match_hash() requests the number of keys in a list and it was
mistakenly replaced with the size of the Mok node. This would
made MokManager to remove the whole Mok node instead of one
hash.
Signed-off-by: Gary Ching-Pang Lin <glin@suse.com>
Peter Jones [Tue, 16 Jun 2015 15:41:32 +0000 (11:41 -0400)]
Fix console_print_box*() parameters.
When we made lib build with the correct CFLAGS, it inherited
-Werror=sign-compare, and I fixed up some parameters on
console_print_box() and console_print_box_at() to avoid sign comparison
errors.
The fixups were *completely wrong*, as some behavior relies on negative
values. So this fixes them in a completely different way, by casting
appropriately to signed types where we're doing comparisons.
Peter Jones [Thu, 11 Jun 2015 17:25:56 +0000 (13:25 -0400)]
Ensure that apps launched by shim get correct BS->Exit() behavior
Right now applications run by shim get our wrapper for Exit(), but it
doesn't do as much cleanup as it should - shim itself also exits, but
currently is not doing all the cleanup it should be doing.
This changes it so all of shim's cleanup is also performed.
Based on a patch and lots of review from Gary Lin.
Peter Jones [Thu, 11 Jun 2015 17:20:09 +0000 (13:20 -0400)]
Don't leave in_protocol==1 when shim_verify() isn't enforcing.
Right now if shim_verify() sees secure_mode()==0, it exits with
EFI_SUCCESS, but accidentally leaves in_protocol=1. This means any
other call will have supressed error/warning messages.
Peter Jones [Thu, 4 Jun 2015 14:19:30 +0000 (10:19 -0400)]
Only run MokManager if asked or a security violation occurs.
Don't run MokManager on any random error from start_image(second_stage);
only try it if it /is/ the second stage, or if start_image gave us
EFI_SECURITY_VIOLATION.
The wildcard support was introduced in objcopy since binutils 2.24.
However, objcopy < 2.24 never issues any warning message with the
wildcard and a faulty binary will be generated. This commit makes
the build failed as a notification for the usage of binutils < 2.24.
Signed-off-by: Gary Ching-Pang Lin <glin@suse.com>
Matthew Garrett [Wed, 15 Apr 2015 17:30:52 +0000 (13:30 -0400)]
Explicitly request sysv-style ELF hash sections
We depend on there being a .hash section in the binary, and that's not
the case on distributions that default to building with gnu-style ELF
hashes. Explicitly request sysv-style hashes in order to avoid building
broken binaries.
[fallback] Fix the data size for boot option comparison
corrected the data size used for comparison, but also reduced the
allocation so it doesn't include the trailing UTF16LE '\0\0' at the
end of the string, with the result that the trailer of the buffer
containing the string is overwritten, which OVMF detects as memory
corruption.
Increase the size of the storage buffer in a few places to correct
this problem.
Signed-off-by: Richard W.M. Jones <rjones@redhat.com> Cc: Laszlo Ersek <lersek@redhat.com> Cc: Gary Ching-Pang Lin <glin@suse.com>
fallback: Fix comparison between signed and unsigned in debugging code.
fallback.c: In function ‘update_boot_order’:
fallback.c:334:17: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]
for (j = 0 ; j < size / sizeof (CHAR16); j++)
^
fallback.c: In function ‘add_to_boot_list’:
fallback.c:402:16: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]
for (i = 0; i < s; i++) {
^
Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Peter Jones [Mon, 13 Apr 2015 23:55:25 +0000 (19:55 -0400)]
Don't install our protocols if we're not in secure mode.
System services haven't been hooked if we're not in secure mode, so
do_exit() will never be called. In this case shim never gets control
once grub exits, which means if booting fails and the firmware tries
another boot option, it'll attempt to talk to the shim protocol we
installed.
This is wrong, because it is allowed to have been cleared from ram at
this time, since the task it's under has exited.
So just don't install the protocols when we're not enforcing.
This version also has a message and a 2-second stall after calling
start_image(), so that we can tell if we are on the expected return path
of our execution flow.
Peter Jones [Mon, 13 Apr 2015 23:55:25 +0000 (19:55 -0400)]
Align the sections we're loading, and check for validity /after/ discarding.
Turns out a) the codegen on aarch64 generates code that has real
alignment needs, and b) if we check the length of discardable sections
before discarding them, we error for no reason.
So do the error checking in the right order, and always enforce some
alignment because we know we have to.
Peter Jones [Thu, 2 Oct 2014 05:01:54 +0000 (01:01 -0400)]
Correctly reject bad tftp addresses earlier, rather than later.
This check is for end == NULL but was meant to be *end == '\0'. Without
this change, we'll pass a plausibly bad address (i.e. one with no ']' at
the end) to Mtftp(... READ_FILE ...), which should fail correctly, but
our error messaging will be inconsistent.
I mistakenly added CryptPkcs7VerifyNull.c which may make Pkcs7Verify
always return FALSE. Besides CryptPkcs7VerifyNull.c, there are some
functions we would never use. This commit removes those files to
avoid any potential trouble.
Signed-off-by: Gary Ching-Pang Lin <glin@suse.com>
We replaced the build key with an empty file while compiling shim
for our distro. Skip the verification with the empty build key
since this makes no sense.
Signed-off-by: Gary Ching-Pang Lin <glin@suse.com>
Peter Jones [Wed, 1 Oct 2014 02:51:32 +0000 (22:51 -0400)]
Actually find the relocations correctly and process them that way.
Find the relocations based on the *file* address in the old binary,
because it's only the same as the virtual address some of the time.
Also perform some extra validation before processing it, and don't bail
out in /error/ if both ReloceBase and RelocEnd are null - that condition
is fine.
Which is where the pointer on ia32 for the Base Relocation Table should
be. It points to 0x8447, which isn't a particularly reasonable address as
numbers go, and happens to have this data there:
Peter Jones [Sun, 21 Sep 2014 20:25:27 +0000 (16:25 -0400)]
Generate a sane PE header on shim, fallback, and MokManager.
It turns out a7249a65 was masking a second problem - on some binaries,
when we actually don't have any base relocations at all, binutils'
"objcopy --target efi-app-x86_64" is generating a PE header with a base
relocations pointer that happily points into the middle of our text
section. So with shim processing base relocations correctly, it refuses
to load those binaries.
That wouldn't be so bad, except those binaries are MokManager.efi,
fallback.efi, and shim.efi, and sometimes they're .reloc, which we're
actually trying to handle correctly now because grub builds with a real
and valid .reloc table. So though I didn't think there was any hair
left on this yak, more shaving ensues.
With this change, instead of letting objcopy do whatever it likes, we
switch to "-O binary" and merely link in a header that's appropriate for
our binaries. This is the same method Ard wrote for aarch64, and it
seems to work fine in either place (modulo some minor changes.)
At some point this should be merged into gnu-efi instead of carrying our
own crt0-efi-x86_64.S, but that's a less immediate problem.
Peter Jones [Sun, 21 Sep 2014 20:25:27 +0000 (16:25 -0400)]
Fix our "in_protocol" printing.
When I merged 4bfb13d and fixed the conflicts, I managed to make the
in_protocol test exactly backwards, so that's why we don't currently see
error messages.
Peter Jones [Sun, 21 Sep 2014 20:25:27 +0000 (16:25 -0400)]
Don't call AuthenticodeVerify if vendor_cert_size is 0.
Actually check the size of our vendor cert quite early, so that there's
no confusion as to what's going on.
This isn't strictly necessary, in that in all cases if vendor_cert_size
is 0, then AuthenticodeVerify -> Pkcs7Verify() -> d2i_X509() will result
in a NULL "Cert", and it will return FALSE, and we'll reject the
signature, but better to avoid all that code in the first place. Belt
and suspenders and whatnot.
Peter Jones [Sun, 21 Sep 2014 17:12:03 +0000 (13:12 -0400)]
Make 64-on-32 maybe work on x86_64.
This is mostly based on a patch (https://github.com/mjg59/shim/issues/30)
from https://github.com/TBOpen , which refactors our __LP64__
tests to be tests of the header magic instead. I've simplified things
by using what we've pre-loaded into "context" and making some helper
functions so the conditionals in most of the code say what they do,
instead of how they work.
Note that we're only allowing that from in_protocol's loader - that is,
we'll let 64-bit grub load a 32-bit kernel or 32-bit grub load a 64-bit
kernel, but 32-bit shim isn't loading a 64-bit grub.
Peter Jones [Fri, 19 Sep 2014 13:30:26 +0000 (09:30 -0400)]
Actually refer to the base relocation table of our loaded image.
Currently when we process base relocations, we get the correct Data
Directory pointer from the headers (context->RelocDir), and that header
has been copied into our pristine allocated image when we copied up to
SizeOfHeaders. But the data it points to has not been mirrored in to
the new image, so it is whatever data AllocPool() gave us.
This patch changes relocate_coff() to refer to the base relocation table
from the image we loaded from disk, but apply the fixups to the new
copy.
I have no idea how x86_64 worked without this, but I can't make aarch64
work without it. I also don't know how Ard or Leif have seen aarch64
work. Maybe they haven't? Leif indicated on irc that they may have
only tested shim with simple "hello world" applications from gnu-efi;
they are certainly much less complex than grub.efi, and are generated
through a different linking process.
My only theory is that we're getting recycled data there pretty reliably
that just makes us /not/ process any relocations, but since our
ImageBase is 0, and I don't think we ever load grub with 0 as its base
virtual address, that doesn't follow. I'm open to any other ideas
anybody has.
I do know that on x86_64 (and presumably aarch64 as well), we don't
actually start seeing *symptoms* of this bug until the first chunk[0] of 94c9a77f is applied[1]. Once that is applied, relocate_coff() starts
seeing zero[2] for both RelocBase->VirtualAddress and
RelocBase->SizeOfBlock, because RelocBase is a (generated, relative)
pointer that only makes sense in the context of the original binary, not
our partial copy. Since RelocBase->SizeOfBlock is tested first,
relocate_base() gives us "Reloc block size is invalid"[3] and returns
EFI_UNSUPPORTED. At that point shim exits with an error.
[0] The second chunk of 94c9a77f patch makes no difference on this
issue.
[1] I don't see why at all.
[2] Which could really be any value since it's AllocatePool() and not
AllocateZeroPool() results, but 0 is all I've observed; I think
AllocatePool() has simply never recycled any memory in my test
cases.
[3] which is silent because perror() tries to avoid talking because that
has caused much crashing in the past; work needs to go in to 0.9 for
this.
Peter Jones [Wed, 27 Aug 2014 20:40:57 +0000 (16:40 -0400)]
Make sure we don't try to load a binary from a different arch.
Since in theory you could, for example, get an x86_64 binary signed that
also behaves as an ARM executable, we should be checking this before
people build on other architectures.
Peter Jones [Wed, 27 Aug 2014 20:40:57 +0000 (16:40 -0400)]
Don't name something exit().
On aarch64 due to some terrifying include chain we wind up with
Cryptlib's definition of exit here. I'm not a glutton for punishment,
so I'm just changing the name so it's not coliding.
Ard Biesheuvel [Wed, 27 Aug 2014 15:49:39 +0000 (11:49 -0400)]
Handle empty .reloc section in PE/COFF loader
On archs where no EFI aware objcopy is available, the generated PE/COFF
header contains a .reloc section which is completely empty. Handle this by
- returning early from relocate_coff() with EFI_SUCCESS,
- ignoring discardable sections in the section loader.
Ard Biesheuvel [Tue, 12 Aug 2014 14:54:05 +0000 (10:54 -0400)]
Factor out x86-isms and add cross compile support
This patch cleans up and refactors the Makefiles to better allow new
architectures to be added:
- remove unused Makefile definitions
- import Makefile definitions from top level rather than redefining
- move x86 specific CFLAGS to inside ifeq() blocks
- remove x86 inline asm
- allow $(FORMAT) to be overridden: this is necessary as there exists no
EFI or PE/COFF aware objcopy for ARM
Ard Biesheuvel [Tue, 12 Aug 2014 14:54:05 +0000 (10:54 -0400)]
CryptLib: undefine va_arg and friends before redefining them
Upstream GNU-EFI contains changes to efistdarg.h resulting in the va_start,
va_arg and va_end macros to be #defined unconditionally. Make sure we #undef
them before overriding the definitions.
If ca.crt was added into the certificate database, ca.crt would be the first
certificate in the signature. Because shim couldn't verify ca.crt with the
embedded shim.cer, it failed to load MokManager.efi.signed and
fallback.efi.signed.
Signed-off-by: Gary Ching-Pang Lin <glin@suse.com>
MokManager: handle the error status from ReadKeyStroke
On some machines, even though the key event was signaled, ReadKeyStroke
still got EFI_NOT_READY. This commit handles the error status to avoid
console_get_keystroke from returning unexpected keys.
Signed-off-by: Gary Ching-Pang Lin <glin@suse.com>
Conflicts:
MokManager.c
A non-DER encoding x509 certificate may be mistakenly enrolled into
db or MokList. This commit checks the first 4 bytes of the certificate
to ensure that it's DER encoding.
This commit also removes the iteration of the x509 signature list.
Per UEFI SPEC, each x509 signature list contains only one x509 certificate.
Besides, the size of certificate is incorrect. The size of the header must
be substracted from the signature size.
Signed-off-by: Gary Ching-Pang Lin <glin@suse.com>
The previous strategy is to locate the first available PXE_BASE_CODE
protocol and to fetch the second stage image from it, and this may
cause shim to fetch the wrong second stage image, i.e. grub.efi.
Consider the machine with the following boot order:
1. PXE Boot
2. Hard Drive
Assume that the EFI image, e.g. bootx64.efi, in the PXE server is
broken, then "PXE Boot" will fail and fallback to "Hard Drive". While
shim.efi in "Hard Drive" is loaded, it will find the PXE protocol is
available and fetch grub.efi from the PXE server, not grub.efi in the
disk.
This commit checks the DeviceHandle from Loaded Image. If the device
supports PXE, then shim fetches grub.efi with the PXE protocol. Otherwise,
shim loads grub.efi from the disk.
Signed-off-by: Gary Ching-Pang Lin <glin@suse.com>
[fallback] Try to boot the first boot option anyway
Some UEFI implementations never care the boot options, so the
restored boot options could be just ignored and this results in
endless reboot. To avoid this situation, this commit makes
fallback.efi to load the first matched boot option even if there
is no boot option to be restored. It may not be perfect, but at
least the bootloader is loaded...
Signed-off-by: Gary Ching-Pang Lin <glin@suse.com>
set_boot_order() already copies the old BootOrder to the variable,
bootorder. Besides, we can adjust BootOrder when adding the newly
generated boot option. So, we don't have to copy the old one again
in update_boot_order(). This avoid the duplicate entries in BootOrder.
Signed-off-by: Gary Ching-Pang Lin <glin@suse.com>
This adds additional bounds-checking on the section sizes. Also adds
-Wsign-compare to the Makefile and replaces some signed variables with
unsigned counteparts for robustness.
Peter Jones [Fri, 14 Feb 2014 22:48:01 +0000 (17:48 -0500)]
Allow fallback to use the system's LoadImage/StartImage .
Track use of the system's LoadImage(), and when the next StartImage()
call is for an image the system verified, allow that to count as
participating, since it has been verified by the system's db.
Peter Jones [Fri, 31 Jan 2014 15:31:10 +0000 (10:31 -0500)]
[fallback] Attempt to re-use existing entries when possible.
Some firmwares seem to ignore our boot entries and put their fallback
entries back on top. Right now that results in a lot of boot entries
for our stuff, a la https://bugzilla.redhat.com/show_bug.cgi?id=995834 .
Instead of that happening, if we simply find existing entries that match
the entry we would create and move them to the top of the boot order,
the machine will continue to operate in failure mode (which we can't
avoid), but at least we won't create thousands of extra entries.
Peter Jones [Fri, 31 Jan 2014 15:30:36 +0000 (10:30 -0500)]
[fallback] For HD() device paths, use just the media node and later.
UEFI 2.x section 3.1.2 provides for "short-form device path", where the
first element specified is a "hard drive media device path", so that you
can move a disk around on different buses without invalidating your
device path. Fallback has not been using this option, though in most
cases efibootmgr has.
Note that we still keep the full device path, because LoadImage()
isn't necessarily the layer where HD() works - one some systems BDS is
responsible for resolving the full path and passes that to LoadImage()
instead. So we have to do LoadImage() with the full path.
Peter Jones [Thu, 21 Nov 2013 16:48:24 +0000 (11:48 -0500)]
Rewrite directory traversal allocation path so coverity can grok it.
The things we do for our tools. In this case, make the AllocatePool()
happen outside of a conditional, even though that conditional will
always bee satisfied. This way coverity won't think we're setting fi
to NULL and passing it to StrCaseCmp.
Peter Jones [Thu, 21 Nov 2013 16:48:24 +0000 (11:48 -0500)]
Fix path generation for Dhcpv4 bootloader.
Right now we always look for e.g. "\grubx64.efi", which is completely
wrong. This makes it look for the path shim was loaded from and modify
that to end in a sanitized version of our default loader name.
Matthew Garrett [Tue, 19 Nov 2013 15:20:34 +0000 (10:20 -0500)]
Don't hook system services if shim has no built-in keys
Shim should only need to enforce its security policy when its launching
binaries signed with its built-in key. Binaries signed by keys in db or
Mokdb should be able to rely on their own security policy.
Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
Matthew Garrett [Tue, 19 Nov 2013 15:20:34 +0000 (10:20 -0500)]
Clarify meaning of insecure_mode
insecure_mode was intended to indicate that the user had explicity disabled
checks with mokutil, which means it wasn't the opposite of secure_mode().
Change the names to clarify this and don't show the insecure mode message
unless the user has explicitly enabled that mode.
Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>