diff options
Diffstat (limited to 'libpamc/pamc_converse.c')
| -rw-r--r-- | libpamc/pamc_converse.c | 211 |
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; +} |