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netboot cleanup for additional files #686

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netboot cleanup for additional files #686

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a597437
Suppress file open failures for some netboot cases
jsetje Jul 13, 2024
224e914
Allow indepdent SkuSi and SBAT revocation updates
jsetje Aug 16, 2024
3412508
netboot: process revocations.efi as revocations not shim_certificate
jsetje Aug 16, 2024
e9aef68
netboot can try to load shim_certificate_[0..9].efi
jsetje Aug 16, 2024
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44 changes: 31 additions & 13 deletions shim.c
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Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,7 @@
#include <Library/BaseCryptLib.h>

#include <stdint.h>
#include <stdio.h>

#define OID_EKU_MODSIGN "1.3.6.1.4.1.2312.16.1.2"

Expand All @@ -54,6 +55,8 @@ extern struct {

#define EFI_IMAGE_SECURITY_DATABASE_GUID { 0xd719b2cb, 0x3d3a, 0x4596, { 0xa3, 0xbc, 0xda, 0xd0, 0x0e, 0x67, 0x65, 0x6f }}

#define SUPPRESS_NETBOOT_OPEN_FAILURE_NOISE 1

typedef enum {
DATA_FOUND,
DATA_NOT_FOUND,
Expand Down Expand Up @@ -1091,7 +1094,8 @@ str16_to_str8(CHAR16 *str16, CHAR8 **str8)
* Load and run an EFI executable
*/
EFI_STATUS read_image(EFI_HANDLE image_handle, CHAR16 *ImagePath,
CHAR16 **PathName, void **data, int *datasize)
CHAR16 **PathName, void **data, int *datasize,
int flags)
{
EFI_STATUS efi_status;
void *sourcebuffer = NULL;
Expand Down Expand Up @@ -1130,8 +1134,9 @@ EFI_STATUS read_image(EFI_HANDLE image_handle, CHAR16 *ImagePath,
efi_status = FetchNetbootimage(image_handle, &sourcebuffer,
&sourcesize);
if (EFI_ERROR(efi_status)) {
perror(L"Unable to fetch TFTP image: %r\n",
efi_status);
if (~flags & SUPPRESS_NETBOOT_OPEN_FAILURE_NOISE)
perror(L"Unable to fetch TFTP image: %r\n",
efi_status);
return efi_status;
}
*data = sourcebuffer;
Expand All @@ -1143,8 +1148,9 @@ EFI_STATUS read_image(EFI_HANDLE image_handle, CHAR16 *ImagePath,
&sourcesize,
netbootname);
if (EFI_ERROR(efi_status)) {
perror(L"Unable to fetch HTTP image %a: %r\n",
netbootname, efi_status);
if (~flags & SUPPRESS_NETBOOT_OPEN_FAILURE_NOISE)
perror(L"Unable to fetch HTTP image %a: %r\n",
netbootname, efi_status);
return efi_status;
}
*data = sourcebuffer;
Expand Down Expand Up @@ -1183,7 +1189,7 @@ EFI_STATUS start_image(EFI_HANDLE image_handle, CHAR16 *ImagePath)
int datasize = 0;

efi_status = read_image(image_handle, ImagePath, &PathName, &data,
&datasize);
&datasize, 0);
if (EFI_ERROR(efi_status))
goto done;

Expand Down Expand Up @@ -1459,8 +1465,12 @@ load_revocations_file(EFI_HANDLE image_handle, CHAR16 *PathName)
uint8_t *ssps_latest = NULL;
uint8_t *sspv_latest = NULL;

efi_status = read_image(image_handle, L"revocations.efi", &PathName,
&data, &datasize);
efi_status = read_image(image_handle, L"revocations_sbat.efi", &PathName,
&data, &datasize,
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are you missing a check for efi_status here?

SUPPRESS_NETBOOT_OPEN_FAILURE_NOISE);
efi_status = read_image(image_handle, L"revocations_skusi.efi", &PathName,
&data, &datasize,
SUPPRESS_NETBOOT_OPEN_FAILURE_NOISE);
if (EFI_ERROR(efi_status))
return efi_status;

Expand Down Expand Up @@ -1510,7 +1520,8 @@ load_revocations_file(EFI_HANDLE image_handle, CHAR16 *PathName)
}

EFI_STATUS
load_cert_file(EFI_HANDLE image_handle, CHAR16 *filename, CHAR16 *PathName)
load_cert_file(EFI_HANDLE image_handle, CHAR16 *filename, CHAR16 *PathName,
int flags)
{
EFI_STATUS efi_status;
PE_COFF_LOADER_IMAGE_CONTEXT context;
Expand All @@ -1523,7 +1534,7 @@ load_cert_file(EFI_HANDLE image_handle, CHAR16 *filename, CHAR16 *PathName)
int i;

efi_status = read_image(image_handle, filename, &PathName,
&data, &datasize);
&data, &datasize, flags);
if (EFI_ERROR(efi_status))
return efi_status;

Expand Down Expand Up @@ -1565,13 +1576,15 @@ load_unbundled_trust(EFI_HANDLE image_handle)
EFI_STATUS efi_status;
EFI_LOADED_IMAGE *li = NULL;
CHAR16 *PathName = NULL;
static CHAR16 FileName[] = L"shim_certificate_0.efi";
EFI_FILE *root, *dir;
EFI_FILE_INFO *info;
EFI_HANDLE device;
EFI_FILE_IO_INTERFACE *drive;
UINTN buffersize = 0;
void *buffer = NULL;
BOOLEAN search_revocations = TRUE;
int i = 0;

efi_status = gBS->HandleProtocol(image_handle, &EFI_LOADED_IMAGE_GUID,
(void **)&li);
Expand All @@ -1592,11 +1605,11 @@ load_unbundled_trust(EFI_HANDLE image_handle)
efi_status);
/*
* Network boot cases do not support reading a directory. Try
* to read revocations.efi to pull in any unbundled SBATLevel
* to read revocations to pull in any unbundled SBATLevel
* updates unconditionally in those cases. This may produce
* console noise when the file is not present.
*/
load_cert_file(image_handle, REVOCATIONFILE, PathName);
load_revocations_file(image_handle, PathName);
goto done;
}

Expand Down Expand Up @@ -1683,13 +1696,18 @@ load_unbundled_trust(EFI_HANDLE image_handle)
if (EFI_ERROR(efi_status)) {
perror(L"Failed to open %s - %r\n",
PathName, efi_status);
while (load_cert_file(image_handle, FileName, PathName,
SUPPRESS_NETBOOT_OPEN_FAILURE_NOISE)
== EFI_SUCCESS && i++ < 10) {
FileName[17]++;
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I think it's going to be confusing having to rename shim_certificate_sbat.efi to shim_certificate_0.efi, shim_certificate_ski.efi to shim_certificate_1.efi etc. Can't we just use those names?

}
goto done;
}
}

if (!search_revocations &&
StrnCaseCmp(info->FileName, L"shim_certificate", 16) == 0) {
load_cert_file(image_handle, info->FileName, PathName);
load_cert_file(image_handle, info->FileName, PathName, 0);
}
}
done:
Expand Down
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