core/namespace: reafactor applying mounts in a separate function
The setup_namespace code to apply mounts is a big if block that keeps growing, so refactor it in a separate function.
This commit is contained in:
Luca Boccassi
+111
-93
@@ -1003,7 +1003,7 @@ static int mount_run(const MountEntry *m) {
|
||||
return mount_tmpfs(m);
|
||||
}
|
||||
|
||||
static int mount_images(const MountEntry *m) {
|
||||
static int mount_image(const MountEntry *m) {
|
||||
int r;
|
||||
|
||||
assert(m);
|
||||
@@ -1049,7 +1049,7 @@ static int follow_symlink(
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int apply_mount(
|
||||
static int apply_one_mount(
|
||||
const char *root_directory,
|
||||
MountEntry *m,
|
||||
const NamespaceInfo *ns_info) {
|
||||
@@ -1173,7 +1173,7 @@ static int apply_mount(
|
||||
return mount_run(m);
|
||||
|
||||
case MOUNT_IMAGES:
|
||||
return mount_images(m);
|
||||
return mount_image(m);
|
||||
|
||||
default:
|
||||
assert_not_reached("Unknown mode");
|
||||
@@ -1378,6 +1378,110 @@ static void normalize_mounts(const char *root_directory, MountEntry *mounts, siz
|
||||
drop_nop(mounts, n_mounts);
|
||||
}
|
||||
|
||||
static int apply_mounts(
|
||||
const char *root,
|
||||
const NamespaceInfo *ns_info,
|
||||
MountEntry *mounts,
|
||||
size_t *n_mounts,
|
||||
char **error_path) {
|
||||
|
||||
_cleanup_fclose_ FILE *proc_self_mountinfo = NULL;
|
||||
_cleanup_free_ char **deny_list = NULL;
|
||||
size_t j;
|
||||
int r;
|
||||
|
||||
if (n_mounts == 0) /* Shortcut: nothing to do */
|
||||
return 0;
|
||||
|
||||
assert(root);
|
||||
assert(mounts);
|
||||
assert(n_mounts);
|
||||
|
||||
/* Open /proc/self/mountinfo now as it may become unavailable if we mount anything on top of
|
||||
* /proc. For example, this is the case with the option: 'InaccessiblePaths=/proc'. */
|
||||
proc_self_mountinfo = fopen("/proc/self/mountinfo", "re");
|
||||
if (!proc_self_mountinfo) {
|
||||
if (error_path)
|
||||
*error_path = strdup("/proc/self/mountinfo");
|
||||
return log_debug_errno(errno, "Failed to open /proc/self/mountinfo: %m");
|
||||
}
|
||||
|
||||
/* First round, establish all mounts we need */
|
||||
for (;;) {
|
||||
bool again = false;
|
||||
|
||||
for (MountEntry *m = mounts; m < mounts + *n_mounts; ++m) {
|
||||
|
||||
if (m->applied)
|
||||
continue;
|
||||
|
||||
r = follow_symlink(root, m);
|
||||
if (r < 0) {
|
||||
if (error_path && mount_entry_path(m))
|
||||
*error_path = strdup(mount_entry_path(m));
|
||||
return r;
|
||||
}
|
||||
if (r == 0) {
|
||||
/* We hit a symlinked mount point. The entry got rewritten and might
|
||||
* point to a very different place now. Let's normalize the changed
|
||||
* list, and start from the beginning. After all to mount the entry
|
||||
* at the new location we might need some other mounts first */
|
||||
again = true;
|
||||
break;
|
||||
}
|
||||
|
||||
r = apply_one_mount(root, m, ns_info);
|
||||
if (r < 0) {
|
||||
if (error_path && mount_entry_path(m))
|
||||
*error_path = strdup(mount_entry_path(m));
|
||||
return r;
|
||||
}
|
||||
|
||||
m->applied = true;
|
||||
}
|
||||
|
||||
if (!again)
|
||||
break;
|
||||
|
||||
normalize_mounts(root, mounts, n_mounts);
|
||||
}
|
||||
|
||||
/* Create a deny list we can pass to bind_mount_recursive() */
|
||||
deny_list = new(char*, (*n_mounts)+1);
|
||||
if (!deny_list)
|
||||
return -ENOMEM;
|
||||
for (j = 0; j < *n_mounts; j++)
|
||||
deny_list[j] = (char*) mount_entry_path(mounts+j);
|
||||
deny_list[j] = NULL;
|
||||
|
||||
/* Second round, flip the ro bits if necessary. */
|
||||
for (MountEntry *m = mounts; m < mounts + *n_mounts; ++m) {
|
||||
r = make_read_only(m, deny_list, proc_self_mountinfo);
|
||||
if (r < 0) {
|
||||
if (error_path && mount_entry_path(m))
|
||||
*error_path = strdup(mount_entry_path(m));
|
||||
return r;
|
||||
}
|
||||
}
|
||||
|
||||
/* Third round, flip the noexec bits with a simplified deny list. */
|
||||
for (j = 0; j < *n_mounts; j++)
|
||||
if (IN_SET((mounts+j)->mode, EXEC, NOEXEC))
|
||||
deny_list[j] = (char*) mount_entry_path(mounts+j);
|
||||
deny_list[j] = NULL;
|
||||
|
||||
for (MountEntry *m = mounts; m < mounts + *n_mounts; ++m) {
|
||||
r = make_noexec(m, deny_list, proc_self_mountinfo);
|
||||
if (r < 0) {
|
||||
if (error_path && mount_entry_path(m))
|
||||
*error_path = strdup(mount_entry_path(m));
|
||||
return r;
|
||||
}
|
||||
}
|
||||
|
||||
return 1;
|
||||
}
|
||||
|
||||
static bool root_read_only(
|
||||
char **read_only_paths,
|
||||
ProtectSystem protect_system) {
|
||||
@@ -1894,96 +1998,10 @@ int setup_namespace(
|
||||
if (root_image || root_directory)
|
||||
(void) base_filesystem_create(root, UID_INVALID, GID_INVALID);
|
||||
|
||||
if (n_mounts > 0) {
|
||||
_cleanup_fclose_ FILE *proc_self_mountinfo = NULL;
|
||||
_cleanup_free_ char **deny_list = NULL;
|
||||
size_t j;
|
||||
|
||||
/* Open /proc/self/mountinfo now as it may become unavailable if we mount anything on top of
|
||||
* /proc. For example, this is the case with the option: 'InaccessiblePaths=/proc'. */
|
||||
proc_self_mountinfo = fopen("/proc/self/mountinfo", "re");
|
||||
if (!proc_self_mountinfo) {
|
||||
r = log_debug_errno(errno, "Failed to open /proc/self/mountinfo: %m");
|
||||
if (error_path)
|
||||
*error_path = strdup("/proc/self/mountinfo");
|
||||
goto finish;
|
||||
}
|
||||
|
||||
/* First round, establish all mounts we need */
|
||||
for (;;) {
|
||||
bool again = false;
|
||||
|
||||
for (m = mounts; m < mounts + n_mounts; ++m) {
|
||||
|
||||
if (m->applied)
|
||||
continue;
|
||||
|
||||
r = follow_symlink(root, m);
|
||||
if (r < 0) {
|
||||
if (error_path && mount_entry_path(m))
|
||||
*error_path = strdup(mount_entry_path(m));
|
||||
goto finish;
|
||||
}
|
||||
if (r == 0) {
|
||||
/* We hit a symlinked mount point. The entry got rewritten and might
|
||||
* point to a very different place now. Let's normalize the changed
|
||||
* list, and start from the beginning. After all to mount the entry
|
||||
* at the new location we might need some other mounts first */
|
||||
again = true;
|
||||
break;
|
||||
}
|
||||
|
||||
r = apply_mount(root, m, ns_info);
|
||||
if (r < 0) {
|
||||
if (error_path && mount_entry_path(m))
|
||||
*error_path = strdup(mount_entry_path(m));
|
||||
goto finish;
|
||||
}
|
||||
|
||||
m->applied = true;
|
||||
}
|
||||
|
||||
if (!again)
|
||||
break;
|
||||
|
||||
normalize_mounts(root, mounts, &n_mounts);
|
||||
}
|
||||
|
||||
/* Create a deny list we can pass to bind_mount_recursive() */
|
||||
deny_list = new(char*, n_mounts+1);
|
||||
if (!deny_list) {
|
||||
r = -ENOMEM;
|
||||
goto finish;
|
||||
}
|
||||
for (j = 0; j < n_mounts; j++)
|
||||
deny_list[j] = (char*) mount_entry_path(mounts+j);
|
||||
deny_list[j] = NULL;
|
||||
|
||||
/* Second round, flip the ro bits if necessary. */
|
||||
for (m = mounts; m < mounts + n_mounts; ++m) {
|
||||
r = make_read_only(m, deny_list, proc_self_mountinfo);
|
||||
if (r < 0) {
|
||||
if (error_path && mount_entry_path(m))
|
||||
*error_path = strdup(mount_entry_path(m));
|
||||
goto finish;
|
||||
}
|
||||
}
|
||||
|
||||
/* Third round, flip the noexec bits with a simplified deny list. */
|
||||
for (m = mounts, j = 0; m < mounts + n_mounts; ++m)
|
||||
if (IN_SET(m->mode, EXEC, NOEXEC))
|
||||
deny_list[j++] = (char*) mount_entry_path(m);
|
||||
deny_list[j] = NULL;
|
||||
|
||||
for (m = mounts; m < mounts + n_mounts; ++m) {
|
||||
r = make_noexec(m, deny_list, proc_self_mountinfo);
|
||||
if (r < 0) {
|
||||
if (error_path && mount_entry_path(m))
|
||||
*error_path = strdup(mount_entry_path(m));
|
||||
goto finish;
|
||||
}
|
||||
}
|
||||
}
|
||||
/* Now make the magic happen */
|
||||
r = apply_mounts(root, ns_info, mounts, &n_mounts, error_path);
|
||||
if (r < 0)
|
||||
goto finish;
|
||||
|
||||
/* MS_MOVE does not work on MS_SHARED so the remount MS_SHARED will be done later */
|
||||
r = mount_move_root(root);
|
||||
|
||||
Reference in New Issue
Block a user