From: Ard Biesheuvel ardb@kernel.org

mainline inclusion from mainline-v6.12-rc1 commit 77d48d39e99170b528e4f2e9fc5d1d64cdedd386 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IAYQSJ CVE: CVE-2024-49858

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

--------------------------------

The TPM event log table is a Linux specific construct, where the data produced by the GetEventLog() boot service is cached in memory, and passed on to the OS using an EFI configuration table.

The use of EFI_LOADER_DATA here results in the region being left unreserved in the E820 memory map constructed by the EFI stub, and this is the memory description that is passed on to the incoming kernel by kexec, which is therefore unaware that the region should be reserved.

Even though the utility of the TPM2 event log after a kexec is questionable, any corruption might send the parsing code off into the weeds and crash the kernel. So let's use EFI_ACPI_RECLAIM_MEMORY instead, which is always treated as reserved by the E820 conversion logic.

Cc: stable@vger.kernel.org Reported-by: Breno Leitao leitao@debian.org Tested-by: Usama Arif usamaarif642@gmail.com Reviewed-by: Ilias Apalodimas ilias.apalodimas@linaro.org Signed-off-by: Ard Biesheuvel ardb@kernel.org Signed-off-by: Qi Xi xiqi2@huawei.com --- drivers/firmware/efi/libstub/tpm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firmware/efi/libstub/tpm.c b/drivers/firmware/efi/libstub/tpm.c index df3182f2e63a..1fd6823248ab 100644 --- a/drivers/firmware/efi/libstub/tpm.c +++ b/drivers/firmware/efi/libstub/tpm.c @@ -96,7 +96,7 @@ static void efi_retrieve_tcg2_eventlog(int version, efi_physical_addr_t log_loca }

/* Allocate space for the logs and copy them. */ - status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, + status = efi_bs_call(allocate_pool, EFI_ACPI_RECLAIM_MEMORY, sizeof(*log_tbl) + log_size, (void **)&log_tbl);

if (status != EFI_SUCCESS) {