+STACK_OF(X509) *PKCS7_iget_signers(PKCS7 *p7, STACK_OF(X509) *certs, int flags)
+{
+ STACK_OF(X509) *signers;
+ STACK_OF(PKCS7_SIGNER_INFO) *sinfos;
+ PKCS7_SIGNER_INFO *si;
+ PKCS7_ISSUER_AND_SERIAL *ias;
+ X509 *signer;
+ int i;
+
+ if(!p7) {
+ PKCS7err(PKCS7_F_PKCS7_IGET_SIGNERS,PKCS7_R_INVALID_NULL_POINTER);
+ return NULL;
+ }
+
+ if(!PKCS7_type_is_signed(p7)) {
+ PKCS7err(PKCS7_F_PKCS7_IGET_SIGNERS,PKCS7_R_WRONG_CONTENT_TYPE);
+ return NULL;
+ }
+ if(!(signers = sk_X509_new(NULL))) {
+ PKCS7err(PKCS7_F_PKCS7_IGET_SIGNERS,ERR_R_MALLOC_FAILURE);
+ return NULL;
+ }
+
+ /* Collect all the signers together */
+
+ sinfos = PKCS7_get_signer_info(p7);
+
+ if(sk_PKCS7_SIGNER_INFO_num(sinfos) <= 0) {
+ PKCS7err(PKCS7_F_PKCS7_IGET_SIGNERS,PKCS7_R_NO_SIGNERS);
+ return 0;
+ }
+
+ for (i = 0; i < sk_PKCS7_SIGNER_INFO_num(sinfos); i++)
+ {
+ si = sk_PKCS7_SIGNER_INFO_value(sinfos, i);
+ ias = si->issuer_and_serial;
+ signer = NULL;
+ /* If any certificates passed they take priority */
+ if (certs) signer = X509_find_by_issuer_and_serial (certs,
+ ias->issuer, ias->serial);
+ if (!signer && !(flags & PKCS7_NOINTERN)
+ && p7->d.sign->cert) signer =
+ X509_find_by_issuer_and_serial (p7->d.sign->cert,
+ ias->issuer, ias->serial);
+ if (!signer) {
+ PKCS7err(PKCS7_F_PKCS7_IGET_SIGNERS,PKCS7_R_SIGNER_CERTIFICATE_NOT_FOUND);
+ sk_X509_free(signers);
+ return 0;
+ }
+
+ sk_X509_push(signers, signer);
+ }
+ return signers;
+}
+
+