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-rw-r--r--debian/patches/machine-basic-factor-out-helper-function-to-add-airlocked.patch499
1 files changed, 499 insertions, 0 deletions
diff --git a/debian/patches/machine-basic-factor-out-helper-function-to-add-airlocked.patch b/debian/patches/machine-basic-factor-out-helper-function-to-add-airlocked.patch
new file mode 100644
index 0000000..965e925
--- /dev/null
+++ b/debian/patches/machine-basic-factor-out-helper-function-to-add-airlocked.patch
@@ -0,0 +1,499 @@
+From: Luca Boccassi <luca.boccassi@microsoft.com>
+Date: Thu, 13 Aug 2020 14:01:34 +0100
+Subject: machine/basic: factor out helper function to add airlocked mount to
+ namespace
+
+(cherry picked from commit 6af52c3a458691b016bedeba34c1e72294a67c81)
+---
+ src/machine/machine-dbus.c | 214 ++------------------------------------------
+ src/shared/mount-util.c | 217 +++++++++++++++++++++++++++++++++++++++++++++
+ src/shared/mount-util.h | 2 +
+ 3 files changed, 227 insertions(+), 206 deletions(-)
+
+diff --git a/src/machine/machine-dbus.c b/src/machine/machine-dbus.c
+index 1105008..3c8f4fd 100644
+--- a/src/machine/machine-dbus.c
++++ b/src/machine/machine-dbus.c
+@@ -810,17 +810,9 @@ int bus_machine_method_open_shell(sd_bus_message *message, void *userdata, sd_bu
+ }
+
+ int bus_machine_method_bind_mount(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+- _cleanup_close_pair_ int errno_pipe_fd[2] = { -1, -1 };
+- char mount_slave[] = "/tmp/propagate.XXXXXX", *mount_tmp, *mount_outside, *p;
+- bool mount_slave_created = false, mount_slave_mounted = false,
+- mount_tmp_created = false, mount_tmp_mounted = false,
+- mount_outside_created = false, mount_outside_mounted = false;
+- _cleanup_free_ char *chased_src = NULL;
+ int read_only, make_file_or_directory;
+- const char *dest, *src;
++ const char *dest, *src, *propagate_directory;
+ Machine *m = userdata;
+- struct stat st;
+- pid_t child;
+ uid_t uid;
+ int r;
+
+@@ -862,205 +854,15 @@ int bus_machine_method_bind_mount(sd_bus_message *message, void *userdata, sd_bu
+ if (uid != 0)
+ return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED, "Can't bind mount on container with user namespacing applied.");
+
+- /* One day, when bind mounting /proc/self/fd/n works across
+- * namespace boundaries we should rework this logic to make
+- * use of it... */
+-
+- p = strjoina("/run/systemd/nspawn/propagate/", m->name, "/");
+- if (laccess(p, F_OK) < 0)
+- return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED, "Container does not allow propagation of mount points.");
+-
+- r = chase_symlinks(src, NULL, CHASE_TRAIL_SLASH, &chased_src, NULL);
++ propagate_directory = strjoina("/run/systemd/nspawn/propagate/", m->name);
++ r = bind_mount_in_namespace(m->leader,
++ propagate_directory,
++ "/run/host/incoming/",
++ src, dest, read_only, make_file_or_directory);
+ if (r < 0)
+- return sd_bus_error_set_errnof(error, r, "Failed to resolve source path: %m");
+-
+- if (lstat(chased_src, &st) < 0)
+- return sd_bus_error_set_errnof(error, errno, "Failed to stat() source path: %m");
+- if (S_ISLNK(st.st_mode)) /* This shouldn't really happen, given that we just chased the symlinks above, but let's better be safe… */
+- return sd_bus_error_setf(error, SD_BUS_ERROR_NOT_SUPPORTED, "Source directory can't be a symbolic link");
+-
+- /* Our goal is to install a new bind mount into the container,
+- possibly read-only. This is irritatingly complex
+- unfortunately, currently.
+-
+- First, we start by creating a private playground in /tmp,
+- that we can mount MS_SLAVE. (Which is necessary, since
+- MS_MOVE cannot be applied to mounts with MS_SHARED parent
+- mounts.) */
+-
+- if (!mkdtemp(mount_slave))
+- return sd_bus_error_set_errnof(error, errno, "Failed to create playground %s: %m", mount_slave);
+-
+- mount_slave_created = true;
+-
+- r = mount_nofollow_verbose(LOG_DEBUG, mount_slave, mount_slave, NULL, MS_BIND, NULL);
+- if (r < 0) {
+- sd_bus_error_set_errnof(error, r, "Failed to make bind mount %s: %m", mount_slave);
+- goto finish;
+- }
+-
+- mount_slave_mounted = true;
+-
+- r = mount_nofollow_verbose(LOG_DEBUG, NULL, mount_slave, NULL, MS_SLAVE, NULL);
+- if (r < 0) {
+- sd_bus_error_set_errnof(error, r, "Failed to remount slave %s: %m", mount_slave);
+- goto finish;
+- }
+-
+- /* Second, we mount the source file or directory to a directory inside of our MS_SLAVE playground. */
+- mount_tmp = strjoina(mount_slave, "/mount");
+- r = make_mount_point_inode_from_stat(&st, mount_tmp, 0700);
+- if (r < 0) {
+- sd_bus_error_set_errnof(error, r, "Failed to create temporary mount point %s: %m", mount_tmp);
+- goto finish;
+- }
+-
+- mount_tmp_created = true;
+-
+- r = mount_nofollow_verbose(LOG_DEBUG, chased_src, mount_tmp, NULL, MS_BIND, NULL);
+- if (r < 0) {
+- sd_bus_error_set_errnof(error, r, "Failed to mount %s: %m", chased_src);
+- goto finish;
+- }
+-
+- mount_tmp_mounted = true;
+-
+- /* Third, we remount the new bind mount read-only if requested. */
+- if (read_only) {
+- r = mount_nofollow_verbose(LOG_DEBUG, NULL, mount_tmp, NULL, MS_BIND|MS_REMOUNT|MS_RDONLY, NULL);
+- if (r < 0) {
+- sd_bus_error_set_errnof(error, r, "Failed to remount read-only %s: %m", mount_tmp);
+- goto finish;
+- }
+- }
+-
+- /* Fourth, we move the new bind mount into the propagation directory. This way it will appear there read-only
+- * right-away. */
+-
+- mount_outside = strjoina("/run/systemd/nspawn/propagate/", m->name, "/XXXXXX");
+- if (S_ISDIR(st.st_mode))
+- r = mkdtemp(mount_outside) ? 0 : -errno;
+- else {
+- r = mkostemp_safe(mount_outside);
+- safe_close(r);
+- }
+- if (r < 0) {
+- sd_bus_error_set_errnof(error, r, "Cannot create propagation file or directory %s: %m", mount_outside);
+- goto finish;
+- }
+-
+- mount_outside_created = true;
+-
+- r = mount_nofollow_verbose(LOG_DEBUG, mount_tmp, mount_outside, NULL, MS_MOVE, NULL);
+- if (r < 0) {
+- sd_bus_error_set_errnof(error, r, "Failed to move %s to %s: %m", mount_tmp, mount_outside);
+- goto finish;
+- }
+-
+- mount_outside_mounted = true;
+- mount_tmp_mounted = false;
+-
+- if (S_ISDIR(st.st_mode))
+- (void) rmdir(mount_tmp);
+- else
+- (void) unlink(mount_tmp);
+- mount_tmp_created = false;
+-
+- (void) umount_verbose(LOG_DEBUG, mount_slave, UMOUNT_NOFOLLOW);
+- mount_slave_mounted = false;
+-
+- (void) rmdir(mount_slave);
+- mount_slave_created = false;
+-
+- if (pipe2(errno_pipe_fd, O_CLOEXEC|O_NONBLOCK) < 0) {
+- r = sd_bus_error_set_errnof(error, errno, "Failed to create pipe: %m");
+- goto finish;
+- }
+-
+- r = safe_fork("(sd-bindmnt)", FORK_RESET_SIGNALS, &child);
+- if (r < 0) {
+- sd_bus_error_set_errnof(error, r, "Failed to fork(): %m");
+- goto finish;
+- }
+- if (r == 0) {
+- const char *mount_inside, *q;
+- int mntfd;
+-
+- errno_pipe_fd[0] = safe_close(errno_pipe_fd[0]);
+-
+- q = procfs_file_alloca(m->leader, "ns/mnt");
+- mntfd = open(q, O_RDONLY|O_NOCTTY|O_CLOEXEC);
+- if (mntfd < 0) {
+- r = log_error_errno(errno, "Failed to open mount namespace of leader: %m");
+- goto child_fail;
+- }
+-
+- if (setns(mntfd, CLONE_NEWNS) < 0) {
+- r = log_error_errno(errno, "Failed to join namespace of leader: %m");
+- goto child_fail;
+- }
+-
+- if (make_file_or_directory) {
+- (void) mkdir_parents(dest, 0755);
+- (void) make_mount_point_inode_from_stat(&st, dest, 0700);
+- }
+-
+- mount_inside = strjoina("/run/host/incoming/", basename(mount_outside));
+- r = mount_nofollow_verbose(LOG_ERR, mount_inside, dest, NULL, MS_MOVE, NULL);
+- if (r < 0)
+- goto child_fail;
+-
+- _exit(EXIT_SUCCESS);
+-
+- child_fail:
+- (void) write(errno_pipe_fd[1], &r, sizeof(r));
+- errno_pipe_fd[1] = safe_close(errno_pipe_fd[1]);
+-
+- _exit(EXIT_FAILURE);
+- }
+-
+- errno_pipe_fd[1] = safe_close(errno_pipe_fd[1]);
++ return sd_bus_error_set_errnof(error, r, "Failed to mount %s on %s in machine's namespace: %m", src, dest);
+
+- r = wait_for_terminate_and_check("(sd-bindmnt)", child, 0);
+- if (r < 0) {
+- r = sd_bus_error_set_errnof(error, r, "Failed to wait for child: %m");
+- goto finish;
+- }
+- if (r != EXIT_SUCCESS) {
+- if (read(errno_pipe_fd[0], &r, sizeof(r)) == sizeof(r))
+- r = sd_bus_error_set_errnof(error, r, "Failed to mount: %m");
+- else
+- r = sd_bus_error_setf(error, SD_BUS_ERROR_FAILED, "Child failed.");
+- goto finish;
+- }
+-
+- r = sd_bus_reply_method_return(message, NULL);
+-
+-finish:
+- if (mount_outside_mounted)
+- (void) umount_verbose(LOG_DEBUG, mount_outside, UMOUNT_NOFOLLOW);
+- if (mount_outside_created) {
+- if (S_ISDIR(st.st_mode))
+- (void) rmdir(mount_outside);
+- else
+- (void) unlink(mount_outside);
+- }
+-
+- if (mount_tmp_mounted)
+- (void) umount_verbose(LOG_DEBUG, mount_tmp, UMOUNT_NOFOLLOW);
+- if (mount_tmp_created) {
+- if (S_ISDIR(st.st_mode))
+- (void) rmdir(mount_tmp);
+- else
+- (void) unlink(mount_tmp);
+- }
+-
+- if (mount_slave_mounted)
+- (void) umount_verbose(LOG_DEBUG, mount_slave, UMOUNT_NOFOLLOW);
+- if (mount_slave_created)
+- (void) rmdir(mount_slave);
+-
+- return r;
++ return sd_bus_reply_method_return(message, NULL);
+ }
+
+ int bus_machine_method_copy(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+diff --git a/src/shared/mount-util.c b/src/shared/mount-util.c
+index b19b384..4cfbb55 100644
+--- a/src/shared/mount-util.c
++++ b/src/shared/mount-util.c
+@@ -14,15 +14,18 @@
+ #include "fs-util.h"
+ #include "hashmap.h"
+ #include "libmount-util.h"
++#include "mkdir.h"
+ #include "mount-util.h"
+ #include "mountpoint-util.h"
+ #include "parse-util.h"
+ #include "path-util.h"
++#include "process-util.h"
+ #include "set.h"
+ #include "stat-util.h"
+ #include "stdio-util.h"
+ #include "string-util.h"
+ #include "strv.h"
++#include "tmpfile-util.h"
+
+ int mount_fd(const char *source,
+ int target_fd,
+@@ -742,3 +745,217 @@ int mount_option_mangle(
+
+ return 0;
+ }
++
++int bind_mount_in_namespace(
++ pid_t target,
++ const char *propagate_path,
++ const char *incoming_path,
++ const char *src,
++ const char *dest,
++ bool read_only,
++ bool make_file_or_directory) {
++
++ _cleanup_close_pair_ int errno_pipe_fd[2] = { -1, -1 };
++ char mount_slave[] = "/tmp/propagate.XXXXXX", *mount_tmp, *mount_outside, *p;
++ bool mount_slave_created = false, mount_slave_mounted = false,
++ mount_tmp_created = false, mount_tmp_mounted = false,
++ mount_outside_created = false, mount_outside_mounted = false;
++ _cleanup_free_ char *chased_src = NULL;
++ struct stat st;
++ pid_t child;
++ int r;
++
++ assert(target > 0);
++ assert(propagate_path);
++ assert(incoming_path);
++ assert(src);
++ assert(dest);
++
++ /* One day, when bind mounting /proc/self/fd/n works across
++ * namespace boundaries we should rework this logic to make
++ * use of it... */
++
++ p = strjoina(propagate_path, "/");
++ r = laccess(p, F_OK);
++ if (r < 0)
++ return log_debug_errno(r == -ENOENT ? SYNTHETIC_ERRNO(EOPNOTSUPP) : r, "Target does not allow propagation of mount points");
++
++ r = chase_symlinks(src, NULL, CHASE_TRAIL_SLASH, &chased_src, NULL);
++ if (r < 0)
++ return log_debug_errno(r, "Failed to resolve source path of %s: %m", src);
++
++ if (lstat(chased_src, &st) < 0)
++ return log_debug_errno(errno, "Failed to stat() resolved source path %s: %m", chased_src);
++ if (S_ISLNK(st.st_mode)) /* This shouldn't really happen, given that we just chased the symlinks above, but let's better be safe… */
++ return log_debug_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "Source directory %s can't be a symbolic link", chased_src);
++
++ /* Our goal is to install a new bind mount into the container,
++ possibly read-only. This is irritatingly complex
++ unfortunately, currently.
++
++ First, we start by creating a private playground in /tmp,
++ that we can mount MS_SLAVE. (Which is necessary, since
++ MS_MOVE cannot be applied to mounts with MS_SHARED parent
++ mounts.) */
++
++ if (!mkdtemp(mount_slave))
++ return log_debug_errno(errno, "Failed to create playground %s: %m", mount_slave);
++
++ mount_slave_created = true;
++
++ r = mount_nofollow_verbose(LOG_DEBUG, mount_slave, mount_slave, NULL, MS_BIND, NULL);
++ if (r < 0)
++ goto finish;
++
++ mount_slave_mounted = true;
++
++ r = mount_nofollow_verbose(LOG_DEBUG, NULL, mount_slave, NULL, MS_SLAVE, NULL);
++ if (r < 0)
++ goto finish;
++
++ /* Second, we mount the source file or directory to a directory inside of our MS_SLAVE playground. */
++ mount_tmp = strjoina(mount_slave, "/mount");
++ r = make_mount_point_inode_from_stat(&st, mount_tmp, 0700);
++ if (r < 0) {
++ log_debug_errno(r, "Failed to create temporary mount point %s: %m", mount_tmp);
++ goto finish;
++ }
++
++ mount_tmp_created = true;
++
++ r = mount_nofollow_verbose(LOG_DEBUG, chased_src, mount_tmp, NULL, MS_BIND, NULL);
++ if (r < 0)
++ goto finish;
++
++ mount_tmp_mounted = true;
++
++ /* Third, we remount the new bind mount read-only if requested. */
++ if (read_only) {
++ r = mount_nofollow_verbose(LOG_DEBUG, NULL, mount_tmp, NULL, MS_BIND|MS_REMOUNT|MS_RDONLY, NULL);
++ if (r < 0)
++ goto finish;
++ }
++
++ /* Fourth, we move the new bind mount into the propagation directory. This way it will appear there read-only
++ * right-away. */
++
++ mount_outside = strjoina(propagate_path, "/XXXXXX");
++ if (S_ISDIR(st.st_mode))
++ r = mkdtemp(mount_outside) ? 0 : -errno;
++ else {
++ r = mkostemp_safe(mount_outside);
++ safe_close(r);
++ }
++ if (r < 0) {
++ log_debug_errno(r, "Cannot create propagation file or directory %s: %m", mount_outside);
++ goto finish;
++ }
++
++ mount_outside_created = true;
++
++ r = mount_nofollow_verbose(LOG_DEBUG, mount_tmp, mount_outside, NULL, MS_MOVE, NULL);
++ if (r < 0)
++ goto finish;
++
++ mount_outside_mounted = true;
++ mount_tmp_mounted = false;
++
++ if (S_ISDIR(st.st_mode))
++ (void) rmdir(mount_tmp);
++ else
++ (void) unlink(mount_tmp);
++ mount_tmp_created = false;
++
++ (void) umount_verbose(LOG_DEBUG, mount_slave, UMOUNT_NOFOLLOW);
++ mount_slave_mounted = false;
++
++ (void) rmdir(mount_slave);
++ mount_slave_created = false;
++
++ if (pipe2(errno_pipe_fd, O_CLOEXEC|O_NONBLOCK) < 0) {
++ log_debug_errno(errno, "Failed to create pipe: %m");
++ goto finish;
++ }
++
++ r = safe_fork("(sd-bindmnt)", FORK_RESET_SIGNALS, &child);
++ if (r < 0)
++ goto finish;
++ if (r == 0) {
++ const char *mount_inside, *q;
++ int mntfd;
++
++ errno_pipe_fd[0] = safe_close(errno_pipe_fd[0]);
++
++ q = procfs_file_alloca(target, "ns/mnt");
++ mntfd = open(q, O_RDONLY|O_NOCTTY|O_CLOEXEC);
++ if (mntfd < 0) {
++ r = log_error_errno(errno, "Failed to open mount namespace of leader: %m");
++ goto child_fail;
++ }
++
++ if (setns(mntfd, CLONE_NEWNS) < 0) {
++ r = log_error_errno(errno, "Failed to join namespace of leader: %m");
++ goto child_fail;
++ }
++
++ if (make_file_or_directory) {
++ (void) mkdir_parents(dest, 0755);
++ (void) make_mount_point_inode_from_stat(&st, dest, 0700);
++ }
++
++ /* Fifth, move the mount to the right place inside */
++ mount_inside = strjoina(incoming_path, basename(mount_outside));
++ r = mount_nofollow_verbose(LOG_ERR, mount_inside, dest, NULL, MS_MOVE, NULL);
++ if (r < 0)
++ goto child_fail;
++
++ _exit(EXIT_SUCCESS);
++
++ child_fail:
++ (void) write(errno_pipe_fd[1], &r, sizeof(r));
++ errno_pipe_fd[1] = safe_close(errno_pipe_fd[1]);
++
++ _exit(EXIT_FAILURE);
++ }
++
++ errno_pipe_fd[1] = safe_close(errno_pipe_fd[1]);
++
++ r = wait_for_terminate_and_check("(sd-bindmnt)", child, 0);
++ if (r < 0) {
++ log_debug_errno(r, "Failed to wait for child: %m");
++ goto finish;
++ }
++ if (r != EXIT_SUCCESS) {
++ if (read(errno_pipe_fd[0], &r, sizeof(r)) == sizeof(r))
++ log_debug_errno(r, "Failed to mount: %m");
++ else
++ log_debug("Child failed.");
++ goto finish;
++ }
++
++finish:
++ if (mount_outside_mounted)
++ (void) umount_verbose(LOG_DEBUG, mount_outside, UMOUNT_NOFOLLOW);
++ if (mount_outside_created) {
++ if (S_ISDIR(st.st_mode))
++ (void) rmdir(mount_outside);
++ else
++ (void) unlink(mount_outside);
++ }
++
++ if (mount_tmp_mounted)
++ (void) umount_verbose(LOG_DEBUG, mount_tmp, UMOUNT_NOFOLLOW);
++ if (mount_tmp_created) {
++ if (S_ISDIR(st.st_mode))
++ (void) rmdir(mount_tmp);
++ else
++ (void) unlink(mount_tmp);
++ }
++
++ if (mount_slave_mounted)
++ (void) umount_verbose(LOG_DEBUG, mount_slave, UMOUNT_NOFOLLOW);
++ if (mount_slave_created)
++ (void) rmdir(mount_slave);
++
++ return r;
++}
+diff --git a/src/shared/mount-util.h b/src/shared/mount-util.h
+index 6202008..c3500a0 100644
+--- a/src/shared/mount-util.h
++++ b/src/shared/mount-util.h
+@@ -97,3 +97,5 @@ static inline char* umount_and_rmdir_and_free(char *p) {
+ return NULL;
+ }
+ DEFINE_TRIVIAL_CLEANUP_FUNC(char*, umount_and_rmdir_and_free);
++
++int bind_mount_in_namespace(pid_t target, const char *propagate_path, const char *incoming_path, const char *src, const char *dest, bool read_only, bool make_file_or_directory);