Add support for using a shim as a helper to execute an EFI image.
When a shim has been specified via shim(), the shim image will be
passed to LoadImage() instead of the selected EFI image and the
command line will be prepended with the name of the selected EFI
image. The selected EFI image will be accessible to the shim via the
virtual filesystem as a hidden file.
Reduce the Secure Boot attack surface by removing, where possible, the
spurious requirement for a third party second stage loader binary such
as GRUB to be used solely in order to call the "shim lock protocol"
entry point.
Do not install the EFI PXE APIs when using a shim, since if shim finds
EFI_PXE_BASE_CODE_PROTOCOL on the loaded image's device handle then it
will attempt to download files afresh instead of using the files
already downloaded by iPXE and exposed via the EFI_SIMPLE_FILE_SYSTEM
protocol. (Experience shows that there is no point in trying to get a
fix for this upstreamed into shim.)
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Most image flags are independent values: any combination of flags may
be set for any image, and the flags for one image are independent of
the flags for any other image. The "selected" flag does not follow
this pattern: at most one image may be marked as selected at any time.
When invoking a kernel via the UEFI shim, there will be multiple
"special" images: the selected kernel itself, the shim image, and
potentially a shim-signed GRUB binary to be used as a crutch to assist
shim in loading the kernel (since current versions of the UEFI shim
are not capable of directly loading a Linux kernel).
Remove the "selected" image flag and replace it with a general concept
of an image tag with the same semantics: a given tag may be assigned
to at most one image, an image may be found by its tag only while the
image is currently registered, and a tag will survive unregistration
and reregistration of an image (if it has not already been assigned to
a new image). For visual consistency, also replace the current image
pointer with a current image tag.
The image pointer stored within the image tag holds only a weak
reference to the image, since the selection of an image should not
prevent that image from being freed. (The strong reference to the
currently executing image is held locally within the execution scope
of image_exec(), and is logically separate from the current image
pointer.)
Signed-off-by: Michael Brown <mcb30@ipxe.org>
When invoking a kernel via the UEFI shim, the kernel (and potentially
also a helper binary such as GRUB) must be accessible via the virtual
filesystem exposed via EFI_SIMPLE_FILE_SYSTEM_PROTOCOL but must not be
present in the magic initrd constructed from all registered images.
Allow for images to be flagged as hidden, which will cause them to be
excluded from API-level lists of all images such as the virtual
filesystem directory contents, the magic initrd, or the Multiboot
module list. Hidden images remain visible to iPXE commands including
"imgstat", which will show a "[HIDDEN]" flag for such images.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The Linux kernel bzImage image format and the CPIO archive constructor
will parse the image command line for certain arguments of the form
"key=value". This parsing is currently implemented using strstr() in
a way that can cause a false positive suffix match. For example, a
command line containing "highmem=<n>" would erroneously be treated as
containing a value for "mem=<n>".
Fix by centralising the logic used for parsing such arguments, and
including a check that the argument immediately follows a whitespace
delimiter (or is at the start of the string).
Reported-by: Filippo Giunchedi <filippo@esaurito.net>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Provide image_extract_exec() as a helper method to allow single-member
archive images (such as gzip compressed images) to be executed without
an explicit "imgextract" step.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Add the concept of extracting an image from an archive (which could be
a single-file archive such as a gzip-compressed file), along with an
"imgextract" command to expose this functionality to scripts.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Consolidate the remaining logic common to initrd_init() and imgmem()
into a shared image_memory() function.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The current usage pattern of image_probe() is a legacy from the time
before commit 34b6ecb ("[image] Simplify image management") when
loading an image to its executable location in memory was a separate
action from actually executing the image.
Call image_probe() as soon as an image is registered. This allows
"imgstat" to display image type information for all images and allows
image-consuming code to assume that image->type is already set
correctly.
Ignore failures if image_probe() does not recognise the image, since
we do expect to handle unrecognised images (initrds, modules, etc).
Unrecognised images will be left with a NULL image->type, which
image-consuming code can easily check.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Remove the name, cmdline, and action parameters from imgdownload() and
imgdownload_string(). These functions now simply download and return
an image.
Add the function imgacquire(), which will interpret a "name or URI
string" parameter and return either an existing image or a newly
downloaded image.
Use imgacquire() to merge similar image-management commands that
currently differ only by whether they take the name of an existing
image or the URI of a new image to download. For example, "chain" and
"imgexec" can now be merged.
Extend imgstat and imgfree commands to take an optional list of
images.
Remove the arbitrary restriction on the length of image names.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Trusted images may always be executed. Untrusted images may be
executed only if the current image trust requirement allows untrusted
images.
Images can be marked as trusted using image_trust(), and marked as
untrusted using image_untrust().
The current image trust requirement can be changed using
image_set_trust(). It is possible to make the change permanent, in
which case any future attempts to change the image trust requirement
will fail.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
These functions are used only as the "action" parameters to
imgdownload() or imgfetch(), and so belong in imgmgmt.c rather than
image.c
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Refactor the {load,exec} image operations as {probe,exec}. This makes
the probe mechanism cleaner, eliminates some forward declarations,
avoids holding magic state in image->priv, eliminates the possibility
of screwing up between the "load" and "exec" stages, and makes the
documentation simpler since the concept of "loading" (as distinct from
"executing") no longer needs to be explained.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Access to the gpxe.org and etherboot.org domains and associated
resources has been revoked by the registrant of the domain. Work
around this problem by renaming project from gPXE to iPXE, and
updating URLs to match.
Also update README, LOG and COPYRIGHTS to remove obsolete information.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Michael Brown