Re: dlopen failure

[Dimitri Priimak <priimak networking Stanford EDU>]

What do you mean by dlopen errors?
I added line 
printf("dlopen : %s\n", dlerror());
right after calling pam_authenticate(pamh, 0);
output is 'dlopen : (null)'
Do you want to see output of strace, everything looks fine there.

BTW, originally I used strdup() but removed it lately, may be
thoughtlessly, anyway this program never gave me segfault, while
I guess you are right that strdup() should be used, thus I put 
strdup back in a form '(char *)strdup("dummmy")', of course I get
the same result, as I described below.

On Sun, 10 Sep 2000, Andrew Morgan wrote:

> What are the dlopen errors?
> 
> BTW. I would expect this program to segfault. You need to strdup() your
> "dummy" and "dummypass" to avoid this. (The module will try to free()
> these conversation responses.)
> 
> Cheers
> 
> Andrew
> 
> Dimitri Priimak wrote:
> > 
> > Hi.
> > 
> > I am trying to authenicate my user using pam (,pam-0.72-20) on RedHat
> > 6.2 and I did many things but nothing works and get error message which
> > correspond to dlopen failure. So, below I wrote simple program which is
> > trying to authenicate user 'dummy' with pussword 'dummypass'.
> > Can somebody tell me what I am doing wrong?
> > 
> > /****
> >  * file pam_test.c
> >  ****/
> > #include <unistd.h>
> > #include <stdlib.h>
> > #include <stdio.h>
> > #include <security/pam_appl.h>
> > 
> > #define PAM_CHECK_ERROR if( pam_result != PAM_SUCCESS ){ \
> >     pam_end(pamh, 0); \
> >     exit(-1); \
> > }
> > 
> > static int pam_convf(int num_msg, const struct pam_message **msg,
> >       struct pam_response **resp, void *appdata_ptr);
> > 
> > static struct pam_conv pam_conversation =
> > {
> >  &pam_convf,
> >  NULL
> > };
> > 
> > int pam_result;
> > pam_handle_t *pamh;
> > 
> > int main(int argc, char *argv){
> >   /* init pam, using xlock service  */
> >   pam_result = pam_start("xlock", "priimak", &pam_conversation, &pamh);
> >   printf("pam_start : %s\n", pam_strerror(pamh, pam_result));
> >   PAM_CHECK_ERROR;
> >   pam_result = pam_set_item(pamh, PAM_USER, "dummy");
> >   printf("pam_set_item : %s\n", pam_strerror(pamh, pam_result));
> >   PAM_CHECK_ERROR;
> >   /* try to authenticate */
> >   pam_result = pam_authenticate(pamh, 0);
> >   printf("pam_authenticate : %s\n", pam_strerror(pamh, pam_result));
> >   PAM_CHECK_ERROR;
> > 
> >   pam_end(pamh, 0);
> >   exit(0);
> > }
> > 
> > static int pam_convf(int num_msg, const struct pam_message **msg,
> >                                         struct pam_response **resp, void
> > 
> > *appdata_ptr){
> >   struct pam_response *reply = NULL;
> >   int replies;
> > 
> >   reply = (struct pam_response *) malloc(sizeof (struct pam_response) *
> > num_msg);
> > 
> >   for( replies = 0; replies < num_msg; replies++ ){
> >     switch (msg[replies]->msg_style) {
> >     case PAM_PROMPT_ECHO_ON :
> >       printf("PAM_PROMPT_ECHO_ON\n");
> >       reply[replies].resp_retcode = PAM_SUCCESS;
> >       reply[replies].resp = "dummy";
> >       break;
> > 
> >     case PAM_PROMPT_ECHO_OFF :
> >       printf("PAM_PROMPT_ECHO_OFF\n");
> >       reply[replies].resp_retcode = PAM_SUCCESS;
> >       reply[replies].resp = "dummypass";
> >       break;
> > 
> >     case PAM_TEXT_INFO :
> >       printf("PAM_TEXT_INFO\n");
> >       reply[replies].resp_retcode = PAM_SUCCESS;
> >       reply[replies].resp = NULL;
> >       break;
> > 
> >     case PAM_ERROR_MSG :
> >       printf("PAM_ERROR_MSG\n");
> >       reply[replies].resp_retcode = PAM_SUCCESS;
> >       reply[replies].resp = NULL;
> >       break;
> > 
> >     default:
> >       (void) free((void *) reply);
> >       return PAM_CONV_ERR;
> > 
> >     }
> >   }
> > }
> > 
> > *********
> > I compile it like this
> > % gcc -lc -lpam -ldl pam_test.c -o pam_tes
> > 
> > Fianally when I run it I get following output:
> > % ./pam_test
> > pam_start : Success
> > PAM_PROMPT_ECHO_OFF
> > pam_authenticate : dlopen() failure
> > %
> > 
> > When I look into /var/log/message I see
> > % cat /var/log/messages | grep -i pam
> > ...
> > Sep  9 23:07:48 kez PAM_pwdb[5843]: auth could not identify password for
> > [dummy]
> > 
> > Note that I am using 'xlock' service and here it is
> > % cat /etc/pam.d/xlock
> > #%PAM-1.0
> > auth       required     /lib/security/pam_pwdb.so shadow nullok
> > %
> > 
> > I do have this file /lib/security/pam_pwdb.so and I checkd with strace
> > it actally opens it
> > as well as other libs. I also run xlock with strace and so that xlock
> > using service 'xlock'
> > Any ideas what is wrong?
> > 
> > Thanks in advance.
> > Dmitri Priimak.
> > 
> > _______________________________________________
> > Pam-list mailing list
> > Pam-list@redhat.com
> > https://listman.redhat.com/mailman/listinfo/pam-list
> 
> 
> 
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