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Merge pull request #9977 from sourcejedi/no-remount-superblock3

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Namespace fixes
This commit is contained in:
Yu Watanabe
2018-09-01 23:18:01 +09:00
committed by GitHub
parent 2af83a2e41 fcac12d150
commit 0c09cb0e78
5 changed files with 36 additions and 31 deletions
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src/core/namespace.c
+25 -27
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@@ -265,7 +265,6 @@ static int append_empty_dir_mounts(MountEntry **p, char **strv) {
.path_const = *i,
.mode = EMPTY_DIR,
.ignore = false,
.has_prefix = false,
.read_only = true,
.options_const = "mode=755",
.flags = MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME,
@@ -304,7 +303,7 @@ static int append_tmpfs_mounts(MountEntry **p, const TemporaryFileSystem *tmpfs,
for (i = 0; i < n; i++) {
const TemporaryFileSystem *t = tmpfs + i;
_cleanup_free_ char *o = NULL, *str = NULL;
unsigned long flags = MS_NODEV|MS_STRICTATIME;
unsigned long flags;
bool ro = false;
if (!path_is_absolute(t->path)) {
@@ -312,29 +311,25 @@ static int append_tmpfs_mounts(MountEntry **p, const TemporaryFileSystem *tmpfs,
return -EINVAL;
}
if (!isempty(t->options)) {
str = strjoin("mode=0755,", t->options);
if (!str)
return -ENOMEM;
str = strjoin("mode=0755,", t->options);
if (!str)
return -ENOMEM;
r = mount_option_mangle(str, MS_NODEV|MS_STRICTATIME, &flags, &o);
if (r < 0)
return log_debug_errno(r, "Failed to parse mount option '%s': %m", str);
r = mount_option_mangle(str, MS_NODEV|MS_STRICTATIME, &flags, &o);
if (r < 0)
return log_debug_errno(r, "Failed to parse mount option '%s': %m", str);
ro = flags & MS_RDONLY;
if (ro)
flags ^= MS_RDONLY;
}
ro = flags & MS_RDONLY;
if (ro)
flags ^= MS_RDONLY;
*((*p)++) = (MountEntry) {
.path_const = t->path,
.mode = TMPFS,
.read_only = ro,
.options_malloc = o,
.options_malloc = TAKE_PTR(o),
.flags = flags,
};
o = NULL;
}
return 0;
@@ -423,11 +418,7 @@ static int mount_path_compare(const void *a, const void *b) {
static int prefix_where_needed(MountEntry *m, size_t n, const char *root_directory) {
size_t i;
/* Prefixes all paths in the bind mount table with the root directory if it is specified and the entry needs
* that. */
if (!root_directory)
return 0;
/* Prefixes all paths in the bind mount table with the root directory if the entry needs that. */
for (i = 0; i < n; i++) {
char *s;
@@ -1026,6 +1017,15 @@ static int apply_mount(
return 0;
}
/* Change the per-mount readonly flag on an existing mount */
static int remount_bind_readonly(const char *path, unsigned long orig_flags) {
int r;
r = mount(NULL, path, NULL, MS_REMOUNT | MS_BIND | MS_RDONLY | orig_flags, NULL);
return r < 0 ? -errno : 0;
}
static int make_read_only(const MountEntry *m, char **blacklist, FILE *proc_self_mountinfo) {
bool submounts = false;
int r = 0;
@@ -1035,17 +1035,15 @@ static int make_read_only(const MountEntry *m, char **blacklist, FILE *proc_self
if (mount_entry_read_only(m)) {
if (IN_SET(m->mode, EMPTY_DIR, TMPFS)) {
/* Make superblock readonly */
if (mount(NULL, mount_entry_path(m), NULL, MS_REMOUNT | MS_RDONLY | m->flags, mount_entry_options(m)) < 0)
r = -errno;
r = remount_bind_readonly(mount_entry_path(m), m->flags);
} else {
submounts = true;
r = bind_remount_recursive_with_mountinfo(mount_entry_path(m), true, blacklist, proc_self_mountinfo);
}
} else if (m->mode == PRIVATE_DEV) {
/* Superblock can be readonly but the submounts can't */
if (mount(NULL, mount_entry_path(m), NULL, MS_REMOUNT|DEV_MOUNT_OPTIONS|MS_RDONLY, NULL) < 0)
r = -errno;
/* Set /dev readonly, but not submounts like /dev/shm. Also, we only set the per-mount read-only flag.
* We can't set it on the superblock, if we are inside a user namespace and running Linux <= 4.17. */
r = remount_bind_readonly(mount_entry_path(m), DEV_MOUNT_OPTIONS);
} else
return 0;