This commit adds the grub_cryptodisk_erasesecrets() function to wipe
master keys from all cryptodisks. This function is EFI-only.
Since there is no easy way to "force unmount" a given encrypted disk,
this function renders all mounted cryptodisks unusable. An attempt to
read them will return garbage.
This is why this function must be used in "no way back" conditions.
Currently, it is used when unloading the cryptodisk module and when
performing the "exit" command (it is often used to switch to the next
EFI application). This function is not called when performing the
"chainloader" command, because the callee may return to GRUB. For this
reason, users are encouraged to use "exit" instead of "chainloader" to
execute third-party boot applications.
This function does not guarantee that all secrets are wiped from RAM.
Console output, chunks from disk read requests and other may remain.
This function does not clear the IV prefix and rekey key for geli disks.
Also, this commit adds the relevant documentation improvements.
Signed-off-by: Maxim Suhanov <dfirblog@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The dump enables a user to read memory which should not be possible
in lockdown mode.
Fixes: CVE-2025-1118
Reported-by: B Horn <b@horn.uk>
Reported-by: Jonathan Bar Or <jonathanbaror@gmail.com>
Signed-off-by: B Horn <b@horn.uk>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
It was possible to overflow the value of mod->ref_count, a signed
integer, by repeatedly invoking insmod on an already loaded module.
This led to a use-after-free. As once ref_count was overflowed it became
possible to unload the module while there was still references to it.
This resolves the issue by using grub_add() to check if the ref_count
will overflow and then stops further increments. Further changes were
also made to grub_dl_unref() to check for the underflow condition and
the reference count was changed to an unsigned 64-bit integer.
Reported-by: B Horn <b@horn.uk>
Signed-off-by: B Horn <b@horn.uk>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
When a module is attempted to be removed its reference counter is always
decremented. This means that repeated rmmod invocations will cause the
module to be unloaded even if another module depends on it.
This may lead to a use-after-free scenario allowing an attacker to execute
arbitrary code and by-pass the UEFI Secure Boot protection.
While being there, add the extern keyword to some function declarations in
that header file.
Fixes: CVE-2020-25632
Reported-by: Chris Coulson <chris.coulson@canonical.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This type of modules cannot be unloaded. This is useful if a given
functionality, e.g. UEFI secure boot shim signature verification, should
not be disabled if it was enabled at some point in time. Somebody may
say that we can use standalone GRUB2 here. That is true. However, the
code is not so big nor complicated hence it make sense to support
modularized configs too.
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
Let's provide file type info to the I/O layer. This way verifiers
framework and its users will be able to differentiate files and verify
only required ones.
This is preparatory patch.
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
* configure.ac: --enable-cache-stats added.
* config.h.in (DISK_CACHE_STATS): New define.
* grub-core/Makefile.core.def (cacheinfo): New command.
* include/grub/disk.h(grub_disk_cache_get_performance): New function.
* grub-core/commands/cacheinfo.c: New file.
* grub-core/commands/minicmd.c (grub_rescue_cmd_info): Updated and
moved to cacheinfo.c.
* grub-core/kern/disk.c: Use DISK_CACHE_STATS to disable disk cache
debug code.
* include/grub/disk.h: Likewise.
* grub-core/commands/minicmd.c (grub_rescue_cmd_testload) [0]: Moved
from here ...
* grub-core/commands/testload.c (grub_cmd_testload): ... here.
(GRUB_MOD_INIT): New function.
(GRUB_MOD_FINI): Likewise.
* grub-core/Makefile.core.def (testload): New module.
