krb5 commit [krb5-1.12]: Fix error checking in PKINIT authdata creation

[Tom Yu]

https://github.com/krb5/krb5/commit/62c9e504261a07b8da297854c9fc9549acecc7d3
commit 62c9e504261a07b8da297854c9fc9549acecc7d3
Author: Greg Hudson <ghudson at mit.edu>
Date:   Sat Jun 14 11:23:08 2014 -0400

    Fix error checking in PKINIT authdata creation
    
    In create_identifiers_from_stack: check for allocation errors from
    PKCS7_ISSUER_AND_SERIAL_new and M_ASN1_INTEGER_dup.  Use
    PKCS7_ISSUER_AND_SERIAL_free to more concisely clean up the OpenSSL
    issuer variable, and make sure that any partially processed value is
    cleaned up on error.  Use calloc to allocate krb5_cas so that all of
    its pointers are initially nulled, so that
    free_krb5_external_principal_identifier can operate on it safely in
    case of error.  Eliminate the retval variable as it was not used
    safely.  Rename the error label from "cleanup" to "oom" and separate
    it from the successful return path (which has nothing to clean up).
    
    (back ported from commit 09246e64e20f079bef6163e9e1d0ecda7917b8c2)
    
    ticket: 7943
    version_fixed: 1.12.2
    status: resolved

 src/plugins/preauth/pkinit/pkinit_crypto_openssl.c |   51 +++++++++----------
 1 files changed, 24 insertions(+), 27 deletions(-)

diff --git a/src/plugins/preauth/pkinit/pkinit_crypto_openssl.c b/src/plugins/preauth/pkinit/pkinit_crypto_openssl.c
index e00bd73..f010bd7 100644
--- a/src/plugins/preauth/pkinit/pkinit_crypto_openssl.c
+++ b/src/plugins/preauth/pkinit/pkinit_crypto_openssl.c
@@ -5640,7 +5640,6 @@ static krb5_error_code
 create_identifiers_from_stack(STACK_OF(X509) *sk,
                               krb5_external_principal_identifier *** ids)
 {
-    krb5_error_code retval = ENOMEM;
     int i = 0, sk_size = sk_X509_num(sk);
     krb5_external_principal_identifier **krb5_cas = NULL;
     X509 *x = NULL;
@@ -5652,11 +5651,9 @@ create_identifiers_from_stack(STACK_OF(X509) *sk,
 
     *ids = NULL;
 
-    krb5_cas =
-        malloc((sk_size + 1) * sizeof(krb5_external_principal_identifier *));
+    krb5_cas = calloc(sk_size + 1, sizeof(*krb5_cas));
     if (krb5_cas == NULL)
         return ENOMEM;
-    krb5_cas[sk_size] = NULL;
 
     for (i = 0; i < sk_size; i++) {
         krb5_cas[i] = malloc(sizeof(krb5_external_principal_identifier));
@@ -5674,7 +5671,7 @@ create_identifiers_from_stack(STACK_OF(X509) *sk,
         xn = X509_get_subject_name(x);
         len = i2d_X509_NAME(xn, NULL);
         if ((p = malloc((size_t) len)) == NULL)
-            goto cleanup;
+            goto oom;
         krb5_cas[i]->subjectName.data = (char *)p;
         i2d_X509_NAME(xn, &p);
         krb5_cas[i]->subjectName.length = len;
@@ -5688,12 +5685,17 @@ create_identifiers_from_stack(STACK_OF(X509) *sk,
         if (longhorn == 0) { /* XXX Longhorn doesn't like this */
 #endif
             is = PKCS7_ISSUER_AND_SERIAL_new();
+            if (is == NULL)
+                goto oom;
             X509_NAME_set(&is->issuer, X509_get_issuer_name(x));
             M_ASN1_INTEGER_free(is->serial);
             is->serial = M_ASN1_INTEGER_dup(X509_get_serialNumber(x));
+            if (is->serial == NULL)
+                goto oom;
             len = i2d_PKCS7_ISSUER_AND_SERIAL(is, NULL);
-            if ((p = malloc((size_t) len)) == NULL)
-                goto cleanup;
+            p = malloc(len);
+            if (p == NULL)
+                goto oom;
             krb5_cas[i]->issuerAndSerialNumber.data = (char *)p;
             i2d_PKCS7_ISSUER_AND_SERIAL(is, &p);
             krb5_cas[i]->issuerAndSerialNumber.length = len;
@@ -5711,40 +5713,35 @@ create_identifiers_from_stack(STACK_OF(X509) *sk,
         if (longhorn == 0) {    /* XXX Longhorn doesn't like this */
 #endif
             if (X509_get_ext_by_NID(x, NID_subject_key_identifier, -1) >= 0) {
-                ASN1_OCTET_STRING *ikeyid = NULL;
+                ASN1_OCTET_STRING *ikeyid;
 
-                if ((ikeyid = X509_get_ext_d2i(x, NID_subject_key_identifier, NULL,
-                                               NULL))) {
+                ikeyid = X509_get_ext_d2i(x, NID_subject_key_identifier, NULL,
+                                          NULL);
+                if (ikeyid != NULL) {
                     len = i2d_ASN1_OCTET_STRING(ikeyid, NULL);
-                    if ((p = malloc((size_t) len)) == NULL)
-                        goto cleanup;
+                    p = malloc(len);
+                    if (p == NULL)
+                        goto oom;
                     krb5_cas[i]->subjectKeyIdentifier.data = (char *)p;
                     i2d_ASN1_OCTET_STRING(ikeyid, &p);
                     krb5_cas[i]->subjectKeyIdentifier.length = len;
-                }
-                if (ikeyid != NULL)
                     ASN1_OCTET_STRING_free(ikeyid);
+                }
             }
 #ifdef LONGHORN_BETA_COMPAT
         }
 #endif
-        if (is != NULL) {
-            if (is->issuer != NULL)
-                X509_NAME_free(is->issuer);
-            if (is->serial != NULL)
-                ASN1_INTEGER_free(is->serial);
-            free(is);
-        }
+        PKCS7_ISSUER_AND_SERIAL_free(is);
+        is = NULL;
     }
 
     *ids = krb5_cas;
+    return 0;
 
-    retval = 0;
-cleanup:
-    if (retval)
-        free_krb5_external_principal_identifier(&krb5_cas);
-
-    return retval;
+oom:
+    free_krb5_external_principal_identifier(&krb5_cas);
+    PKCS7_ISSUER_AND_SERIAL_free(is);
+    return ENOMEM;
 }
 
 static krb5_error_code