Raise limit for passwd and shadow entry length

- also prevent writing longer entries (#1422497)

shadow-4.5-long-entry.patch

@@ -0,0 +1,84 @@
+diff -up shadow-4.5/lib/defines.h.long-entry shadow-4.5/lib/defines.h
+--- shadow-4.5/lib/defines.h.long-entry	2014-09-01 16:36:40.000000000 +0200
++++ shadow-4.5/lib/defines.h	2018-04-20 11:53:07.419308212 +0200
+@@ -382,4 +382,7 @@ extern char *strerror ();
+ # endif
+ #endif
+ 
++/* Maximum length of passwd entry */
++#define PASSWD_ENTRY_MAX_LENGTH 32768
++
+ #endif				/* _DEFINES_H_ */
+diff -up shadow-4.5/lib/pwio.c.long-entry shadow-4.5/lib/pwio.c
+--- shadow-4.5/lib/pwio.c.long-entry	2015-11-17 17:45:15.000000000 +0100
++++ shadow-4.5/lib/pwio.c	2018-04-20 12:10:24.400837235 +0200
+@@ -79,7 +79,10 @@ static int passwd_put (const void *ent,
+ 	    || (pw->pw_gid == (gid_t)-1)
+ 	    || (valid_field (pw->pw_gecos, ":\n") == -1)
+ 	    || (valid_field (pw->pw_dir, ":\n") == -1)
+-	    || (valid_field (pw->pw_shell, ":\n") == -1)) {
++	    || (valid_field (pw->pw_shell, ":\n") == -1)
++	    || (strlen (pw->pw_name) + strlen (pw->pw_passwd) +
++	        strlen (pw->pw_gecos) + strlen (pw->pw_dir) +
++	        strlen (pw->pw_shell) + 100 > PASSWD_ENTRY_MAX_LENGTH)) {
+ 		return -1;
+ 	}
+ 
+diff -up shadow-4.5/lib/sgetpwent.c.long-entry shadow-4.5/lib/sgetpwent.c
+--- shadow-4.5/lib/sgetpwent.c.long-entry	2014-09-01 16:36:40.000000000 +0200
++++ shadow-4.5/lib/sgetpwent.c	2018-04-20 12:16:31.911513808 +0200
+@@ -57,7 +57,7 @@
+ struct passwd *sgetpwent (const char *buf)
+ {
+ 	static struct passwd pwent;
+-	static char pwdbuf[1024];
++	static char pwdbuf[PASSWD_ENTRY_MAX_LENGTH];
+ 	register int i;
+ 	register char *cp;
+ 	char *fields[NFIELDS];
+@@ -67,8 +67,10 @@ struct passwd *sgetpwent (const char *bu
+ 	 * the password structure remain valid.
+ 	 */
+ 
+-	if (strlen (buf) >= sizeof pwdbuf)
++	if (strlen (buf) >= sizeof pwdbuf) {
++		fprintf (stderr, "Too long passwd entry encountered, file corruption?\n");
+ 		return 0;	/* fail if too long */
++	}
+ 	strcpy (pwdbuf, buf);
+ 
+ 	/*
+diff -up shadow-4.5/lib/sgetspent.c.long-entry shadow-4.5/lib/sgetspent.c
+--- shadow-4.5/lib/sgetspent.c.long-entry	2014-09-01 16:36:40.000000000 +0200
++++ shadow-4.5/lib/sgetspent.c	2018-04-20 12:16:54.505056257 +0200
+@@ -48,7 +48,7 @@
+  */
+ struct spwd *sgetspent (const char *string)
+ {
+-	static char spwbuf[1024];
++	static char spwbuf[PASSWD_ENTRY_MAX_LENGTH];
+ 	static struct spwd spwd;
+ 	char *fields[FIELDS];
+ 	char *cp;
+@@ -61,6 +61,7 @@ struct spwd *sgetspent (const char *stri
+ 	 */
+ 
+ 	if (strlen (string) >= sizeof spwbuf) {
++		fprintf (stderr, "Too long shadow entry encountered, file corruption?\n");
+ 		return 0;	/* fail if too long */
+ 	}
+ 	strcpy (spwbuf, string);
+diff -up shadow-4.5/lib/shadowio.c.long-entry shadow-4.5/lib/shadowio.c
+--- shadow-4.5/lib/shadowio.c.long-entry	2016-12-07 06:30:41.000000001 +0100
++++ shadow-4.5/lib/shadowio.c	2018-04-20 12:12:03.292171667 +0200
+@@ -79,7 +79,9 @@ static int shadow_put (const void *ent,
+ 
+ 	if (   (NULL == sp)
+ 	    || (valid_field (sp->sp_namp, ":\n") == -1)
+-	    || (valid_field (sp->sp_pwdp, ":\n") == -1)) {
++	    || (valid_field (sp->sp_pwdp, ":\n") == -1)
++	    || (strlen (sp->sp_namp) + strlen (sp->sp_pwdp) +
++	        1000 > PASSWD_ENTRY_MAX_LENGTH)) {
+ 		return -1;
+ 	}
+ 

shadow-utils.spec

@@ -1,7 +1,7 @@
 Summary: Utilities for managing accounts and shadow password files
 Name: shadow-utils
 Version: 4.5
-Release: 9%{?dist}
+Release: 10%{?dist}
 Epoch: 2
 URL: http://pkg-shadow.alioth.debian.org/
 Source0: https://github.com/shadow-maint/shadow/releases/download/%{version}/shadow-%{version}.tar.xz
@@ -31,6 +31,7 @@ Patch29: shadow-4.2.1-null-tm.patch
 Patch30: shadow-4.1.5.1-newgrp-grouplist.patch
 Patch31: shadow-4.5-userdel-chroot.patch
 Patch32: shadow-4.5-crypt_h.patch
+Patch33: shadow-4.5-long-entry.patch
 
 License: BSD and GPLv2+
 Group: System Environment/Base
@@ -83,6 +84,7 @@ are used for managing group accounts.
 %patch30 -p1 -b .grouplist
 %patch31 -p1 -b .userdel-chroot
 %patch32 -p1 -b .crypt_h
+%patch33 -p1 -b .long-entry
 
 iconv -f ISO88591 -t utf-8  doc/HOWTO > doc/HOWTO.utf8
 cp -f doc/HOWTO.utf8 doc/HOWTO
@@ -235,6 +237,10 @@ done
 %{_mandir}/man8/vigr.8*
 
 %changelog
+* Fri Apr 20 2018 Tomáš Mráz <tmraz@redhat.com> - 2:4.5-10
+- Raise limit for passwd and shadow entry length but also prevent
+  writing longer entries (#1422497)
+
 * Tue Feb 06 2018 Björn Esser <besser82@fedoraproject.org> - 2:4.5-9
 - Add patch to include crypt.h, if present
 - Use %%make_{build,install} macros