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-rw-r--r--libpamc/pamc_converse.c211
1 files changed, 211 insertions, 0 deletions
diff --git a/libpamc/pamc_converse.c b/libpamc/pamc_converse.c
new file mode 100644
index 0000000..f8f60ed
--- /dev/null
+++ b/libpamc/pamc_converse.c
@@ -0,0 +1,211 @@
+/*
+ * $Id$
+ *
+ * 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;
+}