From: "Kiryl Shutsemau (Meta)" <kas@kernel.org> stable inclusion from stable-v6.6.128 commit b7bc182ec1846be437351e44164089d988f9d0dd category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/15103 CVE: CVE-2026-45851 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 0862438c90487e79822d5647f854977d50381505 ] The reserve_unaccepted() function incorrectly calculates the size of the memblock reservation for the unaccepted memory table. It aligns the size of the table, but fails to account for cases where the table's starting physical address (efi.unaccepted) is not page-aligned. If the table starts at an offset within a page and its end crosses into a subsequent page that the aligned size does not cover, the end of the table will not be reserved. This can lead to the table being overwritten or inaccessible, causing a kernel panic in accept_memory(). This issue was observed when starting Intel TDX VMs with specific memory sizes (e.g., > 64GB). Fix this by calculating the end address first (including the unaligned start) and then aligning it up, ensuring the entire range is covered by the reservation. Fixes: 8dbe33956d96 ("efi/unaccepted: Make sure unaccepted table is mapped") Reported-by: Moritz Sanft <ms@edgeless.systems> Signed-off-by: Kiryl Shutsemau (Meta) <kas@kernel.org> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> --- drivers/firmware/efi/efi.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 30f6c4397b40..7e1f96c06d18 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -649,13 +649,13 @@ static __init int match_config_table(const efi_guid_t *guid, static __init void reserve_unaccepted(struct efi_unaccepted_memory *unaccepted) { - phys_addr_t start, size; + phys_addr_t start, end; start = PAGE_ALIGN_DOWN(efi.unaccepted); - size = PAGE_ALIGN(sizeof(*unaccepted) + unaccepted->size); + end = PAGE_ALIGN(efi.unaccepted + sizeof(*unaccepted) + unaccepted->size); - memblock_add(start, size); - memblock_reserve(start, size); + memblock_add(start, end - start); + memblock_reserve(start, end - start); } int __init efi_config_parse_tables(const efi_config_table_t *config_tables, -- 2.34.1