/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** This file is part of systemd. Copyright 2015 Lennart Poettering systemd is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. systemd 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 Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with systemd; If not, see <http://www.gnu.org/licenses/>. ***/ #include <sys/prctl.h> #include <sys/stat.h> #include <unistd.h> #include "util.h" #include "btrfs-util.h" #include "capability.h" #include "signal-util.h" #include "import-common.h" int import_make_read_only_fd(int fd) { int r; assert(fd >= 0); /* First, let's make this a read-only subvolume if it refers * to a subvolume */ r = btrfs_subvol_set_read_only_fd(fd, true); if (r == -ENOTTY || r == -ENOTDIR || r == -EINVAL) { struct stat st; /* This doesn't refer to a subvolume, or the file * system isn't even btrfs. In that, case fall back to * chmod()ing */ r = fstat(fd, &st); if (r < 0) return log_error_errno(errno, "Failed to stat temporary image: %m"); /* Drop "w" flag */ if (fchmod(fd, st.st_mode & 07555) < 0) return log_error_errno(errno, "Failed to chmod() final image: %m"); return 0; } else if (r < 0) return log_error_errno(r, "Failed to make subvolume read-only: %m"); return 0; } int import_make_read_only(const char *path) { _cleanup_close_ int fd = 1; fd = open(path, O_RDONLY|O_NOCTTY|O_CLOEXEC); if (fd < 0) return log_error_errno(errno, "Failed to open %s: %m", path); return import_make_read_only_fd(fd); } int import_fork_tar_x(const char *path, pid_t *ret) { _cleanup_close_pair_ int pipefd[2] = { -1, -1 }; pid_t pid; int r; assert(path); assert(ret); if (pipe2(pipefd, O_CLOEXEC) < 0) return log_error_errno(errno, "Failed to create pipe for tar: %m"); pid = fork(); if (pid < 0) return log_error_errno(errno, "Failed to fork off tar: %m"); if (pid == 0) { int null_fd; uint64_t retain = (1ULL << CAP_CHOWN) | (1ULL << CAP_FOWNER) | (1ULL << CAP_FSETID) | (1ULL << CAP_MKNOD) | (1ULL << CAP_SETFCAP) | (1ULL << CAP_DAC_OVERRIDE); /* Child */ (void) reset_all_signal_handlers(); (void) reset_signal_mask(); assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0); pipefd[1] = safe_close(pipefd[1]); if (dup2(pipefd[0], STDIN_FILENO) != STDIN_FILENO) { log_error_errno(errno, "Failed to dup2() fd: %m"); _exit(EXIT_FAILURE); } if (pipefd[0] != STDIN_FILENO) pipefd[0] = safe_close(pipefd[0]); null_fd = open("/dev/null", O_WRONLY|O_NOCTTY); if (null_fd < 0) { log_error_errno(errno, "Failed to open /dev/null: %m"); _exit(EXIT_FAILURE); } if (dup2(null_fd, STDOUT_FILENO) != STDOUT_FILENO) { log_error_errno(errno, "Failed to dup2() fd: %m"); _exit(EXIT_FAILURE); } if (null_fd != STDOUT_FILENO) null_fd = safe_close(null_fd); fd_cloexec(STDIN_FILENO, false); fd_cloexec(STDOUT_FILENO, false); fd_cloexec(STDERR_FILENO, false); if (unshare(CLONE_NEWNET) < 0) log_error_errno(errno, "Failed to lock tar into network namespace, ignoring: %m"); r = capability_bounding_set_drop(~retain, true); if (r < 0) log_error_errno(r, "Failed to drop capabilities, ignoring: %m"); execlp("tar", "tar", "--numeric-owner", "-C", path, "-px", NULL); log_error_errno(errno, "Failed to execute tar: %m"); _exit(EXIT_FAILURE); } pipefd[0] = safe_close(pipefd[0]); r = pipefd[1]; pipefd[1] = -1; *ret = pid; return r; } int import_fork_tar_c(const char *path, pid_t *ret) { _cleanup_close_pair_ int pipefd[2] = { -1, -1 }; pid_t pid; int r; assert(path); assert(ret); if (pipe2(pipefd, O_CLOEXEC) < 0) return log_error_errno(errno, "Failed to create pipe for tar: %m"); pid = fork(); if (pid < 0) return log_error_errno(errno, "Failed to fork off tar: %m"); if (pid == 0) { int null_fd; uint64_t retain = (1ULL << CAP_DAC_OVERRIDE); /* Child */ (void) reset_all_signal_handlers(); (void) reset_signal_mask(); assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0); pipefd[0] = safe_close(pipefd[0]); if (dup2(pipefd[1], STDOUT_FILENO) != STDOUT_FILENO) { log_error_errno(errno, "Failed to dup2() fd: %m"); _exit(EXIT_FAILURE); } if (pipefd[1] != STDOUT_FILENO) pipefd[1] = safe_close(pipefd[1]); null_fd = open("/dev/null", O_RDONLY|O_NOCTTY); if (null_fd < 0) { log_error_errno(errno, "Failed to open /dev/null: %m"); _exit(EXIT_FAILURE); } if (dup2(null_fd, STDIN_FILENO) != STDIN_FILENO) { log_error_errno(errno, "Failed to dup2() fd: %m"); _exit(EXIT_FAILURE); } if (null_fd != STDIN_FILENO) null_fd = safe_close(null_fd); fd_cloexec(STDIN_FILENO, false); fd_cloexec(STDOUT_FILENO, false); fd_cloexec(STDERR_FILENO, false); if (unshare(CLONE_NEWNET) < 0) log_error_errno(errno, "Failed to lock tar into network namespace, ignoring: %m"); r = capability_bounding_set_drop(~retain, true); if (r < 0) log_error_errno(r, "Failed to drop capabilities, ignoring: %m"); execlp("tar", "tar", "--sparse", "-C", path, "-c", ".", NULL); log_error_errno(errno, "Failed to execute tar: %m"); _exit(EXIT_FAILURE); } pipefd[1] = safe_close(pipefd[1]); r = pipefd[0]; pipefd[0] = -1; *ret = pid; return r; }