Add NSS version of p11_child

Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>

3 files changed, 661 insertions, 1 deletions

diff --git a/Makefile.am b/Makefile.am
index 277166ec6..e4add9757 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -148,7 +148,9 @@ endif
 if BUILD_SEMANAGE
 sssdlibexec_PROGRAMS += selinux_child
 endif
-
+if HAVE_NSS
+sssdlibexec_PROGRAMS += p11_child
+endif
 
 if BUILD_PAC_RESPONDER
     sssdlibexec_PROGRAMS += sssd_pac
@@ -3146,6 +3148,23 @@ proxy_child_LDADD = \
     $(SSSD_LIBS) \
     $(SSSD_INTERNAL_LTLIBS)
 
+p11_child_SOURCES = \
+    src/p11_child/p11_child_nss.c \
+    src/util/atomic_io.c \
+    $(NULL)
+p11_child_CFLAGS = \
+    $(AM_CFLAGS) \
+    $(POPT_CFLAGS) \
+    $(NSS_CFLAGS) \
+    $(NULL)
+p11_child_LDADD = \
+    libsss_debug.la \
+    $(TALLOC_LIBS) \
+    $(POPT_LIBS) \
+    $(NSS_LIBS) \
+    libsss_crypt.la \
+    $(NULL)
+
 memberof_la_SOURCES = \
     src/ldb_modules/memberof.c \
     src/util/util.c
@@ -3541,6 +3560,10 @@ if BUILD_SEMANAGE
 	-chgrp $(SSSD_USER) $(DESTDIR)$(sssdlibexecdir)/selinux_child
 	chmod 4750 $(DESTDIR)$(sssdlibexecdir)/selinux_child
 endif
+if HAVE_NSS
+	-chgrp $(SSSD_USER) $(DESTDIR)$(sssdlibexecdir)/p11_child
+	chmod 4750 $(DESTDIR)$(sssdlibexecdir)/p11_child
+endif
 endif
 
 install-data-hook:
diff --git a/contrib/sssd.spec.in b/contrib/sssd.spec.in
index 128153419..0606e5e4f 100644
--- a/contrib/sssd.spec.in
+++ b/contrib/sssd.spec.in
@@ -681,6 +681,7 @@ rm -rf $RPM_BUILD_ROOT
 %{_libexecdir}/%{servicename}/sssd_autofs
 %{_libexecdir}/%{servicename}/sssd_ssh
 %{_libexecdir}/%{servicename}/sssd_sudo
+%attr(4750,root,sssd) %{_libexecdir}/%{servicename}/p11_child
 
 %dir %{_libdir}/%{name}
 %{_libdir}/%{name}/libsss_simple.so
diff --git a/src/p11_child/p11_child_nss.c b/src/p11_child/p11_child_nss.c
new file mode 100644
index 000000000..6948c142a
--- /dev/null
+++ b/src/p11_child/p11_child_nss.c
@@ -0,0 +1,636 @@
+/*
+    SSSD
+
+    Helper child to commmunicate with SmartCard via NSS
+
+    Authors:
+        Sumit Bose <sbose@redhat.com>
+
+    Copyright (C) 2015 Red Hat
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <popt.h>
+
+#include "util/util.h"
+
+#include <nss.h>
+#include <base64.h>
+#include <cryptohi.h>
+#include <secmod.h>
+#include <cert.h>
+#include <keyhi.h>
+#include <pk11pub.h>
+#include <prerror.h>
+
+#include "util/child_common.h"
+#include "providers/dp_backend.h"
+#include "util/crypto/sss_crypto.h"
+
+enum op_mode {
+    OP_NONE,
+    OP_AUTH,
+    OP_PREAUTH
+};
+
+enum pin_mode {
+    PIN_NONE,
+    PIN_STDIN,
+    PIN_KEYPAD
+};
+
+static char *password_passthrough(PK11SlotInfo *slot, PRBool retry, void *arg)
+{
+  /* give up if 1) no password was supplied, or 2) the password has already
+   * been rejected once by this token. */
+  if (retry || (arg == NULL)) {
+    return NULL;
+  }
+  return PL_strdup((char *)arg);
+}
+
+
+
+int do_work(TALLOC_CTX *mem_ctx, const char *nss_db, const char *slot_name_in,
+            enum op_mode mode, const char *pin, char **cert,
+            char **token_name_out)
+{
+    int ret;
+    SECStatus rv;
+    NSSInitContext *nss_ctx;
+    SECMODModuleList *mod_list;
+    SECMODModuleList *mod_list_item;
+    const char *slot_name;
+    const char *token_name;
+    uint32_t flags = NSS_INIT_READONLY
+                                   | NSS_INIT_FORCEOPEN
+                                   | NSS_INIT_NOROOTINIT
+                                   | NSS_INIT_OPTIMIZESPACE
+                                   | NSS_INIT_PK11RELOAD;
+    NSSInitParameters parameters = { 0 };
+    parameters.length =  sizeof (parameters);
+    PK11SlotInfo *slot = NULL;
+    CK_SLOT_ID slot_id;
+    SECMODModuleID module_id;
+    CERTCertList *cert_list = NULL;
+    CERTCertListNode *cert_list_node;
+    const PK11DefaultArrayEntry friendly_attr = { "Publicly-readable certs",
+                                                  SECMOD_FRIENDLY_FLAG,
+                                                  CKM_INVALID_MECHANISM };
+    CERTCertDBHandle *handle;
+    unsigned char random_value[128];
+    SECKEYPrivateKey *priv_key;
+    SECOidTag algtag;
+    SECItem signed_random_value = {0};
+    SECKEYPublicKey *pub_key;
+    CERTCertificate *found_cert = NULL;
+    PK11SlotList *list = NULL;
+    PK11SlotListElement *le;
+
+
+    nss_ctx = NSS_InitContext(nss_db, "", "", SECMOD_DB, &parameters, flags);
+    if (nss_ctx == NULL) {
+        DEBUG(SSSDBG_OP_FAILURE, "NSS_InitContext failed [%d].\n",
+                                 PR_GetError());
+        return EIO;
+    }
+
+    PK11_SetPasswordFunc(password_passthrough);
+
+    DEBUG(SSSDBG_TRACE_ALL, "Default Module List:\n");
+    mod_list = SECMOD_GetDefaultModuleList();
+    for (mod_list_item = mod_list; mod_list_item != NULL;
+                                   mod_list_item = mod_list_item->next) {
+        DEBUG(SSSDBG_TRACE_ALL, "common name: [%s].\n",
+                                mod_list_item->module->commonName);
+        DEBUG(SSSDBG_TRACE_ALL, "dll name: [%s].\n",
+                                mod_list_item->module->dllName);
+    }
+
+    DEBUG(SSSDBG_TRACE_ALL, "Dead Module List:\n");
+    mod_list = SECMOD_GetDeadModuleList();
+    for (mod_list_item = mod_list; mod_list_item != NULL;
+                                   mod_list_item = mod_list_item->next) {
+        DEBUG(SSSDBG_TRACE_ALL, "common name: [%s].\n",
+                                mod_list_item->module->commonName);
+        DEBUG(SSSDBG_TRACE_ALL, "dll name: [%s].\n",
+                                mod_list_item->module->dllName);
+    }
+
+    DEBUG(SSSDBG_TRACE_ALL, "DB Module List:\n");
+    mod_list = SECMOD_GetDBModuleList();
+    for (mod_list_item = mod_list; mod_list_item != NULL;
+                                   mod_list_item = mod_list_item->next) {
+        DEBUG(SSSDBG_TRACE_ALL, "common name: [%s].\n",
+                                mod_list_item->module->commonName);
+        DEBUG(SSSDBG_TRACE_ALL, "dll name: [%s].\n",
+                                mod_list_item->module->dllName);
+    }
+
+    if (slot_name_in != NULL) {
+        slot = PK11_FindSlotByName(slot_name_in);
+        if (slot == NULL) {
+            DEBUG(SSSDBG_OP_FAILURE, "PK11_FindSlotByName failed for [%s]: [%d].\n",
+                                     slot_name_in, PR_GetError());
+            return EIO;
+        }
+    } else {
+
+        list = PK11_GetAllTokens(CKM_INVALID_MECHANISM, PR_FALSE, PR_TRUE,
+                                 NULL);
+        if (list == NULL) {
+            DEBUG(SSSDBG_OP_FAILURE, "PK11_GetAllTokens failed.\n");
+            return EIO;
+        }
+
+        for (le = list->head; le; le = le->next) {
+            CK_SLOT_INFO slInfo;
+
+            slInfo.flags = 0;
+            rv = PK11_GetSlotInfo(le->slot, &slInfo);
+            DEBUG(SSSDBG_TRACE_ALL,
+                  "Description [%s] Manufacturer [%s] flags [%lu].\n",
+                  slInfo.slotDescription, slInfo.manufacturerID, slInfo.flags);
+            if (rv == SECSuccess && (slInfo.flags & CKF_REMOVABLE_DEVICE)) {
+                slot = PK11_ReferenceSlot(le->slot);
+                break;
+           }
+        }
+        PK11_FreeSlotList(list);
+        if (slot == NULL) {
+            DEBUG(SSSDBG_OP_FAILURE, "No removable slots found.\n");
+            return EIO;
+        }
+    }
+
+
+    slot_id = PK11_GetSlotID(slot);
+    module_id = PK11_GetModuleID(slot);
+    slot_name = PK11_GetSlotName(slot);
+    token_name = PK11_GetTokenName(slot);
+    DEBUG(SSSDBG_TRACE_ALL, "Found [%s] in slot [%s][%d] of module [%d].\n",
+          token_name, slot_name, (int) slot_id, (int) module_id);
+
+    if (PK11_IsFriendly(slot)) {
+        DEBUG(SSSDBG_TRACE_ALL, "Token is friendly.\n");
+    } else {
+        DEBUG(SSSDBG_TRACE_ALL,
+              "Token is NOT friendly.\n");
+        if (mode == OP_PREAUTH) {
+            DEBUG(SSSDBG_TRACE_ALL, "Trying to switch to friendly to read certificate.\n");
+            rv = PK11_UpdateSlotAttribute(slot, &friendly_attr, PR_TRUE);
+            if (rv != SECSuccess) {
+                DEBUG(SSSDBG_OP_FAILURE,
+                      "PK11_UpdateSlotAttribute failed, continue.\n");
+            }
+        }
+    }
+
+    /* TODO: check  PK11_ProtectedAuthenticationPath() and return the result */
+    if (mode == OP_AUTH || PK11_NeedLogin(slot)) {
+        DEBUG(SSSDBG_TRACE_ALL, "Login required.\n");
+        if (pin != NULL) {
+            rv = PK11_Authenticate(slot, PR_FALSE, discard_const(pin));
+            if (rv !=  SECSuccess) {
+                DEBUG(SSSDBG_OP_FAILURE, "PK11_Authenticate failed: [%d].\n",
+                                         PR_GetError());
+                return EIO;
+            }
+        } else {
+            DEBUG(SSSDBG_CRIT_FAILURE,
+                  "Login required but no pin available, continue.\n");
+        }
+    } else {
+        DEBUG(SSSDBG_TRACE_ALL, "Login NOT required.\n");
+    }
+
+    cert_list = PK11_ListCertsInSlot(slot);
+    if (cert_list == NULL) {
+        DEBUG(SSSDBG_OP_FAILURE, "PK11_ListCertsInSlot failed: [%d].\n",
+                                 PR_GetError());
+        return EIO;
+    }
+
+    for (cert_list_node = CERT_LIST_HEAD(cert_list);
+                !CERT_LIST_END(cert_list_node, cert_list);
+                cert_list_node = CERT_LIST_NEXT(cert_list_node)) {
+        if (cert_list_node->cert) {
+            DEBUG(SSSDBG_TRACE_ALL, "found cert[%s][%s]\n",
+                             cert_list_node->cert->nickname,
+                             cert_list_node->cert->subjectName);
+        } else {
+            DEBUG(SSSDBG_TRACE_ALL, "--- empty cert list node ---\n");
+        }
+    }
+
+    rv = CERT_FilterCertListByUsage(cert_list, certUsageSSLClient, PR_FALSE);
+    if (rv != SECSuccess) {
+        DEBUG(SSSDBG_OP_FAILURE, "CERT_FilterCertListByUsage failed: [%d].\n",
+                                 PR_GetError());
+        return EIO;
+    }
+
+    rv = CERT_FilterCertListForUserCerts(cert_list);
+    if (rv != SECSuccess) {
+        DEBUG(SSSDBG_OP_FAILURE, "CERT_FilterCertListForUserCerts failed: [%d].\n",
+                                 PR_GetError());
+        return EIO;
+    }
+
+
+    handle = CERT_GetDefaultCertDB();
+    if (handle == NULL) {
+        DEBUG(SSSDBG_OP_FAILURE, "CERT_GetDefaultCertDB failed: [%d].\n",
+                                 PR_GetError());
+        return EIO;
+    }
+
+
+    found_cert = NULL;
+    DEBUG(SSSDBG_TRACE_ALL, "Filtered certificates:\n");
+    for (cert_list_node = CERT_LIST_HEAD(cert_list);
+                !CERT_LIST_END(cert_list_node, cert_list);
+                cert_list_node = CERT_LIST_NEXT(cert_list_node)) {
+        if (cert_list_node->cert) {
+            DEBUG(SSSDBG_TRACE_ALL, "found cert[%s][%s]\n",
+                             cert_list_node->cert->nickname,
+                             cert_list_node->cert->subjectName);
+
+            if (found_cert == NULL) {
+                found_cert = cert_list_node->cert;
+            } else {
+                DEBUG(SSSDBG_TRACE_ALL, "More than one certificate found, " \
+                                        "using just the first one.\n");
+            }
+        } else {
+            DEBUG(SSSDBG_TRACE_ALL, "--- empty cert list node ---\n");
+        }
+    }
+
+    if (found_cert == NULL) {
+        DEBUG(SSSDBG_TRACE_ALL, "No certificate found.\n");
+        *cert = NULL;
+        *token_name_out = NULL;
+        ret = EOK;
+        goto done;
+    }
+
+    rv = CERT_VerifyCertificateNow(handle, found_cert, PR_TRUE,
+                                   certificateUsageSSLClient, NULL, NULL);
+    if (rv != SECSuccess) {
+        DEBUG(SSSDBG_OP_FAILURE,
+              "CERT_VerifyCertificateNow failed [%d].\n",
+              PR_GetError());
+        ret = EIO;
+        goto done;
+    }
+
+    if (mode == OP_AUTH) {
+        rv = PK11_GenerateRandom(random_value, sizeof(random_value));
+        if (rv != SECSuccess) {
+            DEBUG(SSSDBG_OP_FAILURE,
+                  "PK11_GenerateRandom failed [%d].\n", PR_GetError());
+            return EIO;
+        }
+
+        priv_key = PK11_FindPrivateKeyFromCert(slot, found_cert, NULL);
+        if (priv_key == NULL) {
+            DEBUG(SSSDBG_OP_FAILURE,
+                  "PK11_FindPrivateKeyFromCert failed [%d]." \
+                  "Maybe pin is missing.\n", PR_GetError());
+            ret = EIO;
+            goto done;
+        }
+
+        algtag = SEC_GetSignatureAlgorithmOidTag(priv_key->keyType,
+                                                  SEC_OID_SHA1);
+        if (algtag == SEC_OID_UNKNOWN) {
+            SECKEY_DestroyPrivateKey(priv_key);
+            DEBUG(SSSDBG_OP_FAILURE,
+                  "SEC_GetSignatureAlgorithmOidTag failed [%d].",
+                  PR_GetError());
+            ret = EIO;
+            goto done;
+        }
+
+        rv = SEC_SignData(&signed_random_value,
+                          random_value, sizeof(random_value),
+                          priv_key, algtag);
+        SECKEY_DestroyPrivateKey(priv_key);
+        if (rv != SECSuccess) {
+            DEBUG(SSSDBG_OP_FAILURE, "SEC_SignData failed [%d].",
+                                     PR_GetError());
+            ret = EIO;
+            goto done;
+        }
+
+        pub_key = CERT_ExtractPublicKey(found_cert);
+        if (pub_key == NULL) {
+            DEBUG(SSSDBG_OP_FAILURE,
+                  "CERT_ExtractPublicKey failed [%d].", PR_GetError());
+            ret = EIO;
+            goto done;
+        }
+
+        rv = VFY_VerifyData(random_value, sizeof(random_value),
+                            pub_key, &signed_random_value, algtag,
+                            NULL);
+        SECKEY_DestroyPublicKey(pub_key);
+        if (rv != SECSuccess) {
+            DEBUG(SSSDBG_OP_FAILURE, "VFY_VerifyData failed [%d].",
+                                     PR_GetError());
+            ret = EACCES;
+            goto done;
+        }
+
+        DEBUG(SSSDBG_TRACE_ALL,
+              "Certificate verified and validated.\n");
+    }
+
+    *cert = sss_base64_encode(mem_ctx, found_cert->derCert.data,
+                                       found_cert->derCert.len);
+    if (*cert == NULL) {
+        DEBUG(SSSDBG_OP_FAILURE, "sss_base64_encode failed.\n");
+        ret = ENOMEM;
+        goto done;
+    }
+
+    *token_name_out = talloc_strdup(mem_ctx, token_name);
+    if (*token_name_out == NULL) {
+        DEBUG(SSSDBG_CRIT_FAILURE, "Failed to copy slot name.\n");
+        ret = ENOMEM;
+        goto done;
+    }
+
+    ret = EOK;
+
+done:
+    if (slot != NULL) {
+        PK11_FreeSlot(slot);
+    }
+
+    if (cert_list != NULL) {
+        CERT_DestroyCertList(cert_list);
+    }
+
+    PORT_Free(signed_random_value.data);
+
+    rv = NSS_ShutdownContext(nss_ctx);
+    if (rv != SECSuccess) {
+        DEBUG(SSSDBG_OP_FAILURE, "NSS_ShutdownContext failed [%d].\n",
+                                 PR_GetError());
+    }
+
+    return ret;
+}
+
+static errno_t p11c_recv_data(TALLOC_CTX *mem_ctx, int fd, char **pin)
+{
+    uint8_t buf[IN_BUF_SIZE];
+    ssize_t len;
+    errno_t ret;
+    char *str;
+
+    errno = 0;
+    len = sss_atomic_read_s(fd, buf, IN_BUF_SIZE);
+    if (len == -1) {
+        ret = errno;
+        ret = (ret == 0) ? EINVAL: ret;
+        DEBUG(SSSDBG_CRIT_FAILURE,
+              "read failed [%d][%s].\n", ret, strerror(ret));
+        return ret;
+    }
+
+    if (len == 0 || *buf == '\0') {
+        DEBUG(SSSDBG_CRIT_FAILURE, "Missing PIN.\n");
+        return EINVAL;
+    }
+
+    str = talloc_strndup(mem_ctx, (char *) buf, len);
+    if (str == NULL) {
+        DEBUG(SSSDBG_OP_FAILURE, "talloc_strndup failed.\n");
+        return ENOMEM;
+    }
+
+    if (strlen(str) != len) {
+        DEBUG(SSSDBG_CRIT_FAILURE,
+              "Input contains additional data, only PIN expected.\n");
+        talloc_free(str);
+        return EINVAL;
+    }
+
+    *pin = str;
+
+    return EOK;
+}
+
+int main(int argc, const char *argv[])
+{
+    int opt;
+    poptContext pc;
+    int debug_fd = -1;
+    errno_t ret;
+    TALLOC_CTX *main_ctx = NULL;
+    char *cert;
+    enum op_mode mode = OP_NONE;
+    enum pin_mode pin_mode = PIN_NONE;
+    char *pin = NULL;
+    char *slot_name_in = NULL;
+    char *token_name_out = NULL;
+    char *nss_db = NULL;
+
+    struct poptOption long_options[] = {
+        POPT_AUTOHELP
+        {"debug-level", 'd', POPT_ARG_INT, &debug_level, 0,
+         _("Debug level"), NULL},
+        {"debug-timestamps", 0, POPT_ARG_INT, &debug_timestamps, 0,
+         _("Add debug timestamps"), NULL},
+        {"debug-microseconds", 0, POPT_ARG_INT, &debug_microseconds, 0,
+         _("Show timestamps with microseconds"), NULL},
+        {"debug-fd", 0, POPT_ARG_INT, &debug_fd, 0,
+         _("An open file descriptor for the debug logs"), NULL},
+        {"debug-to-stderr", 0, POPT_ARG_NONE | POPT_ARGFLAG_DOC_HIDDEN,
+         &debug_to_stderr, 0,
+         _("Send the debug output to stderr directly."), NULL },
+        {"auth", 0, POPT_ARG_NONE, NULL, 'a', _("Run in auth mode"), NULL},
+        {"pre", 0, POPT_ARG_NONE, NULL, 'p', _("Run in pre-auth mode"), NULL},
+        {"pin", 0, POPT_ARG_NONE, NULL, 'i', _("Expect PIN on stdin"), NULL},
+        {"keypad", 0, POPT_ARG_NONE, NULL, 'k', _("Expect PIN on keypad"),
+         NULL},
+        {"nssdb", 0, POPT_ARG_STRING, &nss_db, 0, _("NSS DB to use"),
+         NULL},
+        POPT_TABLEEND
+    };
+
+    /* Set debug level to invalid value so we can decide if -d 0 was used. */
+    debug_level = SSSDBG_INVALID;
+
+    pc = poptGetContext(argv[0], argc, argv, long_options, 0);
+    while ((opt = poptGetNextOpt(pc)) != -1) {
+        switch(opt) {
+        case 'a':
+            if (mode != OP_NONE) {
+                fprintf(stderr,
+                        "\n--auth and --pre are mutually exclusive and " \
+                        "should be only used once.\n\n");
+                poptPrintUsage(pc, stderr, 0);
+                _exit(-1);
+            }
+            mode = OP_AUTH;
+            break;
+        case 'p':
+            if (mode != OP_NONE) {
+                fprintf(stderr,
+                        "\n--auth and --pre are mutually exclusive and " \
+                        "should be only used once.\n\n");
+                poptPrintUsage(pc, stderr, 0);
+                _exit(-1);
+            }
+            mode = OP_PREAUTH;
+            break;
+        case 'i':
+            if (pin_mode != PIN_NONE) {
+                fprintf(stderr, "\n--pin and --keypad are mutually exclusive " \
+                                "and should be only used once.\n\n");
+                poptPrintUsage(pc, stderr, 0);
+                _exit(-1);
+            }
+            pin_mode = PIN_STDIN;
+            break;
+        case 'k':
+            if (pin_mode != PIN_NONE) {
+                fprintf(stderr, "\n--pin and --keypad are mutually exclusive " \
+                                "and should be only used once.\n\n");
+                poptPrintUsage(pc, stderr, 0);
+                _exit(-1);
+            }
+            pin_mode = PIN_KEYPAD;
+            break;
+        default:
+            fprintf(stderr, "\nInvalid option %s: %s\n\n",
+                  poptBadOption(pc, 0), poptStrerror(opt));
+            poptPrintUsage(pc, stderr, 0);
+            _exit(-1);
+        }
+    }
+
+    if (nss_db == NULL) {
+        fprintf(stderr, "\nMissing NSS DB --nssdb must be specified.\n\n");
+        poptPrintUsage(pc, stderr, 0);
+        _exit(-1);
+    }
+
+    if (mode == OP_NONE) {
+        fprintf(stderr, "\nMissing operation mode, " \
+                        "either --auth or --pre must be specified.\n\n");
+        poptPrintUsage(pc, stderr, 0);
+        _exit(-1);
+    } else if (mode == OP_AUTH && pin_mode == PIN_NONE) {
+        fprintf(stderr, "\nMissing pin mode for authentication, " \
+                        "either --pin or --keypad must be specified.\n");
+        poptPrintUsage(pc, stderr, 0);
+        _exit(-1);
+    }
+
+    poptFreeContext(pc);
+
+    DEBUG_INIT(debug_level);
+
+    debug_prg_name = talloc_asprintf(NULL, "[sssd[p11_child[%d]]]", getpid());
+    if (debug_prg_name == NULL) {
+        DEBUG(SSSDBG_CRIT_FAILURE, "talloc_asprintf failed.\n");
+        goto fail;
+    }
+
+    if (debug_fd != -1) {
+        ret = set_debug_file_from_fd(debug_fd);
+        if (ret != EOK) {
+            DEBUG(SSSDBG_CRIT_FAILURE, "set_debug_file_from_fd failed.\n");
+        }
+    }
+
+    DEBUG(SSSDBG_TRACE_FUNC, "p11_child started.\n");
+
+    DEBUG(SSSDBG_TRACE_INTERNAL, "Running in [%s] mode.\n",
+          mode == OP_AUTH ? "auth"
+                          : (mode == OP_PREAUTH ? "pre-auth" : "unknown"));
+
+    DEBUG(SSSDBG_TRACE_INTERNAL,
+          "Running with effective IDs: [%"SPRIuid"][%"SPRIgid"].\n",
+          geteuid(), getegid());
+
+    if (getuid() != 0) {
+        ret = setuid(0);
+        if (ret == -1) {
+            ret = errno;
+            DEBUG(SSSDBG_CRIT_FAILURE,
+                  "setuid failed: %d, p11_child might not work!\n", ret);
+        }
+    }
+
+    if (getgid() != 0) {
+        ret = setgid(0);
+        if (ret == -1) {
+            ret = errno;
+            DEBUG(SSSDBG_CRIT_FAILURE,
+                  "setgid failed: %d, p11_child might not work!\n", ret);
+        }
+    }
+
+    DEBUG(SSSDBG_TRACE_INTERNAL,
+          "Running with real IDs [%"SPRIuid"][%"SPRIgid"].\n",
+          getuid(), getgid());
+
+    main_ctx = talloc_new(NULL);
+    if (main_ctx == NULL) {
+        DEBUG(SSSDBG_CRIT_FAILURE, "talloc_new failed.\n");
+        talloc_free(discard_const(debug_prg_name));
+        goto fail;
+    }
+    talloc_steal(main_ctx, debug_prg_name);
+
+
+    if (mode == OP_AUTH && pin_mode == PIN_STDIN) {
+        ret = p11c_recv_data(main_ctx, STDIN_FILENO, &pin);
+        if (ret != EOK) {
+            DEBUG(SSSDBG_FATAL_FAILURE, "Failed to read pin.\n");
+            goto fail;
+        }
+    }
+
+    ret = do_work(main_ctx, nss_db, slot_name_in, mode, pin, &cert,
+                  &token_name_out);
+    if (ret != EOK) {
+        DEBUG(SSSDBG_OP_FAILURE, "do_work failed.\n");
+        goto fail;
+    }
+
+    if (cert != NULL) {
+        fprintf(stdout, "%s\n", token_name_out);
+        fprintf(stdout, "%s\n", cert);
+    }
+
+    talloc_free(main_ctx);
+    return EXIT_SUCCESS;
+fail:
+    DEBUG(SSSDBG_CRIT_FAILURE, "p11_child failed!\n");
+    close(STDOUT_FILENO);
+    talloc_free(main_ctx);
+    return EXIT_FAILURE;
+}