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Diffstat (limited to 'src/nss-systemd/userdb-glue.c')
-rw-r--r--src/nss-systemd/userdb-glue.c344
1 files changed, 344 insertions, 0 deletions
diff --git a/src/nss-systemd/userdb-glue.c b/src/nss-systemd/userdb-glue.c
new file mode 100644
index 0000000000..81705fa1b6
--- /dev/null
+++ b/src/nss-systemd/userdb-glue.c
@@ -0,0 +1,344 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include "env-util.h"
+#include "fd-util.h"
+#include "group-record-nss.h"
+#include "strv.h"
+#include "user-record.h"
+#include "userdb-glue.h"
+#include "userdb.h"
+
+UserDBFlags nss_glue_userdb_flags(void) {
+ UserDBFlags flags = USERDB_AVOID_NSS;
+
+ /* Make sure that we don't go in circles when allocating a dynamic UID by checking our own database */
+ if (getenv_bool_secure("SYSTEMD_NSS_DYNAMIC_BYPASS") > 0)
+ flags |= USERDB_AVOID_DYNAMIC_USER;
+
+ return flags;
+}
+
+int nss_pack_user_record(
+ UserRecord *hr,
+ struct passwd *pwd,
+ char *buffer,
+ size_t buflen) {
+
+ const char *rn, *hd, *shell;
+ size_t required;
+
+ assert(hr);
+ assert(pwd);
+
+ assert_se(hr->user_name);
+ required = strlen(hr->user_name) + 1;
+
+ assert_se(rn = user_record_real_name(hr));
+ required += strlen(rn) + 1;
+
+ assert_se(hd = user_record_home_directory(hr));
+ required += strlen(hd) + 1;
+
+ assert_se(shell = user_record_shell(hr));
+ required += strlen(shell) + 1;
+
+ if (buflen < required)
+ return -ERANGE;
+
+ *pwd = (struct passwd) {
+ .pw_name = buffer,
+ .pw_uid = hr->uid,
+ .pw_gid = user_record_gid(hr),
+ .pw_passwd = (char*) "x", /* means: see shadow file */
+ };
+
+ assert(buffer);
+
+ pwd->pw_gecos = stpcpy(pwd->pw_name, hr->user_name) + 1;
+ pwd->pw_dir = stpcpy(pwd->pw_gecos, rn) + 1;
+ pwd->pw_shell = stpcpy(pwd->pw_dir, hd) + 1;
+ strcpy(pwd->pw_shell, shell);
+
+ return 0;
+}
+
+enum nss_status userdb_getpwnam(
+ const char *name,
+ struct passwd *pwd,
+ char *buffer, size_t buflen,
+ int *errnop) {
+
+ _cleanup_(user_record_unrefp) UserRecord *hr = NULL;
+ int r;
+
+ assert(pwd);
+ assert(errnop);
+
+ r = userdb_nss_compat_is_enabled();
+ if (r < 0) {
+ *errnop = -r;
+ return NSS_STATUS_UNAVAIL;
+ }
+ if (!r)
+ return NSS_STATUS_NOTFOUND;
+
+ r = userdb_by_name(name, nss_glue_userdb_flags(), &hr);
+ if (r == -ESRCH)
+ return NSS_STATUS_NOTFOUND;
+ if (r < 0) {
+ *errnop = -r;
+ return NSS_STATUS_UNAVAIL;
+ }
+
+ r = nss_pack_user_record(hr, pwd, buffer, buflen);
+ if (r < 0) {
+ *errnop = -r;
+ return NSS_STATUS_TRYAGAIN;
+ }
+
+ return NSS_STATUS_SUCCESS;
+}
+
+enum nss_status userdb_getpwuid(
+ uid_t uid,
+ struct passwd *pwd,
+ char *buffer,
+ size_t buflen,
+ int *errnop) {
+
+ _cleanup_(user_record_unrefp) UserRecord *hr = NULL;
+ int r;
+
+ assert(pwd);
+ assert(errnop);
+
+ r = userdb_nss_compat_is_enabled();
+ if (r < 0) {
+ *errnop = -r;
+ return NSS_STATUS_UNAVAIL;
+ }
+ if (!r)
+ return NSS_STATUS_NOTFOUND;
+
+ r = userdb_by_uid(uid, nss_glue_userdb_flags(), &hr);
+ if (r == -ESRCH)
+ return NSS_STATUS_NOTFOUND;
+ if (r < 0) {
+ *errnop = -r;
+ return NSS_STATUS_UNAVAIL;
+ }
+
+ r = nss_pack_user_record(hr, pwd, buffer, buflen);
+ if (r < 0) {
+ *errnop = -r;
+ return NSS_STATUS_TRYAGAIN;
+ }
+
+ return NSS_STATUS_SUCCESS;
+}
+
+int nss_pack_group_record(
+ GroupRecord *g,
+ char **extra_members,
+ struct group *gr,
+ char *buffer,
+ size_t buflen) {
+
+ char **array = NULL, *p, **m;
+ size_t required, n = 0, i = 0;
+
+ assert(g);
+ assert(gr);
+
+ assert_se(g->group_name);
+ required = strlen(g->group_name) + 1;
+
+ STRV_FOREACH(m, g->members) {
+ required += sizeof(char*); /* space for ptr array entry */
+ required += strlen(*m) + 1;
+ n++;
+ }
+ STRV_FOREACH(m, extra_members) {
+ if (strv_contains(g->members, *m))
+ continue;
+
+ required += sizeof(char*);
+ required += strlen(*m) + 1;
+ n++;
+ }
+
+ required += sizeof(char*); /* trailing NULL in ptr array entry */
+
+ if (buflen < required)
+ return -ERANGE;
+
+ array = (char**) buffer; /* place ptr array at beginning of buffer, under assumption buffer is aligned */
+ p = buffer + sizeof(void*) * (n + 1); /* place member strings right after the ptr array */
+
+ STRV_FOREACH(m, g->members) {
+ array[i++] = p;
+ p = stpcpy(p, *m) + 1;
+ }
+ STRV_FOREACH(m, extra_members) {
+ if (strv_contains(g->members, *m))
+ continue;
+
+ array[i++] = p;
+ p = stpcpy(p, *m) + 1;
+ }
+
+ assert_se(i == n);
+ array[n] = NULL;
+
+ *gr = (struct group) {
+ .gr_name = strcpy(p, g->group_name),
+ .gr_gid = g->gid,
+ .gr_passwd = (char*) "x", /* means: see shadow file */
+ .gr_mem = array,
+ };
+
+ return 0;
+}
+
+enum nss_status userdb_getgrnam(
+ const char *name,
+ struct group *gr,
+ char *buffer,
+ size_t buflen,
+ int *errnop) {
+
+ _cleanup_(group_record_unrefp) GroupRecord *g = NULL;
+ _cleanup_strv_free_ char **members = NULL;
+ int r;
+
+ assert(gr);
+ assert(errnop);
+
+ r = userdb_nss_compat_is_enabled();
+ if (r < 0) {
+ *errnop = -r;
+ return NSS_STATUS_UNAVAIL;
+ }
+ if (!r)
+ return NSS_STATUS_NOTFOUND;
+
+ r = groupdb_by_name(name, nss_glue_userdb_flags(), &g);
+ if (r < 0 && r != -ESRCH) {
+ *errnop = -r;
+ return NSS_STATUS_UNAVAIL;
+ }
+
+ r = membershipdb_by_group_strv(name, nss_glue_userdb_flags(), &members);
+ if (r < 0) {
+ *errnop = -r;
+ return NSS_STATUS_UNAVAIL;
+ }
+
+ if (!g) {
+ _cleanup_close_ int lock_fd = -1;
+
+ if (strv_isempty(members))
+ return NSS_STATUS_NOTFOUND;
+
+ /* Grmbl, so we are supposed to extend a group entry, but the group entry itself is not
+ * accessible via non-NSS. Hence let's do what we have to do, and query NSS after all to
+ * acquire it, so that we can extend it (that's because glibc's group merging feature will
+ * merge groups only if both GID and name match and thus we need to have both first). It
+ * sucks behaving recursively likely this, but it's apparently what everybody does. We break
+ * the recursion for ourselves via the userdb_nss_compat_disable() lock. */
+
+ lock_fd = userdb_nss_compat_disable();
+ if (lock_fd < 0 && lock_fd != -EBUSY)
+ return lock_fd;
+
+ r = nss_group_record_by_name(name, &g);
+ if (r == -ESRCH)
+ return NSS_STATUS_NOTFOUND;
+ if (r < 0) {
+ *errnop = -r;
+ return NSS_STATUS_UNAVAIL;
+ }
+ }
+
+ r = nss_pack_group_record(g, members, gr, buffer, buflen);
+ if (r < 0) {
+ *errnop = -r;
+ return NSS_STATUS_TRYAGAIN;
+ }
+
+ return NSS_STATUS_SUCCESS;
+}
+
+enum nss_status userdb_getgrgid(
+ gid_t gid,
+ struct group *gr,
+ char *buffer,
+ size_t buflen,
+ int *errnop) {
+
+
+ _cleanup_(group_record_unrefp) GroupRecord *g = NULL;
+ _cleanup_strv_free_ char **members = NULL;
+ bool from_nss;
+ int r;
+
+ assert(gr);
+ assert(errnop);
+
+ r = userdb_nss_compat_is_enabled();
+ if (r < 0) {
+ *errnop = -r;
+ return NSS_STATUS_UNAVAIL;
+ }
+ if (r)
+ return NSS_STATUS_NOTFOUND;
+
+ r = groupdb_by_gid(gid, nss_glue_userdb_flags(), &g);
+ if (r < 0 && r != -ESRCH) {
+ *errnop = -r;
+ return NSS_STATUS_UNAVAIL;
+ }
+
+ if (!g) {
+ _cleanup_close_ int lock_fd = -1;
+
+ /* So, quite possibly we have to extend an existing group record with additional members. But
+ * to do this we need to know the group name first. The group didn't exist via non-NSS
+ * queries though, hence let's try to acquire it here recursively via NSS. */
+
+ lock_fd = userdb_nss_compat_disable();
+ if (lock_fd < 0 && lock_fd != -EBUSY)
+ return lock_fd;
+
+ r = nss_group_record_by_gid(gid, &g);
+ if (r == -ESRCH)
+ return NSS_STATUS_NOTFOUND;
+
+ if (r < 0) {
+ *errnop = -r;
+ return NSS_STATUS_UNAVAIL;
+ }
+
+ from_nss = true;
+ } else
+ from_nss = false;
+
+ r = membershipdb_by_group_strv(g->group_name, nss_glue_userdb_flags(), &members);
+ if (r < 0) {
+ *errnop = -r;
+ return NSS_STATUS_UNAVAIL;
+ }
+
+ /* If we acquired the record via NSS then there's no reason to respond unless we have to agument the
+ * list of members of the group */
+ if (from_nss && strv_isempty(members))
+ return NSS_STATUS_NOTFOUND;
+
+ r = nss_pack_group_record(g, members, gr, buffer, buflen);
+ if (r < 0) {
+ *errnop = -r;
+ return NSS_STATUS_TRYAGAIN;
+ }
+
+ return NSS_STATUS_SUCCESS;
+}
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