From 71482861ae99aa642773bd52e0ce26658f175889 Mon Sep 17 00:00:00 2001
From: Nate Choe <natechoe9@gmail.com>
Date: Sun, 3 Apr 2022 20:42:13 -0500
Subject: [PATCH] Fixed frequent segfault with children

---
 Makefile         |  7 ++++---
 example/sitefile |  2 +-
 src/util.c       | 38 ++++++++++++++++++++++++++++++--------
 3 files changed, 35 insertions(+), 12 deletions(-)

diff --git a/Makefile b/Makefile
index 5c4cc2e..57269eb 100644
--- a/Makefile
+++ b/Makefile
@@ -1,15 +1,16 @@
 SRC = $(wildcard src/*.c)
 OBJ = $(subst .c,.o,$(subst src,work,$(SRC)))
-LIBS = -pie -lrt -ldl $(shell pkg-config --libs gnutls)
+LIBS = gnutls
+LDFLAGS = -pie -lrt -ldl $(shell pkg-config --libs $(LIBS))
 CFLAGS := -O2 -pipe -Wall -Wpedantic -Wshadow -ansi
-CFLAGS += -Isrc/ -fpie -D_POSIX_C_SOURCE=200809L $(shell pkg-config --cflags gnutls)
+CFLAGS += -Isrc/ -fpie -D_POSIX_C_SOURCE=200809L $(shell pkg-config --cflags $(LIBS))
 INSTALLDIR := /usr/sbin
 HEADERDIR := /usr/include/
 INCLUDE_DIRECTORY := swebs
 OUT = swebs
 
 build/$(OUT): $(OBJ)
-	$(CC) $(OBJ) -o build/$(OUT) $(LIBS)
+	$(CC) $(OBJ) -o build/$(OUT) $(LDFLAGS)
 
 work/%.o: src/%.c $(wildcard src/swebs/*.h)
 	$(CC) $(CFLAGS) $< -c -o $@
diff --git a/example/sitefile b/example/sitefile
index 2380c2b..d8d93b2 100644
--- a/example/sitefile
+++ b/example/sitefile
@@ -1,6 +1,6 @@
 define port 8000
 
-define transport TLS
+#define transport TLS
 define key domain.key
 define cert domain.crt
 define timeout 2000
diff --git a/src/util.c b/src/util.c
index 8818957..354c4de 100644
--- a/src/util.c
+++ b/src/util.c
@@ -129,17 +129,39 @@ void sendFd(int fd, int dest) {
 }
 
 int recvFd(int source) {
+	union {
+		char buff[CMSG_SPACE(sizeof(int))];
+		struct cmsghdr align;
+	} cmsghdr;
 	struct msghdr msg;
 	struct cmsghdr *cmsg;
-	char cmsgbuf[CMSG_SPACE(sizeof(int))];
-	unsigned char *data;
+	struct iovec iov;
+	int data;
+	ssize_t nr;
 	int ret;
-	memset(&msg, 0, sizeof(msg));
-	msg.msg_control = cmsgbuf;
-	msg.msg_controllen = sizeof(cmsgbuf);
-	recvmsg(source, &msg, 0);
+
+	msg.msg_name = NULL;
+	msg.msg_namelen = 0;
+
+	iov.iov_base = &data;
+	iov.iov_len = sizeof(data);
+	msg.msg_iov = &iov;
+	msg.msg_iovlen = 1;
+
+	msg.msg_control = cmsghdr.buff;
+	msg.msg_controllen = sizeof(cmsghdr.buff);
+	nr = recvmsg(source, &msg, 0);
+	if (nr < 0)
+		return -1;
+
 	cmsg = CMSG_FIRSTHDR(&msg);
-	data = CMSG_DATA(cmsg);
-	memcpy(&ret, data, sizeof(ret));
+	if (cmsg == NULL || cmsg->cmsg_len != CMSG_LEN(sizeof(data)))
+		return -1;
+	if (cmsg->cmsg_level != SOL_SOCKET)
+		return -1;
+	if (cmsg->cmsg_type != SCM_RIGHTS)
+		return -1;
+
+	memcpy(&ret, CMSG_DATA(cmsg), sizeof(ret));
 	return ret;
 }