From 9453d246d99c5f176f0214b085bb59409bd43843 Mon Sep 17 00:00:00 2001
From: Pavel Otchertsov <pavel.otchertsov@gmail.com>
Date: Wed, 24 Mar 2021 09:39:16 +0300
Subject: [PATCH] unix: fix usage of getpwnam_r and friends

These functions can return 0 code but still store NULL in result, if no matching group or username found.
Also the buffer of 64 size could be too small to store all string fields in result.
---
 lib/plat/unix/unix-caps.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/lib/plat/unix/unix-caps.c b/lib/plat/unix/unix-caps.c
index 1cb62a653..054e3d138 100644
--- a/lib/plat/unix/unix-caps.c
+++ b/lib/plat/unix/unix-caps.c
@@ -71,9 +71,9 @@ lws_plat_user_colon_group_to_ids(const char *u_colon_g, uid_t *puid, gid_t *pgid
 #if defined(LWS_HAVE_GETGRNAM_R)
 	{
 		struct group gr;
-		char strs[64];
+		char strs[1024];
 
-		if (getgrnam_r(colon, &gr, strs, sizeof(strs), &g)) {
+		if (getgrnam_r(colon, &gr, strs, sizeof(strs), &g) || !g) {
 #else
 	{
 		g = getgrnam(colon);
@@ -89,9 +89,9 @@ lws_plat_user_colon_group_to_ids(const char *u_colon_g, uid_t *puid, gid_t *pgid
 #if defined(LWS_HAVE_GETPWNAM_R)
 	{
 		struct passwd pr;
-		char strs[64];
+		char strs[1024];
 
-		if (getpwnam_r(u, &pr, strs, sizeof(strs), &p)) {
+		if (getpwnam_r(u, &pr, strs, sizeof(strs), &p) || !p) {
 #else
 	{
 		p = getpwnam(u);
@@ -118,9 +118,9 @@ lws_plat_drop_app_privileges(struct lws_context *context, int actually_drop)
 	if (context->groupname) {
 #if defined(LWS_HAVE_GETGRNAM_R)
 		struct group gr;
-		char strs[64];
+		char strs[1024];
 
-		if (!getgrnam_r(context->groupname, &gr, strs, sizeof(strs), &g)) {
+		if (!getgrnam_r(context->groupname, &gr, strs, sizeof(strs), &g) && g) {
 #else
 		g = getgrnam(context->groupname);
 		if (g) {
@@ -141,9 +141,9 @@ lws_plat_drop_app_privileges(struct lws_context *context, int actually_drop)
 	if (context->username) {
 #if defined(LWS_HAVE_GETPWNAM_R)
 		struct passwd pr;
-		char strs[64];
+		char strs[1024];
 
-		if (!getpwnam_r(context->username, &pr, strs, sizeof(strs), &p)) {
+		if (!getpwnam_r(context->username, &pr, strs, sizeof(strs), &p) && p) {
 #else
 		p = getpwnam(context->username);
 		if (p) {
@@ -168,9 +168,9 @@ lws_plat_drop_app_privileges(struct lws_context *context, int actually_drop)
 	if (context->gid && context->gid != (gid_t)-1l) {
 #if defined(LWS_HAVE_GETGRGID_R)
 		struct group gr;
-		char strs[64];
+		char strs[1024];
 
-		if (getgrgid_r(context->gid, &gr, strs, sizeof(strs), &g)) {
+		if (getgrgid_r(context->gid, &gr, strs, sizeof(strs), &g) || !g) {
 #else
 		g = getgrgid(context->gid);
 		if (!g) {
@@ -199,9 +199,9 @@ lws_plat_drop_app_privileges(struct lws_context *context, int actually_drop)
 	if (context->uid && context->uid != (uid_t)-1l) {
 #if defined(LWS_HAVE_GETPWUID_R)
 		struct passwd pr;
-		char strs[64];
+		char strs[1024];
 
-		if (getpwuid_r(context->uid, &pr, strs, sizeof(strs), &p)) {
+		if (getpwuid_r(context->uid, &pr, strs, sizeof(strs), &p) || !p) {
 #else
 		p = getpwuid(context->uid);
 		if (!p) {