Fix off-by-one mistakes

The buffers have a size of 512 (see xmalloc() above), which is what
snprintf(3) expects.

Link: <https://github.com/shadow-maint/shadow/pull/607>
Signed-off-by: Alejandro Colomar <alx@kernel.org>

diff --git a/src/groupmod.c b/src/groupmod.c
index 006eca1c46a8638591cbd40d1436b1cc5faee54b..828c7c0bf6dd402d9f2d497264094299c305da63 100644 (file)
--- a/src/groupmod.c
+++ b/src/groupmod.c
@@ -554,13 +554,13 @@ static void prepare_failure_reports (void)
 #endif
        info_passwd.audit_msg  = xmalloc (512);
 
-       (void) snprintf (info_group.audit_msg, 511,
+       (void) snprintf (info_group.audit_msg, 512,
                         "changing %s; ", gr_dbname ());
 #ifdef SHADOWGRP
-       (void) snprintf (info_gshadow.audit_msg, 511,
+       (void) snprintf (info_gshadow.audit_msg, 512,
                         "changing %s; ", sgr_dbname ());
 #endif
-       (void) snprintf (info_passwd.audit_msg, 511,
+       (void) snprintf (info_passwd.audit_msg, 512,
                         "changing %s; ", pw_dbname ());
 
        info_group.action   =   info_group.audit_msg
@@ -573,16 +573,16 @@ static void prepare_failure_reports (void)
                              + strlen (info_passwd.audit_msg);
 
        (void) snprintf (info_group.action,
-                        511 - strlen (info_group.audit_msg),
+                        512 - strlen (info_group.audit_msg),
                         "group %s/%lu",
                         group_name, (unsigned long int) group_id);
 #ifdef SHADOWGRP
        (void) snprintf (info_gshadow.action,
-                        511 - strlen (info_group.audit_msg),
+                        512 - strlen (info_group.audit_msg),
                         "group %s", group_name);
 #endif
        (void) snprintf (info_passwd.action,
-                        511 - strlen (info_group.audit_msg),
+                        512 - strlen (info_group.audit_msg),
                         "group %s/%lu",
                         group_name, (unsigned long int) group_id);
 
@@ -617,13 +617,13 @@ static void prepare_failure_reports (void)
                strncat (info_group.action, ", new gid: ",
                         511 - strlen (info_group.audit_msg));
                (void) snprintf (info_group.action+strlen (info_group.action),
-                                511 - strlen (info_group.audit_msg),
+                                512 - strlen (info_group.audit_msg),
                                 "%lu", (unsigned long int) group_newid);
 
                strncat (info_passwd.action, ", new gid: ",
                         511 - strlen (info_passwd.audit_msg));
                (void) snprintf (info_passwd.action+strlen (info_passwd.action),
-                                511 - strlen (info_passwd.audit_msg),
+                                512 - strlen (info_passwd.audit_msg),
                                 "%lu", (unsigned long int) group_newid);
        }
        info_group.audit_msg[511]   = '\0';