diff --git a/ChangeLog b/ChangeLog
index 57e7e56f..befe7550 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,20 @@
+2009-09-07  Nicolas François  <nicolas.francois@centraliens.net>
+
+	* lib/shadowmem.c: Only copy the required fields of the struct
+	spwd. (start with the primitive types)
+	* lib/shadowmem.c: Avoid memzero() on a possibly NULL pointer.
+	* lib/groupmem.c: Only copy the required fields of the struct
+	group. (start with the primitive types)
+	* lib/groupmem.c: Avoid memzero() on a possibly NULL pointer.
+	* lib/groupmem.c: Free gr_mem in addition to its elements.
+	* lib/sgroupio.c: The struct sgrp has no primitive types to be
+	copied initially.
+	* lib/sgroupio.c: Avoid memzero() on a possibly NULL pointer.
+	* lib/sgroupio.c: Free sg_mem and sg_add in addition to their
+	elements.
+	* lib/pwmem.c: Only copy the required fields of the struct
+	passwd. (start with the primitive types)
+
 2009-09-07  Nicolas François  <nicolas.francois@centraliens.net>
 
 	* lib/sgroupio.h: Harmonize splint annotations of sgr_locate()
diff --git a/lib/groupmem.c b/lib/groupmem.c
index fed03bc6..3add3c80 100644
--- a/lib/groupmem.c
+++ b/lib/groupmem.c
@@ -48,7 +48,7 @@
 	if (NULL == gr) {
 		return NULL;
 	}
-	*gr = *grent;
+	gr->gr_gid = grent->gr_gid;
 	gr->gr_name = strdup (grent->gr_name);
 	if (NULL == gr->gr_name) {
 		free(gr);
@@ -90,12 +90,17 @@
 
 void gr_free (/*@out@*/ /*@only@*/struct group *grent)
 {
+	size_t i;
 	free (grent->gr_name);
-	memzero (grent->gr_passwd, strlen (grent->gr_passwd));
-	free (grent->gr_passwd);
-	while (*(grent->gr_mem)) {
-		free (*(grent->gr_mem));
-		grent->gr_mem++;
+	if (NULL != grent->gr_passwd) {
+		memzero (grent->gr_passwd, strlen (grent->gr_passwd));
+		free (grent->gr_passwd);
+	}
+	if (NULL != grent->gr_mem) {
+		for (i = 0; NULL != grent->gr_mem[i]; i++) {
+			free (grent->gr_mem[i]);
+		}
+		free (grent->gr_mem);
 	}
 	free (grent);
 }
diff --git a/lib/pwmem.c b/lib/pwmem.c
index a1b3411b..5569191a 100644
--- a/lib/pwmem.c
+++ b/lib/pwmem.c
@@ -48,7 +48,8 @@
 	if (NULL == pw) {
 		return NULL;
 	}
-	*pw = *pwent;
+	pw->pw_uid = pwent->pw_uid;
+	pw->pw_gid = pwent->pw_gid;
 	pw->pw_name = strdup (pwent->pw_name);
 	if (NULL == pw->pw_name) {
 		free(pw);
@@ -91,8 +92,10 @@
 void pw_free (/*@out@*/ /*@only@*/struct passwd *pwent)
 {
 	free (pwent->pw_name);
-	memzero (pwent->pw_passwd, strlen (pwent->pw_passwd));
-	free (pwent->pw_passwd);
+	if (pwent->pw_passwd) {
+		memzero (pwent->pw_passwd, strlen (pwent->pw_passwd));
+		free (pwent->pw_passwd);
+	}
 	free (pwent->pw_gecos);
 	free (pwent->pw_dir);
 	free (pwent->pw_shell);
diff --git a/lib/sgroupio.c b/lib/sgroupio.c
index 5a882cc9..836fc276 100644
--- a/lib/sgroupio.c
+++ b/lib/sgroupio.c
@@ -51,7 +51,6 @@
 	if (NULL == sg) {
 		return NULL;
 	}
-	*sg = *sgent;
 	sg->sg_name = strdup (sgent->sg_name);
 	if (NULL == sg->sg_name) {
 		free (sg);
@@ -137,17 +136,20 @@ static void gshadow_free (/*@out@*/ /*@only@*/void *ent)
 
 void sgr_free (/*@out@*/ /*@only@*/struct sgrp *sgent)
 {
+	size_t i;
 	free (sgent->sg_name);
-	memzero (sgent->sg_passwd, strlen (sgent->sg_passwd));
-	free (sgent->sg_passwd);
-	while (NULL != *(sgent->sg_adm)) {
-		free (*(sgent->sg_adm));
-		sgent->sg_adm++;
+	if (NULL != sgent->sg_passwd) {
+		memzero (sgent->sg_passwd, strlen (sgent->sg_passwd));
+		free (sgent->sg_passwd);
 	}
-	while (NULL != *(sgent->sg_mem)) {
-		free (*(sgent->sg_mem));
-		sgent->sg_mem++;
+	for (i = 0; NULL != sgent->sg_adm[i]; i++) {
+		free (sgent->sg_adm[i]);
 	}
+	free (sgent->sg_adm);
+	for (i = 0; NULL != sgent->sg_mem[i]; i++) {
+		free (sgent->sg_mem[i]);
+	}
+	free (sgent->sg_mem);
 	free (sgent);
 }
 
diff --git a/lib/shadowmem.c b/lib/shadowmem.c
index a7a8592d..2dece383 100644
--- a/lib/shadowmem.c
+++ b/lib/shadowmem.c
@@ -49,8 +49,14 @@
 	if (NULL == sp) {
 		return NULL;
 	}
-	*sp = *spent;
-	sp->sp_namp = strdup (spent->sp_namp);
+	sp->sp_lstchg = spent->sp_lstchg;
+	sp->sp_min    = spent->sp_min;
+	sp->sp_max    = spent->sp_max;
+	sp->sp_warn   = spent->sp_warn;
+	sp->sp_inact  = spent->sp_inact;
+	sp->sp_expire = spent->sp_expire;
+	sp->sp_flag   = spent->sp_flag;
+	sp->sp_namp   = strdup (spent->sp_namp);
 	if (NULL == sp->sp_namp) {
 		free(sp);
 		return NULL;
@@ -68,8 +74,10 @@
 void spw_free (/*@out@*/ /*@only@*/struct spwd *spent)
 {
 	free (spent->sp_namp);
-	memzero (spent->sp_pwdp, strlen (spent->sp_pwdp));
-	free (spent->sp_pwdp);
+	if (NULL != spent->sp_pwdp) {
+		memzero (spent->sp_pwdp, strlen (spent->sp_pwdp));
+		free (spent->sp_pwdp);
+	}
 	free (spent);
 }