krb5 commit [krb5-1.12]: Don't blindly use PKCS11 slot IDs in PKINIT

[Tom Yu]

https://github.com/krb5/krb5/commit/2e56aa65e8d362b2ffe90c61e377594c822e893d
commit 2e56aa65e8d362b2ffe90c61e377594c822e893d
Author: Greg Hudson <ghudson at mit.edu>
Date:   Thu May 22 19:18:34 2014 -0400

    Don't blindly use PKCS11 slot IDs in PKINIT
    
    Passing invalid slot IDs to C_OpenSession can cause some PKCS #11
    implementations (such as the Solaris one) to crash.  If a PKINIT
    identity specifies a slotid, use it to filter the result of
    C_GetSlotList, but don't try it if it does not appear in the list.
    
    (cherry picked from commit ac406bac3d73a7e4efcc74adbb90c722457da969)
    
    ticket: 7916
    version_fixed: 1.12.2
    status: resolved

 src/plugins/preauth/pkinit/pkinit_crypto_openssl.c |   27 +++++++++----------
 1 files changed, 13 insertions(+), 14 deletions(-)

diff --git a/src/plugins/preauth/pkinit/pkinit_crypto_openssl.c b/src/plugins/preauth/pkinit/pkinit_crypto_openssl.c
index b661320..651d5e8 100644
--- a/src/plugins/preauth/pkinit/pkinit_crypto_openssl.c
+++ b/src/plugins/preauth/pkinit/pkinit_crypto_openssl.c
@@ -3801,23 +3801,22 @@ pkinit_open_session(krb5_context context,
     }
 
     /* Get the list of available slots */
-    if (cctx->slotid != PK_NOSLOT) {
-        /* A slot was specified, so that's the only one in the list */
-        count = 1;
-        slotlist = malloc(sizeof(CK_SLOT_ID));
-        slotlist[0] = cctx->slotid;
-    } else {
-        if (cctx->p11->C_GetSlotList(TRUE, NULL, &count) != CKR_OK)
-            return KRB5KDC_ERR_PREAUTH_FAILED;
-        if (count == 0)
-            return KRB5KDC_ERR_PREAUTH_FAILED;
-        slotlist = malloc(count * sizeof (CK_SLOT_ID));
-        if (cctx->p11->C_GetSlotList(TRUE, slotlist, &count) != CKR_OK)
-            return KRB5KDC_ERR_PREAUTH_FAILED;
-    }
+    if (cctx->p11->C_GetSlotList(TRUE, NULL, &count) != CKR_OK)
+        return KRB5KDC_ERR_PREAUTH_FAILED;
+    if (count == 0)
+        return KRB5KDC_ERR_PREAUTH_FAILED;
+    slotlist = calloc(count, sizeof(CK_SLOT_ID));
+    if (slotlist == NULL)
+        return ENOMEM;
+    if (cctx->p11->C_GetSlotList(TRUE, slotlist, &count) != CKR_OK)
+        return KRB5KDC_ERR_PREAUTH_FAILED;
 
     /* Look for the given token label, or if none given take the first one */
     for (i = 0; i < count; i++) {
+        /* Skip slots that don't match the specified slotid, if given. */
+        if (cctx->slotid != PK_NOSLOT && cctx->slotid != slotlist[i])
+            continue;
+
         /* Open session */
         if ((r = cctx->p11->C_OpenSession(slotlist[i], CKF_SERIAL_SESSION,
                                           NULL, NULL, &cctx->session)) != CKR_OK) {