Merge pull request #10996 from poettering/oci-prep

Preparation for the nspawn-OCI work

src/shared/bootspec.c

@@ -405,7 +405,7 @@ static int verify_esp(
                 sd_id128_t *ret_uuid) {
 #if HAVE_BLKID
         _cleanup_(blkid_free_probep) blkid_probe b = NULL;
-        char t[DEV_NUM_PATH_MAX];
+        _cleanup_free_ char *node = NULL;
         const char *v;
 #endif
         uint64_t pstart = 0, psize = 0;
@@ -469,9 +469,11 @@ static int verify_esp(
                 goto finish;
 
 #if HAVE_BLKID
-        xsprintf_dev_num_path(t, "block", st.st_dev);
+        r = device_path_make_major_minor(S_IFBLK, st.st_dev, &node);
+        if (r < 0)
+                return log_error_errno(r, "Failed to format major/minor device path: %m");
         errno = 0;
-        b = blkid_new_probe_from_filename(t);
+        b = blkid_new_probe_from_filename(node);
         if (!b)
                 return log_error_errno(errno ?: ENOMEM, "Failed to open file system \"%s\": %m", p);
 

src/shared/dev-setup.c

@@ -9,6 +9,7 @@
 #include "label.h"
 #include "log.h"
 #include "path-util.h"
+#include "umask-util.h"
 #include "user-util.h"
 #include "util.h"
 
@@ -54,3 +55,61 @@ int dev_setup(const char *prefix, uid_t uid, gid_t gid) {
 
         return 0;
 }
+
+int make_inaccessible_nodes(const char *root, uid_t uid, gid_t gid) {
+        static const struct {
+                const char *name;
+                mode_t mode;
+        } table[] = {
+                { "/run/systemd",                   S_IFDIR  | 0755 },
+                { "/run/systemd/inaccessible",      S_IFDIR  | 0000 },
+                { "/run/systemd/inaccessible/reg",  S_IFREG  | 0000 },
+                { "/run/systemd/inaccessible/dir",  S_IFDIR  | 0000 },
+                { "/run/systemd/inaccessible/fifo", S_IFIFO  | 0000 },
+                { "/run/systemd/inaccessible/sock", S_IFSOCK | 0000 },
+
+                /* The following two are likely to fail if we lack the privs for it (for example in an userns
+                 * environment, if CAP_SYS_MKNOD is missing, or if a device node policy prohibit major/minor of 0
+                 * device nodes to be created). But that's entirely fine. Consumers of these files should carry
+                 * fallback to use a different node then, for example /run/systemd/inaccessible/sock, which is close
+                 * enough in behaviour and semantics for most uses. */
+                { "/run/systemd/inaccessible/chr",  S_IFCHR  | 0000 },
+                { "/run/systemd/inaccessible/blk",  S_IFBLK  | 0000 },
+        };
+
+        _cleanup_umask_ mode_t u;
+        size_t i;
+        int r;
+
+        u = umask(0000);
+
+        /* Set up inaccessible (and empty) file nodes of all types. This are used to as mount sources for over-mounting
+         * ("masking") file nodes that shall become inaccessible and empty for specific containers or services. We try
+         * to lock down these nodes as much as we can, but otherwise try to match them as closely as possible with the
+         * underlying file, i.e. in the best case we offer the same node type as the underlying node. */
+
+        for (i = 0; i < ELEMENTSOF(table); i++) {
+                _cleanup_free_ char *path = NULL;
+
+                path = prefix_root(root, table[i].name);
+                if (!path)
+                        return log_oom();
+
+                if (S_ISDIR(table[i].mode))
+                        r = mkdir(path, table[i].mode & 07777);
+                else
+                        r = mknod(path, table[i].mode, makedev(0, 0));
+                if (r < 0) {
+                        if (errno != EEXIST)
+                                log_debug_errno(errno, "Failed to create '%s', ignoring: %m", path);
+                        continue;
+                }
+
+                if (uid != UID_INVALID || gid != GID_INVALID) {
+                        if (lchown(path, uid, gid) < 0)
+                                log_debug_errno(errno, "Failed to chown '%s': %m", path);
+                }
+        }
+
+        return 0;
+}

src/shared/dev-setup.h

@@ -4,3 +4,5 @@
 #include <sys/types.h>
 
 int dev_setup(const char *prefix, uid_t uid, gid_t gid);
+
+int make_inaccessible_nodes(const char *root, uid_t uid, gid_t gid);

src/shared/dissect-image.c

@@ -220,8 +220,9 @@ int dissect_image(
                                         return -ENOMEM;
                         }
 
-                        if (asprintf(&n, "/dev/block/%u:%u", major(st.st_rdev), minor(st.st_rdev)) < 0)
-                                return -ENOMEM;
+                        r = device_path_make_major_minor(st.st_mode, st.st_rdev, &n);
+                        if (r < 0)
+                                return r;
 
                         m->partitions[PARTITION_ROOT] = (DissectedPartition) {
                                 .found = true,

src/shared/ptyfwd.c

@@ -392,11 +392,14 @@ int pty_forward_new(
         struct winsize ws;
         int r;
 
-        f = new0(PTYForward, 1);
+        f = new(PTYForward, 1);
         if (!f)
                 return -ENOMEM;
 
-        f->flags = flags;
+        *f = (struct PTYForward) {
+                .flags = flags,
+                .master = -1,
+        };
 
         if (event)
                 f->event = sd_event_ref(event);
@@ -587,3 +590,42 @@ int pty_forward_set_priority(PTYForward *f, int64_t priority) {
 
         return 0;
 }
+
+int pty_forward_set_width_height(PTYForward *f, unsigned width, unsigned height) {
+        struct winsize ws;
+
+        assert(f);
+
+        if (width == (unsigned) -1 && height == (unsigned) -1)
+                return 0; /* noop */
+
+        if (width != (unsigned) -1 &&
+            (width == 0 || width > USHRT_MAX))
+                return -ERANGE;
+
+        if (height != (unsigned) -1 &&
+            (height == 0 || height > USHRT_MAX))
+                return -ERANGE;
+
+        if (width == (unsigned) -1 || height == (unsigned) -1) {
+                if (ioctl(f->master, TIOCGWINSZ, &ws) < 0)
+                        return -errno;
+
+                if (width != (unsigned) -1)
+                        ws.ws_col = width;
+                if (height != (unsigned) -1)
+                        ws.ws_row = height;
+        } else
+                ws = (struct winsize) {
+                        .ws_row = height,
+                        .ws_col = width,
+                };
+
+        if (ioctl(f->master, TIOCSWINSZ, &ws) < 0)
+                return -errno;
+
+        /* Make sure we ignore SIGWINCH window size events from now on */
+        f->sigwinch_event_source = sd_event_source_unref(f->sigwinch_event_source);
+
+        return 0;
+}

src/shared/ptyfwd.h

@@ -37,4 +37,6 @@ bool pty_forward_drain(PTYForward *f);
 
 int pty_forward_set_priority(PTYForward *f, int64_t priority);
 
+int pty_forward_set_width_height(PTYForward *f, unsigned width, unsigned height);
+
 DEFINE_TRIVIAL_CLEANUP_FUNC(PTYForward*, pty_forward_free);