libtpmtss: Read RSA public key exponent instead of assuming its value

[thirdparty/strongswan.git] / src / libtpmtss / tpm_tss_tss2_v1.c

diff --git a/src/libtpmtss/tpm_tss_tss2_v1.c b/src/libtpmtss/tpm_tss_tss2_v1.c
index f904442edebe2c8a0a18049a01bc1273cfa33563..1c214afa37aa723f27076876d0f0c54743485dca 100644 (file)
--- a/src/libtpmtss/tpm_tss_tss2_v1.c
+++ b/src/libtpmtss/tpm_tss_tss2_v1.c
@@ -481,6 +481,7 @@ METHOD(tpm_tss_t, get_public, chunk_t,
                        TPM2B_PUBLIC_KEY_RSA *rsa;
                        TPMT_RSA_SCHEME *scheme;
                        chunk_t aik_exponent, aik_modulus;
+                       uint32_t exponent;
 
                        scheme = &public.t.publicArea.parameters.rsaDetail.scheme;
                        sig_alg   = scheme->scheme;
@@ -488,7 +489,15 @@ METHOD(tpm_tss_t, get_public, chunk_t,
 
                        rsa = &public.t.publicArea.unique.rsa;
                        aik_modulus = chunk_create(rsa->t.buffer, rsa->t.size);
-                       aik_exponent = chunk_from_chars(0x01, 0x00, 0x01);
+                       exponent = public.t.publicArea.parameters.rsaDetail.exponent;
+                       if (!exponent)
+                       {
+                               aik_exponent = chunk_from_chars(0x01, 0x00, 0x01);
+                       }
+                       else
+                       {
+                               aik_exponent = chunk_from_thing(exponent);
+                       }
 
                        /* subjectPublicKeyInfo encoding of RSA public key */
                        if (!lib->encoding->encode(lib->encoding, PUBKEY_SPKI_ASN1_DER,