klog.krb5: remove "save and reuse password" logic

In order to avoid repeated requests for the user's password, klog.krb5
caches and reuses it whenever necessary. However, with the introduction
of commit 3a9a5783cd1fd73902655f0876e2069b42688c94, klog.krb5 always
requests a TGT regardless of the state of writeTicketFile, eliminating
the need for possible extra requests for the user's password.

Moreover, krb5_get_init_creds_password() does not accept a custom
prompter on macOS (returns EINVAL). Consequently, if the -password
argument is omitted, klog.krb5 fails with the following error:

klog: Invalid argument Unable to authenticate in realm <REALM>

Given that the user won't be prompted for a password multiple times,
remove the "save and reuse password" logic and use krb5_prompter_posix()
as the prompter function (instead of klog_prompter).

Relevant issue identified by gangovind@in.ibm.com.

Change-Id: Ia994a18d1d166893f12ee78d3e6f25192ff327ee
Reviewed-on: https://gerrit.openafs.org/14643
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Ganesh G. Chaudhari <gangovind@in.ibm.com>
Tested-by: Ganesh G. Chaudhari <gangovind@in.ibm.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>

diff --git a/src/aklog/klog.c b/src/aklog/klog.c
index df4a062..e30175b 100644 (file)
--- a/src/aklog/klog.c
+++ b/src/aklog/klog.c
@@ -258,89 +258,6 @@ k5_to_k4_name(krb5_context k5context,
        }
 }
 
-#if defined(USING_HEIMDAL) || defined(HAVE_KRB5_PROMPT_TYPE)
-static int
-klog_is_pass_prompt(int index, krb5_context context, krb5_prompt prompts[])
-{
-    switch (prompts[index].type) {
-    case KRB5_PROMPT_TYPE_PASSWORD:
-    case KRB5_PROMPT_TYPE_NEW_PASSWORD_AGAIN:
-       return 1;
-    default:
-       return 0;
-    }
-}
-#elif defined(HAVE_KRB5_GET_PROMPT_TYPES)
-static int
-klog_is_pass_prompt(int index, krb5_context context, krb5_prompt prompts[])
-{
-    /* this isn't thread-safe or anything obviously; it just should be good
-     * enough to work with klog */
-    static krb5_prompt_type *types = NULL;
-    if (index == 0) {
-       types = NULL;
-    }
-    if (!types) {
-       types = krb5_get_prompt_types(context);
-    }
-    if (!types) {
-       return 0;
-    }
-    switch (types[index]) {
-    case KRB5_PROMPT_TYPE_PASSWORD:
-    case KRB5_PROMPT_TYPE_NEW_PASSWORD_AGAIN:
-       return 1;
-    default:
-       return 0;
-    }
-}
-#else
-static int
-klog_is_pass_prompt(int index, krb5_context context, krb5_prompt prompts[])
-{
-    /* AIX 5.3 doesn't have krb5_get_prompt_types. Neither does HP-UX, which
-     * also doesn't even define KRB5_PROMPT_TYPE_PASSWORD &co. We have no way
-     * of determining the the prompt type, so just assume it's a password */
-    return 1;
-}
-#endif
-
-/* save and reuse password.  This is necessary to make
- *  "direct to service" authentication work with most
- *  flavors of kerberos, when the afs principal has no instance.
- */
-struct kp_arg {
-    char **pp, *pstore;
-    size_t allocated;
-};
-krb5_error_code
-klog_prompter(krb5_context context,
-    void *a,
-    const char *name,
-    const char *banner,
-    int num_prompts,
-    krb5_prompt prompts[])
-{
-    krb5_error_code code;
-    int i;
-    struct kp_arg *kparg = (struct kp_arg *) a;
-    size_t length;
-
-    code = krb5_prompter_posix(context, a, name, banner, num_prompts, prompts);
-    if (code) return code;
-    for (i = 0; i < num_prompts; ++i) {
-       if (klog_is_pass_prompt(i, context, prompts)) {
-           length = prompts[i].reply->length;
-           if (length > kparg->allocated - 1)
-               length = kparg->allocated - 1;
-           memcpy(kparg->pstore, prompts[i].reply->data, length);
-           kparg->pstore[length] = 0;
-           *kparg->pp = kparg->pstore;
-       }
-    }
-    return 0;
-}
-
 static int
 CommandProc(struct cmd_syndesc *as, void *arock)
 {
@@ -362,10 +279,7 @@ CommandProc(struct cmd_syndesc *as, void *arock)
     int authtype;
 #endif
     krb5_data enc_part[1];
-    krb5_prompter_fct pf = NULL;
     char *pass = 0;
-    void *pa = 0;
-    struct kp_arg klog_arg[1];
 
     char passwd[BUFSIZ];
     struct afsconf_cell cellconfig[1];
@@ -382,7 +296,6 @@ CommandProc(struct cmd_syndesc *as, void *arock)
     for (i = 1; i < zero_argc; i++)
        memset(zero_argv[i], 0, strlen(zero_argv[i]));
     zero_argc = 0;
-    memset(klog_arg, 0, sizeof *klog_arg);
 
     /* first determine quiet flag based on -silent switch */
     Silent = (as->parms[aSILENT].items ? 1 : 0);
@@ -513,15 +426,10 @@ CommandProc(struct cmd_syndesc *as, void *arock)
        pass = passwd;
     }
 
-    /* Get the password if it wasn't provided. */
-    if (!pass) {
-       if (Pipe) {
-           strncpy(passwd, getpipepass(), sizeof(passwd));
-           pass = passwd;
-       } else {
-           pf = klog_prompter;
-           pa = klog_arg;
-       }
+    /* Get the password from stdin if it wasn't provided. */
+    if (!pass && Pipe) {
+       strncpy(passwd, getpipepass(), sizeof(passwd));
+       pass = passwd;
     }
 
     service = 0;
@@ -533,9 +441,6 @@ CommandProc(struct cmd_syndesc *as, void *arock)
 #endif
     snprintf (service_temp, sizeof service_temp, "afs/%s", cellconfig->name);
 
-    klog_arg->pp = &pass;
-    klog_arg->pstore = passwd;
-    klog_arg->allocated = sizeof(passwd);
     /* XXX should allow k5 to prompt in most cases -- what about expired pw?*/
 #ifdef HAVE_KRB5_GET_INIT_CREDS_OPT_ALLOC
     code = krb5_get_init_creds_opt_alloc(k5context, &gic_opts);
@@ -552,10 +457,10 @@ CommandProc(struct cmd_syndesc *as, void *arock)
            incred,
            princ,
            pass,
-           pf, /* prompter */
-           pa, /* data */
-           0,  /* start_time */
-           0,  /* in_tkt_service */
+           krb5_prompter_posix,        /* prompter */
+           NULL,                       /* data */
+           0,                          /* start_time */
+           0,                          /* in_tkt_service */
            gic_opts);
        if (code != KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN)
             break;