The GRUB is failing to build with GCC-12 in many places like this:
In function 'init_cbfsdisk',
inlined from 'grub_mod_init' at ../../grub-core/fs/cbfs.c:391:3:
../../grub-core/fs/cbfs.c:345:7: error: array subscript 0 is outside array bounds of 'grub_uint32_t[0]' {aka 'unsigned int[]'} [-Werror=array-bounds]
345 | ptr = *(grub_uint32_t *) 0xfffffffc;
| ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This is caused by GCC regression in 11/12 [1]. In a nut shell, the
warning is about detected invalid accesses at non-zero offsets to NULL
pointers. Since hardwired constant address is treated as NULL plus an
offset in the same underlying code, the warning is therefore triggered.
Instead of inserting #pragma all over the places where literal pointers
are accessed to avoid diagnosing array-bounds, we can try to borrow the
idea from Linux kernel that the absolute_pointer() macro [2][3] is used
to disconnect a pointer using literal address from it's original object,
hence GCC won't be able to make assumptions on the boundary while doing
pointer arithmetic. With that we can greatly reduce the code we have to
cover up by making initial literal pointer assignment to use the new
wrapper but not having to track everywhere literal pointers are
accessed. This also makes code looks cleaner.
Please note the grub_absolute_pointer() macro requires to be invoked in
a function as long as it is compound expression. Some global variables
with literal pointers has been changed to local ones in order to use
grub_absolute_pointer() to initialize it. The shuffling is basically done
in a selective and careful way that the variable's scope doesn't matter
being local or global, for example, the global variable must not get
modified at run time throughout. For the record, here's the list of
global variables got shuffled in this patch:
grub-core/commands/i386/pc/drivemap.c:int13slot
grub-core/term/i386/pc/console.c:bios_data_area
grub-core/term/ns8250.c:serial_hw_io_addr
[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578
[2] https://elixir.bootlin.com/linux/v5.16.14/source/include/linux/compiler.h#L180
[3] https://elixir.bootlin.com/linux/v5.16.14/source/include/linux/compiler-gcc.h#L31
Signed-off-by: Michael Chang <mchang@suse.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>
* grub-core/video/i386/pc/vbe.c (framebuffer): New member mtrr.
(cpuid): New define.
(rdmsr): Likewise.
(wrmsr): Likewise.
(mtrr_base): Likewise.
(mtrr_mask): Likewise.
(grub_vbe_enable_mtrr_entry): New function.
(grub_vbe_enable_mtrr): Likewise.
(grub_vbe_disable_mtrr): Likewise.
(grub_vbe_bios_set_display_start): Disable mtrr when handing the
control off to BIOS.
(grub_video_vbe_init): Fill mtrr.
(grub_video_vbe_fini): Disable mtrr.
(grub_video_vbe_get_info_and_fini): Likewise.
(grub_video_vbe_setup): Enable mtrr.
* grub-core/video/video.c (grub_video_edid_checksum): New function.
(grub_video_edid_preferred_mode): Likewise. Try EDID followed by
the Flat Panel extension, in line with the X.org VESA driver.
* grub-core/video/i386/pc/vbe.c (grub_vbe_bios_get_flat_panel_info):
New function.
(grub_vbe_bios_get_ddc_capabilities): Likewise.
(grub_vbe_bios_read_edid): Likewise.
(grub_vbe_get_preferred_mode): Likewise.
(grub_video_vbe_setup): When the mode is "auto", try to get the
preferred mode from VBE, and use the largest mode that is no larger
than the preferred mode (some BIOSes expose a preferred mode that is
not in their mode list!). If this fails, fall back to 640x480 as a
safe conservative choice.
(grub_video_vbe_get_edid): New function.
(grub_video_vbe_adapter): Add get_edid.
* include/grub/video.h (struct grub_vbe_edid_info): New structure.
(struct grub_video_adapter): Add get_edid.
(grub_video_edid_checksum): Add prototype.
(grub_video_edid_preferred_mode): Likewise.
* include/grub/i386/pc/vbe.h (struct grub_vbe_flat_panel_info): New
structure.
* grub-core/commands/videoinfo.c (print_edid): New function.
(grub_cmd_videoinfo): Print EDID if available.
* util/grub.d/00_header.in (GRUB_GFXMODE): Default to "auto". This
is more appropriate on a wider range of platforms than 640x480.
* docs/grub.texi (Simple configuration): Update GRUB_GFXMODE
documentation.
video adapter has not necessarily yet been set. Use grub_video_vbe_get_edid
and grub_video_edid_checksum directly instead. Remove grub_video_get_edid
as it now has no users.
Reported by: Marjo Mercado.
* grub-core/video/i386/pc/vbe.c (grub_vbe_bios_get_flat_panel_info):
New function.
(grub_vbe_bios_get_ddc_capabilities): Likewise.
(grub_vbe_bios_read_edid): Likewise.
(grub_vbe_edid_checksum): Likewise.
(grub_vbe_get_preferred_mode): Likewise. Try EDID followed by the
Flat Panel extension, in line with the X.org VESA driver.
(grub_video_vbe_setup): When the mode is "auto", try to get the
preferred mode from VBE, and use the largest mode that is no larger
than the preferred mode (some BIOSes expose a preferred mode that is
not in their mode list!). If this fails, fall back to 640x480 as a
safe conservative choice.
* include/grub/i386/pc/vbe.h (struct grub_vbe_flat_panel_info): New
structure.
(struct grub_vbe_edid_info): Likewise.
(grub_vbe_bios_get_flat_panel_info): Add prototype.
(grub_vbe_bios_get_ddc_capabilities): Likewise.
(grub_vbe_bios_read_edid): Likewise.
* util/grub.d/00_header.in (GRUB_GFXMODE): Default to "auto". This
is more appropriate on a wider range of platforms than 640x480.
