From 493bd940e5c6e28e673034687de7adef9529efff Mon Sep 17 00:00:00 2001 From: Peter Jones Date: Sat, 10 Apr 2021 16:05:23 -0400 Subject: [PATCH 05/35] Don't call QueryVariableInfo() on EFI 1.10 machines The EFI 1.10 spec (and presumably earlier revisions as well) didn't have RT->QueryVariableInfo(), and on Chris Murphy's MacBookPro8,2 , that memory appears to be initialized randomly. This patch changes it to not call RT->QueryVariableInfo() if the EFI_RUNTIME_SERVICES table's major revision is less than two, and assumes our maximum variable size is 1024 in that case. Signed-off-by: Peter Jones --- mok.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) diff --git a/mok.c b/mok.c index 9b8fc2bc..beac0ff6 100644 --- a/mok.c +++ b/mok.c @@ -261,6 +261,9 @@ static const uint8_t null_sha256[32] = { 0, }; typedef UINTN SIZE_T; +#define EFI_MAJOR_VERSION(tablep) ((UINT16)((((tablep)->Hdr.Revision) >> 16) & 0xfffful)) +#define EFI_MINOR_VERSION(tablep) ((UINT16)(((tablep)->Hdr.Revision) & 0xfffful)) + static EFI_STATUS get_max_var_sz(UINT32 attrs, SIZE_T *max_var_szp) { @@ -270,11 +273,21 @@ get_max_var_sz(UINT32 attrs, SIZE_T *max_var_szp) uint64_t max_var_sz = 0; *max_var_szp = 0; - efi_status = gRT->QueryVariableInfo(attrs, &max_storage_sz, - &remaining_sz, &max_var_sz); - if (EFI_ERROR(efi_status)) { - perror(L"Could not get variable storage info: %r\n", efi_status); - return efi_status; + if (EFI_MAJOR_VERSION(gRT) < 2) { + dprint(L"EFI %d.%d; no RT->QueryVariableInfo(). Using 1024!\n", + EFI_MAJOR_VERSION(gRT), EFI_MINOR_VERSION(gRT)); + max_var_sz = remaining_sz = max_storage_sz = 1024; + efi_status = EFI_SUCCESS; + } else { + dprint(L"calling RT->QueryVariableInfo() at 0x%lx\n", + gRT->QueryVariableInfo); + efi_status = gRT->QueryVariableInfo(attrs, &max_storage_sz, + &remaining_sz, &max_var_sz); + if (EFI_ERROR(efi_status)) { + perror(L"Could not get variable storage info: %r\n", + efi_status); + return efi_status; + } } /* -- 2.32.0