP has not yet completed.  This allows "ifclose ; ifopen" to be used
to restart the EAP process.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-09-19 23:16:58 +01:00
Michael Brown 56cc61a168 [eap] Define a supplicant model for EAP and EAPoL
Extend the EAP model to include a record of whether or not EAP
authentication has completed (successfully or otherwise), and to
provide a method for transmitting EAP responses.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-09-18 12:07:28 +01:00
Michael Brown cac3a584dc [fcoe] Use driver-private data to hold FCoE port structure
Simplify the FCoE code by using driver-private data to hold the FCoE
port for each network device, instead of using a separate allocation.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-09-14 13:25:19 +01:00
Michael Brown 8cbf248198 [vmware] Use driver-private data to hold GuestInfo settings block
Simplify the per-netdevice GuestInfo settings code by using
driver-private data to hold the settings block, instead of using a
separate allocation.

The settings block (if existent) will be automatically unregistered
when the parent network device settings block is unregistered, and no
longer needs to be separately freed.  The guestinfo_net_remove()
function may therefore be omitted completely.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-09-14 12:55:56 +01:00
Michael Brown 8b1d34badf [ipv6] Use driver-private data to hold link-local IPv6 settings block
Simplify the IPv6 link-local settings code by using driver-private
data to hold the settings block, instead of using a separate
allocation.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-09-13 23:02:54 +01:00
Michael Brown cc1e27e525 [lldp] Use driver-private data to hold LLDP settings block
Simplify the LLDP code by using driver-private data to hold the LLDP
settings block, instead of using a separate allocation.  This avoids
the need to maintain a list of LLDP settings blocks (since the LLDP
settings block pointer can always be obtained using netdev_priv()) and
obviates several failure paths.

Any recorded LLDP data is now freed when the network device is
unregistered, since there is no longer a dedicated reference counter
for the LLDP settings block.  To minimise surprise, we also now
explicitly unregister the settings block.  This is not strictly
necessary (since the block will be automatically unregistered when the
parent network device settings block is unregistered), but it
maintains symmetry between lldp_probe() and lldp_remove().

The overall reduction in the size of the LLDP code is around 15%.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-09-13 23:02:47 +01:00
Michael Brown ae4e85bde9 [netdevice] Allocate private data for each network upper-layer driver
Allow network upper-layer drivers (such as LLDP, which attaches to
each network device in order to provide a corresponding LLDP settings
block) to specify a size for private data, which will be allocated as
part of the network device structure (as with the existing private
data allocated for the underlying device driver).

This will allow network upper-layer drivers to be simplified by
omitting memory allocation and freeing code.  If the upper-layer
driver requires a reference counter (e.g. for interface
initialisation), then it may use the network device's existing
reference counter, since this is now the reference counter for the
containing block of memory.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-09-13 20:23:46 +01:00
Michael Brown eeb7cd56e5 [netdevice] Remove netdev_priv() helper function
Some network device drivers use the trivial netdev_priv() helper
function while others use the netdev->priv pointer directly.

Standardise on direct use of netdev->priv, in order to free up the
function name netdev_priv() for reuse.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-09-13 16:29:48 +01:00
Michael Brown 0aa2e4ec96 [librm] Use explicit operand size when pushing a label address
We currently use "push $1f" within inline assembly to push the address
of the real-mode code fragment, relying on the assembler to treat this
as "pushl" for 32-bit code or "pushq" for 64-bit code.

As of binutils commit 5cc0077 ("x86: further adjust extend-to-32bit-
address conditions"), first included in binutils-2.41, this implicit
operand size is no longer calculated as expected and 64-bit builds
will fail with

  Error: operand size mismatch for `push'

Fix by adding an explicit operand size to the "push" instruction.

Originally-fixed-by: Justin Cano <jstncno@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-09-05 12:47:42 +01:00
Alexander Eichner 9e99a55b31 [virtio] Fix implementation of vpm_ioread32()
The current implementation of vpm_ioread32() erroneously reads only 16
bits of data, which fails when used with the (stricter) virtio device
emulation in VirtualBox.

Fix by using the correct readl()/inl() I/O wrappers.

Reworded-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-08-22 13:45:44 +01:00
Cornelius Hoffmann c1834f323f [dhcp] Request NTP server option
Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-07-19 11:13:52 +01:00
Michael Brown d5c08f78bd [ntp] Define NTP server setting
Define the IPv4 NTP server setting to simplify the use of a
DHCP-provided NTP server in scripts, using e.g.

  #!ipxe
  dhcp
  ntp ${ntp}

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-07-19 11:10:15 +01:00
Michael Brown c30b71ee9c [console] Restore compatibility with "--key" values in existing scripts
Commit 3ef4f7e ("[console] Avoid overlap between special keys and
Unicode characters") renumbered the special key encoding to avoid
collisions with Unicode key values outside the ASCII range.  This
change broke backwards compatibility with existing scripts that
specify key values using e.g. "prompt --key" or "menu --key".

Restore compatibility with existing scripts by tweaking the special
key encoding so that the relative key value (i.e. the delta from
KEY_MIN) is numerically equal to the old pre-Unicode key value, and by
modifying parse_key() to accept a relative key value.

Reported-by: Sven Dreyer <sven@dreyer-net.de>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-07-07 15:14:00 +01:00
Michael Brown f3036fc213 [linux] Set a default MAC address for tap devices
Avoid the need to always specify a local MAC address on the command
line by setting a default hardware MAC address (using the same default
address as for slirp devices).

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-07-05 15:24:32 +01:00
Michael Brown 59d065c9ac [linux] Fix error control flow in af_packet_nic_probe()
Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-07-05 15:17:58 +01:00
Michael Brown 48ae5d5361 [linux] Fix error control flow in tap_probe()
Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-07-05 14:47:13 +01:00
Michael Brown 6701d91c50 [netdevice] Stop link block timer when device is closed
A running link block timer holds a reference to the network device and
will prevent it from being freed until the timer expires.  It is
impossible for free_netdev() to be called while the timer is still
running: the call to stop_timer() therein is therefore a no-op.

Stop the link block timer when the device is closed, to allow a
link-blocked device to be freed immediately upon unregistration of the
device.  (Since link block state is updated in response to received
packets, the state is effectively undefined for a closed device: there
is therefore no reason to leave the timer running.)

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-07-05 14:30:54 +01:00
Michael Brown b5b60ea33d [interface] Fix debug message values for temporary interfaces
The interface debug message values constructed by INTF_DBG() et al
rely on the interface being embedded within a containing object.  This
assumption is not valid for the temporary outbound-only interfaces
constructed on the stack by intf_shutdown() and xfer_vredirect().

Formalise the notion of a temporary outbound-only interface as having
a NULL interface descriptor, and overload the "original interface
descriptor" field to contain a pointer to the original interface that
the temporary interface is shadowing.

Originally-fixed-by: Vincent Fazio <vfazio@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-07-04 16:54:39 +01:00
Michael Brown 8244410690 [build] Inhibit more linker warnings about an implied executable stack
Add .note.GNU-stack section declarations to the autogenerated PCI
device ID list objects.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-07-04 15:12:49 +01:00
Michael Brown daa9e54ab8 [build] Silence the "creating blib.a" message
Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-07-04 15:03:31 +01:00
Michael Brown 3ef4f7e2ef [console] Avoid overlap between special keys and Unicode characters
The special key range (from KEY_MIN upwards) currently overlaps with
the valid range for Unicode characters, and therefore prohibits the
use of Unicode key values outside the ASCII range.

Create space for Unicode key values by moving the special keys to the
range immediately above the maximum valid Unicode character.  This
allows the existing encoding of special keys as an efficiently packed
representation of the equivalent ANSI escape sequence to be maintained
almost as-is.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-07-04 14:33:43 +01:00
Michael Brown cc07ed7c7e [console] Avoid overlap between remapping flags and character values
The keyboard remapping flags currently occupy bits 8 and upwards of
the to-be-mapped character value.  This overlaps the range used for
special keys (KEY_MIN and upwards) and also overlaps the valid Unicode
character range.

No conflict is created by this overlap, since by design only ASCII
character values (as generated by an ASCII-only keyboard driver) are
subject to remapping, and so the to-be-remapped character values exist
in a conceptually separate namespace from either special keys or
non-ASCII Unicode characters.  However, the overlap is potentially
confusing for readers of the code.

Minimise cognitive load by using bits 24 and upwards for the keyboard
remapping flags.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-07-04 14:17:48 +01:00
Michael Brown 6f57d91935 [build] Use separate code segment if supported by linker
Some versions of ld will complain that the automatically created (and
unused by our build process) ELF program headers include a "LOAD
segment with RWX permissions".

Silence this warning by adding "-z separate-code" to the linker
options, where supported.

For BIOS builds, where the prefix will generally require writable
access to its own (tiny) code segment, simply inhibit the warning
completely via "--no-warn-rwx-segments".

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-07-03 13:31:31 +01:00
Geert Stappers e17568ad06 [build] Inhibit linker warnings about an implied executable stack
Signed-off-by: Geert Stappers <stappers@stappers.it>
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-06-30 11:05:37 +01:00
Michael Brown 2524a60550 [build] Avoid using multiple target patterns in pattern rules
Multiple target patterns in pattern rules are treated as grouped
targets regardless of the separator character.  Newer verions of make
will generate "warning: pattern recipe did not update peer target" to
warn that the rule was expected to update all of the (implicitly)
grouped targets.

Fix by splitting all multiple target pattern rules into single target
pattern rules.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-06-30 10:31:52 +01:00
Xiaotian Wu 280942a92a [loong64] Add support for building EFI binaries
Signed-off-by: Xiaotian Wu <wuxiaotian@loongson.cn>
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-06-29 15:53:57 +01:00
Xiaotian Wu 6d98e0ca47 [loong64] Add CPU sleeping API for EFI LoongArch64
Signed-off-by: Xiaotian Wu <wuxiaotian@loongson.cn>
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-06-29 15:53:33 +01:00
Xiaotian Wu 0c67a3632d [loong64] Add I/O API for LoongArch64
Signed-off-by: Xiaotian Wu <wuxiaotian@loongson.cn>
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-06-29 15:40:24 +01:00
Michael Brown c57887bfc8 [ioapi] Centralise definitions for dummy PIO
There is no common standard for I/O-space access for non-x86 CPU
families, and non-MMIO peripherals are vanishingly rare.

Generalise the existing ARM definitions for dummy PIO to allow for
reuse by other CPU architectures.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-06-29 15:40:24 +01:00
Michael Brown 18af669701 [arm] Add missing arch/arm/core source directory
Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-06-29 15:40:24 +01:00
Michael Brown cfe65aa826 [arm] Remove redundant inclusion of io.h
The PCI I/O API (supporting accesses to PCI configuration space) is
not related to the general I/O API (supporting accesses to
memory-mapped I/O peripherals).

Remove the spurious inclusion of ipxe/io.h from the PCI I/O header.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-06-29 15:40:24 +01:00
Michael Brown ae435cb4cc [efi] Process veto objects in reverse order of enumeration
While not guaranteed by the UEFI specification, the enumeration of
handles, protocols, and openers will generally return results in order
of creation.  Processing these objects in reverse order (as is already
done when calling DisconnectController() on the list of all handles)
will generally therefore perform the forcible uninstallation
operations in reverse order of object creation, which minimises the
number of implicit operations performed (e.g. when disconnecting a
controller that itself still has existent child controllers).

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-06-23 16:51:10 +01:00
Michael Brown f8a0d1c0b8 [efi] Check for protocols opened by vetoed driver and image handles
The UEFI specification states that the AgentHandle may be either the
driving binding protocol handle or the image handle.

Check for both handles when searching for stale handles to be forcibly
closed on behalf of a vetoed driver.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-06-23 16:51:10 +01:00
Michael Brown f0b1025503 [efi] Unload vetoed drivers by image handle rather than driver handle
In most cases, the driver handle will be the image handle itself.
However, this is not required by the UEFI specification, and some
images will install multiple driver binding handles.

Use the image handle (extracted from the driver binding protocol
instance) when attempting to unload the driver's image.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-06-23 16:51:10 +01:00
Michael Brown c832580f19 [efi] Pass more detailed driver information to veto methods
Pass the driver binding handle, the driver binding protocol instance,
the image handle, and the loaded image protocol instance to all veto
methods.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-06-23 16:22:27 +01:00
Michael Brown 9a118322a0 [efi] Show manufacturer in veto debug output
Simplify the process of adding new entries to the veto list by
including the manufacturer name within the standard debug output.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-06-22 23:20:37 +01:00
Michael Brown 2689a6e776 [efi] Always poll for TX completions
Polling for TX completions is arguably redundant when there are no
transmissions currently in progress.  Commit c6c7e78 ("[efi] Poll for
TX completions only when there is an outstanding TX buffer") switched
to setting the PXE_OPFLAGS_GET_TRANSMITTED_BUFFERS flag only when
there is an in-progress transmission awaiting completion, in order to
reduce reported TX errors and debug message noise from buggy NII
implementations that report spurious TX completions whenever the
transmit queue is empty.

Some other NII implementations (observed with the Realtek driver in a
Dell Latitude 3440) seem to have a bug in the transmit datapath
handling which results in the transmit ring freezing after sending a
few hundred packets under heavy load.  The symptoms are that the
TPPoll register's NPQ bit remains set and the 256-entry transmit ring
contains a large number of uncompleted descriptors (with the OWN bit
set), the first two of which have identical data buffer addresses.

Though iPXE will submit at most one in-progress transmission via NII,
the Dell/Realtek driver seems to make a page-aligned copy of each
transmit data buffer and to report TX completions immediately without
waiting for the packet to actually be transmitted.  These synthetic TX
completions continue even after the hardware transmit ring freezes.

Setting PXE_OPFLAGS_GET_TRANSMITTED_BUFFERS on every poll reduces the
probability of this Dell/Realtek driver bug being triggered by a
factor of around 500, which brings the failure rate down to the point
that it can sensibly be managed by external logic such as the
"--timeout" option for image downloads.  Closing and reopening the
interface (via "ifclose"/"ifopen") will clear the error condition and
allow transmissions to resume.

Revert to setting PXE_OPFLAGS_GET_TRANSMITTED_BUFFERS on every poll,
and silently ignore situations in which the hardware reports a
completion when no transmission is in progress.  This approximately
matches the behaviour of the SnpDxe driver, which will also generally
set PXE_OPFLAGS_GET_TRANSMITTED_BUFFERS on every poll.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-06-21 11:49:53 +01:00
Michael Brown 4fa4052c7e [efi] Provide read-only access to EFI variables via settings mechanism
EFI variables do not map neatly to the iPXE settings mechanism, since
the EFI variable identifier includes a namespace GUID that cannot
cleanly be supplied as part of a setting name.  Creating a new EFI
variable requires the variable's attributes to be specified, which
does not fit within iPXE's settings concept.

However, EFI variable names are generally unique even without the
namespace GUID, and EFI does provide a mechanism to iterate over all
existent variables.  We can therefore provide read-only access to EFI
variables by comparing only the names and ignoring the namespace
GUIDs.

Provide an "efi" settings block that implements this mechanism using a
syntax such as:

  echo Platform language is ${efi/PlatformLang:string}

  show efi/SecureBoot:int8

Settings are returned as raw binary values by default since an EFI
variable may contain boolean flags, integer values, ASCII strings,
UCS-2 strings, EFI device paths, X.509 certificates, or any other
arbitrary blob of data.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-06-09 14:37:44 +01:00
Michael Brown 25a3d3acab [efi] Veto the VMware UefiPxeBcDxe driver
The EDK2 UefiPxeBcDxe driver includes some remarkably convoluted and
unsafe logic in its driver binding protocol Start() and Stop() methods
in order to support a pair of nominally independent driver binding
protocols (one for IPv4, one for IPv6) sharing a single dynamically
allocated data structure.  This PXEBC_PRIVATE_DATA structure is
installed as a dummy protocol on the NIC handle in order to allow both
IPv4 and IPv6 driver binding protocols to locate it as needed.

The error handling code path in the UefiPxeBcDxe driver's Start()
method may attempt to uninstall the dummy protocol but fail to do so.
This failure is ignored and the containing memory is subsequently
freed anyway.  On the next invocation of the driver binding protocol,
it will find and use this already freed block of memory.  At some
point another memory allocation will occur, the PXEBC_PRIVATE_DATA
structure will be corrupted, and some undefined behaviour will occur.

The UEFI firmware used in VMware ESX 8 includes some proprietary
changes which attempt to install copies of the EFI_LOAD_FILE_PROTOCOL
and EFI_PXE_BASE_CODE_PROTOCOL instances from the IPv4 child handle
onto the NIC handle (along with a VMware-specific protocol with GUID
5190120d-453b-4d48-958d-f0bab3bc2161 and a NULL instance pointer).
This will inevitably fail with iPXE, since the NIC handle already
includes an EFI_LOAD_FILE_PROTOCOL instance.

These VMware proprietary changes end up triggering the unsafe error
handling code path described above.  The typical symptom is that an
attempt to exit from iPXE back to the UEFI firmware will crash the VM
with a General Protection fault from within the UefiPxeBcDxe driver:
this happens when the UefiPxeBcDxe driver's Stop() method attempts to
call through a function pointer in the (freed) PXEBC_PRIVATE_DATA
structure, but the function pointer has by then been overwritten by
UCS-2 character data from an unrelated memory allocation.

Work around this failure by adding the VMware UefiPxeBcDxe driver to
the driver veto list.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
2023-06-08 12:24:07 +01:00