Merge pull request #106 from rekiofoldhome/unaligned-access

Use byte-per-byte accesses when accessing possibly unaligned data.

nfq/helpers.h

@@ -23,3 +23,16 @@ bool set_socket_buffers(int fd, int rcvbuf, int sndbuf);
 
 uint64_t pntoh64(const void *p);
 void phton64(uint8_t *p, uint64_t v);
+
+static inline uint16_t pntoh16(const uint8_t *p) {
+	return ((uint16_t)p[0] << 8) | (uint16_t)p[1];
+}
+
+static inline void phton16(uint8_t *p, uint16_t v) {
+    p[0] = (uint8_t)(v >> 8);
+    p[1] = v & 0xFF;
+}
+
+static inline uint32_t pntoh32(const uint8_t *p) {
+	return ((uint32_t)p[0] << 24) | ((uint32_t)p[1] << 16) | ((uint32_t)p[2] << 8) | (uint32_t)p[3];
+}

nfq/protocol.c

@@ -44,8 +44,6 @@ bool HttpExtractHost(const uint8_t *data, size_t len, char *host, size_t len_hos
 	return false;
 }
 
-
-
 static uint8_t tvb_get_varint(const uint8_t *tvb, uint64_t *value)
 {
 	switch (*tvb >> 6)
@@ -54,10 +52,10 @@ static uint8_t tvb_get_varint(const uint8_t *tvb, uint64_t *value)
 		if (value) *value = *tvb & 0x3F;
 		return 1;
 	case 1: /* 0b01 => 2 bytes length (14 bits Usable) */
-		if (value) *value = ntohs(*(uint16_t*)tvb) & 0x3FFF;
+		if (value) *value = pntoh16(tvb) & 0x3FFF;
 		return 2;
 	case 2: /* 0b10 => 4 bytes length (30 bits Usable) */
-		if (value) *value = ntohl(*(uint32_t*)tvb) & 0x3FFFFFFF;
+		if (value) *value = pntoh32(tvb) & 0x3FFFFFFF;
 		return 4;
 	case 3: /* 0b11 => 8 bytes length (62 bits Usable) */
 		if (value) *value = pntoh64(tvb) & 0x3FFFFFFFFFFFFFFF;
@@ -87,7 +85,7 @@ bool IsQUICCryptoHello(const uint8_t *data, size_t len, size_t *hello_offset, si
 }
 bool IsTLSClientHello(const uint8_t *data, size_t len)
 {
-	return len >= 6 && data[0] == 0x16 && data[1] == 0x03 && data[2] >= 0x01 && data[2] <= 0x03 && data[5] == 0x01 && (ntohs(*(uint16_t*)(data + 3)) + 5) <= len;
+	return len >= 6 && data[0] == 0x16 && data[1] == 0x03 && data[2] >= 0x01 && data[2] <= 0x03 && data[5] == 0x01 && (pntoh16(data + 3) + 5) <= len;
 }
 bool TLSFindExtInHandshake(const uint8_t *data, size_t len, uint16_t type, const uint8_t **ext, size_t *len_ext)
 {
@@ -114,7 +112,7 @@ bool TLSFindExtInHandshake(const uint8_t *data, size_t len, uint16_t type, const
 	l += data[l] + 1;
 	// CipherSuitesLength
 	if (len < (l + 2)) return false;
-	l += ntohs(*(uint16_t*)(data + l)) + 2;
+	l += pntoh16(data + l) + 2;
 	// CompressionMethodsLength
 	if (len < (l + 1)) return false;
 	l += data[l] + 1;
@@ -122,18 +120,17 @@ bool TLSFindExtInHandshake(const uint8_t *data, size_t len, uint16_t type, const
 	if (len < (l + 2)) return false;
 
 	data += l; len -= l;
-	l = ntohs(*(uint16_t*)data);
+	l = pntoh16(data);
 	data += 2; len -= 2;
 	if (l < len) return false;
 
-	uint16_t ntype = htons(type);
 	while (l >= 4)
 	{
-		uint16_t etype = *(uint16_t*)data;
-		size_t elen = ntohs(*(uint16_t*)(data + 2));
+		uint16_t etype = pntoh16(data);
+		size_t elen = pntoh16(data + 2);
 		data += 4; l -= 4;
 		if (l < elen) break;
-		if (etype == ntype)
+		if (etype == type)
 		{
 			if (ext && len_ext)
 			{
@@ -162,7 +159,7 @@ static bool TLSExtractHostFromExt(const uint8_t *ext, size_t elen, char *host, s
 	// u8	data+2 - server name type. 0=host_name
 	// u16	data+3 - server name length
 	if (elen < 5 || ext[2] != 0) return false;
-	size_t slen = ntohs(*(uint16_t*)(ext + 3));
+	size_t slen = pntoh16(ext + 3);
 	ext += 5; elen -= 5;
 	if (slen < elen) return false;
 	if (ext && len_host)
@@ -262,7 +259,7 @@ static bool quic_hkdf_expand_label(const uint8_t *secret, uint8_t secret_len, co
 	size_t hkdflabel_size = 2 + 1 + label_size + 1;
 	if (hkdflabel_size > sizeof(hkdflabel)) return false;
 
-	*(uint16_t*)hkdflabel = htons(out_len);
+	phton16(hkdflabel, out_len);
 	hkdflabel[2] = (uint8_t)label_size;
 	memcpy(hkdflabel + 3, label, label_size);
 	hkdflabel[3 + label_size] = 0;

tpws/helpers.h

@@ -27,3 +27,7 @@ bool is_private6(const struct sockaddr_in6* a);
 
 int set_keepalive(int fd);
 int get_so_error(int fd);
+
+static inline uint16_t pntoh16(const uint8_t *p) {
+	return ((uint16_t)p[0] << 8) | (uint16_t)p[1];
+}

tpws/protocol.c

@@ -45,7 +45,7 @@ bool HttpExtractHost(const uint8_t *data, size_t len, char *host, size_t len_hos
 }
 bool IsTLSClientHello(const uint8_t *data, size_t len)
 {
-	return len>=6 && data[0]==0x16 && data[1]==0x03 && data[2]>=0x01 && data[2]<=0x03 && data[5]==0x01 && (ntohs(*(uint16_t*)(data+3))+5)<=len;
+	return len>=6 && data[0]==0x16 && data[1]==0x03 && data[2]>=0x01 && data[2]<=0x03 && data[5]==0x01 && (pntoh16(data+3)+5)<=len;
 }
 bool TLSFindExt(const uint8_t *data, size_t len, uint16_t type, const uint8_t **ext, size_t *len_ext)
 {
@@ -76,7 +76,7 @@ bool TLSFindExt(const uint8_t *data, size_t len, uint16_t type, const uint8_t **
 	l += data[l]+1;
 	// CipherSuitesLength
 	if (len<(l+2)) return false;
-	l += ntohs(*(uint16_t*)(data+l))+2;
+	l += pntoh16(data+l)+2;
 	// CompressionMethodsLength
 	if (len<(l+1)) return false;
 	l += data[l]+1;
@@ -84,18 +84,17 @@ bool TLSFindExt(const uint8_t *data, size_t len, uint16_t type, const uint8_t **
 	if (len<(l+2)) return false;
 
 	data+=l; len-=l;
-	l=ntohs(*(uint16_t*)data);
+	l=pntoh16(data);
 	data+=2; len-=2;
 	if (l<len) return false;
 
-	uint16_t ntype=htons(type);
 	while(l>=4)
 	{
-		uint16_t etype=*(uint16_t*)data;
-		size_t elen=ntohs(*(uint16_t*)(data+2));
+		uint16_t etype=pntoh16(data);
+		size_t elen=pntoh16(data+2);
 		data+=4; l-=4;
 		if (l<elen) break;
-		if (etype==ntype)
+		if (etype==type)
 		{
 			if (ext && len_ext)
 			{
@@ -119,7 +118,7 @@ bool TLSHelloExtractHost(const uint8_t *data, size_t len, char *host, size_t len
 	// u8	data+2 - server name type. 0=host_name
 	// u16	data+3 - server name length
 	if (elen<5 || ext[2]!=0) return false;
-	size_t slen = ntohs(*(uint16_t*)(ext+3));
+	size_t slen = pntoh16(ext+3);
 	ext+=5; elen-=5;
 	if (slen<elen) return false;
 	if (ext && len_host)