[PATCH app/sessreg] Replace strncpy calls with a sane version that always terminates

[Peter Hutterer]

Fixes coverity complaints about potentially unterminated strings

Signed-off-by: Peter Hutterer <peter.hutte...@who-t.net>
---
 sessreg.c | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/sessreg.c b/sessreg.c
index 0a8fdb2..53b30b0 100644
--- a/sessreg.c
+++ b/sessreg.c
@@ -192,6 +192,14 @@ sysnerr (int x, const char *s)
        return x;
 }
 
+static void
+safe_strncpy(char *dest, const char *src, size_t n)
+{
+    (void)strncpy(dest, src, n);
+    if (n > 0)
+        dest[n - 1] = '\0';
+}
+
 int
 main (int argc, char **argv)
 {
@@ -406,9 +414,9 @@ main (int argc, char **argv)
                        memset(&ll, 0, sizeof(ll));
                        ll.ll_time = current_time;
                        if (line)
-                        (void) strncpy (ll.ll_line, line, sizeof (ll.ll_line));
+                        safe_strncpy (ll.ll_line, line, sizeof (ll.ll_line));
                        if (host_name)
-                        (void) strncpy (ll.ll_host, host_name, sizeof 
(ll.ll_host));
+                        safe_strncpy (ll.ll_host, host_name, sizeof 
(ll.ll_host));
 
                        sysnerr (write (llog, (char *) &ll, sizeof (ll))
                                        == sizeof (ll), "write lastlog entry");
@@ -429,11 +437,11 @@ set_utmp (struct utmp *u, char *line, char *user, char 
*host, time_t date, int a
 {
        memset (u, 0, sizeof (*u));
        if (line)
-               (void) strncpy (u->ut_line, line, sizeof (u->ut_line));
+               safe_strncpy (u->ut_line, line, sizeof (u->ut_line));
        else
                memset (u->ut_line, 0, sizeof (u->ut_line));
        if (addp && user)
-               (void) strncpy (u->ut_name, user, sizeof (u->ut_name));
+               safe_strncpy (u->ut_name, user, sizeof (u->ut_name));
        else
                memset (u->ut_name, 0, sizeof (u->ut_name));
 #ifdef HAVE_STRUCT_UTMP_UT_ID
@@ -451,7 +459,7 @@ set_utmp (struct utmp *u, char *line, char *user, char 
*host, time_t date, int a
                        i -= sizeof (u->ut_id);
                else
                        i = 0;
-               (void) strncpy (u->ut_id, line + i, sizeof (u->ut_id));
+               safe_strncpy (u->ut_id, line + i, sizeof (u->ut_id));
        } else
                memset (u->ut_id, 0, sizeof (u->ut_id));
 #endif
@@ -469,7 +477,7 @@ set_utmp (struct utmp *u, char *line, char *user, char 
*host, time_t date, int a
 #endif
 #ifdef HAVE_STRUCT_UTMP_UT_HOST
        if (addp && host)
-               (void) strncpy (u->ut_host, host, sizeof (u->ut_host));
+               safe_strncpy (u->ut_host, host, sizeof (u->ut_host));
        else
                memset (u->ut_host, 0, sizeof (u->ut_host));
 #endif
@@ -513,7 +521,7 @@ set_utmpx (struct utmpx *u, const char *line, const char 
*user,
                if(strcmp(line, ":0") == 0)
                        (void) strcpy(u->ut_line, "console");
                else
-                       (void) strncpy (u->ut_line, line, sizeof (u->ut_line));
+                       safe_strncpy (u->ut_line, line, sizeof (u->ut_line));
 
                strncpy(u->ut_host, line, sizeof(u->ut_host));
 #ifdef HAVE_STRUCT_UTMPX_UT_SYSLEN
@@ -523,7 +531,7 @@ set_utmpx (struct utmpx *u, const char *line, const char 
*user,
        else
                memset (u->ut_line, 0, sizeof (u->ut_line));
        if (addp && user)
-               (void) strncpy (u->ut_user, user, sizeof (u->ut_user));
+               safe_strncpy (u->ut_user, user, sizeof (u->ut_user));
        else
                memset (u->ut_user, 0, sizeof (u->ut_user));
 
@@ -541,7 +549,7 @@ set_utmpx (struct utmpx *u, const char *line, const char 
*user,
                        i -= sizeof (u->ut_id);
                else
                        i = 0;
-               (void) strncpy (u->ut_id, line + i, sizeof (u->ut_id));
+               safe_strncpy (u->ut_id, line + i, sizeof (u->ut_id));
 
                /* make sure there is no entry using identical ut_id */
                if (!UtmpxIdOpen(u->ut_id) && addp) {
-- 
2.17.1

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