diff options
Diffstat (limited to 'src/core')
| -rw-r--r-- | src/core/dynamic-user.c | 51 | ||||
| -rw-r--r-- | src/core/execute.c | 15 |
2 files changed, 59 insertions, 7 deletions
diff --git a/src/core/dynamic-user.c b/src/core/dynamic-user.c index 8035bee231..185d0e5f00 100644 --- a/src/core/dynamic-user.c +++ b/src/core/dynamic-user.c @@ -150,6 +150,42 @@ int dynamic_user_acquire(Manager *m, const char *name, DynamicUser** ret) { return 1; } +static int make_uid_symlinks(uid_t uid, const char *name, bool b) { + + char path1[strlen("/run/systemd/dynamic-uid/direct:") + DECIMAL_STR_MAX(uid_t) + 1]; + const char *path2; + int r = 0; + + /* Add direct additional symlinks for direct lookups of dynamic UIDs and their names by userspace code. The + * only reason we have this is because dbus-daemon cannot use D-Bus for resolving users and groups (since it + * would be its own client then). We hence keep these world-readable symlinks in place, so that the + * unprivileged dbus user can read the mappings when it needs them via these symlinks instead of having to go + * via the bus. Ideally, we'd use the lock files we keep for this anyway, but we can't since we use BSD locks + * on them and as those may be taken by any user with read access we can't make them world-readable. */ + + xsprintf(path1, "/run/systemd/dynamic-uid/direct:" UID_FMT, uid); + if (unlink(path1) < 0) { + if (errno != ENOENT) + r = -errno; + } + if (b) { + if (symlink(name, path1) < 0) + r = -errno; + } + + path2 = strjoina("/run/systemd/dynamic-uid/direct:", name); + if (unlink(path2) < 0) { + if (errno != ENOENT) + r = -errno; + } + if (b) { + if (symlink(path1 + strlen("/run/systemd/dynamic-uid/direct:"), path2) < 0) + r = -errno; + } + + return r; +} + static int pick_uid(const char *name, uid_t *ret_uid) { static const uint8_t hash_key[] = { @@ -223,6 +259,7 @@ static int pick_uid(const char *name, uid_t *ret_uid) { } (void) ftruncate(lock_fd, l); + (void) make_uid_symlinks(candidate, name, true); /* also add direct lookup symlinks */ *ret_uid = candidate; r = lock_fd; @@ -324,14 +361,16 @@ static int dynamic_user_push(DynamicUser *d, uid_t uid, int lock_fd) { return 0; } -static void unlink_uid_lock(int lock_fd, uid_t uid) { +static void unlink_uid_lock(int lock_fd, uid_t uid, const char *name) { char lock_path[strlen("/run/systemd/dynamic-uid/") + DECIMAL_STR_MAX(uid_t) + 1]; if (lock_fd < 0) return; xsprintf(lock_path, "/run/systemd/dynamic-uid/" UID_FMT, uid); - (void) unlink_noerrno(lock_path); + (void) unlink(lock_path); + + (void) make_uid_symlinks(uid, name, false); /* remove direct lookup symlinks */ } int dynamic_user_realize(DynamicUser *d, uid_t *ret) { @@ -399,7 +438,7 @@ int dynamic_user_realize(DynamicUser *d, uid_t *ret) { /* So, we found a working UID/lock combination. Let's see if we actually still need it. */ if (lockf(d->storage_socket[0], F_LOCK, 0) < 0) { - unlink_uid_lock(uid_lock_fd, uid); + unlink_uid_lock(uid_lock_fd, uid, d->name); return -errno; } @@ -407,7 +446,7 @@ int dynamic_user_realize(DynamicUser *d, uid_t *ret) { if (r < 0) { if (r != -EAGAIN) { /* OK, something bad happened, let's get rid of the bits we acquired. */ - unlink_uid_lock(uid_lock_fd, uid); + unlink_uid_lock(uid_lock_fd, uid, d->name); goto finish; } @@ -416,7 +455,7 @@ int dynamic_user_realize(DynamicUser *d, uid_t *ret) { /* Hmm, so as it appears there's now something stored in the storage socket. Throw away what we * acquired, and use what's stored now. */ - unlink_uid_lock(uid_lock_fd, uid); + unlink_uid_lock(uid_lock_fd, uid, d->name); safe_close(uid_lock_fd); uid = new_uid; @@ -513,7 +552,7 @@ static int dynamic_user_close(DynamicUser *d) { goto finish; /* This dynamic user was realized and dynamically allocated. In this case, let's remove the lock file. */ - unlink_uid_lock(lock_fd, uid); + unlink_uid_lock(lock_fd, uid, d->name); r = 1; finish: diff --git a/src/core/execute.c b/src/core/execute.c index 4c786a2e33..0af8eb5a02 100644 --- a/src/core/execute.c +++ b/src/core/execute.c @@ -91,6 +91,7 @@ #include "selinux-util.h" #include "signal-util.h" #include "smack-util.h" +#include "special.h" #include "string-table.h" #include "string-util.h" #include "strv.h" @@ -1384,6 +1385,7 @@ static void do_idle_pipe_dance(int idle_pipe[4]) { } static int build_environment( + Unit *u, const ExecContext *c, const ExecParameters *p, unsigned n_fds, @@ -1401,7 +1403,7 @@ static int build_environment( assert(c); assert(ret); - our_env = new0(char*, 12); + our_env = new0(char*, 13); if (!our_env) return -ENOMEM; @@ -1436,6 +1438,16 @@ static int build_environment( our_env[n_env++] = x; } + /* If this is D-Bus, tell the nss-systemd module, since it relies on being able to use D-Bus look up dynamic + * users via PID 1, possibly dead-locking the dbus daemon. This way it will not use D-Bus to resolve names, but + * check the database directly. */ + if (unit_has_name(u, SPECIAL_DBUS_SERVICE)) { + x = strdup("SYSTEMD_NSS_BYPASS_BUS=1"); + if (!x) + return -ENOMEM; + our_env[n_env++] = x; + } + if (home) { x = strappend("HOME=", home); if (!x) @@ -2100,6 +2112,7 @@ static int exec_child( } r = build_environment( + unit, context, params, n_fds, |