diff options
Diffstat (limited to 'dirmngr/ldap-wrapper.c')
| -rw-r--r-- | dirmngr/ldap-wrapper.c | 788 |
1 files changed, 788 insertions, 0 deletions
diff --git a/dirmngr/ldap-wrapper.c b/dirmngr/ldap-wrapper.c new file mode 100644 index 0000000..f2aaf59 --- /dev/null +++ b/dirmngr/ldap-wrapper.c @@ -0,0 +1,788 @@ +/* ldap-wrapper.c - LDAP access via a wrapper process + * Copyright (C) 2004, 2005, 2007, 2008 g10 Code GmbH + * Copyright (C) 2010 Free Software Foundation, Inc. + * + * This file is part of GnuPG. + * + * GnuPG is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 3 of the License, or + * (at your option) any later version. + * + * GnuPG is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <http://www.gnu.org/licenses/>. + */ + +/* + We can't use LDAP directly for these reasons: + + 1. On some systems the LDAP library uses (indirectly) pthreads and + that is not compatible with PTh. + + 2. It is huge library in particular if TLS comes into play. So + problems with unfreed memory might turn up and we don't want + this in a long running daemon. + + 3. There is no easy way for timeouts. In particular the timeout + value does not work for DNS lookups (well, this is usual) and it + seems not to work while loading a large attribute like a + CRL. Having a separate process allows us to either tell the + process to commit suicide or have our own housekepping function + kill it after some time. The latter also allows proper + cancellation of a query at any point of time. + + 4. Given that we are going out to the network and usually get back + a long response, the fork/exec overhead is acceptable. + + Note that under WindowsCE the number of processes is strongly + limited (32 processes including the kernel processes) and thus we + don't use the process approach but implement a different wrapper in + ldap-wrapper-ce.c. +*/ + + +#include <config.h> + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> +#include <unistd.h> +#include <fcntl.h> +#include <time.h> +#include <npth.h> + +#include "dirmngr.h" +#include "exechelp.h" +#include "misc.h" +#include "ldap-wrapper.h" + + +#ifdef HAVE_W32_SYSTEM +#define setenv(a,b,c) SetEnvironmentVariable ((a),(b)) +#else +#define pth_close(fd) close(fd) +#endif + +#ifndef USE_LDAPWRAPPER +# error This module is not expected to be build. +#endif + +/* In case sysconf does not return a value we need to have a limit. */ +#ifdef _POSIX_OPEN_MAX +#define MAX_OPEN_FDS _POSIX_OPEN_MAX +#else +#define MAX_OPEN_FDS 20 +#endif + +#define INACTIVITY_TIMEOUT (opt.ldaptimeout + 60*5) /* seconds */ + +#define TIMERTICK_INTERVAL 2 + +/* To keep track of the LDAP wrapper state we use this structure. */ +struct wrapper_context_s +{ + struct wrapper_context_s *next; + + pid_t pid; /* The pid of the wrapper process. */ + int printable_pid; /* Helper to print diagnostics after the process has + been cleaned up. */ + int fd; /* Connected with stdout of the ldap wrapper. */ + gpg_error_t fd_error; /* Set to the gpg_error of the last read error + if any. */ + int log_fd; /* Connected with stderr of the ldap wrapper. */ + ctrl_t ctrl; /* Connection data. */ + int ready; /* Internally used to mark to be removed contexts. */ + ksba_reader_t reader; /* The ksba reader object or NULL. */ + char *line; /* Used to print the log lines (malloced). */ + size_t linesize;/* Allocated size of LINE. */ + size_t linelen; /* Use size of LINE. */ + time_t stamp; /* The last time we noticed ativity. */ +}; + + + +/* We keep a global list of spawed wrapper process. A separate thread + makes use of this list to log error messages and to watch out for + finished processes. */ +static struct wrapper_context_s *wrapper_list; + +/* We need to know whether we are shutting down the process. */ +static int shutting_down; + +/* Close the pth file descriptor FD and set it to -1. */ +#define SAFE_CLOSE(fd) \ + do { int _fd = fd; if (_fd != -1) { close (_fd); fd = -1;} } while (0) + + + + +/* Read a fixed amount of data from READER into BUFFER. */ +static gpg_error_t +read_buffer (ksba_reader_t reader, unsigned char *buffer, size_t count) +{ + gpg_error_t err; + size_t nread; + + while (count) + { + err = ksba_reader_read (reader, buffer, count, &nread); + if (err) + return err; + buffer += nread; + count -= nread; + } + return 0; +} + + +/* Release the wrapper context and kill a running wrapper process. */ +static void +destroy_wrapper (struct wrapper_context_s *ctx) +{ + if (ctx->pid != (pid_t)(-1)) + { + gnupg_kill_process (ctx->pid); + gnupg_release_process (ctx->pid); + } + ksba_reader_release (ctx->reader); + SAFE_CLOSE (ctx->fd); + SAFE_CLOSE (ctx->log_fd); + xfree (ctx->line); + xfree (ctx); +} + + +/* Print the content of LINE to thye log stream but make sure to only + print complete lines. Using NULL for LINE will flush any pending + output. LINE may be modified by this fucntion. */ +static void +print_log_line (struct wrapper_context_s *ctx, char *line) +{ + char *s; + size_t n; + + if (!line) + { + if (ctx->line && ctx->linelen) + { + + log_info ("%s\n", ctx->line); + ctx->linelen = 0; + } + return; + } + + while ((s = strchr (line, '\n'))) + { + *s = 0; + if (ctx->line && ctx->linelen) + { + log_info ("%s", ctx->line); + ctx->linelen = 0; + log_printf ("%s\n", line); + } + else + log_info ("%s\n", line); + line = s + 1; + } + n = strlen (line); + if (n) + { + if (ctx->linelen + n + 1 >= ctx->linesize) + { + char *tmp; + size_t newsize; + + newsize = ctx->linesize + ((n + 255) & ~255) + 1; + tmp = (ctx->line ? xtryrealloc (ctx->line, newsize) + : xtrymalloc (newsize)); + if (!tmp) + { + log_error (_("error printing log line: %s\n"), strerror (errno)); + return; + } + ctx->line = tmp; + ctx->linesize = newsize; + } + memcpy (ctx->line + ctx->linelen, line, n); + ctx->linelen += n; + ctx->line[ctx->linelen] = 0; + } +} + + +/* Read data from the log stream. Returns true if the log stream + indicated EOF or error. */ +static int +read_log_data (struct wrapper_context_s *ctx) +{ + int n; + char line[256]; + + /* We must use the npth_read function for pipes, always. */ + do + n = npth_read (ctx->log_fd, line, sizeof line - 1); + while (n < 0 && errno == EINTR); + + if (n <= 0) /* EOF or error. */ + { + if (n < 0) + log_error (_("error reading log from ldap wrapper %d: %s\n"), + ctx->pid, strerror (errno)); + print_log_line (ctx, NULL); + SAFE_CLOSE (ctx->log_fd); + return 1; + } + + line[n] = 0; + print_log_line (ctx, line); + if (ctx->stamp != (time_t)(-1)) + ctx->stamp = time (NULL); + return 0; +} + + +/* This function is run by a separate thread to maintain the list of + wrappers and to log error messages from these wrappers. */ +void * +ldap_wrapper_thread (void *dummy) +{ + int nfds; + struct wrapper_context_s *ctx; + struct wrapper_context_s *ctx_prev; + struct timespec abstime; + struct timespec curtime; + struct timespec timeout; + int saved_errno; + fd_set fdset, read_fdset; + int ret; + time_t exptime; + + (void)dummy; + + FD_ZERO (&fdset); + nfds = -1; + for (ctx = wrapper_list; ctx; ctx = ctx->next) + { + if (ctx->log_fd != -1) + { + FD_SET (ctx->log_fd, &fdset); + if (ctx->log_fd > nfds) + nfds = ctx->log_fd; + } + } + nfds++; + + npth_clock_gettime (&abstime); + abstime.tv_sec += TIMERTICK_INTERVAL; + + for (;;) + { + int any_action = 0; + + /* POSIX says that fd_set should be implemented as a structure, + thus a simple assignment is fine to copy the entire set. */ + read_fdset = fdset; + + npth_clock_gettime (&curtime); + if (!(npth_timercmp (&curtime, &abstime, <))) + { + /* Inactivity is checked below. Nothing else to do. */ + // handle_tick (); + npth_clock_gettime (&abstime); + abstime.tv_sec += TIMERTICK_INTERVAL; + } + npth_timersub (&abstime, &curtime, &timeout); + + /* FIXME: For Windows, we have to use a reader thread on the + pipe that signals an event (and a npth_select_ev variant). */ + ret = npth_pselect (nfds + 1, &read_fdset, NULL, NULL, &timeout, NULL); + saved_errno = errno; + + if (ret == -1 && saved_errno != EINTR) + { + log_error (_("npth_select failed: %s - waiting 1s\n"), + strerror (saved_errno)); + npth_sleep (1); + continue; + } + + if (ret <= 0) + /* Interrupt or timeout. Will be handled when calculating the + next timeout. */ + continue; + + /* All timestamps before exptime should be considered expired. */ + exptime = time (NULL); + if (exptime > INACTIVITY_TIMEOUT) + exptime -= INACTIVITY_TIMEOUT; + + /* Note that there is no need to lock the list because we always + add entries at the head (with a pending event status) and + thus traversing the list will even work if we have a context + switch in waitpid (which should anyway only happen with Pth's + hard system call mapping). */ + for (ctx = wrapper_list; ctx; ctx = ctx->next) + { + /* Check whether there is any logging to be done. */ + if (nfds && ctx->log_fd != -1 && FD_ISSET (ctx->log_fd, &read_fdset)) + { + if (read_log_data (ctx)) + any_action = 1; + } + + /* Check whether the process is still running. */ + if (ctx->pid != (pid_t)(-1)) + { + gpg_error_t err; + int status; + + err = gnupg_wait_process ("[dirmngr_ldap]", ctx->pid, 0, + &status); + if (!err) + { + log_info (_("ldap wrapper %d ready"), (int)ctx->pid); + ctx->ready = 1; + gnupg_release_process (ctx->pid); + ctx->pid = (pid_t)(-1); + any_action = 1; + } + else if (gpg_err_code (err) == GPG_ERR_GENERAL) + { + if (status == 10) + log_info (_("ldap wrapper %d ready: timeout\n"), + (int)ctx->pid); + else + log_info (_("ldap wrapper %d ready: exitcode=%d\n"), + (int)ctx->pid, status); + ctx->ready = 1; + gnupg_release_process (ctx->pid); + ctx->pid = (pid_t)(-1); + any_action = 1; + } + else if (gpg_err_code (err) != GPG_ERR_TIMEOUT) + { + log_error (_("waiting for ldap wrapper %d failed: %s\n"), + (int)ctx->pid, gpg_strerror (err)); + any_action = 1; + } + } + + /* Check whether we should terminate the process. */ + if (ctx->pid != (pid_t)(-1) + && ctx->stamp != (time_t)(-1) && ctx->stamp < exptime) + { + gnupg_kill_process (ctx->pid); + ctx->stamp = (time_t)(-1); + log_info (_("ldap wrapper %d stalled - killing\n"), + (int)ctx->pid); + /* We need to close the log fd because the cleanup loop + waits for it. */ + SAFE_CLOSE (ctx->log_fd); + any_action = 1; + } + } + + /* If something has been printed to the log file or we got an + EOF from a wrapper, we now print the list of active + wrappers. */ + if (any_action && DBG_LOOKUP) + { + log_info ("ldap worker stati:\n"); + for (ctx = wrapper_list; ctx; ctx = ctx->next) + log_info (" c=%p pid=%d/%d rdr=%p ctrl=%p/%d la=%lu rdy=%d\n", + ctx, + (int)ctx->pid, (int)ctx->printable_pid, + ctx->reader, + ctx->ctrl, ctx->ctrl? ctx->ctrl->refcount:0, + (unsigned long)ctx->stamp, ctx->ready); + } + + + /* Use a separate loop to check whether ready marked wrappers + may be removed. We may only do so if the ksba reader object + is not anymore in use or we are in shutdown state. */ + again: + for (ctx_prev=NULL, ctx=wrapper_list; ctx; ctx_prev=ctx, ctx=ctx->next) + if (ctx->ready + && ((ctx->log_fd == -1 && !ctx->reader) || shutting_down)) + { + if (ctx_prev) + ctx_prev->next = ctx->next; + else + wrapper_list = ctx->next; + destroy_wrapper (ctx); + /* We need to restart because destroy_wrapper might have + done a context switch. */ + goto again; + } + } + /*NOTREACHED*/ + return NULL; /* Make the compiler happy. */ +} + + + +/* Start the reaper thread for the ldap wrapper. */ +void +ldap_wrapper_launch_thread (void) +{ + static int done; + npth_attr_t tattr; + npth_t thread; + int err; + + if (done) + return; + done = 1; + + npth_attr_init (&tattr); + npth_attr_setdetachstate (&tattr, NPTH_CREATE_DETACHED); + + err = npth_create (&thread, &tattr, ldap_wrapper_thread, NULL); + if (err) + { + log_error (_("error spawning ldap wrapper reaper thread: %s\n"), + strerror (err) ); + dirmngr_exit (1); + } + npth_setname_np (thread, "ldap-reaper"); + npth_attr_destroy (&tattr); +} + + + + + +/* Wait until all ldap wrappers have terminated. We assume that the + kill has already been sent to all of them. */ +void +ldap_wrapper_wait_connections () +{ + shutting_down = 1; + /* FIXME: This is a busy wait. */ + while (wrapper_list) + npth_usleep (200); +} + + +/* This function is to be used to release a context associated with the + given reader object. */ +void +ldap_wrapper_release_context (ksba_reader_t reader) +{ + struct wrapper_context_s *ctx; + + if (!reader ) + return; + + for (ctx=wrapper_list; ctx; ctx=ctx->next) + if (ctx->reader == reader) + { + if (DBG_LOOKUP) + log_info ("releasing ldap worker c=%p pid=%d/%d rdr=%p ctrl=%p/%d\n", + ctx, + (int)ctx->pid, (int)ctx->printable_pid, + ctx->reader, + ctx->ctrl, ctx->ctrl? ctx->ctrl->refcount:0); + + ctx->reader = NULL; + SAFE_CLOSE (ctx->fd); + if (ctx->ctrl) + { + ctx->ctrl->refcount--; + ctx->ctrl = NULL; + } + if (ctx->fd_error) + log_info (_("reading from ldap wrapper %d failed: %s\n"), + ctx->printable_pid, gpg_strerror (ctx->fd_error)); + break; + } +} + +/* Cleanup all resources held by the connection associated with + CTRL. This is used after a cancel to kill running wrappers. */ +void +ldap_wrapper_connection_cleanup (ctrl_t ctrl) +{ + struct wrapper_context_s *ctx; + + for (ctx=wrapper_list; ctx; ctx=ctx->next) + if (ctx->ctrl && ctx->ctrl == ctrl) + { + ctx->ctrl->refcount--; + ctx->ctrl = NULL; + if (ctx->pid != (pid_t)(-1)) + gnupg_kill_process (ctx->pid); + if (ctx->fd_error) + log_info (_("reading from ldap wrapper %d failed: %s\n"), + ctx->printable_pid, gpg_strerror (ctx->fd_error)); + } +} + + +/* This is the callback used by the ldap wrapper to feed the ksba + reader with the wrappers stdout. See the description of + ksba_reader_set_cb for details. */ +static int +reader_callback (void *cb_value, char *buffer, size_t count, size_t *nread) +{ + struct wrapper_context_s *ctx = cb_value; + size_t nleft = count; + int nfds; + struct timespec abstime; + struct timespec curtime; + struct timespec timeout; + int saved_errno; + fd_set fdset, read_fdset; + int ret; + + /* FIXME: We might want to add some internal buffering because the + ksba code does not do any buffering for itself (because a ksba + reader may be detached from another stream to read other data and + the it would be cumbersome to get back already buffered + stuff). */ + + if (!buffer && !count && !nread) + return -1; /* Rewind is not supported. */ + + /* If we ever encountered a read error don't allow to continue and + possible overwrite the last error cause. Bail out also if the + file descriptor has been closed. */ + if (ctx->fd_error || ctx->fd == -1) + { + *nread = 0; + return -1; + } + + FD_ZERO (&fdset); + FD_SET (ctx->fd, &fdset); + nfds = ctx->fd + 1; + + npth_clock_gettime (&abstime); + abstime.tv_sec += TIMERTICK_INTERVAL; + + while (nleft > 0) + { + int n; + gpg_error_t err; + + npth_clock_gettime (&curtime); + if (!(npth_timercmp (&curtime, &abstime, <))) + { + err = dirmngr_tick (ctx->ctrl); + if (err) + { + ctx->fd_error = err; + SAFE_CLOSE (ctx->fd); + return -1; + } + npth_clock_gettime (&abstime); + abstime.tv_sec += TIMERTICK_INTERVAL; + } + npth_timersub (&abstime, &curtime, &timeout); + + read_fdset = fdset; + ret = npth_pselect (nfds, &read_fdset, NULL, NULL, &timeout, NULL); + saved_errno = errno; + + if (ret == -1 && saved_errno != EINTR) + { + ctx->fd_error = gpg_error_from_errno (errno); + SAFE_CLOSE (ctx->fd); + return -1; + } + if (ret <= 0) + /* Timeout. Will be handled when calculating the next timeout. */ + continue; + + /* This should not block now that select returned with a file + descriptor. So it shouldn't be necessary to use npth_read + (and it is slightly dangerous in the sense that a concurrent + thread might (accidentially?) change the status of ctx->fd + before we read. FIXME: Set ctx->fd to nonblocking? */ + n = read (ctx->fd, buffer, nleft); + if (n < 0) + { + ctx->fd_error = gpg_error_from_errno (errno); + SAFE_CLOSE (ctx->fd); + return -1; + } + else if (!n) + { + if (nleft == count) + return -1; /* EOF. */ + break; + } + nleft -= n; + buffer += n; + if (n > 0 && ctx->stamp != (time_t)(-1)) + ctx->stamp = time (NULL); + } + *nread = count - nleft; + + return 0; +} + +/* Fork and exec the LDAP wrapper and returns a new libksba reader + object at READER. ARGV is a NULL terminated list of arguments for + the wrapper. The function returns 0 on success or an error code. + + Special hack to avoid passing a password through the command line + which is globally visible: If the first element of ARGV is "--pass" + it will be removed and instead the environment variable + DIRMNGR_LDAP_PASS will be set to the next value of ARGV. On modern + OSes the environment is not visible to other users. For those old + systems where it can't be avoided, we don't want to go into the + hassle of passing the password via stdin; it's just too complicated + and an LDAP password used for public directory lookups should not + be that confidential. */ +gpg_error_t +ldap_wrapper (ctrl_t ctrl, ksba_reader_t *reader, const char *argv[]) +{ + gpg_error_t err; + pid_t pid; + struct wrapper_context_s *ctx; + int i; + int j; + const char **arg_list; + const char *pgmname; + int outpipe[2], errpipe[2]; + + /* It would be too simple to connect stderr just to our logging + stream. The problem is that if we are running multi-threaded + everything gets intermixed. Clearly we don't want this. So the + only viable solutions are either to have another thread + responsible for logging the messages or to add an option to the + wrapper module to do the logging on its own. Given that we anyway + need a way to rip the child process and this is best done using a + general ripping thread, that thread can do the logging too. */ + + *reader = NULL; + + /* Files: We need to prepare stdin and stdout. We get stderr from + the function. */ + if (!opt.ldap_wrapper_program || !*opt.ldap_wrapper_program) + pgmname = gnupg_module_name (GNUPG_MODULE_NAME_DIRMNGR_LDAP); + else + pgmname = opt.ldap_wrapper_program; + + /* Create command line argument array. */ + for (i = 0; argv[i]; i++) + ; + arg_list = xtrycalloc (i + 2, sizeof *arg_list); + if (!arg_list) + { + err = gpg_error_from_syserror (); + log_error (_("error allocating memory: %s\n"), strerror (errno)); + return err; + } + for (i = j = 0; argv[i]; i++, j++) + if (!i && argv[i + 1] && !strcmp (*argv, "--pass")) + { + arg_list[j] = "--env-pass"; + setenv ("DIRMNGR_LDAP_PASS", argv[1], 1); + i++; + } + else + arg_list[j] = (char*) argv[i]; + + ctx = xtrycalloc (1, sizeof *ctx); + if (!ctx) + { + err = gpg_error_from_syserror (); + log_error (_("error allocating memory: %s\n"), strerror (errno)); + xfree (arg_list); + return err; + } + + err = gnupg_create_inbound_pipe (outpipe); + if (!err) + { + err = gnupg_create_inbound_pipe (errpipe); + if (err) + { + close (outpipe[0]); + close (outpipe[1]); + } + } + if (err) + { + log_error (_("error creating a pipe: %s\n"), gpg_strerror (err)); + xfree (arg_list); + xfree (ctx); + return err; + } + + err = gnupg_spawn_process_fd (pgmname, arg_list, + -1, outpipe[1], errpipe[1], &pid); + xfree (arg_list); + close (outpipe[1]); + close (errpipe[1]); + if (err) + { + close (outpipe[0]); + close (errpipe[0]); + xfree (ctx); + return err; + } + + ctx->pid = pid; + ctx->printable_pid = (int) pid; + ctx->fd = outpipe[0]; + ctx->log_fd = errpipe[0]; + ctx->ctrl = ctrl; + ctrl->refcount++; + ctx->stamp = time (NULL); + + err = ksba_reader_new (reader); + if (!err) + err = ksba_reader_set_cb (*reader, reader_callback, ctx); + if (err) + { + log_error (_("error initializing reader object: %s\n"), + gpg_strerror (err)); + destroy_wrapper (ctx); + ksba_reader_release (*reader); + *reader = NULL; + return err; + } + + /* Hook the context into our list of running wrappers. */ + ctx->reader = *reader; + ctx->next = wrapper_list; + wrapper_list = ctx; + if (opt.verbose) + log_info ("ldap wrapper %d started (reader %p)\n", + (int)ctx->pid, ctx->reader); + + /* Need to wait for the first byte so we are able to detect an empty + output and not let the consumer see an EOF without further error + indications. The CRL loading logic assumes that after return + from this function, a failed search (e.g. host not found ) is + indicated right away. */ + { + unsigned char c; + + err = read_buffer (*reader, &c, 1); + if (err) + { + ldap_wrapper_release_context (*reader); + ksba_reader_release (*reader); + *reader = NULL; + if (gpg_err_code (err) == GPG_ERR_EOF) + return gpg_error (GPG_ERR_NO_DATA); + else + return err; + } + ksba_reader_unread (*reader, &c, 1); + } + + return 0; +} |