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path: root/lib/efi_loader/efi_image_loader.c
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Diffstat (limited to 'lib/efi_loader/efi_image_loader.c')
-rw-r--r--lib/efi_loader/efi_image_loader.c164
1 files changed, 120 insertions, 44 deletions
diff --git a/lib/efi_loader/efi_image_loader.c b/lib/efi_loader/efi_image_loader.c
index 06a2ebdb90..fef0bb870c 100644
--- a/lib/efi_loader/efi_image_loader.c
+++ b/lib/efi_loader/efi_image_loader.c
@@ -267,6 +267,8 @@ bool efi_image_parse(void *efi, size_t len, struct efi_image_regions **regp,
dos = (void *)efi;
nt = (void *)(efi + dos->e_lfanew);
+ authoff = 0;
+ authsz = 0;
/*
* Count maximum number of regions to be digested.
@@ -305,25 +307,36 @@ bool efi_image_parse(void *efi, size_t len, struct efi_image_regions **regp,
efi_image_region_add(regs,
&opt->DataDirectory[ctidx] + 1,
efi + opt->SizeOfHeaders, 0);
+
+ authoff = opt->DataDirectory[ctidx].VirtualAddress;
+ authsz = opt->DataDirectory[ctidx].Size;
}
bytes_hashed = opt->SizeOfHeaders;
align = opt->FileAlignment;
- authoff = opt->DataDirectory[ctidx].VirtualAddress;
- authsz = opt->DataDirectory[ctidx].Size;
} else if (nt->OptionalHeader.Magic == IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
IMAGE_OPTIONAL_HEADER32 *opt = &nt->OptionalHeader;
+ /* Skip CheckSum */
efi_image_region_add(regs, efi, &opt->CheckSum, 0);
- efi_image_region_add(regs, &opt->Subsystem,
- &opt->DataDirectory[ctidx], 0);
- efi_image_region_add(regs, &opt->DataDirectory[ctidx] + 1,
- efi + opt->SizeOfHeaders, 0);
+ if (nt->OptionalHeader.NumberOfRvaAndSizes <= ctidx) {
+ efi_image_region_add(regs,
+ &opt->Subsystem,
+ efi + opt->SizeOfHeaders, 0);
+ } else {
+ /* Skip Certificates Table */
+ efi_image_region_add(regs, &opt->Subsystem,
+ &opt->DataDirectory[ctidx], 0);
+ efi_image_region_add(regs,
+ &opt->DataDirectory[ctidx] + 1,
+ efi + opt->SizeOfHeaders, 0);
+
+ authoff = opt->DataDirectory[ctidx].VirtualAddress;
+ authsz = opt->DataDirectory[ctidx].Size;
+ }
bytes_hashed = opt->SizeOfHeaders;
align = opt->FileAlignment;
- authoff = opt->DataDirectory[ctidx].VirtualAddress;
- authsz = opt->DataDirectory[ctidx].Size;
} else {
EFI_PRINT("%s: Invalid optional header magic %x\n", __func__,
nt->OptionalHeader.Magic);
@@ -369,7 +382,7 @@ bool efi_image_parse(void *efi, size_t len, struct efi_image_regions **regp,
/* 3. Extra data excluding Certificates Table */
if (bytes_hashed + authsz < len) {
- EFI_PRINT("extra data for hash: %lu\n",
+ EFI_PRINT("extra data for hash: %zu\n",
len - (bytes_hashed + authsz));
efi_image_region_add(regs, efi + bytes_hashed,
efi + len - authsz, 0);
@@ -435,16 +448,16 @@ static bool efi_image_unsigned_authenticate(struct efi_image_regions *regs)
}
/* try black-list first */
- if (efi_signature_verify_with_sigdb(regs, NULL, dbx, NULL)) {
- EFI_PRINT("Image is not signed and rejected by \"dbx\"\n");
+ if (efi_signature_lookup_digest(regs, dbx)) {
+ EFI_PRINT("Image is not signed and its digest found in \"dbx\"\n");
goto out;
}
/* try white-list */
- if (efi_signature_verify_with_sigdb(regs, NULL, db, NULL))
+ if (efi_signature_lookup_digest(regs, db))
ret = true;
else
- EFI_PRINT("Image is not signed and not found in \"db\" or \"dbx\"\n");
+ EFI_PRINT("Image is not signed and its digest not found in \"db\" or \"dbx\"\n");
out:
efi_sigstore_free(db);
@@ -481,11 +494,13 @@ static bool efi_image_authenticate(void *efi, size_t efi_size)
size_t wincerts_len;
struct pkcs7_message *msg = NULL;
struct efi_signature_store *db = NULL, *dbx = NULL;
- struct x509_certificate *cert = NULL;
void *new_efi = NULL;
- size_t new_efi_size;
+ u8 *auth, *wincerts_end;
+ size_t new_efi_size, auth_size;
bool ret = false;
+ debug("%s: Enter, %d\n", __func__, ret);
+
if (!efi_secure_boot_enabled())
return true;
@@ -531,61 +546,122 @@ static bool efi_image_authenticate(void *efi, size_t efi_size)
goto err;
}
- /* go through WIN_CERTIFICATE list */
- for (wincert = wincerts;
- (void *)wincert < (void *)wincerts + wincerts_len;
- wincert = (void *)wincert + ALIGN(wincert->dwLength, 8)) {
- if (wincert->dwLength < sizeof(*wincert)) {
- EFI_PRINT("%s: dwLength too small: %u < %zu\n",
- __func__, wincert->dwLength,
- sizeof(*wincert));
- goto err;
+ /*
+ * go through WIN_CERTIFICATE list
+ * NOTE:
+ * We may have multiple signatures either as WIN_CERTIFICATE's
+ * in PE header, or as pkcs7 SignerInfo's in SignedData.
+ * So the verification policy here is:
+ * - Success if, at least, one of signatures is verified
+ * - unless
+ * any of signatures is rejected explicitly, or
+ * none of digest algorithms are supported
+ */
+ for (wincert = wincerts, wincerts_end = (u8 *)wincerts + wincerts_len;
+ (u8 *)wincert < wincerts_end;
+ wincert = (WIN_CERTIFICATE *)
+ ((u8 *)wincert + ALIGN(wincert->dwLength, 8))) {
+ if ((u8 *)wincert + sizeof(*wincert) >= wincerts_end)
+ break;
+
+ if (wincert->dwLength <= sizeof(*wincert)) {
+ EFI_PRINT("dwLength too small: %u < %zu\n",
+ wincert->dwLength, sizeof(*wincert));
+ continue;
}
- msg = pkcs7_parse_message((void *)wincert + sizeof(*wincert),
- wincert->dwLength - sizeof(*wincert));
+
+ EFI_PRINT("WIN_CERTIFICATE_TYPE: 0x%x\n",
+ wincert->wCertificateType);
+
+ auth = (u8 *)wincert + sizeof(*wincert);
+ auth_size = wincert->dwLength - sizeof(*wincert);
+ if (wincert->wCertificateType == WIN_CERT_TYPE_EFI_GUID) {
+ if (auth + sizeof(efi_guid_t) >= wincerts_end)
+ break;
+
+ if (auth_size <= sizeof(efi_guid_t)) {
+ EFI_PRINT("dwLength too small: %u < %zu\n",
+ wincert->dwLength, sizeof(*wincert));
+ continue;
+ }
+ if (guidcmp(auth, &efi_guid_cert_type_pkcs7)) {
+ EFI_PRINT("Certificate type not supported: %pUl\n",
+ auth);
+ continue;
+ }
+
+ auth += sizeof(efi_guid_t);
+ auth_size -= sizeof(efi_guid_t);
+ } else if (wincert->wCertificateType
+ != WIN_CERT_TYPE_PKCS_SIGNED_DATA) {
+ EFI_PRINT("Certificate type not supported\n");
+ continue;
+ }
+
+ msg = pkcs7_parse_message(auth, auth_size);
if (IS_ERR(msg)) {
EFI_PRINT("Parsing image's signature failed\n");
msg = NULL;
- goto err;
+ continue;
}
+ /*
+ * NOTE:
+ * UEFI specification defines two signature types possible
+ * in signature database:
+ * a. x509 certificate, where a signature in image is
+ * a message digest encrypted by RSA public key
+ * (EFI_CERT_X509_GUID)
+ * b. bare hash value of message digest
+ * (EFI_CERT_SHAxxx_GUID)
+ *
+ * efi_signature_verify() handles case (a), while
+ * efi_signature_lookup_digest() handles case (b).
+ *
+ * There is a third type:
+ * c. message digest of a certificate
+ * (EFI_CERT_X509_SHAAxxx_GUID)
+ * This type of signature is used only in revocation list
+ * (dbx) and handled as part of efi_signatgure_verify().
+ */
/* try black-list first */
- if (efi_signature_verify_with_sigdb(regs, msg, dbx, NULL)) {
+ if (efi_signature_verify_one(regs, msg, dbx)) {
EFI_PRINT("Signature was rejected by \"dbx\"\n");
goto err;
}
- if (!efi_signature_verify_signers(msg, dbx)) {
- EFI_PRINT("Signer was rejected by \"dbx\"\n");
+ if (!efi_signature_check_signers(msg, dbx)) {
+ EFI_PRINT("Signer(s) in \"dbx\"\n");
goto err;
- } else {
- ret = true;
}
- /* try white-list */
- if (!efi_signature_verify_with_sigdb(regs, msg, db, &cert)) {
- EFI_PRINT("Verifying signature with \"db\" failed\n");
+ if (efi_signature_lookup_digest(regs, dbx)) {
+ EFI_PRINT("Image's digest was found in \"dbx\"\n");
goto err;
- } else {
- ret = true;
}
- if (!efi_signature_verify_cert(cert, dbx)) {
- EFI_PRINT("Certificate was rejected by \"dbx\"\n");
- goto err;
- } else {
- ret = true;
- }
+ /* try white-list */
+ if (efi_signature_verify_with_sigdb(regs, msg, db, dbx))
+ continue;
+
+ debug("Signature was not verified by \"db\"\n");
+
+ if (efi_signature_lookup_digest(regs, db))
+ continue;
+
+ debug("Image's digest was not found in \"db\" or \"dbx\"\n");
+ goto err;
}
+ ret = true;
err:
- x509_free_certificate(cert);
efi_sigstore_free(db);
efi_sigstore_free(dbx);
pkcs7_free_message(msg);
free(regs);
free(new_efi);
+ debug("%s: Exit, %d\n", __func__, ret);
return ret;
}
#else
generated by cgit v1.2.3 (git 2.39.1) at 2025-05-24 11:52:40 +0000