[evolution-data-server] Bug 763029 - S/MIME encrypt fails to find certificate in other slots

[Milan Crha <mcrha src gnome org>]

commit d4c58194b365e0fdaac5d7d2d3e9848e0367a4d8
Author: Milan Crha <mcrha redhat com>
Date:   Thu May 31 11:21:17 2018 +0200

    Bug 763029 - S/MIME encrypt fails to find certificate in other slots
    
    Based on patch by Watson Yuuma Sato.

 src/camel/camel-smime-context.c | 221 +++++++++++++++++++++++++++++++++++++---
 1 file changed, 209 insertions(+), 12 deletions(-)
---
diff --git a/src/camel/camel-smime-context.c b/src/camel/camel-smime-context.c
index 85fe0be1a..1ba916cbe 100644
--- a/src/camel/camel-smime-context.c
+++ b/src/camel/camel-smime-context.c
@@ -53,6 +53,7 @@
 #include "camel-stream-filter.h"
 #include "camel-stream-fs.h"
 #include "camel-stream-mem.h"
+#include "camel-string-utils.h"
 
 #define d(x)
 
@@ -1024,6 +1025,151 @@ fail:
        return valid;
 }
 
+static gboolean
+camel_smime_first_certificate_is_better (CERTCertificate *cert1,
+                                        CERTCertificate *cert2,
+                                        PRTime now)
+{
+       PRTime notBefore1, notAfter1, notBefore2, notAfter2;
+       CERTCertTrust trust;
+       gboolean cert1_trusted, cert2_trusted;
+
+       if (!cert1)
+               return FALSE;
+
+       if (!cert2)
+               return cert1 != NULL;
+
+       /* Both certificates are valid at the time, it's ensured with CERT_CheckCertValidTimes()
+          in camel_smime_find_recipients_certs() */
+
+       if (SECSuccess == CERT_GetCertTrust (cert1, &trust))
+               cert1_trusted = (trust.emailFlags & CERTDB_TRUSTED) != 0;
+       else
+               cert1_trusted = FALSE;
+
+       if (SECSuccess == CERT_GetCertTrust (cert2, &trust))
+               cert2_trusted = (trust.emailFlags & CERTDB_TRUSTED) != 0;
+       else
+               cert2_trusted = FALSE;
+
+       if (cert1_trusted && !cert2_trusted)
+               return TRUE;
+
+       if (!cert1_trusted && cert2_trusted)
+               return FALSE;
+
+       /* Both are trusted or untrusted, then get the newer */
+       if (CERT_GetCertTimes (cert1, &notBefore1, &notAfter1) != SECSuccess)
+               return FALSE;
+
+       if (CERT_GetCertTimes (cert2, &notBefore2, &notAfter2) != SECSuccess)
+               return TRUE;
+
+       /* cert1 is valid after cert2, thus it is newer */
+       return notBefore1 > notBefore2;
+}
+
+typedef struct FindRecipientsData {
+       GHashTable *recipients_table;
+       guint certs_missing;
+       PRTime now;
+} FindRecipientsData;
+
+static SECStatus
+camel_smime_find_recipients_certs (CERTCertificate *cert,
+                                  SECItem *item,
+                                  gpointer user_data)
+{
+       FindRecipientsData *frd = user_data;
+       const char *cert_email = NULL;
+       CERTCertificate **hash_value = NULL;
+
+       /* Cannot short-circuit when cbparam->certs_missing is 0, because there can be better certificates */
+       if (!frd->recipients_table ||
+           CERT_CheckCertValidTimes (cert, frd->now, PR_FALSE) != secCertTimeValid) {
+               return SECFailure;
+       }
+
+       /* Loop over all cert's email addresses */
+       for (cert_email = CERT_GetFirstEmailAddress (cert);
+            cert_email && frd->certs_missing > 0;
+            cert_email = CERT_GetNextEmailAddress (cert, cert_email)) {
+               hash_value = g_hash_table_lookup (frd->recipients_table, cert_email);
+
+               if (hash_value && !*hash_value) {
+                       /* Cannot break now, because there can be multiple addresses for this certificate */
+                       *hash_value = CERT_DupCertificate (cert);
+                       frd->certs_missing--;
+               } else if (hash_value && !camel_smime_first_certificate_is_better (*hash_value, cert, 
frd->now)) {
+                       CERT_DestroyCertificate (*hash_value);
+                       *hash_value = CERT_DupCertificate (cert);
+               }
+       }
+
+       /* Is the sender referenced by nickname rather than its email address? */
+       if (cert->nickname) {
+               hash_value = g_hash_table_lookup (frd->recipients_table, cert->nickname);
+
+               if (hash_value && !*hash_value) {
+                       *hash_value = CERT_DupCertificate (cert);
+                       frd->certs_missing--;
+               } else if (hash_value && !camel_smime_first_certificate_is_better (*hash_value, cert, 
frd->now)) {
+                       CERT_DestroyCertificate (*hash_value);
+                       *hash_value = CERT_DupCertificate (cert);
+               }
+       }
+
+       return SECFailure;
+}
+
+static guint
+camel_smime_cert_hash (gconstpointer ptr)
+{
+       const CERTCertificate *cert = ptr;
+       guint hashval = 0, ii;
+
+       if (!cert)
+               return 0;
+
+       if (cert->serialNumber.len && cert->serialNumber.data) {
+               for (ii = 0; ii < cert->serialNumber.len; ii += 4) {
+                       guint num = cert->serialNumber.data[ii];
+
+                       if (ii + 1 < cert->serialNumber.len)
+                               num = num | (cert->serialNumber.data[ii + 1] << 8);
+                       if (ii + 2 < cert->serialNumber.len)
+                               num = num | (cert->serialNumber.data[ii + 2] << 16);
+                       if (ii + 3 < cert->serialNumber.len)
+                               num = num | (cert->serialNumber.data[ii + 3] << 24);
+
+                       hashval = hashval ^ num;
+               }
+       }
+
+       return hashval;
+}
+
+static gboolean
+camel_smime_cert_equal (gconstpointer ptr1,
+                       gconstpointer ptr2)
+{
+       const CERTCertificate *cert1 = ptr1, *cert2 = ptr2;
+
+       if (!cert1 || !cert2)
+               return cert1 == cert2;
+
+       if (cert1 == cert2)
+               return TRUE;
+
+       if (cert1->derCert.len != cert2->derCert.len ||
+           !cert1->derCert.data || !cert2->derCert.data) {
+               return FALSE;
+       }
+
+       return memcmp (cert1->derCert.data, cert2->derCert.data, cert1->derCert.len) == 0;
+}
+
 static gboolean
 smime_context_encrypt_sync (CamelCipherContext *context,
                             const gchar *userid,
@@ -1033,9 +1179,9 @@ smime_context_encrypt_sync (CamelCipherContext *context,
                             GCancellable *cancellable,
                             GError **error)
 {
-       CamelSMIMEContextPrivate *p = ((CamelSMIMEContext *) context)->priv;
        /*NSSCMSRecipientInfo **recipient_infos;*/
        CERTCertificate **recipient_certs = NULL;
+       FindRecipientsData frd;
        NSSCMSContentInfo *cinfo;
        PK11SymKey *bulkkey = NULL;
        SECOidTag bulkalgtag;
@@ -1065,17 +1211,64 @@ smime_context_encrypt_sync (CamelCipherContext *context,
                goto fail;
        }
 
+       frd.recipients_table = g_hash_table_new (camel_strcase_hash, camel_strcase_equal);
        for (i = 0; i < recipients->len; i++) {
-               recipient_certs[i] = CERT_FindCertByNicknameOrEmailAddr (p->certdb, recipients->pdata[i]);
-               if (recipient_certs[i] == NULL) {
-                       g_set_error (
-                               error, CAMEL_ERROR, CAMEL_ERROR_GENERIC,
-                               _("Cannot find certificate for “%s”"),
-                               (gchar *) recipients->pdata[i]);
-                       goto fail;
+               g_hash_table_insert (
+                               frd.recipients_table,
+                               recipients->pdata[i],
+                               &recipient_certs[i]);
+       }
+       frd.certs_missing = g_hash_table_size (frd.recipients_table);
+       frd.now = PR_Now();
+
+       /* Just ignore the return value */
+       (void) PK11_TraverseSlotCerts (camel_smime_find_recipients_certs, &frd, NULL);
+
+       if (frd.certs_missing) {
+               i = 0;
+               while (i < recipients->len) {
+                       CERTCertificate **hash_value = g_hash_table_lookup (frd.recipients_table, 
recipients->pdata[i]);
+                       if (!hash_value || !*hash_value) {
+                               g_set_error (
+                                       error, CAMEL_ERROR, CAMEL_ERROR_GENERIC,
+                                       _("No valid or appropriate certificate for '%s' was found"),
+                                       (gchar *) recipients->pdata[i]);
+                               g_hash_table_destroy (frd.recipients_table);
+                               goto fail;
+                       }
+                       i++;
+               }
+       } else {
+               /* Addresses and certificates can be duplicated, thus update the recipient_certs array */
+               GHashTable *final_certs;
+               GHashTableIter iter;
+               gpointer key;
+
+               final_certs = g_hash_table_new_full (camel_smime_cert_hash, camel_smime_cert_equal,
+                       (GDestroyNotify) CERT_DestroyCertificate, NULL);
+
+               for (i = 0; i < recipients->len; i++) {
+                       if (recipient_certs[i]) {
+                               /* Passes ownership to final_certs */
+                               g_hash_table_insert (final_certs, recipient_certs[i], NULL);
+                               recipient_certs[i] = NULL;
+                       }
+               }
+
+               i = 0;
+               g_hash_table_iter_init (&iter, final_certs);
+               while (g_hash_table_iter_next (&iter, &key, NULL)) {
+                       CERTCertificate *cert = key;
+
+                       recipient_certs[i] = CERT_DupCertificate (cert);
+                       i++;
                }
+
+               g_hash_table_destroy (final_certs);
        }
 
+       g_hash_table_destroy (frd.recipients_table);
+
        /* Find a common algorithm, probably 3DES anyway ... */
        if (NSS_SMIMEUtil_FindBulkAlgForRecipients (recipient_certs, &bulkalgtag, &bulkkeysize) != 
SECSuccess) {
                set_nss_error (error, _("Cannot find common bulk encryption algorithm"));
@@ -1167,8 +1360,10 @@ smime_context_encrypt_sync (CamelCipherContext *context,
 
        PK11_FreeSymKey (bulkkey);
        NSS_CMSMessage_Destroy (cmsg);
-       for (i = 0; recipient_certs[i]; i++)
-               CERT_DestroyCertificate (recipient_certs[i]);
+       for (i = 0; i < recipients->len; i++) {
+               if (recipient_certs[i])
+                       CERT_DestroyCertificate (recipient_certs[i]);
+       }
        PORT_FreeArena (poolp, PR_FALSE);
 
        dw = camel_data_wrapper_new ();
@@ -1202,8 +1397,10 @@ fail:
                PK11_FreeSymKey (bulkkey);
 
        if (recipient_certs) {
-               for (i = 0; recipient_certs[i]; i++)
-                       CERT_DestroyCertificate (recipient_certs[i]);
+               for (i = 0; i < recipients->len; i++) {
+                       if (recipient_certs[i])
+                               CERT_DestroyCertificate (recipient_certs[i]);
+               }
        }
 
        PORT_FreeArena (poolp, PR_FALSE);