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Simplify digest-to-efi-sign-list #2

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Simplify digest-to-efi-sign-list #2

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43 changes: 19 additions & 24 deletions digest-to-efi-sig-list/main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -8,25 +8,24 @@
#include <unistd.h>
#include <efi.h>

#define SHA256_DIGEST_SIZE (32)
#define HASH_SIZE (SHA256_DIGEST_SIZE)
#define HASH_LENGTH (HASH_SIZE*2)
#define HASH_SIZE (sizeof(EFI_SHA256_HASH))
#define HASH_LENGTH (HASH_SIZE*2)

EFI_GUID EFI_CERT_SHA256_GUID = { 0xc1c41626, 0x504c, 0x4092, { 0xac, 0xa9, 0x41, 0xf9, 0x36, 0x93, 0x43, 0x28 } };
EFI_GUID MOK_OWNER = { 0x605dab50, 0xe046, 0x4300, {0xab, 0xb6, 0x3d, 0xd8, 0x10, 0xdd, 0x8b, 0x23} };

#pragma pack(1)
typedef struct {
EFI_GUID SignatureOwner;
UINT8 SignatureData[1];
} EFI_SIGNATURE_DATA;

typedef struct {
// Signature list
EFI_GUID SignatureType;
UINT32 SignatureListSize;
UINT32 SignatureHeaderSize;
UINT32 SignatureSize;
} EFI_SIGNATURE_LIST;

// Signature data
EFI_GUID SignatureOwner;
EFI_SHA256_HASH SignatureData;
} EFI_SIGNATURE;
#pragma pack()

void usage(const char *str) {
Expand All @@ -44,37 +43,33 @@ int main(int argc, char *argv[]) {
exit(1);
}

EFI_SIGNATURE sig = {
EFI_CERT_SHA256_GUID,
sizeof(EFI_SIGNATURE),
0,
16 + 32, /* UEFI defined */
MOK_OWNER,
{0},
};

/* Read digest */
unsigned char digest[HASH_SIZE];
char buffer[3] = {0, 0, '\0'};
char *ptr;

for (size_t i = 0; i < HASH_SIZE; ++i) {
buffer[0] = argv[1][i*2];
buffer[1] = argv[1][(i*2) + 1];
digest[i] = (unsigned char)strtoul(buffer, &ptr, 16);
sig.SignatureData[i] = (UINT8)strtoul(buffer, &ptr, 16);
}

/* Convert to signature list */
unsigned char sig[sizeof(EFI_SIGNATURE_LIST) + (sizeof(EFI_SIGNATURE_DATA) - 1 + SHA256_DIGEST_SIZE)];
EFI_SIGNATURE_LIST *l = (void *)sig;

memset(sig, 0, sizeof(sig));
l->SignatureType = EFI_CERT_SHA256_GUID;
l->SignatureListSize = sizeof(sig);
l->SignatureSize = 16 + 32; /* UEFI defined */
EFI_SIGNATURE_DATA *d = (void *)sig + sizeof(EFI_SIGNATURE_LIST);
d->SignatureOwner = MOK_OWNER;
memcpy(&d->SignatureData, digest, sizeof(digest));

/* Write file */
int fdoutfile = open(argv[2], O_CREAT|O_WRONLY|O_TRUNC, S_IWUSR|S_IRUSR);
if (fdoutfile == -1) {
fprintf(stderr, "Failed to open %s: ", argv[2]);
perror("");
exit(1);
}
write(fdoutfile, sig, sizeof(sig));
write(fdoutfile, &sig, sizeof(sig));
close(fdoutfile);

return 0;
Expand Down