Lift RSA/DSA signature MPI calculations to helper functions

- Use function pointers to call appropriate helper, cleaning up
  pgpPrtSigParams() considerably. Supposedly no functional changes.
- Also serves as first step towards isolating NSS-specific bits
  and pieces behind more generic interfaces to enable using
  alternative crypto "engines" later on.

diff --git a/rpmio/rpmpgp.c b/rpmio/rpmpgp.c
index 33f6053..dcde6e4 100644 (file)
--- a/rpmio/rpmpgp.c
+++ b/rpmio/rpmpgp.c
@@ -603,72 +603,83 @@ static const char * const pgpSigDSA[] = {
 #define DSA_SUBPRIME_LEN 20
 #endif
 
+static int pgpSetSigMpiDSA(pgpDigParams pgpsig, int num,
+                          const uint8_t *p, const uint8_t *pend)
+{
+    SECItem *sig = pgpsig->data;
+    int lbits = DSA_SUBPRIME_LEN * 8;
+    int rc = 1; /* assume failure */
+
+    switch (num) {
+    case 0:
+       sig = pgpsig->data = SECITEM_AllocItem(NULL, NULL, 2*DSA_SUBPRIME_LEN);
+       memset(sig->data, 0, 2 * DSA_SUBPRIME_LEN);
+       rc = pgpMpiSet(lbits, sig->data, p, pend);
+       break;
+    case 1:
+       if (sig && pgpMpiSet(lbits, sig->data+DSA_SUBPRIME_LEN, p, pend) == 0) {
+           SECItem *signew = SECITEM_AllocItem(NULL, NULL, 0);
+           if (signew && DSAU_EncodeDerSig(signew, sig) == SECSuccess) {
+               SECITEM_FreeItem(sig, PR_TRUE);
+               pgpsig->data = signew;
+               rc = 0;
+           }
+       }
+       break;
+    }
+
+    return rc;
+}
+
+static int pgpSetSigMpiRSA(pgpDigParams pgpsig, int num,
+                          const uint8_t *p, const uint8_t *pend)
+{
+    SECItem *sigitem = NULL;
+
+    if (num == 0) {
+       sigitem = pgpMpiItem(NULL, pgpsig->data, p, pend);
+       if (sigitem)
+           pgpsig->data = sigitem;
+    }
+    return (sigitem == NULL);
+}
+
+typedef int (*setmpifunc)(pgpDigParams digp,
+                         int num, const uint8_t *p, const uint8_t *pend);
+
 static int pgpPrtSigParams(pgpTag tag, uint8_t pubkey_algo, uint8_t sigtype,
                const uint8_t *p, const uint8_t *h, size_t hlen,
                pgpDigParams sigp)
 {
     const uint8_t * pend = h + hlen;
     int i, mpis = -1;
-    SECItem dsaraw;
-    unsigned char dsabuf[2*DSA_SUBPRIME_LEN];
+    const char * const * sigtbl;
     char *mpi;
+    setmpifunc setmpi = NULL;
 
     switch (pubkey_algo) {
     case PGPPUBKEYALGO_RSA:
        mpis = 1;
+       setmpi = pgpSetSigMpiRSA;
+       sigtbl = pgpSigRSA;
        break;
     case PGPPUBKEYALGO_DSA:
        mpis = 2;
+       setmpi = pgpSetSigMpiDSA;
+       sigtbl = pgpSigDSA;
+       break;
+    default:
+       return 1;
        break;
     }
 
-    dsaraw.type = 0;
-    dsaraw.data = dsabuf;
-    dsaraw.len = sizeof(dsabuf);
-    
     for (i = 0; p < pend && i < mpis; i++, p += pgpMpiLen(p)) {
-       if (pubkey_algo == PGPPUBKEYALGO_RSA) {
-           if (sigtype == PGPSIGTYPE_BINARY || sigtype == PGPSIGTYPE_TEXT) {
-               switch (i) {
-               case 0:         /* m**d */
-                   sigp->data = pgpMpiItem(NULL, sigp->data, p, pend);
-                   if (sigp->data == NULL)
-                       return 1;
-                   break;
-               default:
-                   break;
-               }
-           }
-           pgpPrtStr("", pgpSigRSA[i]);
-       } else if (pubkey_algo == PGPPUBKEYALGO_DSA) {
-           if (sigtype == PGPSIGTYPE_BINARY || sigtype == PGPSIGTYPE_TEXT) {
-               int xx;
-               xx = 0;
-               switch (i) {
-               case 0:
-                   memset(dsaraw.data, '\0', 2*DSA_SUBPRIME_LEN);
-                               /* r */
-                   xx = pgpMpiSet(DSA_SUBPRIME_LEN*8, dsaraw.data, p, pend);
-                   break;
-               case 1:         /* s */
-                   xx = pgpMpiSet(DSA_SUBPRIME_LEN*8, dsaraw.data + DSA_SUBPRIME_LEN, p, pend);
-                   if (sigp->data != NULL)
-                       SECITEM_FreeItem(sigp->data, PR_FALSE);
-                   else if ((sigp->data=SECITEM_AllocItem(NULL, NULL, 0)) == NULL) {
-                       xx = 1;
-                       break;
-                   }
-                   if (DSAU_EncodeDerSig(sigp->data, &dsaraw) != SECSuccess)
-                       xx = 1;
-                   break;
-               default:
-                   xx = 1;
-                   break;
-               }
-               if (xx) return xx;
-           }
-           pgpPrtStr("", pgpSigDSA[i]);
+       if (sigtype == PGPSIGTYPE_BINARY || sigtype == PGPSIGTYPE_TEXT) {
+           if (setmpi(sigp, i, p, pend))
+               return 1;
+           pgpPrtStr("", sigtbl[i]);
        }
+
        mpi = pgpMpiStr(p);
        pgpPrtStr("", mpi);
        free(mpi);