The fuzzer is generating btrfs file systems that have chunks with
invalid combinations of stripes and substripes for the given RAID
configurations.

After examining the Linux kernel fs/btrfs/tree-checker.c code, it
appears that sub-stripes should only be applied to RAID10, and in that
case there should only ever be 2 of them.

Similarly, RAID single should only have 1 stripe, and RAID1/1C3/1C4
should have 2. 3 or 4 stripes respectively, which is what redundancy
corresponds.

Some of the chunks ended up with a size of 0, which grub_malloc() still
returned memory for and in turn generated ASAN errors later when
accessed.

While it would be possible to specifically limit the number of stripes,
a more correct test was on the combination of the chunk item, and the
number of stripes by the size of the chunk stripe structure in
comparison to the size of the chunk itself.

Signed-off-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

According to the btrfs code in Linux, the structure of a directory item
leaf should be of the form:

  |struct btrfs_dir_item|name|data|

in GRUB the name len and data len are in the grub_btrfs_dir_item
structure's n and m fields respectively.

The combined size of the structure, name and data should be less than
the allocated memory, a difference to the Linux kernel's struct
btrfs_dir_item is that the grub_btrfs_dir_item has an extra field for
where the name is stored, so we adjust for that too.

Signed-off-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

A corrupt f2fs file system might specify a name length which is greater
than the maximum name length supported by the GRUB f2fs driver.

We will allocate enough memory to store the overly long name, but there
are only F2FS_NAME_LEN bytes in the source, so we would read past the end
of the source.

While checking directory entries, do not copy a file name with an invalid
length.

Signed-off-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>
Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

A corrupt f2fs filesystem could have a block offset or a bitmap
offset that would cause us to read beyond the bounds of the nat
bitmap.

Introduce the nat_bitmap_size member in grub_f2fs_data which holds
the size of nat bitmap.

Set the size when loading the nat bitmap in nat_bitmap_ptr(), and
catch when an invalid offset would create a pointer past the end of
the allocated space.

Check against the bitmap size in grub_f2fs_test_bit() test bit to avoid
reading past the end of the nat bitmap.

Signed-off-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>
Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

A corrupt f2fs file system could specify a nat journal entry count
that is beyond the maximum NAT_JOURNAL_ENTRIES.

Check if the specified nat journal entry count before accessing the
array, and throw an error if it is too large.

Signed-off-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>
Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

In a similar vein to the previous patch, parse_line() would write
a NUL byte past the end of the buffer if there was an HTTP header
with a LF rather than a CRLF.

RFC-2616 says:

  Many HTTP/1.1 header field values consist of words separated by LWS
  or special characters. These special characters MUST be in a quoted
  string to be used within a parameter value (as defined in section 3.6).

We don't support quoted sections or continuation lines, etc.

If we see an LF that's not part of a CRLF, bail out.

Fixes: CVE-2022-28734

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

GRUB has special code for handling an http header that is split
across two packets.

The code tracks the end of line by looking for a "\n" byte. The
code for split headers has always advanced the pointer just past the
end of the line, whereas the code that handles unsplit headers does
not advance the pointer. This extra advance causes the length to be
one greater, which breaks an assumption in parse_line(), leading to
it writing a NUL byte one byte past the end of the buffer where we
reconstruct the line from the two packets.

It's conceivable that an attacker controlled set of packets could
cause this to zero out the first byte of the "next" pointer of the
grub_mm_region structure following the current_line buffer.

Do not advance the pointer in the split header case.

Fixes: CVE-2022-28734

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

It's possible for data->sock to get torn down in tcp error handling.
If we unconditionally tear it down again we will end up doing writes
to an offset of the NULL pointer when we go to tear it down again.

Detect if it has been torn down and don't do it again.

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

Under tftp errors, we print a tftp error message from the tftp header.
However, the tftph pointer is a pointer inside nb, the netbuff. Previously,
we were freeing the nb and then dereferencing it. Don't do that, use it
and then free it later.

This isn't really _bad_ per se, especially as we're single-threaded, but
it trips up fuzzers.

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

A malicious tftp server can cause UAFs and a double free.

An attempt to read from a network file is handled by grub_net_fs_read(). If
the read is at an offset other than the current offset, grub_net_seek_real()
is invoked.

In grub_net_seek_real(), if a backwards seek cannot be satisfied from the
currently received packets, and the underlying transport does not provide
a seek method, then grub_net_seek_real() will close and reopen the network
protocol layer.

For tftp, the ->close() call goes to tftp_close() and frees the tftp_data_t
file->data. The file->data pointer is not nulled out after the free.

If the ->open() call fails, the file->data will not be reallocated and will
continue point to a freed memory block. This could happen from a server
refusing to send the requisite ack to the new tftp request, for example.

The seek and the read will then fail, but the grub_file continues to exist:
the failed seek does not necessarily cause the entire file to be thrown
away (e.g. where the file is checked to see if it is gzipped/lzio/xz/etc.,
a read failure is interpreted as a decompressor passing on the file, not as
an invalidation of the entire grub_file_t structure).

This means subsequent attempts to read or seek the file will use the old
file->data after free. Eventually, the file will be close()d again and
file->data will be freed again.

Mark a net_fs file that doesn't reopen as broken. Do not permit read() or
close() on a broken file (seek is not exposed directly to the file API -
it is only called as part of read, so this blocks seeks as well).

As an additional defence, null out the ->data pointer if tftp_open() fails.
That would have lead to a simple null pointer dereference rather than
a mess of UAFs.

This may affect other protocols, I haven't checked.

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

I don't really understand what's going on here but fuzzing found
a bug where we read past the end of check_with. That's a C string,
so use grub_strlen() to make sure we don't overread it.

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

grub_net_dns_lookup() takes as inputs a pointer to an array of addresses
("addresses") for the given name, and pointer to a number of addresses
("naddresses"). grub_net_dns_lookup() is responsible for allocating
"addresses", and the caller is responsible for freeing it if
"naddresses" > 0.

The DNS recv_hook will sometimes set and free the addresses array,
for example if the packet is too short:

      if (ptr + 10 >= nb->tail)
	{
	  if (!*data->naddresses)
	    grub_free (*data->addresses);
	  grub_netbuff_free (nb);
	  return GRUB_ERR_NONE;
	}

Later on the nslookup command code unconditionally frees the "addresses"
array. Normally this is fine: the array is either populated with valid
data or is NULL. But in these sorts of error cases it is neither NULL
nor valid and we get a double-free.

Only free "addresses" if "naddresses" > 0.

It looks like the other use of grub_net_dns_lookup() is not affected.

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

This avoids an underflow and subsequent unpleasantness.

Fixes: CVE-2022-28733

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

A netbuff shouldn't be too huge. It's bounded by MTU and TCP segment
reassembly.

This helps avoid some bugs (and provides a spot to instrument to catch
them at their source).

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

In some cases attempting to display arbitrary binary strings leads
to ASAN splats reading the widthspec array out of bounds.

Check the index. If it would be out of bounds, return a width of 1.
I don't know if that's strictly correct, but we're not really expecting
great display of arbitrary binary data, and it's certainly not worse than
an OOB read.

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

Certain 1 px wide images caused a wild pointer write in
grub_jpeg_ycrcb_to_rgb(). This was caused because in grub_jpeg_decode_data(),
we have the following loop:

for (; data->r1 < nr1 && (!data->dri || rst);
     data->r1++, data->bitmap_ptr += (vb * data->image_width - hb * nc1) * 3)

We did not check if vb * width >= hb * nc1.

On a 64-bit platform, if that turns out to be negative, it will underflow,
be interpreted as unsigned 64-bit, then be added to the 64-bit pointer, so
we see data->bitmap_ptr jump, e.g.:

0x6180_0000_0480 to
0x6181_0000_0498
     ^
     ~--- carry has occurred and this pointer is now far away from
          any object.

On a 32-bit platform, it will decrement the pointer, creating a pointer
that won't crash but will overwrite random data.

Catch the underflow and error out.

Fixes: CVE-2021-3697

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

An invalid file could contain multiple start of stream blocks, which
would cause us to reallocate and leak our bitmap. Refuse to handle
multiple start of streams.

Additionally, fix a grub_error() call formatting.

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

Fix a memory leak where an invalid file could cause us to reallocate
memory for a huffman table we had already allocated memory for.

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

Fuzzing revealed some inputs that were taking a long time, potentially
forever, because they did not bail quickly upon encountering an I/O error.

Try to catch I/O errors sooner and bail out.

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

ASAN picked up two OOB global reads: we weren't checking if some code
values fit within the cplens or cpdext arrays. Check and throw an error
if not.

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

In fuzzing we observed crashes where a code would attempt to be inserted
into a huffman table before the start, leading to a set of heap OOB reads
and writes as table entries with negative indices were shifted around and
the new code written in.

Catch the case where we would underflow the array and bail.

Fixes: CVE-2021-3696

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

A 16-bit greyscale PNG without alpha is processed in the following loop:

      for (i = 0; i < (data->image_width * data->image_height);
	   i++, d1 += 4, d2 += 2)
	{
	  d1[R3] = d2[1];
	  d1[G3] = d2[1];
	  d1[B3] = d2[1];
	}

The increment of d1 is wrong. d1 is incremented by 4 bytes per iteration,
but there are only 3 bytes allocated for storage. This means that image
data will overwrite somewhat-attacker-controlled parts of memory - 3 bytes
out of every 4 following the end of the image.

This has existed since greyscale support was added in 2013 in commit
3ccf16df (grub-core/video/readers/png.c: Support grayscale).

Saving starfield.png as a 16-bit greyscale image without alpha in the gimp
and attempting to load it causes grub-emu to crash - I don't think this code
has ever worked.

Delete all PNG greyscale support.

Fixes: CVE-2021-3695

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

This causes the bitmap to be leaked. Do not permit multiple image headers.

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

Fuzzing revealed some inputs that were taking a long time, potentially
forever, because they did not bail quickly upon encountering an I/O error.

Try to catch I/O errors sooner and bail out.

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

If we have an error in grub_file_open() before we free device_name, we
will leak it.

Free device_name in the error path and null out the pointer in the good
path once we free it there.

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

We must not allow other verifiers to pass things like the GRUB modules.
Instead of maintaining a blocklist, maintain an allowlist of things
that we do not care about.

This allowlist really should be made reusable, and shared by the
lockdown verifier, but this is the minimal patch addressing
security concerns where the TPM verifier was able to mark modules
as verified (or the OpenPGP verifier for that matter), when it
should not do so on shim-powered secure boot systems.

Fixes: CVE-2022-28735

Signed-off-by: Julian Andres Klode <julian.klode@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

This ports the EFI chainloader to use grub_loader_set_ex() in order to fix
a use-after-free bug that occurs when grub_cmd_chainloader() is executed
more than once before a boot attempt is performed.

Fixes: CVE-2022-28736

Signed-off-by: Chris Coulson <chris.coulson@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

Loaders rely on global variables for saving context which is consumed
in the boot hook and freed in the unload hook. In the case where a loader
command is executed twice, calling grub_loader_set a second time executes
the unload hook, but in some cases this runs when the loader's global
context has already been updated, resulting in the updated context being
freed and potential use-after-free bugs when the boot hook is subsequently
called.

This adds a new API (grub_loader_set_ex) which allows a loader to specify
context that is passed to its boot and unload hooks. This is an alternative
to requiring that loaders call grub_loader_unset before mutating their
global context.

Signed-off-by: Chris Coulson <chris.coulson@canonical.com>
(cherry picked from commit 4322a64dde7e8fedb58e50b79408667129d45dd3)

The chainloader command retains the source buffer and device path passed
to LoadImage(), requiring the unload hook passed to grub_loader_set() to
free them. It isn't required to retain this state though - they aren't
required by StartImage() or anything else in the boot hook, so clean them
up before grub_cmd_chainloader() finishes.

Signed-off-by: Chris Coulson <chris.coulson@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

minilzo fails to build on a number of Debian release architectures
(armel, mips64el, mipsel, ppc64el) with errors such as:

  ../../grub-core/lib/minilzo/minilzo.c: In function 'lzo_memops_get_le16':
  ../../grub-core/lib/minilzo/minilzo.c:3479:11: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
   3479 |         * (lzo_memops_TU2p) (lzo_memops_TU0p) (dd) = * (const lzo_memops_TU2p) (const lzo_memops_TU0p) (ss); \
        |           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  ../../grub-core/lib/minilzo/minilzo.c:3530:5: note: in expansion of macro 'LZO_MEMOPS_COPY2'
   3530 |     LZO_MEMOPS_COPY2(&v, ss);
        |     ^~~~~~~~~~~~~~~~

The latest upstream version is 2.10, so updating to it seems like a good
idea on general principles, and it fixes builds on all the above
architectures.

The update procedure documented in the GRUB Developers Manual worked; I
just updated the version numbers to make it clear that it's been
executed recently.

Signed-off-by: Colin Watson <cjwatson@debian.org>

Forwarded: https://lists.gnu.org/archive/html/grub-devel/2021-11/msg00095.html
Last-Update: 2021-11-29

Patch-Name: minilzo-2.10.patch

The "ide-drive" device was removed in QEMU 6.0. The "ide-hd" has been
available for more than 10 years now in QEMU. Thus there shouldn't be
any need for backwards compatible names.

Signed-off-by: Marius Bakke <marius@gnu.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

Origin: upstream, https://git.savannah.gnu.org/cgit/grub.git/commit/?id=aaea244a6ddd1e35aed60a5c7a08ddc41f51805b
Last-Update: 2021-09-24

Patch-Name: tests-ahci-update-qemu-device-name.patch

The commit 8b1e5d19 (fs/xfs: Add bigtime incompat feature support)
introduced the bigtime support by adding some features in v3 inodes.
This change extended grub_xfs_inode struct by 76 bytes but also changed
the computation of XFS_V2_INODE_SIZE and XFS_V3_INODE_SIZE. Prior this
commit, XFS_V2_INODE_SIZE was 100 bytes. After the commit it's 84 bytes
XFS_V2_INODE_SIZE becomes 16 bytes too small.

As a result, the data structures aren't properly aligned and the GRUB
generates "attempt to read or write outside of partition" errors when
trying to read the XFS filesystem:

                             GNU GRUB  version 2.11
	....
	grub> set debug=efi,gpt,xfs
	grub> insmod part_gpt
	grub> ls (hd0,gpt1)/
	partmap/gpt.c:93: Read a valid GPT header
	partmap/gpt.c:115: GPT entry 0: start=4096, length=1953125
	fs/xfs.c:931: Reading sb
	fs/xfs.c:270: Validating superblock
	fs/xfs.c:295: XFS v4 superblock detected
	fs/xfs.c:962: Reading root ino 128
	fs/xfs.c:515: Reading inode (128) - 64, 0
	fs/xfs.c:515: Reading inode (739521961424144223) - 344365866970255880, 3840
	error: attempt to read or write outside of partition.

This commit change the XFS_V2_INODE_SIZE computation by subtracting 76
bytes instead of 92 bytes from the actual size of grub_xfs_inode struct.
This 76 bytes value comes from added members:
	20 grub_uint8_t   unused5
	 1 grub_uint64_t  flags2
        48 grub_uint8_t   unused6

This patch explicitly splits the v2 and v3 parts of the structure.
The unused4 is still ending of the v2 structures and the v3 starts
at unused5. Thanks to this we will avoid future corruptions of v2
or v3 inodes.

The XFS_V2_INODE_SIZE is returning to its expected size and the
filesystem is back to a readable state:

                      GNU GRUB  version 2.11
	....
	grub> set debug=efi,gpt,xfs
	grub> insmod part_gpt
	grub> ls (hd0,gpt1)/
	partmap/gpt.c:93: Read a valid GPT header
	partmap/gpt.c:115: GPT entry 0: start=4096, length=1953125
	fs/xfs.c:931: Reading sb
	fs/xfs.c:270: Validating superblock
	fs/xfs.c:295: XFS v4 superblock detected
	fs/xfs.c:962: Reading root ino 128
	fs/xfs.c:515: Reading inode (128) - 64, 0
	fs/xfs.c:515: Reading inode (128) - 64, 0
	fs/xfs.c:931: Reading sb
	fs/xfs.c:270: Validating superblock
	fs/xfs.c:295: XFS v4 superblock detected
	fs/xfs.c:962: Reading root ino 128
	fs/xfs.c:515: Reading inode (128) - 64, 0
	fs/xfs.c:515: Reading inode (128) - 64, 0
	fs/xfs.c:515: Reading inode (128) - 64, 0
	fs/xfs.c:515: Reading inode (131) - 64, 768
	efi/ fs/xfs.c:515: Reading inode (3145856) - 1464904, 0
	grub2/ fs/xfs.c:515: Reading inode (132) - 64, 1024
	grub/ fs/xfs.c:515: Reading inode (139) - 64, 2816
	grub>

Fixes: 8b1e5d19 (fs/xfs: Add bigtime incompat feature support)

Signed-off-by: Erwan Velu <e.velu@criteo.com>
Tested-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

Origin: upstream, https://git.savannah.gnu.org/cgit/grub.git/commit/?id=a4b495520e4dc41a896a8b916a64eda9970c50ea
Last-Update: 2021-09-24

Patch-Name: xfs-fix-v4-superblock.patch

Signed-off-by: Mathieu Trudel-Lapierre <mathieu.trudel-lapierre@canonical.com>

Bug-Debian: https://bugs.debian.org/940911
Bug-Ubuntu: https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1848892
Last-Update: 2021-09-24

Patch-Name: tpm-unknown-error-non-fatal.patch

Commit f60ba9e5 (util/mkimage: Refactor section setup to use a helper)
added a helper function to setup PE sections, but it caused regressions
in some arches where the natural alignment lead to wrong section sizes.

This patch fixes a few things that were caused the section sizes to be
calculated wrongly. These fixes are:

 * Only align the virtual memory addresses but not the raw data offsets.
 * Use aligned sizes for virtual memory sizes but not for raw data sizes.
 * Always align the sizes to set the virtual memory sizes.

These seems to not cause problems for x64 and aa64 EFI platforms but was
a problem for ia64. Because the size of the ".data" and "mods" sections
were wrong and didn't have the correct content. Which lead to GRUB not
being able to load any built-in module.

Reported-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>

Bug-Debian: https://bugs.debian.org/987103

Patch-Name: mkimage-fix-section-sizes.patch

Patch-Name: debug_verifiers.patch

Given no core functions on i386-pc would require verifiers to work and
the only consumer of the verifier API is the pgp module, it looks good
to me that we can move the verifiers out of the kernel image and let
moddep.lst to auto-load it when pgp is loaded on i386-pc platform.

This helps to reduce the size of core image and thus can relax the
tension of exploding on some i386-pc system with very short MBR gap
size. See also a very comprehensive summary from Colin [1] about the
details.

[1] https://lists.gnu.org/archive/html/grub-devel/2021-03/msg00240.html



V2:
Drop COND_NOT_i386_pc and use !COND_i386_pc.
Add comment in kern/verifiers.c to help understanding what's going on
without digging into the commit history.

Reported-by: Colin Watson <cjwatson@debian.org>
Reviewed-by: Colin Watson <cjwatson@debian.org>
Signed-off-by: Michael Chang <mchang@suse.com>

Origin: other, https://lists.gnu.org/archive/html/grub-devel/2021-03/msg00251.html
Bug-Debian: https://bugs.debian.org/984488
Bug-Debian: https://bugs.debian.org/985374
Last-Update: 2021-09-24

Patch-Name: pc-verifiers-module.patch

For complicated reasons, even if you have XSM/FLASK disabled (as is
the default) the Xen build system still builds a policy file and puts
it in /boot.

Even so, we shouldn't be loading this in the usual non-"XSM enabled"
entries.  It doesn't do any particular harm but it is quite confusing.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>

Bug-Debian: https://bugs.debian.org/961673
Last-Update: 2020-05-29

Patch-Name: xen-no-xsm-policy-in-non-xsm-options.patch

Patch-Name: dejavu-font-path.patch

In this case, we need both the signed shim as /EFI/BOOT/BOOTXXX.EFI
and signed Grub as /EFI/BOOT/grubXXX.efi.

Also install the BOOTXXX.CSV into /EFI/debian, and FBXXX.EFI into
/EFI/BOOT/ so that it can work when needed (*iff* we're updating the
NVRAM).

[cjwatson: Refactored also_install_removable somewhat for brevity and so
that we're using consistent case-insensitive logic.]

Bug-Debian: https://bugs.debian.org/930531
Last-Update: 2021-09-24

Patch-Name: grub-install-removable-shim.patch

Some UEFI firmware is easily provoked into running out of space in its
variable storage.  This is usually due to certain kernel drivers (e.g.
pstore), but regardless of the cause it can cause grub-install to fail
because it currently asks efibootmgr to delete and re-add entries, and
the deletion often doesn't result in an immediate garbage collection.
Writing variables frequently also increases wear on the NVRAM which may
have limited write cycles.  For these reasons, it's desirable to find a
way to minimise writes while still allowing grub-install to ensure that
a suitable boot entry exists.

Unfortunately, efibootmgr doesn't offer an interface that would let
grub-install do this.  It doesn't in general make very much effort to
minimise writes; it doesn't allow modifying an existing Boot* variable
entry, except in certain limited ways; and current versions don't have a
way to export the expected variable data so that grub-install can
compare it to the current data.  While it would be possible (and perhaps
desirable?) to add at least some of this to efibootmgr, that would still
leave the problem that there isn't a good upstreamable way for
grub-install to guarantee that it has a new enough version of
efibootmgr.  In any case, it's cumbersome and slow for grub-install to
have to fork efibootmgr to get things done.

Fortunately, a few years ago Peter Jones helpfully factored out a
substantial part of efibootmgr to the efivar and efiboot libraries, and
so it's now possible to have grub-install use those directly.  We still
have to use some code from efibootmgr, but much less than would
previously have been necessary.

grub-install now reuses existing boot entries where possible, and avoids
writing to variables when the new contents are the same as the old
contents.  In the common upgrade case where nothing needs to change, it
no longer writes to NVRAM at all.  It's also now slightly faster, since
using libefivar is faster than forking efibootmgr.

Fixes Debian bug #891434.

Signed-off-by: Colin Watson <cjwatson@ubuntu.com>

Bug-Debian: https://bugs.debian.org/891434
Forwarded: https://lists.gnu.org/archive/html/grub-devel/2019-03/msg00119.html
Last-Update: 2019-03-23

Patch-Name: efi-variable-storage-minimise-writes.patch