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>
Rename has been skipped by mistake in the original commit.
Fixes: 94649c026 (nx: Set page permissions for loaded modules)
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
For NX we need to set write and executable permissions on the sections
of GRUB modules when we load them. All allocatable sections are marked
readable. In addition:
- SHF_WRITE sections are marked as writable,
- and SHF_EXECINSTR sections are marked as executable.
Where relevant for the platform the tramp and GOT areas are marked non-writable.
Signed-off-by: Peter Jones <pjones@redhat.com>
Signed-off-by: Robbie Harwood <rharwood@redhat.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Jan Setje-Eilers <jan.setjeeilers@oracle.com>
Signed-off-by: Mate Kukri <mate.kukri@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Currently we load module sections at whatever alignment gcc+ld happened
to dump into the ELF section header which is often less then the page
size. Since NX protections are page based this alignment must be rounded
up to page size on platforms supporting NX protections. This patch
switches EFI platforms to load module sections at 4 KiB page-aligned
addresses. It then changes the allocation size computation and the
loader code in grub_dl_load_segments() to align the locations and sizes
up to these boundaries and fills any added padding with zeros. All of
this happens before relocations are applied, so the relocations factor
that in with no change.
Signed-off-by: Peter Jones <pjones@redhat.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Jan Setje-Eilers <jan.setjeeilers@oracle.com>
Signed-off-by: Mate Kukri <mate.kukri@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Currently when loading GRUB modules we allocate space for all sections
including those without SHF_ALLOC set. We then copy the sections that
/do/ have SHF_ALLOC set into the allocated memory leaving some of our
allocation untouched forever. Additionally, on platforms with GOT fixups
and trampolines we currently compute alignment round-ups for the
sections and sections with sh_size = 0. This patch removes the extra
space from the allocation computation and makes the allocation
computation loop skip empty sections as the loading loop does.
Signed-off-by: Peter Jones <pjones@redhat.com>
Signed-off-by: Jan Setje-Eilers <jan.setjeeilers@oracle.com>
Signed-off-by: Mate Kukri <mate.kukri@canonical.com>
Reviewed-By: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This patch adds support of the stack-based LoongArch relocations
throughout GRUB, including tools, dynamic linkage, and support for
conversion of ELF relocations into PE ones. A stack machine is required
to handle these per the spec [1] (see the R_LARCH_SOP types), of which
a simple implementation is included.
These relocations are produced by binutils 2.38 and 2.39, while the newer
v2.00 relocs require more recent toolchain (binutils 2.40+ & gcc 13+, or
LLVM 16+). GCC 13 has not been officially released as of early 2023, so
support for v1.00 relocs are expected to stay relevant for a while.
[1] https://loongson.github.io/LoongArch-Documentation/LoongArch-ELF-ABI-EN.html#_relocations
Signed-off-by: Zhou Yang <zhouyang@loongson.cn>
Signed-off-by: Xiaotian Wu <wuxiaotian@loongson.cn>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
In grub_memalign(), there's a commented section which would allow for
unloading of unneeded modules in case where there is not enough free
memory available to satisfy a request. Given that this code is never
compiled in, let's remove it together with grub_dl_unload_unneeded().
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Patrick Steinhardt <ps@pks.im>
Prior to this change, the GRUB would only indicate that the check had
been failed, but not by what module. This made it difficult to track
down either the problem module, or debug the false positive further.
Before performing the license check, resolve the module name so that
it can be printed if the license check fails.
Signed-off-by: Robbie Harwood <rharwood@redhat.com>
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 patch adds awareness of RISC-V relocations throughout the grub tools
as well as dynamic linkage and elf->PE relocation conversion support.
Signed-off-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Daniel Kiper <daniel.kiper@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>
all_video module does not have any code or data and exists solely for
.moddeps section to pull in dependencies. This makes all symbols unneeded.
While in current binutils (last released version as of this commit is 2.26)
``strip --strip-unneeded'' unintentionally adds section symbols for each
existing section, this behavior was considered a bug and changed in commit
14f2c699ddca1e2f706342dffc59a6c7e23e844c to completely strip symbol table
in this case.
Older binutils (verified with 2.17) and some other toolchains (at least
elftoolchain r3223M), both used in FreeBSD, remove symbol table in all_video
as well.
Relax run-time check and do not return error for modules without symbol table.
Add additional checks to module verifier to make sure such modules
a) have non-empty .moddeps section. Without either externally visible symbols
or .moddeps modules are completely useless and should not be built.
b) do not have any relocations.
Closes: 46986
v2: add run-time check for empty symbol table if relocations are present as
suggested by Vladimir.
* grub-core/kern/dl.c (grub_dl_load_segments) [__powerpc__]: Follow
__ia64__ path.
(grub_dl_load_segments): Set mod->sz.
(grub_dl_flush_cache): Flush whole space occupied by module, not just
segments.
* grub-core/kern/ia64/dl.c (nopm): Make const while on it.
(jump): Likewise.
* grub-core/kern/powerpc/dl.c (grub_arch_dl_get_tramp_got_size): New
function.
(trampoline): New struct.
(trampoline_template): New const.
(grub_arch_dl_relocate_symbols): Create trampolines on overflow.
* include/grub/dl.h (grub_dl): Add sz element.
[__powerpc__]: Follow __ia64__.
(GRUB_ARCH_DL_TRAMP_ALIGN): Define on ppc.
(GRUB_ARCH_DL_GOT_ALIGN): Likewise.
(GRUB_ARCH_DL_TRAMP_SIZE): Likewise.
(grub_arch_dl_get_tramp_got_size) [__powerpc__]: New proto.
* Makefile.util.def (libgrubmods.a): Add grub-core/kern/ia64/dl_helper.c
* configure.ac: Add ia64-efi target.
Probe for __ia64_trampoline, __udivsi3, __umoddi3, __udivdi3,
__divsi3, __modsi3, __umodsi3, __moddi3 and __divdi3 symbols.
* gentpl.py: Add ia64_efi platform.
Rename x86_efi to efi and Add ia64-efi. All users updated.
* grub-core/Makefile.am: Set KERNEL_HEADER_FILES for ia64-efi.
* grub-core/Makefile.core.def (kernel.img): Add compile flags for ia64.
Remove kern/generic/rtc_get_time_ms.c on EFI.
Add kern/ia64/efi/startup.S, kern/ia64/efi/init.c, kern/ia64/dl.c,
kern/ia64/dl_helper.c on ia64-efi.
Add kern/emu/cache.c on emu.
(linux): Use on loader/ia64/efi/linux.c on ia64.
* grub-core/gensymlist.sh (grub_register_exported_symbols): Check
whether symbol is a function.
* grub-core/kern/dl.c [GRUB_MACHINE_EMU]: Include sys/mman.h.
(grub_symbol): New field 'isfunc'.
(grub_dl_resolve_symbol): Return whole symbol rather than just address.
(grub_dl_register_symbol): New argument 'isfunc'. All users updated.
(grub_dl_load_segments): Place all sections into the same region.
[__ia64__]: Create trampolines and got.
[GRUB_MACHINE_EMU]: Call mprotect.
(grub_dl_resolve_symbols): Resolve symbol type as well.
[__ia64__]: Create function descriptors.
* grub-core/kern/efi/efi.c (grub_get_rtc): Renamed to ...
(grub_rtc_get_time_ms): ... this. Expressions simplified.
(grub_get_rtc): New function.
* grub-core/kern/emu/cache.c [__ia64__]: New file.
* grub-core/kern/emu/cache.S: Renamed to ...
* grub-core/kern/emu/cache_s.S: ... this.
[__ia64__]: Add a nop.
* grub-core/kern/emu/full.c (grub_arch_dl_get_tramp_got_size)
[__ia64__]: New function.
* grub-core/kern/emu/lite.c [__ia64__]: Include ../ia64/dl.c.
* grub-core/kern/ia64/dl.c: New file.
* grub-core/kern/ia64/dl_helper.c: Likewise.
* grub-core/kern/ia64/efi/init.c: New file.
* grub-core/kern/ia64/efi/startup.S: Likewise.
* grub-core/lib/efi/halt.c [__ia64__]: Don't try acpi.
* grub-core/lib/ia64/longjmp.S: New file (from glibc).
* grub-core/lib/ia64/setjmp.S: Likewise (from glibc).
* grub-core/lib/setjmp.S [__ia64__]: Include ./ia64/setjmp.S.
* grub-core/loader/ia64/efi/linux.c: New file.
* include/grub/dl.h (GRUB_MOD_NAME): Redefined using C rather than asm.
(GRUB_MOD_DEP): Likewise.
(grub_dl) [__ia64__]: New fields got and tramp.
(grub_dl): New field 'base'.
(grub_dl_register_symbol): New argument isfunc. All users updated.
(GRUB_IA64_DL_TRAMP_ALIGN): New definition.
(GRUB_IA64_DL_TRAMP_SIZE): Likewise.
(GRUB_IA64_DL_GOT_ALIGN): Likewise.
(grub_ia64_dl_get_tramp_got_size): New proto.
(GRUB_ARCH_DL_TRAMP_ALIGN) [__ia64__]: Likewise
(GRUB_ARCH_DL_GOT_ALIGN) [__ia64__]: Likewise
(grub_arch_dl_get_tramp_got_size) [__ia64__]: Likewise
* include/grub/efi/api.h: Skip call wrappers on ia64.
* include/grub/efi/pe32.h (GRUB_PE32_MACHINE_IA64): New definition.
* include/grub/efi/time.h (GRUB_TICKS_PER_SECOND): Change to 1000.
* include/grub/elf.h (ELF_ST_INFO): New definition.
* include/grub/ia64/efi/kernel.h: New file.
* include/grub/ia64/efi/memory.h: Likewise.
* include/grub/ia64/efi/time.h: Likewise.
* include/grub/ia64/kernel.h: Likewise.
* include/grub/ia64/setjmp.h: Likewise (from glibc).
* include/grub/ia64/time.h: New file.
* include/grub/ia64/types.h: Likewise.
* include/grub/libgcc.h (__udivsi3, __umodsi3, __umoddi3, __udivdi3,
__moddi3, __divdi3, __divsi3, __modsi3, __ia64_trampoline):
New protos.
* include/grub/offsets.h (GRUB_KERNEL_IA64_EFI_PREFIX): New definition.
(GRUB_KERNEL_IA64_EFI_PREFIX_END): Likewise.
* include/grub/types.h (PRIxGRUB_ADDR): Likewise.
* util/grub-mkimage.c (image_target_desc): New field pe_target.
All users updated.
(EFI64_HEADER_SIZE): New definition. All users updated.
(image_targets): Add ia64-efi.
* util/grub-mkimagexx.c (relocate_symbols): New arguments jumpers and
jumpers_addr. All users updated.
Create function descriptors.
(count_funcs): New function.
(unaligned_uint32): New struct.
(MASK20): New definition.
(MASK19): Likewise.
(MASKF21): Likewise.
(add_value_to_slot_20b): New function.
(add_value_to_slot_21_real): Likewise.
(add_value_to_slot_21): Likewise.
(ia64_kernel_trampoline): New struct.
(nopm): New variable.
(jump): Likewise.
(make_trampoline): New function.
(relocate_addresses): Handle ia64.
(make_reloc_section): Likewise.
(load_image): Likewise.
Also-By: Robert Millan <rmh.grub@aybabtu.com>
Also-By: Vladimir Serbinenko <phcoder@gmail.com>
