GNU bug report logs - #65617
coreutils 9.4: seg.fault in readutmp with systemd

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Package: coreutils;

Reported by: Thorsten Kukuk <kukuk <at> suse.com>

Date: Wed, 30 Aug 2023 11:22:01 UTC

Severity: normal

Done: Paul Eggert <eggert <at> cs.ucla.edu>

Bug is archived. No further changes may be made.

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From: Thorsten Kukuk <kukuk <at> suse.com>
To: 65617 <at> debbugs.gnu.org
Subject: bug#65617: coreutils 9.4: seg.fault in readutmp with systemd
Date: Wed, 30 Aug 2023 11:21:06 +0000
coreutils 9.4 with the --enable-systemd option seg.faults in
lib/readutmp.c, line 801:

for (session_ptr = sessions; *session_ptr != NULL; session_ptr++)

If there is no session, "sessions" is NULL and "*session_ptr" will
dereference a NULL pointer.
Affected are who, pinky and uptime.

A simple fix:

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++)


-- 
Thorsten Kukuk, Distinguished Engineer, Senior Architect, Future Technologies
SUSE Software Solutions Germany GmbH, Frankenstraße 146, 90461 Nuernberg, Germany
Managing Director: Ivo Totev, Andrew McDonald, Werner Knoblich
(HRB 36809, AG Nürnberg)




This bug report was last modified 1 year and 286 days ago.

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