The drive specification alone does not necessarily contain enough
information to perform a SAN boot (or local disk boot) under UEFI. If
the next-stage bootloader is installed in the EFI system partition
under a non-standard name (e.g. "\EFI\debian\grubx64.efi") then this
explicit boot filename must also be specified.
Generalise this concept to use a "SAN boot configuration parameters"
structure (currently containing only the optional explicit boot
filename), to allow for easy expansion to provide other parameters
such as the partition UUID or volume label.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Extend the EFI SAN boot code to allow for booting from a local disk,
as is already possible with the BIOS SAN boot code.
There is unfortunately no direct UEFI equivalent of the BIOS drive
number. The UEFI shell does provide numbered mappings fs0:, blk0:,
etc, but these numberings exist only while the UEFI shell is running
and are not necessarily stable between shell invocations or across
reboots.
A substantial amount of existing third-party documentation for iPXE
will suggest using "sanboot --drive 0x80" to boot from a local disk
(when no SAN drives are present), since this suggestion has been
present in the official documentation for the "sanboot" command for
almost thirteen years. We therefore aim to ensure that this
instruction will also work for UEFI, i.e. that in a situation where
there are local disks but no SAN disks, then the first local disk will
be treated as being drive 0x80.
We therefore assign local disks the virtual drive numbers 0x80, 0x81,
etc, matching the numbering typically used in a BIOS environment.
Where a SAN disk is already occupying one of these drive numbers, the
local disks' virtual drive numbers will be incremented as necessary.
This provides a rough approximation of the equivalent functionality
under BIOS, where existing local disks' drive numbers are remapped to
make way for SAN disks.
We do not make any attempt to sort the list of local disks: the order
used for allocating virtual drive numbers will be whatever order is
returned by LocateHandle(). This will typically match the creation
order of the EFI handles, which will typically match the hardware
enumeration order of the devices, which will typically match user
expectations as to which local disk is first, second, etc.
We explicitly do not attempt to match the numbering used by the UEFI
shell (which initially sorts in increasing order of device path, but
does not renumber when new devices are added or removed). We can
never guarantee matching this partly transient UEFI shell numbering,
so it is best not to set any expectation that it will be matched.
(Using local drive numbers starting at 0x80 helps to avoid setting up
this impossible expectation, since the UEFI shell uses local drive
numbers starting at zero.)
Since floppy disks are essentially non-existent in any plausible UEFI
system, overload "--drive 0" to mean "boot from any drive containing
the specified (or default) boot filename".
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Maintain the SAN device list in order of drive number, and provide
sandev_next() to locate the first SAN device at or above a given drive
number.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Add uuid_aton() to parse a UUID value from a string (analogous to
inet_aton(), inet6_aton(), sock_aton(), etc), treating it as a
32-digit hex string with optional hyphen separators. The placement of
the separators is not checked: each byte within the hex string may be
separated by a hyphen, or not separated at all.
Add dedicated self-tests for UUID parsing and formatting (already
partially covered by the ":uuid" and ":guid" settings self-tests).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Add support for EAP-MSCHAPv2 (note that this is not the same as
PEAP-MSCHAPv2), controllable via the build configuration option
EAP_METHOD_MSCHAPV2 in config/general.h.
Our model for EAP does not encompass mutual authentication: we will
starting sending plaintext packets (e.g. DHCP requests) over the link
even before EAP completes, and our only use for an EAP success is to
mark the link as unblocked.
We therefore ignore the content of the EAP-MSCHAPv2 success request
(containing the MS-CHAPv2 authenticator response) and just send back
an EAP-MSCHAPv2 success response, so that the EAP authenticator will
complete the process and send through the real EAP success packet
(which will, in turn, cause us to unblock the link).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
RFC 3748 states that implementations must support the MD5-Challenge
method. However, some network environments may wish to disable it as
a matter of policy.
Allow support for MD5-Challenge to be controllable via the build
configuration option EAP_METHOD_MD5 in config/general.h.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Inspection of the generated assembly shows that gcc will often emit
standalone implementations of frequently invoked functions such as
digest_update(), which contain no logic and exist only as syntactic
sugar.
Force inlining of these functions to reduce the overall binary size.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Add an implementation of the authentication portions of the MS-CHAPv2
algorithm as defined in RFC 2759, along with the single test vector
provided therein.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Certificates issued by Let's Encrypt have two options for their chain
of trust: the chain can either terminate in the self-signed ISRG Root
X1 root certificate, or in an intermediate ISRG Root X1 certificate
that is signed in turn by the self-signed DST Root CA X3 root
certificate. This is a historical artifact: when Let's Encrypt first
launched as a project, the chain ending in DST Root CA X3 was used
since existing clients would not have recognised the ISRG Root X1
certificate as a trusted root certificate.
The DST Root CA X3 certificate expired in September 2021, and so is no
longer trusted by clients (such as iPXE) that validate the expiry
times of all certificates in the certificate chain.
In order to maintain usability of certificates on older Android
devices, the default certificate chain provided by Let's Encrypt still
terminates in DST Root CA X3, even though that certificate has now
expired. On newer devices which include ISRG Root X1 as a trusted
root certificate, the intermediate version of ISRG Root X1 in the
certificate chain is ignored and validation is performed as though the
chain had terminated in the self-signed ISRG Root X1 root certificate.
On older Android devices which do not include ISRG Root X1 as a
trusted root certificate, the validation succeeds since Android
chooses to ignore expiry times for root certificates and so continues
to trust the DST Root CA X3 root certificate.
This backwards compatibility hack unfortunately breaks the cross-
signing mechanism used by iPXE, which assumes that the certificate
chain will always terminate in a non-expired root certificate.
Generalise the validator's cross-signed certificate download mechanism
to walk up the certificate chain in the event of a failure, attempting
to find a replacement cross-signed certificate chain starting from the
next level up. This allows the validator to step over the expired
(and hence invalidatable) DST Root CA X3 certificate, and instead
download the cross-signed version of the ISRG Root X1 certificate.
This generalisation also gives us the ability to handle servers that
provide a full certificate chain including their root certificate:
iPXE will step over the untrusted public root certificate and attempt
to find a cross-signed version of it instead.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Downloading a cross-signed certificate chain to partially replace
(rather than simply extend) an existing chain will require the ability
to discard all certificates after a specified link in the chain.
Extract the relevant logic from x509_free_chain() and expose it
separately as x509_truncate().
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some versions of gcc (observed with gcc 4.8.5 in CentOS 7) will report
spurious build_assert() failures for some assertions about structure
layouts. There is no clear pattern as to what causes these spurious
failures, and the build assertion does succeed in that no unresolvable
symbol reference is generated in the compiled code.
Adjust the assertions to work around these apparent compiler issues.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The DES block cipher dates back to the 1970s. It is no longer
relevant for use in TLS cipher suites, but it is still used by the
MS-CHAPv2 authentication protocol which remains unfortunately common
for 802.1x port authentication.
Add an implementation of the DES block cipher, complete with the
extremely comprehensive test vectors published by NBS (the precursor
to NIST) in the form of an utterly adorable typewritten and hand-drawn
paper document.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The CBC_CIPHER() macro contains some accidentally hardcoded references
to an underlying AES cipher, instead of using the cipher specified in
the macro parameters.
Fix by using the macro parameter as required.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Define an abstraction of an elliptic curve with a fixed generator and
one supported operation (scalar multiplication of a curve point).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
RFC7748 states that it is entirely optional for X25519 Diffie-Hellman
implementations to check whether or not the result is the all-zero
value (indicating that an attacker sent a malicious public key with a
small order). RFC8422 states that implementations in TLS must abort
the handshake if the all-zero value is obtained.
Return an error if the all-zero value is obtained, so that the TLS
code will not require knowledge specific to the X25519 curve.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Add an implementation of the X25519 key exchange algorithm as defined
in RFC7748.
This implementation is inspired by and partially based upon the paper
"Implementing Curve25519/X25519: A Tutorial on Elliptic Curve
Cryptography" by Martin Kleppmann, available for download from
https://www.cl.cam.ac.uk/teaching/2122/Crypto/curve25519.pdf
The underlying modular addition, subtraction, and multiplication
operations are completely redesigned for substantially improved
efficiency compared to the TweetNaCl implementation studied in that
paper (approximately 5x-10x faster and with 70% less memory usage).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Add a helper function bigint_swap() that can be used to conditionally
swap a pair of big integers in constant time.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Big integers may be efficiently copied using bigint_shrink() (which
will always copy only the size of the destination integer), but this
is potentially confusing to a reader of the code.
Provide bigint_copy() as an alias for bigint_shrink() so that the
intention of the calling code may be more obvious.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Big integer multiplication is currently used only as part of modular
exponentiation, where both multiplicand and multiplier will be the
same size.
Relax this requirement to allow for the use of big integer
multiplication in other contexts.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
We currently implement build-time assertions via a mechanism that
generates a call to an undefined external function that will cause the
link to fail unless the compiler can prove that the asserted condition
is true (and thereby eliminate the undefined function call).
This assertion mechanism can be used for conditions that are not
amenable to the use of static_assert(), since static_assert() will not
allow for proofs via dead code elimination.
Add __attribute__((error(...))) to the undefined external function, so
that the error is raised at compile time rather than at link time.
This allows us to provide a more meaningful error message (which will
include the file name and line number, as with any other compile-time
error), and avoids the need for the caller to specify a unique symbol
name for the external function.
Change the name from linker_assert() to build_assert(), since the
assertion now takes place at compile time rather than at link time.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
RFC 3748 states that support for MD5-Challenge is mandatory for EAP
implementations. The MD5 and CHAP code is already included in the
default build since it is required by iSCSI, and so this does not
substantially increase the binary size.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow the ${netX/username} setting to be used to specify an EAP
identity to be returned in response to a Request-Identity, and provide
a mechanism for responding with a NAK to indicate which authentication
types we support.
If no identity is specified then fall back to the current behaviour of
not sending any Request-Identity response, so that switches will time
out and switch to MAC Authentication Bypass (MAB) if applicable.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
EAP responses (including our own) may be broadcast by switches but are
not of interest to us and can be safely ignored if received.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Support scanning for the 64-bit SMBIOS3 entry point in addition to the
32-bit SMBIOS2 entry point.
Prefer use of the 32-bit entry point if present, since this is
guaranteed to be within accessible memory.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
Michael Brown