Adding upstream version 255.4.upstream/255.4

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 226 insertions, 0 deletions

diff --git a/src/shared/devnode-acl.c b/src/shared/devnode-acl.c
new file mode 100644
index 0000000..b239699
--- /dev/null
+++ b/src/shared/devnode-acl.c
@@ -0,0 +1,226 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+
+#include "sd-device.h"
+
+#include "acl-util.h"
+#include "alloc-util.h"
+#include "device-util.h"
+#include "devnode-acl.h"
+#include "dirent-util.h"
+#include "fd-util.h"
+#include "format-util.h"
+#include "fs-util.h"
+#include "glyph-util.h"
+#include "set.h"
+#include "string-util.h"
+
+static int flush_acl(acl_t acl) {
+        acl_entry_t i;
+        int found;
+        bool changed = false;
+
+        assert(acl);
+
+        for (found = acl_get_entry(acl, ACL_FIRST_ENTRY, &i);
+             found > 0;
+             found = acl_get_entry(acl, ACL_NEXT_ENTRY, &i)) {
+
+                acl_tag_t tag;
+
+                if (acl_get_tag_type(i, &tag) < 0)
+                        return -errno;
+
+                if (tag != ACL_USER)
+                        continue;
+
+                if (acl_delete_entry(acl, i) < 0)
+                        return -errno;
+
+                changed = true;
+        }
+
+        if (found < 0)
+                return -errno;
+
+        return changed;
+}
+
+int devnode_acl(const char *path,
+                bool flush,
+                bool del, uid_t old_uid,
+                bool add, uid_t new_uid) {
+
+        _cleanup_(acl_freep) acl_t acl = NULL;
+        int r;
+        bool changed = false;
+
+        assert(path);
+
+        acl = acl_get_file(path, ACL_TYPE_ACCESS);
+        if (!acl)
+                return -errno;
+
+        if (flush) {
+
+                r = flush_acl(acl);
+                if (r < 0)
+                        return r;
+                if (r > 0)
+                        changed = true;
+
+        } else if (del && old_uid > 0) {
+                acl_entry_t entry;
+
+                r = acl_find_uid(acl, old_uid, &entry);
+                if (r < 0)
+                        return r;
+
+                if (r > 0) {
+                        if (acl_delete_entry(acl, entry) < 0)
+                                return -errno;
+
+                        changed = true;
+                }
+        }
+
+        if (add && new_uid > 0) {
+                acl_entry_t entry;
+                acl_permset_t permset;
+                int rd, wt;
+
+                r = acl_find_uid(acl, new_uid, &entry);
+                if (r < 0)
+                        return r;
+
+                if (r == 0) {
+                        if (acl_create_entry(&acl, &entry) < 0)
+                                return -errno;
+
+                        if (acl_set_tag_type(entry, ACL_USER) < 0 ||
+                            acl_set_qualifier(entry, &new_uid) < 0)
+                                return -errno;
+                }
+
+                if (acl_get_permset(entry, &permset) < 0)
+                        return -errno;
+
+                rd = acl_get_perm(permset, ACL_READ);
+                if (rd < 0)
+                        return -errno;
+
+                wt = acl_get_perm(permset, ACL_WRITE);
+                if (wt < 0)
+                        return -errno;
+
+                if (!rd || !wt) {
+
+                        if (acl_add_perm(permset, ACL_READ|ACL_WRITE) < 0)
+                                return -errno;
+
+                        changed = true;
+                }
+        }
+
+        if (!changed)
+                return 0;
+
+        if (acl_calc_mask(&acl) < 0)
+                return -errno;
+
+        if (acl_set_file(path, ACL_TYPE_ACCESS, acl) < 0)
+                return -errno;
+
+        return 0;
+}
+
+int devnode_acl_all(const char *seat,
+                    bool flush,
+                    bool del, uid_t old_uid,
+                    bool add, uid_t new_uid) {
+
+        _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
+        _cleanup_set_free_ Set *nodes = NULL;
+        _cleanup_closedir_ DIR *dir = NULL;
+        char *n;
+        int r;
+
+        r = sd_device_enumerator_new(&e);
+        if (r < 0)
+                return r;
+
+        if (isempty(seat))
+                seat = "seat0";
+
+        /* We can only match by one tag in libudev. We choose
+         * "uaccess" for that. If we could match for two tags here we
+         * could add the seat name as second match tag, but this would
+         * be hardly optimizable in libudev, and hence checking the
+         * second tag manually in our loop is a good solution. */
+        r = sd_device_enumerator_add_match_tag(e, "uaccess");
+        if (r < 0)
+                return r;
+
+        FOREACH_DEVICE(e, d) {
+                const char *node, *sn;
+
+                /* Make sure the tag is still in place */
+                if (sd_device_has_current_tag(d, "uaccess") <= 0)
+                        continue;
+
+                if (sd_device_get_property_value(d, "ID_SEAT", &sn) < 0 || isempty(sn))
+                        sn = "seat0";
+
+                if (!streq(seat, sn))
+                        continue;
+
+                /* In case people mistag devices with nodes, we need to ignore this */
+                if (sd_device_get_devname(d, &node) < 0)
+                        continue;
+
+                log_device_debug(d, "Found udev node %s for seat %s", node, seat);
+                r = set_put_strdup_full(&nodes, &path_hash_ops_free, node);
+                if (r < 0)
+                        return r;
+        }
+
+        /* udev exports "dead" device nodes to allow module on-demand loading,
+         * these devices are not known to the kernel at this moment */
+        dir = opendir("/run/udev/static_node-tags/uaccess");
+        if (dir) {
+                FOREACH_DIRENT(de, dir, return -errno) {
+                        r = readlinkat_malloc(dirfd(dir), de->d_name, &n);
+                        if (r == -ENOENT)
+                                continue;
+                        if (r < 0) {
+                                log_debug_errno(r,
+                                                "Unable to read symlink '/run/udev/static_node-tags/uaccess/%s', ignoring: %m",
+                                                de->d_name);
+                                continue;
+                        }
+
+                        log_debug("Found static node %s for seat %s", n, seat);
+                        r = set_ensure_consume(&nodes, &path_hash_ops_free, n);
+                        if (r < 0)
+                                return r;
+                }
+        }
+
+        r = 0;
+        SET_FOREACH(n, nodes) {
+                int k;
+
+                log_debug("Changing ACLs at %s for seat %s (uid "UID_FMT"%s"UID_FMT"%s%s)",
+                          n, seat, old_uid, special_glyph(SPECIAL_GLYPH_ARROW_RIGHT), new_uid,
+                          del ? " del" : "", add ? " add" : "");
+
+                k = devnode_acl(n, flush, del, old_uid, add, new_uid);
+                if (k == -ENOENT)
+                        log_debug("Device %s disappeared while setting ACLs", n);
+                else
+                        RET_GATHER(r, k);
+        }
+
+        return r;
+}