The UEFI specification allows uninstallation of a protocol interface
to fail. There is no sensible way for code to react to this, since
uninstallation is likely to be taking place on a code path that cannot
itself fail (e.g. a code path that is itself a failure path).
Where the protocol structure exists within a dynamically allocated
block of memory, this leads to possible use-after-free bugs. Work
around this unfortunate design choice by nullifying the protocol
(i.e. overwriting the method pointers with no-ops) and leaking the
memory containing the protocol structure.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
According to the latest UEFI specification (Version 2.8 Errata B)
p. 7.2:
"Buffer: A pointer to a pointer to the allocated buffer if the call
succeeds; undefined otherwise."
So implementations are obliged neither to return NULL, if the
allocation fails, nor to preserve the contents of the pointer.
Make the logic more reliable by checking the status code from
AllocatePool() instead of checking the returned pointer for NULL
Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
In edk2, there are several drivers that associate HII forms (and
corresponding config access protocol instances) with each individual
network device. (In this context, "network device" means the EFI
handle on which the SNP protocol is installed, and on which the device
path ending with the MAC() node is installed also.) Such edk2 drivers
are, for example: Ip4Dxe, HttpBootDxe, VlanConfigDxe.
In UEFI, any given handle can carry at most one instance of a specific
protocol (see e.g. the specification of the InstallProtocolInterface()
boot service). This implies that the class of drivers mentioned above
can't install their EFI_HII_CONFIG_ACCESS_PROTOCOL instances on the
SNP handle directly -- they would conflict with each other.
Accordingly, each of those edk2 drivers creates a "private" child
handle under the SNP handle, and installs its config access protocol
(and corresponding HII package list) on its child handle.
The device path for the child handle is traditionally derived by
appending a Hardware Vendor Device Path node after the MAC() node.
The VenHw() nodes in question consist of a GUID (by definition), and
no trailing data (by choice). The purpose of these VenHw() nodes is
only that all the child nodes can be uniquely identified by device
path.
At the moment iPXE does not follow this pattern. It doesn't run into
a conflict when it installs its EFI_HII_CONFIG_ACCESS_PROTOCOL
directly on the SNP handle, but that's only because iPXE is the sole
driver not following the pattern. This behavior seems risky (one
might call it a "latent bug"); better align iPXE with the edk2 custom.
Cc: Michael Brown <mcb30@ipxe.org>
Cc: Gary Lin <glin@suse.com>
Cc: Ladi Prosek <lprosek@redhat.com>
Ref: http://thread.gmane.org/gmane.comp.bios.edk2.devel/13494/focus=13532
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Ladi Prosek <lprosek@redhat.com>
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The EFI_HII_CONFIG_ACCESS_PROTOCOL's ExtractConfig() method is passed
a request string which includes the parameters being queried plus an
apparently meaningless blob of information (the ConfigHdr), and is
expected to include this same meaningless blob of information in the
results string.
Neither the specification nor the existing EDK2 code (including the
nominal reference implementation in the DriverSampleDxe driver)
provide any reason for the existence of this meaningless blob of
information. It appears to be consumed in its entirety by the
EFI_HII_CONFIG_ROUTING_PROTOCOL, and to contain zero bits of
information by the time it reaches an EFI_HII_CONFIG_ACCESS_PROTOCOL
instance. It would potentially allow for multiple configuration data
sets to be handled by a single EFI_HII_CONFIG_ACCESS_PROTOCOL
instance, in a style alien to the rest of the UEFI specification
(which implicitly assumes that the instance pointer is always
sufficient to uniquely identify the instance).
iPXE currently handles this by simply copying the ConfigHdr from the
request string to the results string, and otherwise ignoring it. This
approach is also used by some code in EDK2, such as OVMF's PlatformDxe
driver.
As of EDK2 commit 8a45f80 ("MdeModulePkg: Make HII configuration
settings available to OS runtime"), this causes an assertion failure
inside EDK2. The failure arises when iPXE is handled a NULL request
string, and responds (as per the specification) with a results string
including all settings. Since there is no meaningless blob to copy
from the request string, there is no corresponding meaningless blob in
the results string. This now causes an assertion failure in
HiiDatabaseDxe's HiiConfigRoutingExportConfig().
The same failure does not affect the OVMF PlatformDxe driver, which
simply passes the request string to the HII BlockToConfig() utility
function. The BlockToConfig() function returns EFI_INVALID_PARAMETER
when passed a null request string, and PlatformDxe propagates this
error directly to the caller.
Fix by matching the behaviour of OVMF's PlatformDxe driver: explicitly
return EFI_INVALID_PARAMETER if the request string is NULL or empty.
This violates the specification (insofar as it is feasible to
determine what the specification actually requires), but causes
correct behaviour with the EDK2 codebase.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
HII seems to fail on several systems. Since it is non-essential,
treat HII problems as non-fatal.
Debugged-by: Curtis Larsen <larsen@dixie.edu>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Expose the build timestamp (measured in seconds since the Epoch) and
the build name (e.g. "rtl8139.rom" or "ipxe.efi"), and provide the
product name and product short name in a single centralised location.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some UEFI systems (observed with a Mac Pro) do not provide
EFI_HII_DATABASE_PROTOCOL. We can continue to function without
providing access to network device settings via HII, so make this
protocol optional and fall back to simply not providing any HII
protocols.
Reported-by: Matt Woodward <pxematt@woodwardcc.com>
Tested-by: Matt Woodward <pxematt@woodwardcc.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow for multiple setting definitions with the same name but
different scopes and tags. For example, allow for a "filename"
setting with default scope and tag value 67 (for DHCPv4) and a
corresponding "filename" setting with IPv6 scope and tag value 59 (for
DHCPv6).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The fetch_setting() family of functions may currently modify the
definition of the specified setting (e.g. to add missing type
information). Clean up this interface by requiring callers to provide
an explicit buffer to contain the completed definition of the fetched
setting, if required.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Exploit the redefinition of iPXE error codes to include a "platform
error code" to allow for meaningful conversion of EFI_STATUS values to
iPXE errors and vice versa.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Michael Brown
Ignat Korchagin
Laszlo Ersek