The get_part_uuid() function made an assumption that the target grub
device is a partition device and accessed device->disk->partition
without checking for NULL. There are four situations where this
assumption is problematic:
1. The device is a net device instead of a disk.
2. The device is an abstraction device, like LVM, RAID, or CRYPTO, which
is mostly logical "disk" ((lvmid/<UUID>) and so on).
3. Firmware RAID may present the ESP to grub as an EFI disk (hd0) device
if it is contained within a Linux software RAID.
4. When booting from an ISO, the ESP is treated as an El Torito image in
the boot catalog. It is therefore presented by firmware and
interpreted by grub as a disk (cd0).
As a result, get_part_uuid() could lead to a NULL pointer dereference
and trigger a synchronous exception during boot if the ESP falls into
one of these categories. This patch fixes the problem by adding the
necessary checks to handle cases where the ESP is not a partition
device.
Additionally, to avoid disrupting the boot process, this patch relaxes
the severity of the errors in this context to non-critical. Errors will
be logged, but they will not prevent the boot process from continuing.
Fixes: e0fa7dc84 (bli: Add a module for the Boot Loader Interface)
Signed-off-by: Michael Chang <mch...@suse.com>
---
grub-core/commands/bli.c | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)
diff --git a/grub-core/commands/bli.c b/grub-core/commands/bli.c
index e0d8a54f7..298c5f70a 100644
--- a/grub-core/commands/bli.c
+++ b/grub-core/commands/bli.c
@@ -48,6 +48,22 @@ get_part_uuid (const char *device_name, char **part_uuid)
if (device == NULL)
return grub_error (grub_errno, N_("cannot open device: %s"), device_name);
+ if (device->disk == NULL)
+ {
+ grub_dprintf ("bli", "%s is not a disk device, partuuid skipped\n",
device_name);
+ *part_uuid = NULL;
+ grub_device_close (device);
+ return GRUB_ERR_NONE;
+ }
+
+ if (device->disk->partition == NULL)
+ {
+ grub_dprintf ("bli", "%s has no partition, partuuid skipped\n",
device_name);
+ *part_uuid = NULL;
+ grub_device_close (device);
+ return GRUB_ERR_NONE;
+ }
+
disk = grub_disk_open (device->disk->name);
if (disk == NULL)
{
@@ -99,7 +115,7 @@ set_loader_device_part_uuid (void)
status = get_part_uuid (device_name, &part_uuid);
- if (status == GRUB_ERR_NONE)
+ if (status == GRUB_ERR_NONE && part_uuid)
status = grub_efi_set_variable_to_string ("LoaderDevicePartUUID",
&bli_vendor_guid, part_uuid,
GRUB_EFI_VARIABLE_BOOTSERVICE_ACCESS |
GRUB_EFI_VARIABLE_RUNTIME_ACCESS);
@@ -117,4 +133,6 @@ GRUB_MOD_INIT (bli)
GRUB_EFI_VARIABLE_BOOTSERVICE_ACCESS |
GRUB_EFI_VARIABLE_RUNTIME_ACCESS);
set_loader_device_part_uuid ();
+ /* No error here is critical, other than being logged */
+ grub_print_error ();
}
--
2.45.2
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