summaryrefslogtreecommitdiffstats
path: root/plugins/sudoers/timestamp.c
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--plugins/sudoers/timestamp.c1075
1 files changed, 1075 insertions, 0 deletions
diff --git a/plugins/sudoers/timestamp.c b/plugins/sudoers/timestamp.c
new file mode 100644
index 0000000..5930103
--- /dev/null
+++ b/plugins/sudoers/timestamp.c
@@ -0,0 +1,1075 @@
+/*
+ * Copyright (c) 2014-2018 Todd C. Miller <Todd.Miller@sudo.ws>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/*
+ * This is an open source non-commercial project. Dear PVS-Studio, please check it.
+ * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+ */
+
+#include <config.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#if defined(HAVE_STDINT_H)
+# include <stdint.h>
+#elif defined(HAVE_INTTYPES_H)
+# include <inttypes.h>
+#endif
+#ifdef HAVE_STRING_H
+# include <string.h>
+#endif /* HAVE_STRING_H */
+#ifdef HAVE_STRINGS_H
+# include <strings.h>
+#endif /* HAVE_STRINGS_H */
+#include <unistd.h>
+#include <time.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <pwd.h>
+#include <grp.h>
+#include <signal.h>
+
+#include "sudoers.h"
+#include "check.h"
+
+#define TIMESTAMP_OPEN_ERROR -1
+#define TIMESTAMP_PERM_ERROR -2
+
+/*
+ * Each user has a single time stamp file that contains multiple records.
+ * Records are locked to ensure that changes are serialized.
+ *
+ * The first record is of type TS_LOCKEXCL and is used to gain exclusive
+ * access to create new records. This is a short-term lock and sudo
+ * should not sleep while holding it (or the user will not be able to sudo).
+ * The TS_LOCKEXCL entry must be unlocked before locking the actual record.
+ */
+
+struct ts_cookie {
+ char *fname;
+ int fd;
+ pid_t sid;
+ bool locked;
+ off_t pos;
+ struct timestamp_entry key;
+};
+
+/*
+ * Returns true if entry matches key, else false.
+ * We don't match on the sid or actual time stamp.
+ */
+static bool
+ts_match_record(struct timestamp_entry *key, struct timestamp_entry *entry,
+ unsigned int recno)
+{
+ debug_decl(ts_match_record, SUDOERS_DEBUG_AUTH)
+
+ if (entry->version != key->version) {
+ sudo_debug_printf(SUDO_DEBUG_DEBUG,
+ "%s:%u record version mismatch (want %u, got %u)", __func__, recno,
+ key->version, entry->version);
+ debug_return_bool(false);
+ }
+ if (!ISSET(key->flags, TS_ANYUID) && entry->auth_uid != key->auth_uid) {
+ sudo_debug_printf(SUDO_DEBUG_DEBUG,
+ "%s:%u record uid mismatch (want %u, got %u)", __func__, recno,
+ (unsigned int)key->auth_uid, (unsigned int)entry->auth_uid);
+ debug_return_bool(false);
+ }
+ if (entry->type != key->type) {
+ sudo_debug_printf(SUDO_DEBUG_DEBUG,
+ "%s:%u record type mismatch (want %u, got %u)", __func__, recno,
+ key->type, entry->type);
+ debug_return_bool(false);
+ }
+ switch (entry->type) {
+ case TS_GLOBAL:
+ /* no ppid or tty to match */
+ break;
+ case TS_PPID:
+ /* verify parent pid */
+ if (entry->u.ppid != key->u.ppid) {
+ sudo_debug_printf(SUDO_DEBUG_DEBUG,
+ "%s:%u record ppid mismatch (want %d, got %d)", __func__, recno,
+ (int)key->u.ppid, (int)entry->u.ppid);
+ debug_return_bool(false);
+ }
+ if (sudo_timespeccmp(&entry->start_time, &key->start_time, !=)) {
+ sudo_debug_printf(SUDO_DEBUG_DEBUG,
+ "%s:%u ppid start time mismatch", __func__, recno);
+ debug_return_bool(false);
+ }
+ break;
+ case TS_TTY:
+ if (entry->u.ttydev != key->u.ttydev) {
+ sudo_debug_printf(SUDO_DEBUG_DEBUG,
+ "%s:%u record tty mismatch (want 0x%x, got 0x%x)", __func__,
+ recno, (unsigned int)key->u.ttydev, (unsigned int)entry->u.ttydev);
+ debug_return_bool(false);
+ }
+ if (sudo_timespeccmp(&entry->start_time, &key->start_time, !=)) {
+ sudo_debug_printf(SUDO_DEBUG_DEBUG,
+ "%s:%u session leader start time mismatch", __func__, recno);
+ debug_return_bool(false);
+ }
+ break;
+ default:
+ /* unknown record type, ignore it */
+ sudo_debug_printf(SUDO_DEBUG_WARN|SUDO_DEBUG_LINENO,
+ "%s:%u unknown time stamp record type %d", __func__, recno,
+ entry->type);
+ debug_return_bool(false);
+ }
+ debug_return_bool(true);
+}
+
+/*
+ * Searches the time stamp file descriptor for a record that matches key.
+ * On success, fills in entry with the matching record and returns true.
+ * On failure, returns false.
+ *
+ * Note that records are searched starting at the current file offset,
+ * which may not be the beginning of the file.
+ */
+static bool
+ts_find_record(int fd, struct timestamp_entry *key, struct timestamp_entry *entry)
+{
+ struct timestamp_entry cur;
+ unsigned int recno = 0;
+ debug_decl(ts_find_record, SUDOERS_DEBUG_AUTH)
+
+ /*
+ * Find a matching record (does not match sid or time stamp value).
+ */
+ while (read(fd, &cur, sizeof(cur)) == sizeof(cur)) {
+ recno++;
+ if (cur.size != sizeof(cur)) {
+ /* wrong size, seek to start of next record */
+ sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO,
+ "wrong sized record, got %hu, expected %zu",
+ cur.size, sizeof(cur));
+ if (lseek(fd, (off_t)cur.size - (off_t)sizeof(cur), SEEK_CUR) == -1) {
+ sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO|SUDO_DEBUG_LINENO,
+ "unable to seek forward %d",
+ (int)cur.size - (int)sizeof(cur));
+ break;
+ }
+ if (cur.size == 0)
+ break; /* size must be non-zero */
+ continue;
+ }
+ if (ts_match_record(key, &cur, recno)) {
+ memcpy(entry, &cur, sizeof(struct timestamp_entry));
+ debug_return_bool(true);
+ }
+ }
+ debug_return_bool(false);
+}
+
+/*
+ * Create a directory and any missing parent directories with the
+ * specified mode.
+ * Returns true on success.
+ * Returns false on failure and displays a warning to stderr.
+ */
+static bool
+ts_mkdirs(char *path, uid_t owner, gid_t group, mode_t mode,
+ mode_t parent_mode, bool quiet)
+{
+ bool ret;
+ mode_t omask;
+ debug_decl(ts_mkdirs, SUDOERS_DEBUG_AUTH)
+
+ /* umask must not be more restrictive than the file modes. */
+ omask = umask(ACCESSPERMS & ~(mode|parent_mode));
+ ret = sudo_mkdir_parents(path, owner, group, parent_mode, quiet);
+ if (ret) {
+ /* Create final path component. */
+ sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
+ "mkdir %s, mode 0%o, uid %d, gid %d", path, (unsigned int)mode,
+ (int)owner, (int)group);
+ if (mkdir(path, mode) != 0 && errno != EEXIST) {
+ if (!quiet)
+ sudo_warn(U_("unable to mkdir %s"), path);
+ ret = false;
+ } else {
+ if (chown(path, owner, group) != 0) {
+ sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO,
+ "%s: unable to chown %d:%d %s", __func__,
+ (int)owner, (int)group, path);
+ }
+ }
+ }
+ umask(omask);
+ debug_return_bool(ret);
+}
+
+/*
+ * Check that path is owned by timestamp_uid and not writable by
+ * group or other. If path is missing and make_it is true, create
+ * the directory and its parent dirs.
+ * Returns true on success or false on failure, setting errno.
+ */
+static bool
+ts_secure_dir(char *path, bool make_it, bool quiet)
+{
+ struct stat sb;
+ bool ret = false;
+ debug_decl(ts_secure_dir, SUDOERS_DEBUG_AUTH)
+
+ sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO, "checking %s", path);
+ switch (sudo_secure_dir(path, timestamp_uid, -1, &sb)) {
+ case SUDO_PATH_SECURE:
+ ret = true;
+ break;
+ case SUDO_PATH_MISSING:
+ if (make_it && ts_mkdirs(path, timestamp_uid, timestamp_gid, S_IRWXU,
+ S_IRWXU|S_IXGRP|S_IXOTH, quiet)) {
+ ret = true;
+ break;
+ }
+ errno = ENOENT;
+ break;
+ case SUDO_PATH_BAD_TYPE:
+ errno = ENOTDIR;
+ if (!quiet)
+ sudo_warn("%s", path);
+ break;
+ case SUDO_PATH_WRONG_OWNER:
+ if (!quiet) {
+ sudo_warnx(U_("%s is owned by uid %u, should be %u"),
+ path, (unsigned int) sb.st_uid,
+ (unsigned int) timestamp_uid);
+ }
+ errno = EACCES;
+ break;
+ case SUDO_PATH_GROUP_WRITABLE:
+ if (!quiet)
+ sudo_warnx(U_("%s is group writable"), path);
+ errno = EACCES;
+ break;
+ }
+ debug_return_bool(ret);
+}
+
+/*
+ * Open the specified timestamp or lecture file and set the
+ * close on exec flag.
+ * Returns open file descriptor on success.
+ * Returns TIMESTAMP_OPEN_ERROR or TIMESTAMP_PERM_ERROR on error.
+ */
+static int
+ts_open(const char *path, int flags)
+{
+ bool uid_changed = false;
+ int fd;
+ debug_decl(ts_open, SUDOERS_DEBUG_AUTH)
+
+ if (timestamp_uid != 0)
+ uid_changed = set_perms(PERM_TIMESTAMP);
+ fd = open(path, flags, S_IRUSR|S_IWUSR);
+ if (uid_changed && !restore_perms()) {
+ /* Unable to restore permissions, should not happen. */
+ if (fd != -1) {
+ int serrno = errno;
+ close(fd);
+ errno = serrno;
+ fd = TIMESTAMP_PERM_ERROR;
+ }
+ }
+ if (fd >= 0)
+ (void)fcntl(fd, F_SETFD, FD_CLOEXEC);
+
+ debug_return_int(fd);
+}
+
+static ssize_t
+ts_write(int fd, const char *fname, struct timestamp_entry *entry, off_t offset)
+{
+ ssize_t nwritten;
+ off_t old_eof;
+ debug_decl(ts_write, SUDOERS_DEBUG_AUTH)
+
+ if (offset == -1) {
+ old_eof = lseek(fd, 0, SEEK_CUR);
+ nwritten = write(fd, entry, entry->size);
+ } else {
+ old_eof = offset;
+#ifdef HAVE_PWRITE
+ nwritten = pwrite(fd, entry, entry->size, offset);
+#else
+ if (lseek(fd, offset, SEEK_SET) == -1) {
+ sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO|SUDO_DEBUG_LINENO,
+ "unable to seek to %lld", (long long)offset);
+ nwritten = -1;
+ } else {
+ nwritten = write(fd, entry, entry->size);
+ }
+#endif
+ }
+ if ((size_t)nwritten != entry->size) {
+ if (nwritten == -1) {
+ log_warning(SLOG_SEND_MAIL,
+ N_("unable to write to %s"), fname);
+ } else {
+ log_warningx(SLOG_SEND_MAIL,
+ N_("unable to write to %s"), fname);
+ }
+
+ /* Truncate on partial write to be safe (assumes end of file). */
+ if (nwritten > 0) {
+ sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
+ "short write, truncating partial time stamp record");
+ if (ftruncate(fd, old_eof) != 0) {
+ sudo_warn(U_("unable to truncate time stamp file to %lld bytes"),
+ (long long)old_eof);
+ }
+ }
+ debug_return_ssize_t(-1);
+ }
+ debug_return_ssize_t(nwritten);
+}
+
+/*
+ * Full in struct timestamp_entry with the specified flags
+ * based on auth user pw. Does not set the time stamp.
+ */
+static void
+ts_init_key(struct timestamp_entry *entry, struct passwd *pw, int flags,
+ enum def_tuple ticket_type)
+{
+ struct stat sb;
+ debug_decl(ts_init_key, SUDOERS_DEBUG_AUTH)
+
+ memset(entry, 0, sizeof(*entry));
+ entry->version = TS_VERSION;
+ entry->size = sizeof(*entry);
+ entry->flags = flags;
+ if (pw != NULL) {
+ entry->auth_uid = pw->pw_uid;
+ } else {
+ entry->flags |= TS_ANYUID;
+ }
+ entry->sid = user_sid;
+ switch (ticket_type) {
+ default:
+ /* Unknown time stamp ticket type, treat as tty (should not happen). */
+ sudo_warnx("unknown time stamp ticket type %d", ticket_type);
+ /* FALLTHROUGH */
+ case tty:
+ if (user_ttypath != NULL && stat(user_ttypath, &sb) == 0) {
+ /* tty-based time stamp */
+ entry->type = TS_TTY;
+ entry->u.ttydev = sb.st_rdev;
+ if (entry->sid != -1)
+ get_starttime(entry->sid, &entry->start_time);
+ break;
+ }
+ /* FALLTHROUGH */
+ case kernel:
+ case ppid:
+ /* ppid-based time stamp */
+ entry->type = TS_PPID;
+ entry->u.ppid = getppid();
+ get_starttime(entry->u.ppid, &entry->start_time);
+ break;
+ case global:
+ /* global time stamp */
+ entry->type = TS_GLOBAL;
+ break;
+ }
+
+ debug_return;
+}
+
+static void
+ts_init_key_nonglobal(struct timestamp_entry *entry, struct passwd *pw, int flags)
+{
+ /*
+ * Even if the timestamp type is global or kernel we still want to do
+ * per-tty or per-ppid locking so sudo works predictably in a pipeline.
+ */
+ ts_init_key(entry, pw, flags,
+ def_timestamp_type == ppid ? ppid : tty);
+}
+
+/*
+ * Open the user's time stamp file.
+ * Returns a cookie or NULL on error, does not lock the file.
+ */
+void *
+timestamp_open(const char *user, pid_t sid)
+{
+ struct ts_cookie *cookie;
+ char *fname = NULL;
+ int tries, fd = -1;
+ debug_decl(timestamp_open, SUDOERS_DEBUG_AUTH)
+
+ /* Zero timeout means don't use the time stamp file. */
+ if (!sudo_timespecisset(&def_timestamp_timeout)) {
+ errno = ENOENT;
+ goto bad;
+ }
+
+ /* Sanity check timestamp dir and create if missing. */
+ if (!ts_secure_dir(def_timestampdir, true, false))
+ goto bad;
+
+ /* Open time stamp file. */
+ if (asprintf(&fname, "%s/%s", def_timestampdir, user) == -1) {
+ sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+ goto bad;
+ }
+ for (tries = 1; ; tries++) {
+ struct stat sb;
+
+ fd = ts_open(fname, O_RDWR|O_CREAT);
+ switch (fd) {
+ case TIMESTAMP_OPEN_ERROR:
+ log_warning(SLOG_SEND_MAIL, N_("unable to open %s"), fname);
+ goto bad;
+ case TIMESTAMP_PERM_ERROR:
+ /* Already logged set_perms/restore_perms error. */
+ goto bad;
+ }
+
+ /* Remove time stamp file if its mtime predates boot time. */
+ if (tries == 1 && fstat(fd, &sb) == 0) {
+ struct timespec boottime, mtime, now;
+
+ if (sudo_gettime_real(&now) == 0 && get_boottime(&boottime)) {
+ /* Ignore a boot time that is in the future. */
+ if (sudo_timespeccmp(&now, &boottime, <)) {
+ sudo_debug_printf(SUDO_DEBUG_WARN|SUDO_DEBUG_LINENO,
+ "ignoring boot time that is in the future");
+ } else {
+ mtim_get(&sb, mtime);
+ if (sudo_timespeccmp(&mtime, &boottime, <)) {
+ /* Time stamp file too old, remove it. */
+ sudo_debug_printf(SUDO_DEBUG_WARN|SUDO_DEBUG_LINENO,
+ "removing time stamp file that predates boot time");
+ close(fd);
+ unlink(fname);
+ continue;
+ }
+ }
+ }
+ }
+ break;
+ }
+
+ /* Allocate and fill in cookie to store state. */
+ cookie = malloc(sizeof(*cookie));
+ if (cookie == NULL) {
+ sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+ goto bad;
+ }
+ cookie->fd = fd;
+ cookie->fname = fname;
+ cookie->sid = sid;
+ cookie->pos = -1;
+
+ debug_return_ptr(cookie);
+bad:
+ if (fd != -1)
+ close(fd);
+ free(fname);
+ debug_return_ptr(NULL);
+}
+
+static volatile sig_atomic_t got_signal;
+
+static void
+timestamp_handler(int s)
+{
+ got_signal = s;
+}
+
+/*
+ * Wrapper for sudo_lock_region() that is interruptible.
+ */
+static bool
+timestamp_lock_record(int fd, off_t pos, off_t len)
+{
+ struct sigaction sa, saveint, savequit;
+ sigset_t mask, omask;
+ bool ret;
+ debug_decl(timestamp_lock_record, SUDOERS_DEBUG_AUTH)
+
+ if (pos >= 0 && lseek(fd, pos, SEEK_SET) == -1) {
+ sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO|SUDO_DEBUG_LINENO,
+ "unable to seek to %lld", (long long)pos);
+ debug_return_bool(false);
+ }
+
+ /* Allow SIGINT and SIGQUIT to interrupt a lock. */
+ got_signal = 0;
+ memset(&sa, 0, sizeof(sa));
+ sigemptyset(&sa.sa_mask);
+ sa.sa_flags = 0; /* don't restart system calls */
+ sa.sa_handler = timestamp_handler;
+ (void) sigaction(SIGINT, &sa, &saveint);
+ (void) sigaction(SIGQUIT, &sa, &savequit);
+ sigemptyset(&mask);
+ sigaddset(&mask, SIGINT);
+ sigaddset(&mask, SIGQUIT);
+ (void) sigprocmask(SIG_UNBLOCK, &mask, &omask);
+
+ ret = sudo_lock_region(fd, SUDO_LOCK, len);
+ if (!ret) {
+ sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO|SUDO_DEBUG_LINENO,
+ "failed to lock fd %d [%lld, %lld]", fd,
+ (long long)pos, (long long)len);
+ }
+
+ /* Restore the old mask (SIGINT and SIGQUIT blocked) and handlers. */
+ (void) sigprocmask(SIG_SETMASK, &omask, NULL);
+ (void) sigaction(SIGINT, &saveint, NULL);
+ (void) sigaction(SIGQUIT, &savequit, NULL);
+
+ /* Re-deliver the signal that interrupted the lock, if any. */
+ if (!ret && got_signal)
+ kill(getpid(), got_signal);
+
+ debug_return_bool(ret);
+}
+
+static bool
+timestamp_unlock_record(int fd, off_t pos, off_t len)
+{
+ debug_decl(timestamp_unlock_record, SUDOERS_DEBUG_AUTH)
+
+ if (pos >= 0 && lseek(fd, pos, SEEK_SET) == -1) {
+ sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO|SUDO_DEBUG_LINENO,
+ "unable to seek to %lld", (long long)pos);
+ debug_return_bool(false);
+ }
+ debug_return_bool(sudo_lock_region(fd, SUDO_UNLOCK, len));
+}
+
+/*
+ * Seek to the record's position and read it, locking as needed.
+ */
+static ssize_t
+ts_read(struct ts_cookie *cookie, struct timestamp_entry *entry)
+{
+ ssize_t nread = -1;
+ bool should_unlock = false;
+ debug_decl(ts_read, SUDOERS_DEBUG_AUTH)
+
+ /* If the record is not already locked, lock it now. */
+ if (!cookie->locked) {
+ if (!timestamp_lock_record(cookie->fd, cookie->pos, sizeof(*entry)))
+ goto done;
+ should_unlock = true;
+ }
+
+ /* Seek to the record position and read it. */
+#ifdef HAVE_PREAD
+ nread = pread(cookie->fd, entry, sizeof(*entry), cookie->pos);
+#else
+ if (lseek(cookie->fd, cookie->pos, SEEK_SET) == -1) {
+ sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO|SUDO_DEBUG_LINENO,
+ "unable to seek to %lld", (long long)cookie->pos);
+ goto done;
+ }
+ nread = read(cookie->fd, entry, sizeof(*entry));
+#endif
+ if (nread != sizeof(*entry)) {
+ /* short read, should not happen */
+ sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
+ "short read (%zd vs %zu), truncated time stamp file?",
+ nread, sizeof(*entry));
+ goto done;
+ }
+ sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
+ "read %zd byte record at %lld", nread, (long long)cookie->pos);
+
+done:
+ /* If the record was not locked initially, unlock it. */
+ if (should_unlock)
+ timestamp_unlock_record(cookie->fd, cookie->pos, sizeof(*entry));
+
+ debug_return_ssize_t(nread);
+}
+
+/*
+ * Lock a record in the time stamp file for exclusive access.
+ * If the record does not exist, it is created (as disabled).
+ */
+bool
+timestamp_lock(void *vcookie, struct passwd *pw)
+{
+ struct ts_cookie *cookie = vcookie;
+ struct timestamp_entry entry;
+ off_t lock_pos;
+ ssize_t nread;
+ debug_decl(timestamp_lock, SUDOERS_DEBUG_AUTH)
+
+ if (cookie == NULL) {
+ sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
+ "called with a NULL cookie!");
+ debug_return_bool(false);
+ }
+
+ /*
+ * Take a lock on the "write" record (the first record in the file).
+ * This will let us seek for the record or extend as needed
+ * without colliding with anyone else.
+ */
+ if (!timestamp_lock_record(cookie->fd, 0, sizeof(struct timestamp_entry)))
+ debug_return_bool(false);
+
+ /* Make sure the first record is of type TS_LOCKEXCL. */
+ memset(&entry, 0, sizeof(entry));
+ nread = read(cookie->fd, &entry, sizeof(entry));
+ if (nread == 0) {
+ /* New file, add TS_LOCKEXCL record. */
+ entry.version = TS_VERSION;
+ entry.size = sizeof(entry);
+ entry.type = TS_LOCKEXCL;
+ if (ts_write(cookie->fd, cookie->fname, &entry, -1) == -1)
+ debug_return_bool(false);
+ } else if (entry.type != TS_LOCKEXCL) {
+ /* Old sudo record, convert it to TS_LOCKEXCL. */
+ entry.type = TS_LOCKEXCL;
+ memset((char *)&entry + offsetof(struct timestamp_entry, type), 0,
+ nread - offsetof(struct timestamp_entry, type));
+ if (ts_write(cookie->fd, cookie->fname, &entry, 0) == -1)
+ debug_return_bool(false);
+ }
+ if (entry.size != sizeof(entry)) {
+ /* Reset position if the lock record has an unexpected size. */
+ if (lseek(cookie->fd, entry.size, SEEK_SET) == -1) {
+ sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO|SUDO_DEBUG_LINENO,
+ "unable to seek to %lld", (long long)entry.size);
+ debug_return_bool(false);
+ }
+ }
+
+ /* Search for a tty/ppid-based record or append a new one. */
+ sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
+ "searching for %s time stamp record",
+ def_timestamp_type == ppid ? "ppid" : "tty");
+ ts_init_key_nonglobal(&cookie->key, pw, TS_DISABLED);
+ if (ts_find_record(cookie->fd, &cookie->key, &entry)) {
+ sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
+ "found existing %s time stamp record",
+ def_timestamp_type == ppid ? "ppid" : "tty");
+ lock_pos = lseek(cookie->fd, 0, SEEK_CUR) - (off_t)entry.size;
+ } else {
+ sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
+ "appending new %s time stamp record",
+ def_timestamp_type == ppid ? "ppid" : "tty");
+ lock_pos = lseek(cookie->fd, 0, SEEK_CUR);
+ if (ts_write(cookie->fd, cookie->fname, &cookie->key, -1) == -1)
+ debug_return_bool(false);
+ }
+ sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
+ "%s time stamp position is %lld",
+ def_timestamp_type == ppid ? "ppid" : "tty", (long long)lock_pos);
+
+ if (def_timestamp_type == global) {
+ /*
+ * For global tickets we use a separate record lock that we
+ * cannot hold long-term since it is shared between all ttys.
+ */
+ cookie->locked = false;
+ cookie->key.type = TS_GLOBAL; /* find a global record */
+
+ if (lseek(cookie->fd, 0, SEEK_SET) == -1) {
+ sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO|SUDO_DEBUG_LINENO,
+ "unable to rewind fd");
+ debug_return_bool(false);
+ }
+ if (ts_find_record(cookie->fd, &cookie->key, &entry)) {
+ sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
+ "found existing global record");
+ cookie->pos = lseek(cookie->fd, 0, SEEK_CUR) - (off_t)entry.size;
+ } else {
+ sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
+ "appending new global record");
+ cookie->pos = lseek(cookie->fd, 0, SEEK_CUR);
+ if (ts_write(cookie->fd, cookie->fname, &cookie->key, -1) == -1)
+ debug_return_bool(false);
+ }
+ } else {
+ /* For tty/ppid tickets the tty lock is the same as the record lock. */
+ cookie->pos = lock_pos;
+ cookie->locked = true;
+ }
+
+ /* Unlock the TS_LOCKEXCL record. */
+ timestamp_unlock_record(cookie->fd, 0, sizeof(struct timestamp_entry));
+
+ /* Lock the per-tty record (may sleep). */
+ if (!timestamp_lock_record(cookie->fd, lock_pos, sizeof(struct timestamp_entry)))
+ debug_return_bool(false);
+
+ debug_return_bool(true);
+}
+
+void
+timestamp_close(void *vcookie)
+{
+ struct ts_cookie *cookie = vcookie;
+ debug_decl(timestamp_close, SUDOERS_DEBUG_AUTH)
+
+ if (cookie != NULL) {
+ close(cookie->fd);
+ free(cookie->fname);
+ free(cookie);
+ }
+
+ debug_return;
+}
+
+/*
+ * Check the time stamp file and directory and return their status.
+ * Called with the file position before the locked record to read.
+ * Returns one of TS_CURRENT, TS_OLD, TS_MISSING, TS_ERROR, TS_FATAL.
+ * Fills in fdp with an open file descriptor positioned at the
+ * appropriate (and locked) record.
+ */
+int
+timestamp_status(void *vcookie, struct passwd *pw)
+{
+ struct ts_cookie *cookie = vcookie;
+ struct timestamp_entry entry;
+ struct timespec diff, now;
+ int status = TS_ERROR; /* assume the worst */
+ ssize_t nread;
+ debug_decl(timestamp_status, SUDOERS_DEBUG_AUTH)
+
+ /* Zero timeout means don't use time stamp files. */
+ if (!sudo_timespecisset(&def_timestamp_timeout)) {
+ sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
+ "timestamps disabled");
+ status = TS_OLD;
+ goto done;
+ }
+ if (cookie == NULL || cookie->pos < 0) {
+ sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
+ "NULL cookie or invalid position");
+ status = TS_OLD;
+ goto done;
+ }
+
+#ifdef TIOCCHKVERAUTH
+ if (def_timestamp_type == kernel) {
+ int fd = open(_PATH_TTY, O_RDWR);
+ if (fd != -1) {
+ if (ioctl(fd, TIOCCHKVERAUTH) == 0)
+ status = TS_CURRENT;
+ else
+ status = TS_OLD;
+ close(fd);
+ goto done;
+ }
+ }
+#endif
+
+ /* Read the record at the correct position. */
+ if ((nread = ts_read(cookie, &entry)) != sizeof(entry))
+ goto done;
+
+ /* Make sure what we read matched the expected record. */
+ if (entry.version != TS_VERSION || entry.size != nread) {
+ /* do something else? */
+ sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
+ "invalid time stamp file @ %lld", (long long)cookie->pos);
+ status = TS_OLD;
+ goto done;
+ }
+
+ if (ISSET(entry.flags, TS_DISABLED)) {
+ sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
+ "time stamp record disabled");
+ status = TS_OLD; /* disabled via sudo -k */
+ goto done;
+ }
+
+ if (entry.type != TS_GLOBAL && entry.sid != cookie->sid) {
+ sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
+ "time stamp record sid mismatch");
+ status = TS_OLD; /* belongs to different session */
+ goto done;
+ }
+
+ /* Negative timeouts only expire manually (sudo -k). */
+ sudo_timespecclear(&diff);
+ if (sudo_timespeccmp(&def_timestamp_timeout, &diff, <)) {
+ sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
+ "time stamp record does not expire");
+ status = TS_CURRENT;
+ goto done;
+ }
+
+ /* Compare stored time stamp with current time. */
+ if (sudo_gettime_mono(&now) == -1) {
+ log_warning(0, N_("unable to read the clock"));
+ status = TS_ERROR;
+ goto done;
+ }
+ sudo_timespecsub(&now, &entry.ts, &diff);
+ if (sudo_timespeccmp(&diff, &def_timestamp_timeout, <)) {
+ status = TS_CURRENT;
+#if defined(CLOCK_MONOTONIC) || defined(__MACH__)
+ /* A monotonic clock should never run backwards. */
+ if (diff.tv_sec < 0) {
+ log_warningx(SLOG_SEND_MAIL,
+ N_("ignoring time stamp from the future"));
+ status = TS_OLD;
+ SET(entry.flags, TS_DISABLED);
+ (void)ts_write(cookie->fd, cookie->fname, &entry, cookie->pos);
+ }
+#else
+ /*
+ * Check for bogus (future) time in the stampfile.
+ * If diff / 2 > timeout, someone has been fooling with the clock.
+ */
+ sudo_timespecsub(&entry.ts, &now, &diff);
+ diff.tv_nsec /= 2;
+ if (diff.tv_sec & 1)
+ diff.tv_nsec += 500000000;
+ diff.tv_sec /= 2;
+ while (diff.tv_nsec >= 1000000000) {
+ diff.tv_sec++;
+ diff.tv_nsec -= 1000000000;
+ }
+
+ if (sudo_timespeccmp(&diff, &def_timestamp_timeout, >)) {
+ time_t tv_sec = (time_t)entry.ts.tv_sec;
+ log_warningx(SLOG_SEND_MAIL,
+ N_("time stamp too far in the future: %20.20s"),
+ 4 + ctime(&tv_sec));
+ status = TS_OLD;
+ SET(entry.flags, TS_DISABLED);
+ (void)ts_write(cookie->fd, cookie->fname, &entry, cookie->pos);
+ }
+#endif /* CLOCK_MONOTONIC */
+ } else {
+ status = TS_OLD;
+ }
+
+done:
+ debug_return_int(status);
+}
+
+/*
+ * Update the time on the time stamp file/dir or create it if necessary.
+ * Returns true on success, false on failure or -1 on setuid failure.
+ */
+bool
+timestamp_update(void *vcookie, struct passwd *pw)
+{
+ struct ts_cookie *cookie = vcookie;
+ int ret = false;
+ debug_decl(timestamp_update, SUDOERS_DEBUG_AUTH)
+
+ /* Zero timeout means don't use time stamp files. */
+ if (!sudo_timespecisset(&def_timestamp_timeout)) {
+ sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
+ "timestamps disabled");
+ goto done;
+ }
+ if (cookie == NULL || cookie->pos < 0) {
+ sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
+ "NULL cookie or invalid position");
+ goto done;
+ }
+
+#ifdef TIOCSETVERAUTH
+ if (def_timestamp_type == kernel) {
+ int fd = open(_PATH_TTY, O_RDWR);
+ if (fd != -1) {
+ int secs = def_timestamp_timeout.tv_sec;
+ if (secs > 0) {
+ if (secs > 3600)
+ secs = 3600; /* OpenBSD limitation */
+ if (ioctl(fd, TIOCSETVERAUTH, &secs) != 0)
+ sudo_warn("TIOCSETVERAUTH");
+ }
+ close(fd);
+ goto done;
+ }
+ }
+#endif
+
+ /* Update timestamp in key and enable it. */
+ CLR(cookie->key.flags, TS_DISABLED);
+ if (sudo_gettime_mono(&cookie->key.ts) == -1) {
+ log_warning(0, N_("unable to read the clock"));
+ goto done;
+ }
+
+ /* Write out the locked record. */
+ sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
+ "writing %zu byte record at %lld", sizeof(cookie->key),
+ (long long)cookie->pos);
+ if (ts_write(cookie->fd, cookie->fname, &cookie->key, cookie->pos) != -1)
+ ret = true;
+
+done:
+ debug_return_int(ret);
+}
+
+/*
+ * Remove the timestamp entry or file if unlink_it is set.
+ * Returns true on success, false on failure or -1 on setuid failure.
+ * A missing timestamp entry is not considered an error.
+ */
+int
+timestamp_remove(bool unlink_it)
+{
+ struct timestamp_entry key, entry;
+ int fd = -1, ret = true;
+ char *fname = NULL;
+ debug_decl(timestamp_remove, SUDOERS_DEBUG_AUTH)
+
+#ifdef TIOCCLRVERAUTH
+ if (def_timestamp_type == kernel) {
+ fd = open(_PATH_TTY, O_RDWR);
+ if (fd != -1) {
+ ioctl(fd, TIOCCLRVERAUTH);
+ goto done;
+ }
+ }
+#endif
+
+ if (asprintf(&fname, "%s/%s", def_timestampdir, user_name) == -1) {
+ sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+ ret = -1;
+ goto done;
+ }
+
+ /* For "sudo -K" simply unlink the time stamp file. */
+ if (unlink_it) {
+ ret = unlink(fname) ? -1 : true;
+ goto done;
+ }
+
+ /* Open time stamp file and lock it for exclusive access. */
+ fd = ts_open(fname, O_RDWR);
+ switch (fd) {
+ case TIMESTAMP_OPEN_ERROR:
+ if (errno != ENOENT)
+ ret = false;
+ goto done;
+ case TIMESTAMP_PERM_ERROR:
+ /* Already logged set_perms/restore_perms error. */
+ ret = -1;
+ goto done;
+ }
+ /* Lock first record to gain exclusive access. */
+ if (!timestamp_lock_record(fd, -1, sizeof(struct timestamp_entry))) {
+ sudo_warn(U_("unable to lock time stamp file %s"), fname);
+ ret = -1;
+ goto done;
+ }
+
+ /*
+ * Find matching entries and invalidate them.
+ */
+ ts_init_key(&key, NULL, 0, def_timestamp_type);
+ while (ts_find_record(fd, &key, &entry)) {
+ /* Back up and disable the entry. */
+ if (!ISSET(entry.flags, TS_DISABLED)) {
+ SET(entry.flags, TS_DISABLED);
+ if (lseek(fd, 0 - (off_t)sizeof(entry), SEEK_CUR) != -1) {
+ if (ts_write(fd, fname, &entry, -1) == -1)
+ ret = false;
+ }
+ }
+ }
+
+done:
+ if (fd != -1)
+ close(fd);
+ free(fname);
+ debug_return_int(ret);
+}
+
+/*
+ * Returns true if the user has already been lectured.
+ */
+bool
+already_lectured(int unused)
+{
+ char status_file[PATH_MAX];
+ struct stat sb;
+ int len;
+ debug_decl(already_lectured, SUDOERS_DEBUG_AUTH)
+
+ if (ts_secure_dir(def_lecture_status_dir, false, true)) {
+ len = snprintf(status_file, sizeof(status_file), "%s/%s",
+ def_lecture_status_dir, user_name);
+ if (len > 0 && (size_t)len < sizeof(status_file)) {
+ debug_return_bool(stat(status_file, &sb) == 0);
+ }
+ log_warningx(SLOG_SEND_MAIL, N_("lecture status path too long: %s/%s"),
+ def_lecture_status_dir, user_name);
+ }
+ debug_return_bool(false);
+}
+
+/*
+ * Create the lecture status file.
+ * Returns true on success, false on failure or -1 on setuid failure.
+ */
+int
+set_lectured(void)
+{
+ char lecture_status[PATH_MAX];
+ int len, fd, ret = false;
+ debug_decl(set_lectured, SUDOERS_DEBUG_AUTH)
+
+ len = snprintf(lecture_status, sizeof(lecture_status), "%s/%s",
+ def_lecture_status_dir, user_name);
+ if (len <= 0 || (size_t)len >= sizeof(lecture_status)) {
+ log_warningx(SLOG_SEND_MAIL, N_("lecture status path too long: %s/%s"),
+ def_lecture_status_dir, user_name);
+ goto done;
+ }
+
+ /* Sanity check lecture dir and create if missing. */
+ if (!ts_secure_dir(def_lecture_status_dir, true, false))
+ goto done;
+
+ /* Create lecture file. */
+ fd = ts_open(lecture_status, O_WRONLY|O_CREAT|O_EXCL);
+ switch (fd) {
+ case TIMESTAMP_OPEN_ERROR:
+ /* Failed to open, not a fatal error. */
+ break;
+ case TIMESTAMP_PERM_ERROR:
+ /* Already logged set_perms/restore_perms error. */
+ ret = -1;
+ break;
+ default:
+ /* Success. */
+ close(fd);
+ ret = true;
+ break;
+ }
+
+done:
+ debug_return_int(ret);
+}