lib/: Saturate addition to avoid overflow

Very large values in /etc/shadow could lead to overflows.  Make sure
that these calculations are saturated at LONG_MAX.  Since entries are
based on days and not seconds since epoch, saturating won't hurt anyone.

Co-developed-by: Tobias Stoeckmann <tobias@stoeckmann.org>
Co-developed-by: Alejandro Colomar <alx@kernel.org>
Signed-off-by: Alejandro Colomar <alx@kernel.org>

diff --git a/lib/age.c b/lib/age.c
index d9ef88c4c8a026f88611812ec4ab0f2aaf657513..72a13eab51bcc6023ef5dcc96bb7e1808424043e 100644 (file)
--- a/lib/age.c
+++ b/lib/age.c
@@ -13,12 +13,15 @@
 #include <stdio.h>
 #include <time.h>
 #include <errno.h>
-#include "prototypes.h"
-#include "defines.h"
-#include "exitcodes.h"
 #include <pwd.h>
 #include <grp.h>
 
+#include "adds.h"
+#include "defines.h"
+#include "exitcodes.h"
+#include "prototypes.h"
+
+
 #ident "$Id$"
 
 #ifndef PASSWD_PROGRAM
@@ -162,7 +165,8 @@ void agecheck (/*@null@*/const struct spwd *sp)
                return;
        }
 
-       remain = sp->sp_lstchg + sp->sp_max - now;
+       remain = addsl(sp->sp_lstchg, sp->sp_max, -now);
+
        if (remain <= sp->sp_warn) {
                if (remain > 1) {
                        (void) printf (_("Your password will expire in %ld days.\n"),

diff --git a/lib/isexpired.c b/lib/isexpired.c
index 45c7601ec4bef15ef750d454bba281bd2b78b430..c275691f7267065cc9536c1a39ded38193cd8b2b 100644 (file)
--- a/lib/isexpired.c
+++ b/lib/isexpired.c
@@ -15,11 +15,13 @@
 #include <config.h>
 
 #include <sys/types.h>
-#include "prototypes.h"
-#include "defines.h"
 #include <pwd.h>
 #include <time.h>
 
+#include "adds.h"
+#include "defines.h"
+#include "prototypes.h"
+
 #ident "$Id$"
 
 
@@ -38,7 +40,7 @@
  */
 int isexpired (const struct passwd *pw, /*@null@*/const struct spwd *sp)
 {
-       long now;
+       long  now;
 
        now = time(NULL) / DAY;
 
@@ -72,7 +74,8 @@ int isexpired (const struct passwd *pw, /*@null@*/const struct spwd *sp)
        if (   (sp->sp_lstchg > 0)
            && (sp->sp_max >= 0)
            && (sp->sp_inact >= 0)
-           && (now >= (sp->sp_lstchg + sp->sp_max + sp->sp_inact))) {
+           && (now >= addsl(sp->sp_lstchg, sp->sp_max, sp->sp_inact)))
+       {
                return 2;
        }
 
@@ -94,9 +97,9 @@ int isexpired (const struct passwd *pw, /*@null@*/const struct spwd *sp)
         * the password has expired.
         */
 
-       if (now >= (sp->sp_lstchg + sp->sp_max)) {
+       if (now >= addsl(sp->sp_lstchg, sp->sp_max))
                return 1;
-       }
+
        return 0;
 }