RSA requires modular exponentiation using arbitrarily large integers.
Given the sizes of the modulus and exponent, all required calculations
can be done without any further dynamic storage allocation. The x86
architecture allows for efficient large integer support via inline
assembly using the instructions that take advantage of the carry flag
(e.g. "adcl", "rcrl").
This implemention is approximately 80% smaller than the (more generic)
AXTLS implementation.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Minimise code size by forcing the use of memory addresses for
__bswap_16s() and __bswap_64s(). (__bswap_32s() cannot avoid loading the
value into a register.)
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Fix a strict-aliasing error on certain versions of gcc.
Reported-by: Marko Myllynen <myllynen@redhat.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Use the "bswap" instruction to shrink the size of byte-swapping code,
and provide the in-place variants __bswap_{16,32,64}s.
"bswap" is available only on 486 and later processors. (We already
assume the presence of "cpuid" and "rdtsc", which are available only
on Pentium and later processors.)
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some PXE stacks (observed with a QLogic 8242) will always try to
prepend a link-layer header, even if the caller uses P_UNKNOWN to
indicate that the link-layer header has already been filled in. This
results in an invalid packet being transmitted.
Work around these faulty PXE stacks where possible by stripping the
existing link-layer header and allowing the PXE stack to (re)construct
the link-layer header itself.
Originally-fixed-by: Buck Huppmann <buckh@pobox.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The RTC-based entropy source uses the nanosecond-scale CPU TSC to
measure the time between two 1kHz interrupts generated by the CMOS
RTC. In a physical machine these clocks are driven from independent
crystals, resulting in some observable clock drift. In a virtual
machine, the CMOS RTC is typically emulated using host-OS
constructions such as SIGALRM.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
ANS X9.82 specifies several Approved Sources of Entropy Input (SEI).
One such SEI uses an entropy source as the Source of Entropy Input,
condensing each entropy source output after each GetEntropy call.
This can be implemented relatively cheaply in iPXE and avoids the need
to allocate potentially very large buffers.
(Note that the terms "entropy source" and "Source of Entropy Input"
are not synonyms within the context of ANS X9.82.)
Use the iPXE API mechanism to allow entropy sources to be selected at
compilation time.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
initrd_init() calls umalloc() to allocate space for the initrd image,
but does so before hide_etherboot() has been called. It is therefore
possible for the initrd to end up overwriting iPXE itself.
Fix by converting initrd_init() from an init_fn to a startup_fn.
Originally-fixed-by: Till Straumann <strauman@slac.stanford.edu>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The command line may be situated in an area of base memory that will
be overwritten by iPXE's real-mode segments, causing the command line
to be corrupted before it can be used.
Fix by creating a copy of the command line on the prefix stack (below
0x7c00) before installing the real-mode segments.
Reported-by: Dave Hansen <dave@sr71.net>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
PXENV_FILE_EXIT_HOOK is designed to allow ipxelinux.0 to unload both
the iPXE and pxelinux components without affecting the underlying PXE
stack. Unfortunately, it causes unexpected behaviour in other
situations, such as when loading a non-embedded pxelinux.0 via
undionly.kpxe. For example:
PXE ROM -> undionly.kpxe -> pxelinux.0 -> chain.c32 to boot hd0
would cause control to return to iPXE instead of booting from the hard
disk. In some cases, this would result in a harmless but confusing
"No more network devices" message; in other cases stranger things
would happen, such as being returned to the iPXE shell prompt.
The fundamental problem is that when pxelinux detects
PXENV_FILE_EXIT_HOOK, it may attempt to specify an exit hook and then
exit back to iPXE, assuming that iPXE will in turn exit cleanly via
the specified exit hook. This is not a valid assumption in the
general case, since the action of exiting back to iPXE does not
directly cause iPXE to exit itself. (In the specific case of
ipxelinux.0, this will work since the embedded script exits as soon as
pxelinux.0 exits.)
Fix the unexpected behaviour in the non-ipxelinux.0 cases by including
support for PXENV_FILE_EXIT_HOOK only when using a new .kkkpxe format.
The ipxelinux.0 build process should therefore now use undionly.kkkpxe
instead of undionly.kkpxe.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Very nasty things can happen if a NULL network device is used. Check
that pxe_netdev is non-NULL at the applicable entry points, so that
this type of problem gets reported to the caller rather than being
allowed to crash the system.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
On at least one PXE stack (Realtek r8169), PXENV_UNDI_INITIALIZE has
been observed to fail intermittently due to a media test failure (PXE
error 0x00000061). Retrying the call to PXENV_UNDI_INITIALIZE
succeeds, and the NIC is then usable.
It is worth noting that this particular Realtek PXE stack is already
known to be unreliable: for example, it repeatably fails its own
boot-time media test after every warm reboot.
Fix by attempting PXENV_UNDI_INITIALIZE multiple times, with a short
delay between each attempt to allow the link to settle.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow an initrd (such as an embedded script) to be passed to iPXE when
loaded as a .lkrn (or .iso) image. This allows an embedded script to
be varied without recompiling iPXE.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Specify a driver name of "undionly" and a device name based on the
UNDI-reported underlying hardware device. For example:
net0: 52:54:00:12:34:56 using undionly on UNDI-PCI00:03.0 (open)
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some BIOSes are reported to corrupt %ebx when using INT 15,2401 (see
http://opensolaris.org/jive/thread.jspa?messageID=377026). Guard
against this by preserving all (non-segment) registers.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The symbol_text16 is defined globally by the linker. Use rm_text16
instead of _text16 for the local variable within librm.S to avoid
confusion when reading linker maps.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
All users of imgdownload() require registration of the image, so make
registration an integral part of imgdownload() itself and simplify the
"action" parameter to be one of image_select(), image_exec() et al.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
iPXE specifies a value of 0 for cmdline_size, causing GRUB to not pass
in a command line. Fix by setting cmdline_size to the maximum value
of 2047.
Signed-off-by: Valentine Barshak <gvaxon@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow the link layer to directly report whether or not a packet is
multicast or broadcast at the time of calling pull(), rather than
relying on heuristics to determine this at a later stage.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow objects to support both streaming and block device protocols, by
starting streaming data only when the data transfer window opens.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some bootloaders seem to add "BOOT_IMAGE=..." at the end of the
command line; some at the start. Cope with either variation.
Reported-by: Dave Hansen <dave@sr71.net>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
IBM BIOSes ignore the PnP header offset stored at address 0x1a and
instead scan for the $PnP signature on a 16-byte boundary. (This
alignment is not mandated by the PnP specification.)
Force PnP header to a 16-byte boundary to work around these BIOSes.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Several BIOSes (including most IBM BIOSes and many virtual machine
BIOSes) do not provide detectable PnP support, but will use the BEV
entry point for a PnP option ROM. On these semi-PnP BIOSes, iPXE will
respond to the absence of detectable PnP support by hooking INT19,
which disrupts the boot order.
BIOSes that genuinely require hooking INT19 seem to be very rare
nowadays. It may therefore be preferable to assume that the absence
of detectable PnP support indicates a semi-PnP BIOS rather than a
non-PnP BIOS.
Change the default behaviour so that INT19 will never be hooked unless
the compile-time option NONPNP_HOOK_INT19 is enabled. Leave the
redundant PnP detection routine in-place to allow for debugging via
the ROM banner line.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Revert commit 38cd351 ("[romprefix] Attempt to gracefully handle
semi-PnP IBM BIOSes"), since the test for the "IBM " signature in %edi
is not sufficient to identify an IBM BIOS.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some IBM BIOSes provide partial support for PnP: they will use the BEV
entry point but will not advertise PnP support. This causes iPXE to
hook INT 19, which disrupts the boot process.
Attempt to improve this situation by detecting an IBM BIOS and
treating it as a PnP BIOS despite the absence of a PnP signature.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some versions of binutils have curious concepts of what constitutes
subtraction. For example:
0x00000000000000f0 _text16_late = .
0x0000000000000898 _mtext16 = .
0x0000000000000898 _etext16 = .
0x0000000000000898 _text16_late_filesz = ABSOLUTE ((_mtext16 - _text16_late))
0x00000000000007a8 _text16_late_memsz = ABSOLUTE ((_etext16 - _text16_late))
This has interesting side-effects such as producing sizes for .bss
segments that are negative, causing the majority of addressable memory
to be zeroed out.
Fix by using the form
ABSOLUTE ( x ) - ABSOLUTE ( y )
rather than
ABSOLUTE ( x - y )
Reported-by: H. Peter Anvin <hpa@zytor.com>
Suggested-by: H. Peter Anvin <hpa@zytor.com>
Tested-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
This allows older versions of ELTORITO.SYS (such as the version found
on the FreeDOS installation CD-ROM) to use iPXE's emulated CD-ROM
drive.
Reported-by: Robin Smidsrød <robin@smidsrod.no>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
