From 1e6a26f9312bb47e070f94b17b14dc1a6ffbb74f Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Wed, 30 Aug 2023 18:26:52 -0700 Subject: [PATCH] readutmp: fix core dump if --enable-systemd MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Problem reported by Thorsten Kukuk . * lib/readutmp.c (read_utmp_from_systemd): Don’t assume session_ptr != NULL if num_sessions == 0. In practice it can be null, and the man page OKs this behavior. --- ChangeLog | 8 ++++++++ lib/readutmp.c | 2 +- 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/ChangeLog b/ChangeLog index d4b2287307..9c9c89638c 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,11 @@ +2023-08-30 Paul Eggert + + readutmp: fix core dump if --enable-systemd + Problem reported by Thorsten Kukuk . + * lib/readutmp.c (read_utmp_from_systemd): + Don’t assume session_ptr != NULL if num_sessions == 0. + In practice it can be null, and the man page OKs this behavior. + 2023-08-30 Bruno Haible doc: Mention the module 'wchar-single'. diff --git a/lib/readutmp.c b/lib/readutmp.c index 0173b7e0c1..e99158677c 100644 --- a/lib/readutmp.c +++ b/lib/readutmp.c @@ -795,7 +795,7 @@ read_utmp_from_systemd (idx_t *n_entries, STRUCT_UTMP **utmp_buf, int options) { char **sessions; int num_sessions = sd_get_sessions (&sessions); - if (num_sessions >= 0) + if (num_sessions > 0) { char **session_ptr; for (session_ptr = sessions; *session_ptr != NULL; session_ptr++) -- 2.39.2