The two dimensional array p->posSlotEncoder[4][64] is being dereferenced
using the GetLenToPosState() macro which checks if len is less than 5,
and if so subtracts 2 from it. If len = 0, that is 0 - 2 = 4294967294.
Obviously we don't want to dereference that far out so we check if the
position found is greater or equal kNumLenToPosStates (4) and bail out.
N.B.: Upstream LZMA 18.05 and later has this function completely rewritten
without any history.
Fixes: CID 51526
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
When grub_json_parse() succeeds, it returns the root object which
contains a pointer to the provided JSON string. Callers are
responsible for ensuring that this string outlives the root
object and for freeing its memory when it's no longer needed.
If grub_json_parse() fails to parse the provided JSON string,
it frees the string before returning an error. This results
in a double free in luks2_recover_key(), which also frees the
same string after grub_json_parse() returns an error.
This changes grub_json_parse() to never free the JSON string
passed to it, and updates the documentation for it to make it
clear that callers are responsible for ensuring that the string
outlives the root JSON object.
Fixes: CID 292465
Signed-off-by: Chris Coulson <chris.coulson@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
grub_xnu_devprop_add_property() should not free utf8 and utf16 as it get
allocated and freed in the caller.
Minor improvement: do prop fields initialization after memory allocations.
Fixes: CID 292442, CID 292457, CID 292460, CID 292466
Signed-off-by: Alexey Makhalov <amakhalov@vmware.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
self->bitmap should be zeroed after free. Otherwise, there is a chance
to double free (USE_AFTER_FREE) it later in rescale_image().
Fixes: CID 292472
Signed-off-by: Alexey Makhalov <amakhalov@vmware.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The GRUB font file can have one NAME section only. Though if somebody
crafts a broken font file with many NAME sections and loads it then the
GRUB leaks memory. So, prevent against that by loading first NAME
section and failing in controlled way on following one.
Reported-by: Chris Coulson <chris.coulson@canonical.com>
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Jan Setje-Eilers <jan.setjeeilers@oracle.com>
This attempts to fix the places where we do the following where
arithmetic_expr may include unvalidated data:
X = grub_malloc(arithmetic_expr);
It accomplishes this by doing the arithmetic ahead of time using grub_add(),
grub_sub(), grub_mul() and testing for overflow before proceeding.
Among other issues, this fixes:
- allocation of integer overflow in grub_video_bitmap_create()
reported by Chris Coulson,
- allocation of integer overflow in grub_png_decode_image_header()
reported by Chris Coulson,
- allocation of integer overflow in grub_squash_read_symlink()
reported by Chris Coulson,
- allocation of integer overflow in grub_ext2_read_symlink()
reported by Chris Coulson,
- allocation of integer overflow in read_section_as_string()
reported by Chris Coulson.
Fixes: CVE-2020-14309, CVE-2020-14310, CVE-2020-14311
Signed-off-by: Peter Jones <pjones@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This modifies most of the places we do some form of:
X = malloc(Y * Z);
to use calloc(Y, Z) instead.
Among other issues, this fixes:
- allocation of integer overflow in grub_png_decode_image_header()
reported by Chris Coulson,
- allocation of integer overflow in luks_recover_key()
reported by Chris Coulson,
- allocation of integer overflow in grub_lvm_detect()
reported by Chris Coulson.
Fixes: CVE-2020-14308
Signed-off-by: Peter Jones <pjones@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This tries to make sure that everywhere in this source tree, we always have
an appropriate version of calloc() (i.e. grub_calloc(), xcalloc(), etc.)
available, and that they all safely check for overflow and return NULL when
it would occur.
Signed-off-by: Peter Jones <pjones@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This adds a new header, include/grub/safemath.h, that includes easy to
use wrappers for __builtin_{add,sub,mul}_overflow() declared like:
bool OP(a, b, res)
where OP is grub_add, grub_sub or grub_mul. OP() returns true in the
case where the operation would overflow and res is not modified.
Otherwise, false is returned and the operation is executed.
These arithmetic primitives require newer compiler versions. So, bump
these requirements in the INSTALL file too.
Signed-off-by: Peter Jones <pjones@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
When presented with a command that can't be tokenized to anything
smaller than YYLMAX characters, the parser calls YY_FATAL_ERROR(errmsg),
expecting that will stop further processing, as such:
#define YY_DO_BEFORE_ACTION \
yyg->yytext_ptr = yy_bp; \
yyleng = (int) (yy_cp - yy_bp); \
yyg->yy_hold_char = *yy_cp; \
*yy_cp = '\0'; \
if ( yyleng >= YYLMAX ) \
YY_FATAL_ERROR( "token too large, exceeds YYLMAX" ); \
yy_flex_strncpy( yytext, yyg->yytext_ptr, yyleng + 1 , yyscanner); \
yyg->yy_c_buf_p = yy_cp;
The code flex generates expects that YY_FATAL_ERROR() will either return
for it or do some form of longjmp(), or handle the error in some way at
least, and so the strncpy() call isn't in an "else" clause, and thus if
YY_FATAL_ERROR() is *not* actually fatal, it does the call with the
questionable limit, and predictable results ensue.
Unfortunately, our implementation of YY_FATAL_ERROR() is:
#define YY_FATAL_ERROR(msg) \
do { \
grub_printf (_("fatal error: %s\n"), _(msg)); \
} while (0)
The same pattern exists in yyless(), and similar problems exist in users
of YY_INPUT(), several places in the main parsing loop,
yy_get_next_buffer(), yy_load_buffer_state(), yyensure_buffer_stack,
yy_scan_buffer(), etc.
All of these callers expect YY_FATAL_ERROR() to actually be fatal, and
the things they do if it returns after calling it are wildly unsafe.
Fixes: CVE-2020-10713
Signed-off-by: Peter Jones <pjones@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
When booting on an ARMv8 core that implements either CTR.IDC or CTR.DIC
(indicating that some of the cache maintenance operations can be
removed when dealing with I/D-cache coherency, GRUB dies with a
"Unsupported cache type 0x........" message.
This is pretty likely to happen when running in a virtual machine
hosted on an arm64 machine (I've triggered it on a system built around
a bunch of Cortex-A55 cores, which implements CTR.IDC).
It turns out that the way GRUB deals with the CTR register is a bit
harsh for anything from ARMv7 onwards. The layout of the register is
backward compatible, meaning that nothing that gets added is allowed to
break earlier behaviour. In this case, ignoring IDC is completely fine,
and only results in unnecessary cache maintenance.
We can thus avoid being paranoid, and align the 32bit behaviour with
its 64bit equivalent.
This patch has the added benefit that it gets rid of a (gnu-specific)
case range too.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Leif Lindholm <leif@nuviainc.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
XSM is enabled by adding "flask=enforcing" as a Xen command line
argument, and providing the policy file as a grub module.
We make entries for both with and without XSM. If XSM is not compiled
into Xen, then there are no policy files, so no change to the boot
options.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
file_is_not_sym() currently only checks for xen-syms. Extend it to
disregard xenpolicy (XSM policy files) and files ending .config (which
are built by the Xen upstream build system in some configurations and
can therefore end up in /boot).
Rename the function accordingly, to file_is_not_xen_garbage().
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Nested functions are not supported in C, but are permitted as an extension
in the GNU C dialect. Commit cb2f15c544 ("normal/main: Search for specific
config files for netboot") added a nested function which caused the build
to break when compiling with clang.
Break that out into a static helper function to make the code portable again.
Reported-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Tested-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The module is only enabled for x86_64, but there's nothing specific to
x86_64 in the implementation and can be enabled for all EFI platforms.
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
..to reflect the GRUB build reality in them.
Additionally, fix text formatting a bit.
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Leif Lindholm <leif@nuviainc.com>
Commit d5a32255d (misc: Make grub_strtol() "end" pointers have safer
const qualifiers) introduced "restrict" keyword into some functions
definitions. This keyword was introduced in C99 standard. However, some
compilers by default may use C89 or something different. This behavior
leads to the breakage during builds when c89 or gnu89 is in force. So,
let's set gnu99 C language standard for all compilers by default. This
way a bit random build issue will be fixed and the GRUB source will be
build consistently regardless of type and version of the compiler.
It was decided to use gnu99 C language standard because it fixes the
issue mentioned above and also provides some useful extensions which are
used here and there in the GRUB source. Potentially we can use gnu11
too. However, this may reduce pool of older compilers which can be used
to build the GRUB. So, let's live with gnu99 until we discover that we
strongly require a feature from newer C standard.
The user is still able to override C language standard using relevant
*_CFLAGS variables.
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Leif Lindholm <leif@nuviainc.com>
grub_tpm_log_event() and grub_tpm_measure() are two functions that
have the same effect. So, keep grub_tpm_log_event() and rename it
to grub_tpm_measure(). This way we get also a more clear semantics.
Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
..because -iname cannot be used to match paths.
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Leif Lindholm <leif@nuviainc.com>
Reviewed-by: Daniel Axtens <dja@axtens.net>
Support was implemented in commit c7cb11b21 (probe: Support probing for
msdos PARTUUID).
Signed-off-by: Jacob Kroon <jacob.kroon@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Like grub_verifiers_open(), the grub_verify_string() should also
display this debug message, which is very helpful for debugging.
Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
If an existing variable is set with a value whose length is smaller than
the current value, a memory corruption can happen due copying padding '#'
characters outside of the environment block buffer.
This is caused by a wrong calculation of the previous free space position
after moving backward the characters that followed the old variable value.
That position is calculated to fill the remaining of the buffer with the
padding '#' characters. But since isn't calculated correctly, it can lead
to copies outside of the buffer.
The issue can be reproduced by creating a variable with a large value and
then try to set a new value that is much smaller:
$ grub2-editenv --version
grub2-editenv (GRUB) 2.04
$ grub2-editenv env create
$ grub2-editenv env set a="$(for i in {1..500}; do var="b$var"; done; echo $var)"
$ wc -c env
1024 grubenv
$ grub2-editenv env set a="$(for i in {1..50}; do var="b$var"; done; echo $var)"
malloc(): corrupted top size
Aborted (core dumped)
$ wc -c env
0 grubenv
Reported-by: Renaud Métrich <rmetrich@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Remove all documentation of and mentions of the uppermem
command from the docs/grub.texi file.
The uppermem command is not implemented in the GRUB source
at all and appears to never have been implemented despite
former plans to add an uppermem command.
To reduce user confusion, this even removes the paragraph
describing how GRUB's uppermem command was supposed to
complement the Linux kernel's mem= parameter.
Signed-off-by: Hans Ulrich Niedermann <hun@n-dimensional.de>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Remove the documentation of the pxe_unload command from the
docs/grub.texi file.
The pxe_unload command is not implemented in the grub source
at this time at all. It appears to have been removed in commit
671a78acb (cleanup pxe and efi network release).
Signed-off-by: Hans Ulrich Niedermann <hun@n-dimensional.de>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Add a few patterns to .gitignore to cover files which are generated
by building grub ("make", "make check", "make dist") but which have
been forgotten to add to .gitignore in the past.
Signed-off-by: Hans Ulrich Niedermann <hun@n-dimensional.de>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Going through the list of gitignore patterns without a leading slash,
this adds a leading slash where it appears to have been forgotten.
Some gitignore patterns like ".deps/" or "Makefile" clearly should
match everywhere, so those definitively need no leading slash.
For some patterns like "ascii.bitmaps", it is unclear where in the
source tree they should match. Those patterns are kept as they are,
matching the patterns in the whole tree of subdirectories.
Signed-off-by: Hans Ulrich Niedermann <hun@n-dimensional.de>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Add trailing slashes for all patterns matching directories.
Note that we do *not* add trailing slashes for *symlinks*
to directories.
Signed-off-by: Hans Ulrich Niedermann <hun@n-dimensional.de>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Alphabetically sort the two groups of gitignore patterns:
* The group of patterns without slashes, matching anywhere
in the directory subtree.
* The group of patterns with slashes, matching relative to the
.gitignore file's directory
Signed-off-by: Hans Ulrich Niedermann <hun@n-dimensional.de>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Group the .gitignore patterns into two groups:
* Pattern not including a slash, i.e. matching files anywhere in
the .gitignore file's directory and all of its subdirectories.
* Patterns including a slash, i.e. matching only relative to the
.gitignore file's directory.
Signed-off-by: Hans Ulrich Niedermann <hun@n-dimensional.de>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
As all gitignore patterns containing a left or middle slash match
only relative to the .gitignore file's directory, we write them
all in the same manner with a leading slash.
This makes the file significantly easier to read.
Signed-off-by: Hans Ulrich Niedermann <hun@n-dimensional.de>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Lack of them causes random instructions to be executed before the
jump really happens.
Signed-off-by: Vladimir Serbinenko <phcoder@google.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
When decrypting a given keyslot, all error cases except for one set up
an error and return the error code. The only exception is when we try to
read the area key: instead of setting up an error message, we directly
print it via grub_dprintf().
Convert the outlier to use grub_error() to allow more uniform handling
of errors.
Signed-off-by: Patrick Steinhardt <ps@kps.im>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
With the upstream change having landed that adds a name to the
previously anonymous "jsmntok" typedef, we can now add a forward
declaration for that struct in our code. As a result, we no longer have
to store the "tokens" member of "struct grub_json" as a void pointer but
can instead use the forward declaration, allowing us to get rid of casts
of that field.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Update our embedded version of the jsmn library to upstream commit
053d3cd (Merge pull request #175 from pks-t/pks/struct-type,
2020-04-02).
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The fwsetup command allows to reboot into the EFI firmware setup menu, add
a template to include a menu entry on EFI systems that makes use of that
command to reboot into the EFI firmware settings.
This is useful for users since the hotkey to enter into the EFI setup menu
may not be the same on all systems so users can use the menu entry without
needing to figure out what key needs to be pressed.
Also, if fastboot is enabled in the BIOS then often it is not possible to
enter the firmware setup menu. So the entry is again useful for this case.
Signed-off-by: Steve Langasek <steve.langasek@ubuntu.com>
Signed-off-by: Dimitri John Ledkov <xnox@ubuntu.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
On some devices the ESC key is the hotkey to enter the BIOS/EFI setup
screen, making it really hard to time pressing it right. Besides that
ESC is also pretty hard to discover for a user who does not know it
will unhide the menu.
This commit makes F4, which was chosen because is not used as a hotkey
to enter the BIOS setup by any vendor, also interrupt sleeps / stop the
menu countdown.
This solves the ESC gets into the BIOS setup and also somewhat solves
the discoverability issue, but leaves the timing issue unresolved.
This commit fixes the timing issue by also adding support for keeping
SHIFT pressed during boot to stop the menu countdown. This matches
what Ubuntu is doing, which should also help with discoverability.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
If we're running with a hidden menu we may never need text mode, so do not
change the video-mode to text until we actually need it.
This allows to boot a machine without unnecessary graphical transitions and
provide a seamless boot experience to users.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Implement getkeystatus() support in the EFI console driver.
This is needed because the logic to determine if a key was pressed to make
the menu countdown stop will be changed by a later patch to also take into
account the SHIFT key being held down.
For this reason the EFI console driver has to support getkeystatus() to
allow detecting that event.
Note that if a non-modifier key gets pressed and repeated calls to
getkeystatus() are made then it will return the modifier status at the
time of the non-modifier key, until that key-press gets consumed by a
getkey() call.
This is a side-effect of how the EFI simple-text-input protocol works
and cannot be avoided.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This is a preparatory patch for adding getkeystatus() support to the
EFI console driver.
We can get modifier status through the simple_text_input read_key_stroke()
method, but if a non-modifier key is (also) pressed the read_key_stroke()
call will consume that key from the firmware's queue.
The new grub_console_read_key_stroke() helper buffers upto 1 key-stroke.
If it has a non-modifier key buffered, it will return that one, if its
buffer is empty, it will fills its buffer by getting a new key-stroke.
If called with consume=1 it will empty its buffer after copying the
key-data to the callers buffer, this is how getkey() will use it.
If called with consume=0 it will keep the last key-stroke buffered, this
is how getkeystatus() will call it. This means that if a non-modifier
key gets pressed, repeated getkeystatus() calls will return the modifiers
of that key-press until it is consumed by a getkey() call.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Move grub_getkeystatushelper() function from grub-core/commands/keystatus.c
to grub-core/kern/term.c and export it so that it can be used outside of
the keystatus command code too.
There's no logic change in this patch. The function definition is moved so
it can be called from grub-core/kern/term.c in a subsequent patch. It will
be used to determine if a SHIFT key has was held down and use that also to
interrupt the countdown, without the need to press a key at the right time.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This is just a preparatory patch to move the functions higher in the file,
since these will be called by the grub_prepare_for_text_output() function
that will be introduced in a later patch.
The logic is unchanged by this patch. Functions definitions are just moved
to avoid a forward declaration in a later patch, keeping the code clean.
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Currently, an image generated with 'grub-mkimage -n' causes an error when
read with 'readelf -a':
Displaying notes found at file offset 0x000106f0 with length 0x0000002c:
Owner Data size Description
readelf: Warning: note with invalid namesz and/or descsz found at offset 0x0
readelf: Warning: type: 0x1275, namesize: 0x00000008, descsize: 0x0000002c, alignment: 4
This is because the descsz of the CHRP note is set to
sizeof (struct grub_ieee1275_note)
which is the size of the entire note, including name and elf header. The
desczs should contain only the contents, not the name and header sizes.
Set the descsz instead to 'sizeof (struct grub_ieee1275_note_desc)'
Resultant readelf output:
Displaying notes found at file offset 0x00010710 with length 0x0000002c:
Owner Data size Description
PowerPC 0x00000018 Unknown note type: (0x00001275)
description data: ff ff ff ff 00 c0 00 00 ff ff ff ff ff ff ff ff ff ff ff ff 00 00 40 00
So far as I can tell this issue has existed for as long as the note
generation code has existed, but I guess nothing really checks descsz.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
We bumped into the build error while testing gcc-10 pre-release.
In file included from ../../include/grub/file.h:22,
from ../../grub-core/fs/zfs/zfs.c:34:
../../grub-core/fs/zfs/zfs.c: In function 'zap_leaf_lookup':
../../grub-core/fs/zfs/zfs.c:2263:44: error: array subscript '<unknown>' is outside the bounds of an interior zero-length array 'grub_uint16_t[0]' {aka 'short unsigned int[0]'} [-Werror=zero-length-bounds]
2263 | for (chunk = grub_zfs_to_cpu16 (l->l_hash[LEAF_HASH (blksft, h, l)], endian);
../../include/grub/types.h:241:48: note: in definition of macro 'grub_le_to_cpu16'
241 | # define grub_le_to_cpu16(x) ((grub_uint16_t) (x))
| ^
../../grub-core/fs/zfs/zfs.c:2263:16: note: in expansion of macro 'grub_zfs_to_cpu16'
2263 | for (chunk = grub_zfs_to_cpu16 (l->l_hash[LEAF_HASH (blksft, h, l)], endian);
| ^~~~~~~~~~~~~~~~~
In file included from ../../grub-core/fs/zfs/zfs.c:48:
../../include/grub/zfs/zap_leaf.h:72:16: note: while referencing 'l_hash'
72 | grub_uint16_t l_hash[0];
| ^~~~~~
Here I'd like to quote from the gcc document [1] which seems best to
explain what is going on here.
"Although the size of a zero-length array is zero, an array member of
this kind may increase the size of the enclosing type as a result of
tail padding. The offset of a zero-length array member from the
beginning of the enclosing structure is the same as the offset of an
array with one or more elements of the same type. The alignment of a
zero-length array is the same as the alignment of its elements.
Declaring zero-length arrays in other contexts, including as interior
members of structure objects or as non-member objects, is discouraged.
Accessing elements of zero-length arrays declared in such contexts is
undefined and may be diagnosed."
The l_hash[0] is apparnetly an interior member to the enclosed structure
while l_entries[0] is the trailing member. And the offending code tries
to access members in l_hash[0] array that triggers the diagnose.
Given that the l_entries[0] is used to get proper alignment to access
leaf chunks, we can accomplish the same thing through the ALIGN_UP macro
thus eliminating l_entries[0] from the structure. In this way we can
pacify the warning as l_hash[0] now becomes the last member to the
enclosed structure.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
Signed-off-by: Michael Chang <mchang@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
We bumped into the build error while testing gcc-10 pre-release.
../../grub-core/disk/mdraid1x_linux.c: In function 'grub_mdraid_detect':
../../grub-core/disk/mdraid1x_linux.c:181:15: error: array subscript <unknown> is outside array bounds of 'grub_uint16_t[0]' {aka 'short unsigned int[0]'} [-Werror=array-bounds]
181 | (char *) &sb.dev_roles[grub_le_to_cpu32 (sb.dev_number)]
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../grub-core/disk/mdraid1x_linux.c:98:17: note: while referencing 'dev_roles'
98 | grub_uint16_t dev_roles[0]; /* Role in array, or 0xffff for a spare, or 0xfffe for faulty. */
| ^~~~~~~~~
../../grub-core/disk/mdraid1x_linux.c:127:33: note: defined here 'sb'
127 | struct grub_raid_super_1x sb;
| ^~
cc1: all warnings being treated as errors
Apparently gcc issues the warning when trying to access sb.dev_roles
array's member, since it is a zero length array as the last element of
struct grub_raid_super_1x that is allocated sparsely without extra
chunks for the trailing bits, so the warning looks legitimate in this
regard.
As the whole thing here is doing offset computation, it is undue to use
syntax that would imply array member access then take address from it
later. Instead we could accomplish the same thing through basic array
pointer arithmetic to pacify the warning.
Signed-off-by: Michael Chang <mchang@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
With recent versions of gcc on Ubuntu a very large lzma_decompress.img file is
output. (e.g. 134479600 bytes instead of 2864.) This causes grub-mkimage to
fail with: "error: Decompressor is too big."
This seems to be caused by a section .note.gnu.property that is placed at an
offset such that objcopy needs to pad the img file with zeros.
This issue is present on:
Ubuntu 19.10 with gcc (Ubuntu 8.3.0-26ubuntu1~19.10) 8.3.0
Ubuntu 19.10 with gcc (Ubuntu 9.2.1-9ubuntu2) 9.2.1 20191008
This issue is not present on:
Ubuntu 19.10 with gcc (Ubuntu 7.5.0-3ubuntu1~19.10) 7.5.0
RHEL 8.0 with gcc 8.3.1 20190507 (Red Hat 8.3.1-4)
The issue can be fixed by removing the section using objcopy as shown in
this patch.
Signed-off-by: Simon Hardy <simon.hardy@itdev.co.uk>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
