diff options
| -rw-r--r-- | src/core/execute.c | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/src/core/execute.c b/src/core/execute.c index a7e2362236..7796c07fcf 100644 --- a/src/core/execute.c +++ b/src/core/execute.c @@ -50,6 +50,7 @@ #include <sys/apparmor.h> #endif +#include "barrier.h" #include "sd-messages.h" #include "rm-rf.h" #include "strv.h" @@ -768,10 +769,11 @@ static int setup_pam( .appdata_ptr = NULL }; + _cleanup_(barrier_destroy) Barrier barrier = BARRIER_NULL; pam_handle_t *handle = NULL; sigset_t old_ss; int pam_code = PAM_SUCCESS; - int err; + int err = 0; char **e = NULL; bool close_session = false; pid_t pam_pid = 0, parent_pid; @@ -788,6 +790,10 @@ static int setup_pam( * daemon. We do things this way to ensure that the main PID * of the daemon is the one we initially fork()ed. */ + err = barrier_create(&barrier); + if (err < 0) + goto fail; + if (log_get_max_level() < LOG_DEBUG) flags |= PAM_SILENT; @@ -836,6 +842,7 @@ static int setup_pam( /* The child's job is to reset the PAM session on * termination */ + barrier_set_role(&barrier, BARRIER_CHILD); /* This string must fit in 10 chars (i.e. the length * of "/sbin/init"), to look pretty in /bin/ps */ @@ -863,6 +870,11 @@ static int setup_pam( if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0) goto child_finish; + /* Tell the parent that our setup is done. This is especially + * important regarding dropping privileges. Otherwise, unit + * setup might race against our setresuid(2) call. */ + barrier_place(&barrier); + /* Check if our parent process might already have * died? */ if (getppid() == parent_pid) { @@ -898,6 +910,8 @@ static int setup_pam( _exit(r); } + barrier_set_role(&barrier, BARRIER_PARENT); + /* If the child was forked off successfully it will do all the * cleanups, so forget about the handle here. */ handle = NULL; @@ -909,6 +923,11 @@ static int setup_pam( * might have opened it, but we don't want this fd around. */ closelog(); + /* Synchronously wait for the child to initialize. We don't care for + * errors as we cannot recover. However, warn loudly if it happens. */ + if (!barrier_place_and_sync(&barrier)) + log_error("PAM initialization failed"); + *pam_env = e; e = NULL; @@ -919,7 +938,7 @@ fail: log_error("PAM failed: %s", pam_strerror(handle, pam_code)); err = -EPERM; /* PAM errors do not map to errno */ } else { - err = log_error_errno(errno, "PAM failed: %m"); + err = log_error_errno(err < 0 ? err : errno, "PAM failed: %m"); } if (handle) { |