mirror of
https://github.com/mtrojnar/osslsigncode.git
synced 2025-04-04 17:00:11 -05:00
Add support for nested signing and verifying nested signatures for MSI files.
This commit is contained in:
Mikkel Krautz
parent
2fee516164
commit
a4544a1f74
276
osslsigncode.c
276
osslsigncode.c
@ -1104,6 +1104,52 @@ static int verify_leaf_hash(X509 *leaf, char *leafhash) {
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return 0;
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}
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// pkcs7_get_nested_signature exctracts a nested signature from p7.
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// The caller is responsible for freeing the returned object.
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//
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// If has_sig is provided, it will be set to either 1 if there is a
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// SPC_NESTED_SIGNATURE attribute in p7 at all or 0 if not.
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// This allows has_sig to be used to distinguish two possible scenarios
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// when the functon returns NULL: if has_sig is 1, it means d2i_PKCS7
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// failed to decode the nested signature. However, if has_sig is 0, it
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// simply means the given p7 does not have a nested signature.
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static PKCS7 *pkcs7_get_nested_signature(PKCS7 *p7, int *has_sig) {
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PKCS7 *ret = NULL;
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PKCS7_SIGNER_INFO *si = sk_PKCS7_SIGNER_INFO_value(p7->d.sign->signer_info, 0);
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ASN1_TYPE *nestedSignature = PKCS7_get_attribute(si, OBJ_txt2nid(SPC_NESTED_SIGNATURE_OBJID));
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if (nestedSignature) {
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ASN1_STRING *astr = nestedSignature->value.sequence;
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const unsigned char *p = astr->data;
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ret = d2i_PKCS7(NULL, &p, astr->length);
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}
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if (has_sig)
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*has_sig = (nestedSignature != NULL);
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return ret;
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}
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// pkcs7_set_nested_signature adds the p7nest signature to p7
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// as a nested signature (SPC_NESTED_SIGNATURE).
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static int pkcs7_set_nested_signature(PKCS7 *p7, PKCS7 *p7nest) {
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u_char *p = NULL;
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int len = 0;
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if (((len = i2d_PKCS7(p7nest, NULL)) <= 0) ||
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(p = OPENSSL_malloc(len)) == NULL)
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return 0;
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i2d_PKCS7(p7nest, &p);
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p -= len;
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ASN1_STRING *astr = ASN1_STRING_new();
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ASN1_STRING_set(astr, p, len);
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OPENSSL_free(p);
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PKCS7_SIGNER_INFO *si = sk_PKCS7_SIGNER_INFO_value(p7->d.sign->signer_info, 0);
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if (PKCS7_add_attribute(si, OBJ_txt2nid(SPC_NESTED_SIGNATURE_OBJID), V_ASN1_SEQUENCE, astr) == 0)
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return 0;
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return 1;
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}
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#ifdef WITH_GSF
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static gint msi_base64_decode(gint x)
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{
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@ -1368,50 +1414,13 @@ static gboolean msi_handle_dir(GsfInfile *infile, GsfOutfile *outole, BIO *hash)
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}
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/*
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* msi_verify_file checks whether or not the signature of infile is valid.
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* msi_verify_pkcs7 is a helper function for msi_verify_file.
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* It exists to make it easier to implement verification of nested signatures.
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*/
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static int msi_verify_file(GsfInfile *infile, char *leafhash) {
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GsfInput *sig = NULL;
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GsfInput *exsig = NULL;
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unsigned char *exdata = NULL;
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unsigned char *indata = NULL;
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gchar decoded[0x40];
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int i, ret = 0;
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static int msi_verify_pkcs7(PKCS7 *p7, GsfInfile *infile, unsigned char *exdata, unsigned int exlen, char *leafhash, int allownest) {
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int i = 0;
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int ret = 0;
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X509_STORE *store = NULL;
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PKCS7 *p7 = NULL;
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for (i = 0; i < gsf_infile_num_children(infile); i++) {
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GsfInput *child = gsf_infile_child_by_index(infile, i);
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const guint8 *name = (const guint8*)gsf_input_name(child);
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msi_decode(name, decoded);
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if (!g_strcmp0(decoded, "\05DigitalSignature"))
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sig = child;
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if (!g_strcmp0(decoded, "\05MsiDigitalSignatureEx"))
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exsig = child;
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}
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if (sig == NULL) {
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printf("MSI file has no signature\n\n");
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ret = 1;
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goto out;
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}
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unsigned long inlen = (unsigned long) gsf_input_remaining(sig);
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indata = malloc(inlen);
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if (gsf_input_read(sig, inlen, indata) == NULL) {
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ret = 1;
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goto out;
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}
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unsigned long exlen = 0;
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if (exsig != NULL) {
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exlen = (unsigned long) gsf_input_remaining(exsig);
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exdata = malloc(exlen);
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if (gsf_input_read(exsig, exlen, exdata) == NULL) {
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ret = 1;
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goto out;
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}
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}
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int mdtype = -1;
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unsigned char mdbuf[EVP_MAX_MD_SIZE];
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unsigned char cmdbuf[EVP_MAX_MD_SIZE];
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@ -1422,8 +1431,6 @@ static int msi_verify_file(GsfInfile *infile, char *leafhash) {
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BIO *bio = NULL;
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ASN1_OBJECT *indir_objid = OBJ_txt2obj(SPC_INDIRECT_DATA_OBJID, 1);
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const unsigned char *blob = (unsigned char *)indata;
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p7 = d2i_PKCS7(NULL, &blob, inlen);
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if (p7 && PKCS7_type_is_signed(p7) && !OBJ_cmp(p7->d.sign->contents->type, indir_objid) && p7->d.sign->contents->d.other->type == V_ASN1_SEQUENCE) {
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ASN1_STRING *astr = p7->d.sign->contents->d.other->value.sequence;
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const unsigned char *p = astr->data;
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@ -1436,10 +1443,6 @@ static int msi_verify_file(GsfInfile *infile, char *leafhash) {
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SpcIndirectDataContent_free(idc);
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}
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ASN1_OBJECT_free(indir_objid);
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if (p7 && mdtype == -1) {
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PKCS7_free(p7);
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p7 = NULL;
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}
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}
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if (mdtype == -1) {
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@ -1461,7 +1464,7 @@ static int msi_verify_file(GsfInfile *infile, char *leafhash) {
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BIO_set_md(hash, md);
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BIO_push(hash, BIO_new(BIO_s_null()));
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if (exsig) {
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if (exdata) {
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/*
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* Until libgsf can read more MSI metadata, we can't
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* really verify them by plowing through the file.
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@ -1574,12 +1577,84 @@ static int msi_verify_file(GsfInfile *infile, char *leafhash) {
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ret = 1;
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}
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if (allownest) {
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int has_sig = 0;
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PKCS7 *p7nest = pkcs7_get_nested_signature(p7, &has_sig);
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if (p7nest) {
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printf("\n");
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int nest_ret = msi_verify_pkcs7(p7nest, infile, exdata, exlen, leafhash, 0);
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if (ret == 0)
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ret = nest_ret;
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PKCS7_free(p7nest);
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} else if (!p7nest && has_sig) {
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printf("\nFailed to decode nested signature!\n");
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ret = 1;
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} else
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printf("\n");
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} else
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printf("\n");
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out:
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if (store)
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X509_STORE_free(store);
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return ret;
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}
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/*
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* msi_verify_file checks whether or not the signature of infile is valid.
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*/
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static int msi_verify_file(GsfInfile *infile, char *leafhash) {
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GsfInput *sig = NULL;
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GsfInput *exsig = NULL;
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unsigned char *exdata = NULL;
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unsigned char *indata = NULL;
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gchar decoded[0x40];
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int i, ret = 0;
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X509_STORE *store = NULL;
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PKCS7 *p7 = NULL;
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for (i = 0; i < gsf_infile_num_children(infile); i++) {
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GsfInput *child = gsf_infile_child_by_index(infile, i);
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const guint8 *name = (const guint8*)gsf_input_name(child);
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msi_decode(name, decoded);
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if (!g_strcmp0(decoded, "\05DigitalSignature"))
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sig = child;
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if (!g_strcmp0(decoded, "\05MsiDigitalSignatureEx"))
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exsig = child;
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}
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if (sig == NULL) {
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printf("MSI file has no signature\n\n");
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ret = 1;
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goto out;
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}
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unsigned long inlen = (unsigned long) gsf_input_remaining(sig);
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indata = malloc(inlen);
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if (gsf_input_read(sig, inlen, indata) == NULL) {
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ret = 1;
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goto out;
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}
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unsigned long exlen = 0;
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if (exsig != NULL) {
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exlen = (unsigned long) gsf_input_remaining(exsig);
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exdata = malloc(exlen);
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if (gsf_input_read(exsig, exlen, exdata) == NULL) {
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ret = 1;
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goto out;
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}
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}
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const unsigned char *blob = (unsigned char *)indata;
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p7 = d2i_PKCS7(NULL, &blob, inlen);
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ret = msi_verify_pkcs7(p7, infile, exdata, exlen, leafhash, 1);
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out:
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free(indata);
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free(exdata);
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if (store)
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X509_STORE_free(store);
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if (p7)
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PKCS7_free(p7);
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@ -1587,10 +1662,10 @@ out:
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}
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/*
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* msi_extract_signature extracts the MSI DigitalSignaure from infile
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* msi_extract_signature_to_file extracts the MSI DigitalSignaure from infile
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* to a file at the path given by outfile.
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*/
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static int msi_extract_signature(GsfInfile *infile, char *outfile) {
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static int msi_extract_signature_to_file(GsfInfile *infile, char *outfile) {
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unsigned char hexbuf[EVP_MAX_MD_SIZE*2+1];
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GsfInput *sig = NULL;
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GsfInput *exsig = NULL;
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@ -1657,6 +1732,41 @@ out:
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return ret;
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}
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static PKCS7 *msi_extract_signature_to_pkcs7(GsfInfile *infile) {
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unsigned char hexbuf[EVP_MAX_MD_SIZE*2+1];
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GsfInput *sig = NULL;
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BIO *outdata = NULL;
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gchar decoded[0x40];
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PKCS7 *p7 = NULL;
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u_char *buf = NULL;
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gsf_off_t size = 0;
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int i = 0;
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for (i = 0; i < gsf_infile_num_children(infile); i++) {
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GsfInput *child = gsf_infile_child_by_index(infile, i);
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const guint8 *name = (const guint8*)gsf_input_name(child);
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msi_decode(name, decoded);
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if (!g_strcmp0(decoded, "\05DigitalSignature"))
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sig = child;
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}
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if (sig == NULL) {
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goto out;
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}
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size = gsf_input_remaining(sig);
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buf = malloc(size);
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if (gsf_input_read(sig, size, buf) == NULL) {
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goto out;
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}
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const unsigned char *p7buf = buf;
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p7 = d2i_PKCS7(NULL, &p7buf, size);
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out:
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free(buf);
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return p7;
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}
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#endif
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static void calc_pe_digest(BIO *bio, const EVP_MD *md, unsigned char *mdbuf,
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@ -1800,52 +1910,6 @@ static unsigned char *calc_page_hash(char *indata, unsigned int peheader, int pe
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return res;
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}
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// pkcs7_get_nested_signature exctracts a nested signature from p7.
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// The caller is responsible for freeing the returned object.
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//
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// If has_sig is provided, it will be set to either 1 if there is a
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// SPC_NESTED_SIGNATURE attribute in p7 at all or 0 if not.
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// This allows has_sig to be used to distinguish two possible scenarios
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// when the functon returns NULL: if has_sig is 1, it means d2i_PKCS7
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// failed to decode the nested signature. However, if has_sig is 0, it
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// simply means the given p7 does not have a nested signature.
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static PKCS7 *pkcs7_get_nested_signature(PKCS7 *p7, int *has_sig) {
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PKCS7 *ret = NULL;
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PKCS7_SIGNER_INFO *si = sk_PKCS7_SIGNER_INFO_value(p7->d.sign->signer_info, 0);
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ASN1_TYPE *nestedSignature = PKCS7_get_attribute(si, OBJ_txt2nid(SPC_NESTED_SIGNATURE_OBJID));
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if (nestedSignature) {
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ASN1_STRING *astr = nestedSignature->value.sequence;
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const unsigned char *p = astr->data;
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ret = d2i_PKCS7(NULL, &p, astr->length);
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}
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if (has_sig)
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*has_sig = (nestedSignature != NULL);
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return ret;
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}
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// pkcs7_set_nested_signature adds the p7nest signature to p7
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// as a nested signature (SPC_NESTED_SIGNATURE).
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static int pkcs7_set_nested_signature(PKCS7 *p7, PKCS7 *p7nest) {
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u_char *p = NULL;
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int len = 0;
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if (((len = i2d_PKCS7(p7nest, NULL)) <= 0) ||
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(p = OPENSSL_malloc(len)) == NULL)
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return 0;
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i2d_PKCS7(p7nest, &p);
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p -= len;
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ASN1_STRING *astr = ASN1_STRING_new();
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ASN1_STRING_set(astr, p, len);
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OPENSSL_free(p);
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PKCS7_SIGNER_INFO *si = sk_PKCS7_SIGNER_INFO_value(p7->d.sign->signer_info, 0);
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if (PKCS7_add_attribute(si, OBJ_txt2nid(SPC_NESTED_SIGNATURE_OBJID), V_ASN1_SEQUENCE, astr) == 0)
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return 0;
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return 1;
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}
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static int verify_pe_pkcs7(PKCS7 *p7, char *indata, unsigned int peheader, int pe32plus,
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unsigned int sigpos, unsigned int siglen, char *leafhash,
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int allownest)
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@ -2528,11 +2592,18 @@ int main(int argc, char **argv)
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ole = gsf_infile_msole_new(src, NULL);
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if (cmd == CMD_EXTRACT) {
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ret = msi_extract_signature(ole, outfile);
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ret = msi_extract_signature_to_file(ole, outfile);
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goto skip_signing;
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} else if (cmd == CMD_VERIFY) {
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ret = msi_verify_file(ole, leafhash);
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goto skip_signing;
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} else if (cmd == CMD_SIGN) {
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if (nest) {
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cursig = msi_extract_signature_to_pkcs7(ole);
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if (cursig == NULL) {
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DO_EXIT_0("Unable to extract existing signature in -nest mode");
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}
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}
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}
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sink = gsf_output_stdio_new(outfile, NULL);
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@ -2893,8 +2964,11 @@ int main(int argc, char **argv)
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#endif
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if (nest) {
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if (cursig == NULL) {
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DO_EXIT_0("no 'cursig' was extracted. this points to a bug in the code. aborting...\n")
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}
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if (pkcs7_set_nested_signature(cursig, sig) == 0)
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DO_EXIT_0("unable to append the nested signature to the current signature");
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DO_EXIT_0("unable to append the nested signature to the current signature\n");
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outsig = cursig;
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} else {
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outsig = sig;
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