hardened OpenPGP parser

diff --git a/src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c b/src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c
index 76495c7..2bb38bb 100644 (file)
--- a/src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c
+++ b/src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c
@@ -605,39 +605,47 @@ static gmp_rsa_public_key_t *load_asn1_der(chunk_t blob)
  */
 static gmp_rsa_public_key_t* load_pgp(chunk_t blob)
 {
-       chunk_t exponent, modulus;
+       int objectID;
        chunk_t packet = blob;
        private_gmp_rsa_public_key_t *this = gmp_rsa_public_key_create_empty();
 
        mpz_init(this->n);
        mpz_init(this->e);
        
-       /* modulus n */
-       modulus.len = (pgp_length(&packet, 2) + 7) / BITS_PER_BYTE;
-       modulus.ptr = packet.ptr;
-       if (modulus.len > packet.len)
+       for (objectID = PUB_KEY_MODULUS; objectID <= PUB_KEY_EXPONENT; objectID++)
        {
-               DBG1("OpenPGP public key blob too short for modulus");
-               goto end;
-       }
-       packet.ptr += modulus.len;
-       packet.len -= modulus.len;
-       DBG2("L3 - modulus:");
-       DBG3("%B", &modulus);
+               chunk_t object; 
 
-       /* public exponent e */
-       exponent.len = (pgp_length(&packet, 2) + 7) /  BITS_PER_BYTE;
-       exponent.ptr = packet.ptr;
-       if (exponent.len > packet.len)
-       {
-               DBG1("OpenPGP public key blob too short for exponent");
-               goto end;
+               DBG2("L3 - %s:", pubkeyObjects[objectID].name);
+               object.len = pgp_length(&packet, 2);
+
+               if (object.len == PGP_INVALID_LENGTH)
+               {
+                       DBG1("OpenPGP length is invalid");
+                       goto end;
+               }
+               object.len = (object.len + 7) / BITS_PER_BYTE;
+               if (object.len > packet.len)
+               {
+                       DBG1("OpenPGP field is too short");
+                       goto end;
+               }
+               object.ptr = packet.ptr;
+               packet.ptr += object.len;
+               packet.len -= object.len;
+               DBG4("%B", &object);
+
+               switch (objectID)
+               {
+                       case PUB_KEY_MODULUS:
+                               mpz_import(this->n, object.len, 1, 1, 1, 0, object.ptr);
+                               break;
+                       case PUB_KEY_EXPONENT:
+                               mpz_import(this->e, object.len, 1, 1, 1, 0, object.ptr);
+                               break;
+               }
        }
-       DBG2("L3 - public exponent:");
-       DBG3("%B", &exponent);
 
-       mpz_import(this->n, modulus.len,  1, 1, 1, 0, modulus.ptr);
-       mpz_import(this->e, exponent.len, 1, 1, 1, 0, exponent.ptr);
        this->k = (mpz_sizeinbase(this->n, 2) + 7) /  BITS_PER_BYTE;
        free(blob.ptr);