From ebda717383bf29731c3b4d7e809be7c7fae76284 Mon Sep 17 00:00:00 2001

From: Sumit Bose <sbose@redhat.com>

Date: Mon, 1 Dec 2014 17:24:31 +0100

Subject: [PATCH 124/128] ldap_child: copy keytab into memory to drop

 privileges earlier

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

---

 Makefile.am                     |  1 +

 src/providers/ldap/ldap_child.c | 64 +++++++++++++++++++++++++++++------------

 2 files changed, 46 insertions(+), 19 deletions(-)

diff --git a/Makefile.am b/Makefile.am

index 065992b84ce491b8b6ce1826cb5e88d7e0295176..3d16428856d6cb2e9e190b0df8895ab3f45db39c 100644

--- a/Makefile.am

+++ b/Makefile.am

@@ -2564,6 +2564,7 @@ krb5_child_LDADD = \

 ldap_child_SOURCES = \

     src/providers/ldap/ldap_child.c \

+    src/providers/krb5/krb5_keytab.c \

     src/util/sss_krb5.c \

     src/util/atomic_io.c \

     src/util/authtok.c \

diff --git a/src/providers/ldap/ldap_child.c b/src/providers/ldap/ldap_child.c

index a922b181715c5e89301e9f50bdb81723d1ff2a6a..f7f8d1d2eab3f66fe4f7d09e50458b495739c1d2 100644

--- a/src/providers/ldap/ldap_child.c

+++ b/src/providers/ldap/ldap_child.c

@@ -33,6 +33,7 @@

 #include "util/sss_krb5.h"

 #include "util/child_common.h"

 #include "providers/dp_backend.h"

+#include "providers/krb5/krb5_common.h"

 static krb5_context krb5_error_ctx;

 #define LDAP_CHILD_DEBUG(level, error) KRB5_DEBUG(level, krb5_error_ctx, error)

@@ -47,8 +48,9 @@ static const char *__ldap_child_krb5_error_msg;

 struct input_buffer {

     const char *realm_str;

     const char *princ_str;

-    const char *keytab_name;

+    char *keytab_name;

     krb5_deltat lifetime;

+    krb5_context context;

     uid_t uid;

     gid_t gid;

 };

@@ -246,12 +248,11 @@ static int lc_verify_keytab_ex(const char *principal,

 }

 static krb5_error_code ldap_child_get_tgt_sync(TALLOC_CTX *memctx,

+                                               krb5_context context,

                                                const char *realm_str,

                                                const char *princ_str,

                                                const char *keytab_name,

                                                const krb5_deltat lifetime,

-                                               uid_t uid,

-                                               gid_t gid,

                                                const char **ccname_out,

                                                time_t *expire_time_out)

 {

@@ -262,7 +263,6 @@ static krb5_error_code ldap_child_get_tgt_sync(TALLOC_CTX *memctx,

     char *full_princ = NULL;

     char *default_realm = NULL;

     char *tmp_str = NULL;

-    krb5_context context = NULL;

     krb5_keytab keytab = NULL;

     krb5_ccache ccache = NULL;

     krb5_principal kprinc;

@@ -278,13 +278,6 @@ static krb5_error_code ldap_child_get_tgt_sync(TALLOC_CTX *memctx,

     char *ccname_file;

     mode_t old_umask;

-    krberr = krb5_init_context(&context);

-    if (krberr) {

-        DEBUG(SSSDBG_OP_FAILURE, "Failed to init kerberos context\n");

-        return krberr;

-    }

-    DEBUG(SSSDBG_TRACE_INTERNAL, "Kerberos context initialized\n");

-

     tmp_ctx = talloc_new(memctx);

     if (tmp_ctx == NULL) {

         krberr = KRB5KRB_ERR_GENERIC;

@@ -440,12 +433,6 @@ static krb5_error_code ldap_child_get_tgt_sync(TALLOC_CTX *memctx,

     }

     DEBUG(SSSDBG_TRACE_INTERNAL, "credentials initialized\n");

-    krberr = become_user(uid, gid);

-    if (krberr != 0) {

-        DEBUG(SSSDBG_CRIT_FAILURE, "become_user failed.\n");

-        goto done;

-    }

-

     ccname_dummy = talloc_asprintf(tmp_ctx, "FILE:%s", ccname_file_dummy);

     ccname = talloc_asprintf(tmp_ctx, "FILE:%s", ccname_file);

     if (ccname_dummy == NULL || ccname == NULL) {

@@ -558,6 +545,30 @@ static int prepare_response(TALLOC_CTX *mem_ctx,

     return EOK;

 }

+static krb5_error_code privileged_krb5_setup(struct input_buffer *ibuf)

+{

+    krb5_error_code kerr;

+    char *keytab_name;

+

+    kerr = krb5_init_context(&ibuf->context);

+    if (kerr != 0) {

+        DEBUG(SSSDBG_CRIT_FAILURE, "Failed to init kerberos context\n");

+        return kerr;

+    }

+    DEBUG(SSSDBG_TRACE_INTERNAL, "Kerberos context initialized\n");

+

+    kerr = copy_keytab_into_memory(ibuf, ibuf->context, ibuf->keytab_name,

+                                   &keytab_name, NULL);

+    if (kerr != 0) {

+        DEBUG(SSSDBG_OP_FAILURE, "copy_keytab_into_memory failed.\n");

+        return kerr;

+    }

+    talloc_free(ibuf->keytab_name);

+    ibuf->keytab_name = keytab_name;

+

+    return 0;

+}

+

 int main(int argc, const char *argv[])

 {

     int ret;

@@ -662,11 +673,26 @@ int main(int argc, const char *argv[])

         goto fail;

     }

+    kerr = privileged_krb5_setup(ibuf);

+    if (kerr != EOK) {

+        DEBUG(SSSDBG_CRIT_FAILURE, "Privileged Krb5 setup failed.\n");

+        goto fail;

+    }

+    DEBUG(SSSDBG_TRACE_INTERNAL, "Kerberos context initialized\n");

+

+    kerr = become_user(ibuf->uid, ibuf->gid);

+    if (kerr != 0) {

+        DEBUG(SSSDBG_CRIT_FAILURE, "become_user failed.\n");

+        goto fail;

+    }

+

+    DEBUG(SSSDBG_TRACE_INTERNAL,

+          "Running as [%"SPRIuid"][%"SPRIgid"].\n", geteuid(), getegid());

+

     DEBUG(SSSDBG_TRACE_INTERNAL, "getting TGT sync\n");

-    kerr = ldap_child_get_tgt_sync(main_ctx,

+    kerr = ldap_child_get_tgt_sync(main_ctx, ibuf->context,

                                    ibuf->realm_str, ibuf->princ_str,

                                    ibuf->keytab_name, ibuf->lifetime,

-                                   ibuf->uid, ibuf->gid,

                                    &ccname, &expire_time);

     if (kerr != EOK) {

         DEBUG(SSSDBG_CRIT_FAILURE, "ldap_child_get_tgt_sync failed.\n");

-- 

1.9.3