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/*
* $Id$
*
* Copyright (c) Andrew G. Morgan <morgan@ftp.kernel.org>
*
* pamc_converse
*/
#include "libpamc.h"
/*
* select agent
*/
static int __pamc_select_agent(pamc_handle_t pch, char *agent_id)
{
pamc_agent_t *agent;
for (agent = pch->chain; agent; agent = agent->next) {
if (!strcmp(agent->id, agent_id)) {
pch->current = agent;
return PAM_BPC_TRUE;
}
}
D(("failed to locate agent"));
pch->current = NULL;
return PAM_BPC_FALSE;
}
/*
* pass a binary prompt to the active agent and wait for a reply prompt
*/
int pamc_converse(pamc_handle_t pch, pamc_bp_t *prompt_p)
{
uint32_t size, offset=0;
uint8_t control, raw[PAM_BP_MIN_SIZE];
D(("called"));
if (pch == NULL) {
D(("null pch"));
goto pamc_converse_failure;
}
if (prompt_p == NULL) {
D(("null prompt_p"));
goto pamc_converse_failure;
}
if (*prompt_p == NULL) {
D(("null *prompt_p"));
goto pamc_converse_failure;
}
/* from here on, failures are interoperability problems.. */
size = PAM_BP_SIZE(*prompt_p);
if (size < PAM_BP_MIN_SIZE) {
D(("problem with size being too short (%u)", size));
goto pamc_unknown_prompt;
}
if (PAM_BPC_FOR_CLIENT(*prompt_p) != PAM_BPC_TRUE) {
D(("*prompt_p is not legal for the client to use"));
goto pamc_unknown_prompt;
}
/* do we need to select the agent? */
if ((*prompt_p)->control == PAM_BPC_SELECT) {
char *rawh;
size_t i;
int retval;
D(("selecting a specified agent"));
rawh = (char *) *prompt_p;
for (i = PAM_BP_MIN_SIZE; i<size; ++i) {
if (rawh[i] == '/') {
break;
}
}
if ( (i >= size)
|| !__pamc_valid_agent_id(i-PAM_BP_MIN_SIZE,
rawh + PAM_BP_MIN_SIZE) ) {
goto pamc_unknown_prompt;
}
rawh[i] = '\0';
retval = pamc_load(pch, PAM_BP_MIN_SIZE + rawh);
if (retval == PAM_BPC_TRUE) {
retval = __pamc_select_agent(pch, PAM_BP_MIN_SIZE + rawh);
}
rawh[i] = '/';
if (retval != PAM_BPC_TRUE) {
goto pamc_unknown_prompt;
}
D(("agent is loaded"));
}
if (pch->current == NULL) {
D(("unable to address agent"));
goto pamc_unknown_prompt;
}
/* pump all of the prompt into the agent */
do {
int rval = write(pch->current->writer,
offset + (const uint8_t *) (*prompt_p),
size - offset);
if (rval == -1) {
switch (errno) {
case EINTR:
break;
default:
D(("problem writing to agent: %m"));
goto pamc_unknown_prompt;
}
} else {
offset += rval;
}
} while (offset < size);
D(("whole prompt sent to agent"));
/* read size and control for response prompt */
offset = 0;
memset(raw, 0, sizeof(raw));
do {
int rval;
rval = read(pch->current->reader, raw + offset,
PAM_BP_MIN_SIZE - offset);
if (rval == -1) {
switch (errno) {
case EINTR:
break;
default:
D(("problem reading from agent: %m"));
goto pamc_unknown_prompt;
}
} else if (rval) {
offset += rval;
} else {
D(("agent has closed its output pipe - nothing more to read"));
goto pamc_converse_failure;
}
} while (offset < PAM_BP_MIN_SIZE);
/* construct the whole reply prompt */
size = PAM_BP_SIZE(raw);
control = PAM_BP_RCONTROL(raw);
memset(raw, 0, sizeof(raw));
D(("agent replied with prompt of size %d and control %u",
size, control));
PAM_BP_RENEW(prompt_p, control, size - PAM_BP_MIN_SIZE);
if (*prompt_p == NULL) {
D(("problem making a new prompt for reply"));
goto pamc_unknown_prompt;
}
/* read the rest of the reply prompt -- note offset has the correct
value from the previous loop */
while (offset < size) {
int rval = read(pch->current->reader, offset + (uint8_t *) *prompt_p,
size-offset);
if (rval == -1) {
switch (errno) {
case EINTR:
break;
default:
D(("problem reading from agent: %m"));
goto pamc_unknown_prompt;
}
} else if (rval) {
offset += rval;
} else {
D(("problem reading prompt (%d) with %d to go",
size, size-offset));
goto pamc_converse_failure;
}
}
D(("returning success"));
return PAM_BPC_TRUE;
pamc_converse_failure:
D(("conversation failure"));
PAM_BP_RENEW(prompt_p, 0, 0);
return PAM_BPC_FALSE;
pamc_unknown_prompt:
/* the server is trying something that the client does not support */
D(("unknown prompt"));
PAM_BP_RENEW(prompt_p, PAM_BPC_FAIL, 0);
return PAM_BPC_TRUE;
}
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