/* * The Qubes OS Project, http://www.qubes-os.org * * Copyright (C) 2010 Rafal Wojtczuk * * This program 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 2 * of the License, or (at your option) any later version. * * This program 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, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. * */ #include #include #include #include #include #include #include #include #include #include #include #include "dvm.h" int parse_events(char *buf, int len) { int i = 0; while (i < len) { struct inotify_event *ev = (struct inotify_event *) (buf + i); if ((ev->mask & IN_UNMOUNT) || (ev->mask & IN_IGNORED)) return 1; i += sizeof(struct inotify_event) + ev->len; } return 0; } #define BUFLEN 1024 void wait_for_umount(char *name) { char buf[BUFLEN]; int fd = inotify_init(); int len; int ret = inotify_add_watch(fd, name, IN_ATTRIB); if (ret < 0) { perror("inotify_add_watch"); return; } for (;;) { len = read(fd, buf, BUFLEN - 1); if (len <= 0) { perror("read inotify"); return; } if (parse_events(buf, len)) return; } } void background() { int i, fd; for (i = 0; i < 256; i++) close(i); fd = open("/dev/null", O_RDWR); for (i = 0; i <= 2; i++) dup2(fd, i); switch (fork()) { case -1: exit(1); case 0: break; default: exit(0); } } int check_legal_filename(char *name) { if (index(name, '/')) { syslog(LOG_DAEMON | LOG_ERR, "the received filename contains /"); return 0; } return 1; } void drop_to_user() { struct passwd *pw = getpwnam("user"); if (pw) setuid(pw->pw_uid); } int copy_from_xvdh(int destfd, int srcfd, unsigned long long count) { int n, size; char buf[4096]; unsigned long long total = 0; while (total < count) { if (count - total > sizeof(buf)) size = sizeof(buf); else size = count - total; n = read(srcfd, buf, size); if (n != size) { syslog(LOG_DAEMON | LOG_ERR, "reading xvdh"); return 0; } if (write(destfd, buf, size) != size) { syslog(LOG_DAEMON | LOG_ERR, "writing file"); return 0; } total += size; } return 1; } void redirect_stderr() { int fd = open("/var/log/dvm.log", O_CREAT | O_TRUNC | O_WRONLY, 0600); if (fd < 0) { syslog(LOG_DAEMON | LOG_ERR, "open dvm.log"); exit(1); } dup2(fd, 2); } void suicide(struct xs_handle *xs) { xs_write(xs, XBT_NULL, "device/qpen", "killme", 6); xs_daemon_close(xs); exit(1); } // we are DVM, AppVM sends us a document to work on // /dev/xvdh contains the dvm_header and document data void dvm_transaction_request(char *seq, struct xs_handle *xs) { char filename[1024], cmdbuf[1024]; struct dvm_header header; int xvdh_fd, file_fd; char *src_vm; unsigned int len; struct stat stat_pre, stat_post; xvdh_fd = open("/dev/xvdh", O_RDONLY); if (read(xvdh_fd, &header, sizeof(header)) != sizeof(header)) { syslog(LOG_DAEMON | LOG_ERR, "read dvm_header"); suicide(xs); } header.name[sizeof(header.name) - 1] = 0; if (!check_legal_filename(header.name)) suicide(xs); snprintf(filename, sizeof(filename), "/tmp/%s", header.name); drop_to_user(); file_fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600); if (file_fd < 0) { syslog(LOG_DAEMON | LOG_ERR, "open file"); suicide(xs); } if (!copy_from_xvdh(file_fd, xvdh_fd, header.file_size)) suicide(xs); close(xvdh_fd); close(file_fd); if (stat(filename, &stat_pre)) { syslog(LOG_DAEMON | LOG_ERR, "stat pre"); suicide(xs); } snprintf(cmdbuf, sizeof(cmdbuf), "DISPLAY=:0 mimeopen -n '/tmp/%s'", header.name); if (system(cmdbuf)) system("DISPLAY=:0 /usr/bin/kdialog --sorry 'Unable to handle mimetype of the requested file'"); if (stat(filename, &stat_post)) { syslog(LOG_DAEMON | LOG_ERR, "stat post"); suicide(xs); } src_vm = xs_read(xs, XBT_NULL, "qubes_blocksrc", &len); xs_write(xs, XBT_NULL, "device/qpen", "umount", 6); if (stat_pre.st_mtime == stat_post.st_mtime) suicide(xs); xs_daemon_close(xs); // if the modify timestamp of the document file has changed, write back the // modified content to the requestor AppVM execl("/usr/lib/qubes/qvm-dvm-transfer", "qvm-dvm-transfer", src_vm, filename, seq, NULL); syslog(LOG_DAEMON | LOG_ERR, "execl qvm-dvm-transfer"); suicide(xs); } // we are AppVM, DVM sends us a modified document // /dev/xvdh contains the dvm_header and document data void dvm_transaction_return(char *seq_string, struct xs_handle *xs) { int seq = strtoul(seq_string, 0, 10); char db_name[1024]; char file_name[1024]; int db_fd, file_fd, xvdh_fd; struct dvm_header header; xvdh_fd = open("/dev/xvdh", O_RDONLY); if (xvdh_fd < 0) { syslog(LOG_DAEMON | LOG_ERR, "open xvdh"); goto out_err; } if (read(xvdh_fd, &header, sizeof(header)) != sizeof(header)) { syslog(LOG_DAEMON | LOG_ERR, "read dvm_header"); goto out_err; } drop_to_user(); // read the file name for which the open-in-dvm with transaction=="seq" was started snprintf(db_name, sizeof(db_name), DBDIR "/%d", seq); db_fd = open(db_name, O_RDONLY); if (!db_fd) { syslog(LOG_DAEMON | LOG_ERR, "open db"); goto out_err; } if (read(db_fd, file_name, sizeof(file_name)) < 0) { syslog(LOG_DAEMON | LOG_ERR, "read db"); goto out_err; } close(db_fd); file_fd = open(file_name, O_WRONLY | O_TRUNC); if (file_fd < 0) { syslog(LOG_DAEMON | LOG_ERR, "open filename"); goto out_err; } copy_from_xvdh(file_fd, xvdh_fd, header.file_size); close(xvdh_fd); close(file_fd); out_err: xs_write(xs, XBT_NULL, "device/qpen", "umount", 6); xs_daemon_close(xs); } void dvm_transaction(char *seq, struct xs_handle *xs) { struct stat st; redirect_stderr(); if (stat("/etc/this_is_dvm", &st)) dvm_transaction_return(seq, xs); else dvm_transaction_request(seq, xs); } #define MOUNTDIR "/mnt/incoming" int main() { struct xs_handle *xs; char *seq; unsigned int len; background(); openlog("qubes_add_pendrive_script", LOG_CONS | LOG_PID, LOG_DAEMON); xs = xs_domain_open(); if (!xs) { syslog(LOG_DAEMON | LOG_ERR, "xs_domain_open"); exit(1); } seq = xs_read(xs, XBT_NULL, "qubes_transaction_seq", &len); if (seq && len > 0 && strcmp(seq, "0")) { dvm_transaction(seq, xs); exit(0); } if (!system("su - user -c 'mount " MOUNTDIR "'")) wait_for_umount(MOUNTDIR "/."); xs_write(xs, XBT_NULL, "device/qpen", "umount", 6); xs_daemon_close(xs); return 0; }