diff options
Diffstat (limited to 'geo-replication/src/gsyncd.c')
| -rw-r--r-- | geo-replication/src/gsyncd.c | 367 |
1 files changed, 367 insertions, 0 deletions
diff --git a/geo-replication/src/gsyncd.c b/geo-replication/src/gsyncd.c new file mode 100644 index 00000000000..9c4a5bdffb3 --- /dev/null +++ b/geo-replication/src/gsyncd.c @@ -0,0 +1,367 @@ +/* + Copyright (c) 2011-2012 Red Hat, Inc. <http://www.redhat.com> + This file is part of GlusterFS. + + This file is licensed to you under your choice of the GNU Lesser + General Public License, version 3 or any later version (LGPLv3 or + later), or the GNU General Public License, version 2 (GPLv2), in all + cases as published by the Free Software Foundation. +*/ + +#ifndef _CONFIG_H +#define _CONFIG_H +#include "config.h" +#endif + +#include <stdlib.h> +#include <stdio.h> +#include <unistd.h> +#include <string.h> +#include <sys/param.h> /* for PATH_MAX */ + +/* NOTE (USE_LIBGLUSTERFS): + * ------------------------ + * When USE_LIBGLUSTERFS debugging sumbol is passed; perform + * glusterfs translator like initialization so that glusterfs + * globals, contexts are valid when glustefs api's are invoked. + * We unconditionally pass then while building gsyncd binary. + */ +#ifdef USE_LIBGLUSTERFS +#include "glusterfs.h" +#include "globals.h" +#endif + +#include "common-utils.h" +#include "run.h" +#include "procdiggy.h" + +#define _GLUSTERD_CALLED_ "_GLUSTERD_CALLED_" +#define _GSYNCD_DISPATCHED_ "_GSYNCD_DISPATCHED_" +#define GSYNCD_CONF "geo-replication/gsyncd.conf" +#define GSYNCD_PY "gsyncd.py" +#define RSYNC "rsync" + +int restricted = 0; + +static int +duplexpand (void **buf, size_t tsiz, size_t *len) +{ + size_t osiz = tsiz * *len; + char *p = realloc (*buf, osiz << 1); + if (!p) { + free(*buf); + return -1; + } + + memset (p + osiz, 0, osiz); + *buf = p; + *len <<= 1; + + return 0; +} + +static int +str2argv (char *str, char ***argv) +{ + char *p = NULL; + char *savetok = NULL; + int argc = 0; + size_t argv_len = 32; + int ret = 0; + + assert (str); + str = strdup (str); + if (!str) + return -1; + + *argv = calloc (argv_len, sizeof (**argv)); + if (!*argv) + goto error; + + while ((p = strtok_r (str, " ", &savetok))) { + str = NULL; + + argc++; + if (argc == argv_len) { + ret = duplexpand ((void *)argv, + sizeof (**argv), + &argv_len); + if (ret == -1) + goto error; + } + (*argv)[argc - 1] = p; + } + + return argc; + + error: + fprintf (stderr, "out of memory\n"); + return -1; +} + +static int +invoke_gsyncd (int argc, char **argv) +{ + char config_file[PATH_MAX] = {0,}; + size_t gluster_workdir_len = 0; + runner_t runner = {0,}; + int i = 0; + int j = 0; + char *nargv[argc + 4]; + char *python = NULL; + + if (restricted) { + size_t len; + /* in restricted mode we forcibly use the system-wide config */ + runinit (&runner); + runner_add_args (&runner, SBIN_DIR"/gluster", + "--log-file=-", "system::", "getwd", + NULL); + runner_redir (&runner, STDOUT_FILENO, RUN_PIPE); + if (runner_start (&runner) == 0 && + fgets (config_file, PATH_MAX, + runner_chio (&runner, STDOUT_FILENO)) != NULL && + (len = strlen (config_file)) && + config_file[len - 1] == '\n' && + runner_end (&runner) == 0) + gluster_workdir_len = len - 1; + + if (gluster_workdir_len) { + if (gluster_workdir_len + 1 + strlen (GSYNCD_CONF) + 1 > + PATH_MAX) + goto error; + config_file[gluster_workdir_len] = '/'; + strcat (config_file, GSYNCD_CONF); + } else + goto error; + + if (setenv ("_GSYNCD_RESTRICTED_", "1", 1) == -1) + goto error; + } + + if (chdir ("/") == -1) + goto error; + + j = 0; + python = getenv("PYTHON"); + if(!python) + python = PYTHON; + nargv[j++] = python; + nargv[j++] = GSYNCD_PREFIX"/python/syncdaemon/"GSYNCD_PY; + for (i = 1; i < argc; i++) + nargv[j++] = argv[i]; + if (config_file[0]) { + nargv[j++] = "-c"; + nargv[j++] = config_file; + } + nargv[j++] = NULL; + + execvp (python, nargv); + + fprintf (stderr, "exec of '%s' failed\n", python); + return 127; + + error: + fprintf (stderr, "gsyncd initializaion failed\n"); + return 1; +} + + +static int +find_gsyncd (pid_t pid, pid_t ppid, char *name, void *data) +{ + char buf[NAME_MAX * 2] = {0,}; + char path[PATH_MAX] = {0,}; + char *p = NULL; + int zeros = 0; + int ret = 0; + int fd = -1; + pid_t *pida = (pid_t *)data; + + if (ppid != pida[0]) + return 0; + + sprintf (path, PROC"/%d/cmdline", pid); + fd = open (path, O_RDONLY); + if (fd == -1) + return 0; + ret = read (fd, buf, sizeof (buf)); + close (fd); + if (ret == -1) + return 0; + for (zeros = 0, p = buf; zeros < 2 && p < buf + ret; p++) + zeros += !*p; + + ret = 0; + switch (zeros) { + case 2: + if ((strcmp (basename (buf), basename (PYTHON)) || + strcmp (basename (buf + strlen (buf) + 1), GSYNCD_PY)) == 0) { + ret = 1; + break; + } + /* fallthrough */ + case 1: + if (strcmp (basename (buf), GSYNCD_PY) == 0) + ret = 1; + } + + if (ret == 1) { + if (pida[1] != -1) { + fprintf (stderr, GSYNCD_PY" sibling is not unique"); + return -1; + } + pida[1] = pid; + } + + return 0; +} + +static int +invoke_rsync (int argc, char **argv) +{ + int i = 0; + char path[PATH_MAX] = {0,}; + pid_t pid = -1; + pid_t ppid = -1; + pid_t pida[] = {-1, -1}; + char *name = NULL; + char buf[PATH_MAX + 1] = {0,}; + int ret = 0; + + assert (argv[argc] == NULL); + + if (argc < 2 || strcmp (argv[1], "--server") != 0) + goto error; + + for (i = 2; i < argc && argv[i][0] == '-'; i++); + + if (!(i == argc - 2 && strcmp (argv[i], ".") == 0 && argv[i + 1][0] == '/')) { + fprintf (stderr, "need an rsync invocation without protected args\n"); + goto error; + } + + /* look up sshd we are spawned from */ + for (pid = getpid () ;; pid = ppid) { + ppid = pidinfo (pid, &name); + if (ppid < 0) { + fprintf (stderr, "sshd ancestor not found\n"); + goto error; + } + if (strcmp (name, "sshd") == 0) { + GF_FREE (name); + break; + } + GF_FREE (name); + } + /* look up "ssh-sibling" gsyncd */ + pida[0] = pid; + ret = prociter (find_gsyncd, pida); + if (ret == -1 || pida[1] == -1) { + fprintf (stderr, "gsyncd sibling not found\n"); + goto error; + } + /* check if rsync target matches gsyncd target */ + sprintf (path, PROC"/%d/cwd", pida[1]); + ret = readlink (path, buf, sizeof (buf)); + if (ret == -1 || ret == sizeof (buf)) + goto error; + if (strcmp (argv[argc - 1], "/") == 0 /* root dir cannot be a target */ || + (strcmp (argv[argc - 1], path) /* match against gluster target */ && + strcmp (argv[argc - 1], buf) /* match against file target */) != 0) { + fprintf (stderr, "rsync target does not match "GEOREP" session\n"); + goto error; + } + + argv[0] = RSYNC; + + execvp (RSYNC, argv); + + fprintf (stderr, "exec of "RSYNC" failed\n"); + return 127; + + error: + fprintf (stderr, "disallowed "RSYNC" invocation\n"); + return 1; +} + + +struct invocable { + char *name; + int (*invoker) (int argc, char **argv); +}; + +struct invocable invocables[] = { + { "rsync", invoke_rsync }, + { "gsyncd", invoke_gsyncd }, + { NULL, NULL} +}; + +int +main (int argc, char **argv) +{ + char *evas = NULL; + struct invocable *i = NULL; + char *b = NULL; + char *sargv = NULL; + +#ifdef USE_LIBGLUSTERFS + glusterfs_ctx_t *ctx = NULL; + + ctx = glusterfs_ctx_new (); + if (!ctx) + return ENOMEM; + + if (glusterfs_globals_init (ctx)) + return 1; + + THIS->ctx = ctx; +#endif + + evas = getenv (_GLUSTERD_CALLED_); + if (evas && strcmp (evas, "1") == 0) + /* OK, we know glusterd called us, no need to look for further config + * ... altough this conclusion should not inherit to our children + */ + unsetenv (_GLUSTERD_CALLED_); + else { + /* we regard all gsyncd invocations unsafe + * that do not come from glusterd and + * therefore restrict it + */ + restricted = 1; + + if (!getenv (_GSYNCD_DISPATCHED_)) { + evas = getenv ("SSH_ORIGINAL_COMMAND"); + if (evas) + sargv = evas; + else { + evas = getenv ("SHELL"); + if (evas && strcmp (basename (evas), "gsyncd") == 0 && + argc == 3 && strcmp (argv[1], "-c") == 0) + sargv = argv[2]; + } + } + + } + + if (!(sargv && restricted)) + return invoke_gsyncd (argc, argv); + + argc = str2argv (sargv, &argv); + if (argc == -1 || setenv (_GSYNCD_DISPATCHED_, "1", 1) == -1) { + fprintf (stderr, "internal error\n"); + return 1; + } + + b = basename (argv[0]); + for (i = invocables; i->name; i++) { + if (strcmp (b, i->name) == 0) + return i->invoker (argc, argv); + } + + fprintf (stderr, "invoking %s in restricted SSH session is not allowed\n", + b); + + return 1; +} |