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ladybird/Userland/Libraries/LibC/netdb.cpp
sin-ack c70f45ff44 Everywhere: Explicitly specify the size in StringView constructors 
This commit moves the length calculations out to be directly on the
StringView users. This is an important step towards the goal of removing
StringView(char const*), as it moves the responsibility of calculating
the size of the string to the user of the StringView (which will prevent
naive uses causing OOB access).
2022-07-12 23:11:35 +02:00

854 lines
25 KiB
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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Assertions.h>
#include <AK/ByteBuffer.h>
#include <AK/ScopeGuard.h>
#include <AK/String.h>
#include <Kernel/Net/IPv4.h>
#include <arpa/inet.h>
#include <errno.h>
#include <netdb.h>
#include <netinet/in.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
extern "C" {
#ifdef NO_TLS
int h_errno;
#else
__thread int h_errno;
#endif
static hostent __gethostbyname_buffer;
static in_addr_t __gethostbyname_address;
static in_addr_t* __gethostbyname_address_list_buffer[2];
static hostent __gethostbyaddr_buffer;
static in_addr_t* __gethostbyaddr_address_list_buffer[2];
// IPCCompiler depends on LibC. Because of this, it cannot be compiled
// before LibC is. However, the lookup magic can only be obtained from the
// endpoint itself if IPCCompiler has compiled the IPC file, so this creates
// a chicken-and-egg situation. Because of this, the LookupServer endpoint magic
// is hardcoded here.
// Keep the name synchronized with LookupServer/LookupServer.ipc.
static constexpr u32 lookup_server_endpoint_magic = "LookupServer"sv.hash();
// Get service entry buffers and file information for the getservent() family of functions.
static FILE* services_file = nullptr;
static char const* services_path = "/etc/services";
static bool fill_getserv_buffers(char const* line, ssize_t read);
static servent __getserv_buffer;
static String __getserv_name_buffer;
static String __getserv_protocol_buffer;
static int __getserv_port_buffer;
static Vector<ByteBuffer> __getserv_alias_list_buffer;
static Vector<char*> __getserv_alias_list;
static bool keep_service_file_open = false;
static ssize_t service_file_offset = 0;
// Get protocol entry buffers and file information for the getprotent() family of functions.
static FILE* protocols_file = nullptr;
static char const* protocols_path = "/etc/protocols";
static bool fill_getproto_buffers(char const* line, ssize_t read);
static protoent __getproto_buffer;
static String __getproto_name_buffer;
static Vector<ByteBuffer> __getproto_alias_list_buffer;
static Vector<char*> __getproto_alias_list;
static int __getproto_protocol_buffer;
static bool keep_protocols_file_open = false;
static ssize_t protocol_file_offset = 0;
static int connect_to_lookup_server()
{
int fd = socket(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0);
if (fd < 0) {
perror("socket");
return -1;
}
sockaddr_un address {
AF_LOCAL,
"/tmp/portal/lookup"
};
if (connect(fd, (sockaddr const*)&address, sizeof(address)) < 0) {
perror("connect_to_lookup_server");
close(fd);
return -1;
}
return fd;
}
static String gethostbyname_name_buffer;
hostent* gethostbyname(char const* name)
{
h_errno = 0;
auto ipv4_address = IPv4Address::from_string({ name, strlen(name) });
if (ipv4_address.has_value()) {
gethostbyname_name_buffer = ipv4_address.value().to_string();
__gethostbyname_buffer.h_name = const_cast<char*>(gethostbyname_name_buffer.characters());
__gethostbyname_buffer.h_aliases = nullptr;
__gethostbyname_buffer.h_addrtype = AF_INET;
new (&__gethostbyname_address) IPv4Address(ipv4_address.value());
__gethostbyname_address_list_buffer[0] = &__gethostbyname_address;
__gethostbyname_address_list_buffer[1] = nullptr;
__gethostbyname_buffer.h_addr_list = (char**)__gethostbyname_address_list_buffer;
__gethostbyname_buffer.h_length = 4;
return &__gethostbyname_buffer;
}
int fd = connect_to_lookup_server();
if (fd < 0) {
h_errno = TRY_AGAIN;
return nullptr;
}
auto close_fd_on_exit = ScopeGuard([fd] {
close(fd);
});
size_t unsigned_name_length = strlen(name);
VERIFY(unsigned_name_length <= NumericLimits<i32>::max());
i32 name_length = static_cast<i32>(unsigned_name_length);
struct [[gnu::packed]] {
u32 message_size;
u32 endpoint_magic;
i32 message_id;
i32 name_length;
} request_header = {
(u32)(sizeof(request_header) - sizeof(request_header.message_size) + name_length),
lookup_server_endpoint_magic,
1,
name_length,
};
if (auto nsent = write(fd, &request_header, sizeof(request_header)); nsent < 0) {
h_errno = TRY_AGAIN;
return nullptr;
} else if (nsent != sizeof(request_header)) {
h_errno = NO_RECOVERY;
return nullptr;
}
if (auto nsent = write(fd, name, name_length); nsent < 0) {
h_errno = TRY_AGAIN;
return nullptr;
} else if (nsent != name_length) {
h_errno = NO_RECOVERY;
return nullptr;
}
struct [[gnu::packed]] {
u32 message_size;
u32 endpoint_magic;
i32 message_id;
i32 code;
u64 addresses_count;
} response_header;
if (auto nreceived = read(fd, &response_header, sizeof(response_header)); nreceived < 0) {
h_errno = TRY_AGAIN;
return nullptr;
} else if (nreceived != sizeof(response_header)) {
h_errno = NO_RECOVERY;
return nullptr;
}
if (response_header.endpoint_magic != lookup_server_endpoint_magic || response_header.message_id != 2) {
h_errno = NO_RECOVERY;
return nullptr;
}
if (response_header.code != 0) {
h_errno = NO_RECOVERY;
return nullptr;
}
if (response_header.addresses_count == 0) {
h_errno = HOST_NOT_FOUND;
return nullptr;
}
i32 response_length;
if (auto nreceived = read(fd, &response_length, sizeof(response_length)); nreceived < 0) {
h_errno = TRY_AGAIN;
return nullptr;
} else if (nreceived != sizeof(response_length)
|| response_length != sizeof(__gethostbyname_address)) {
h_errno = NO_RECOVERY;
return nullptr;
}
if (auto nreceived = read(fd, &__gethostbyname_address, response_length); nreceived < 0) {
h_errno = TRY_AGAIN;
return nullptr;
} else if (nreceived != response_length) {
h_errno = NO_RECOVERY;
return nullptr;
}
gethostbyname_name_buffer = name;
__gethostbyname_buffer.h_name = const_cast<char*>(gethostbyname_name_buffer.characters());
__gethostbyname_buffer.h_aliases = nullptr;
__gethostbyname_buffer.h_addrtype = AF_INET;
__gethostbyname_address_list_buffer[0] = &__gethostbyname_address;
__gethostbyname_address_list_buffer[1] = nullptr;
__gethostbyname_buffer.h_addr_list = (char**)__gethostbyname_address_list_buffer;
__gethostbyname_buffer.h_length = 4;
return &__gethostbyname_buffer;
}
static String gethostbyaddr_name_buffer;
hostent* gethostbyaddr(void const* addr, socklen_t addr_size, int type)
{
h_errno = 0;
if (type != AF_INET) {
errno = EAFNOSUPPORT;
return nullptr;
}
if (addr_size < sizeof(in_addr)) {
errno = EINVAL;
return nullptr;
}
int fd = connect_to_lookup_server();
if (fd < 0) {
h_errno = TRY_AGAIN;
return nullptr;
}
auto close_fd_on_exit = ScopeGuard([fd] {
close(fd);
});
in_addr_t const& in_addr = ((const struct in_addr*)addr)->s_addr;
struct [[gnu::packed]] {
u32 message_size;
u32 endpoint_magic;
i32 message_id;
i32 address_length;
} request_header = {
sizeof(request_header) - sizeof(request_header.message_size) + sizeof(in_addr),
lookup_server_endpoint_magic,
3,
sizeof(in_addr),
};
if (auto nsent = write(fd, &request_header, sizeof(request_header)); nsent < 0) {
h_errno = TRY_AGAIN;
return nullptr;
} else if (nsent != sizeof(request_header)) {
h_errno = NO_RECOVERY;
return nullptr;
}
if (auto nsent = write(fd, &in_addr, sizeof(in_addr)); nsent < 0) {
h_errno = TRY_AGAIN;
return nullptr;
} else if (nsent != sizeof(in_addr)) {
h_errno = TRY_AGAIN;
return nullptr;
}
struct [[gnu::packed]] {
u32 message_size;
u32 endpoint_magic;
i32 message_id;
i32 code;
i32 name_length;
} response_header;
if (auto nreceived = read(fd, &response_header, sizeof(response_header)); nreceived < 0) {
h_errno = TRY_AGAIN;
return nullptr;
} else if (nreceived != sizeof(response_header)) {
h_errno = NO_RECOVERY;
return nullptr;
}
if (response_header.endpoint_magic != lookup_server_endpoint_magic
|| response_header.message_id != 4
|| response_header.code != 0) {
h_errno = NO_RECOVERY;
return nullptr;
}
char* buffer;
auto string_impl = StringImpl::create_uninitialized(response_header.name_length, buffer);
if (auto nreceived = read(fd, buffer, response_header.name_length); nreceived < 0) {
h_errno = TRY_AGAIN;
return nullptr;
} else if (nreceived != response_header.name_length) {
h_errno = NO_RECOVERY;
return nullptr;
}
gethostbyaddr_name_buffer = move(string_impl);
__gethostbyaddr_buffer.h_name = buffer;
__gethostbyaddr_buffer.h_aliases = nullptr;
__gethostbyaddr_buffer.h_addrtype = AF_INET;
// FIXME: Should we populate the hostent's address list here with a sockaddr_in for the provided host?
__gethostbyaddr_address_list_buffer[0] = nullptr;
__gethostbyaddr_buffer.h_addr_list = (char**)__gethostbyaddr_address_list_buffer;
__gethostbyaddr_buffer.h_length = 4;
return &__gethostbyaddr_buffer;
}
struct servent* getservent()
{
// If the services file is not open, attempt to open it and return null if it fails.
if (!services_file) {
services_file = fopen(services_path, "r");
if (!services_file) {
perror("error opening services file");
return nullptr;
}
}
if (fseek(services_file, service_file_offset, SEEK_SET) != 0) {
perror("error seeking file");
fclose(services_file);
return nullptr;
}
char* line = nullptr;
size_t len = 0;
ssize_t read;
auto free_line_on_exit = ScopeGuard([line] {
if (line) {
free(line);
}
});
// Read lines from services file until an actual service name is found.
do {
read = getline(&line, &len, services_file);
service_file_offset += read;
if (read > 0 && (line[0] >= 65 && line[0] <= 122)) {
break;
}
} while (read != -1);
if (read == -1) {
fclose(services_file);
services_file = nullptr;
service_file_offset = 0;
return nullptr;
}
servent* service_entry = nullptr;
if (!fill_getserv_buffers(line, read))
return nullptr;
__getserv_buffer.s_name = const_cast<char*>(__getserv_name_buffer.characters());
__getserv_buffer.s_port = htons(__getserv_port_buffer);
__getserv_buffer.s_proto = const_cast<char*>(__getserv_protocol_buffer.characters());
__getserv_alias_list.clear_with_capacity();
__getserv_alias_list.ensure_capacity(__getserv_alias_list_buffer.size() + 1);
for (auto& alias : __getserv_alias_list_buffer)
__getserv_alias_list.unchecked_append(reinterpret_cast<char*>(alias.data()));
__getserv_alias_list.unchecked_append(nullptr);
__getserv_buffer.s_aliases = __getserv_alias_list.data();
service_entry = &__getserv_buffer;
if (!keep_service_file_open) {
endservent();
}
return service_entry;
}
struct servent* getservbyname(char const* name, char const* protocol)
{
if (name == nullptr)
return nullptr;
bool previous_file_open_setting = keep_service_file_open;
setservent(1);
struct servent* current_service = nullptr;
auto service_file_handler = ScopeGuard([previous_file_open_setting] {
if (!previous_file_open_setting) {
endservent();
}
});
while (true) {
current_service = getservent();
if (current_service == nullptr)
break;
else if (!protocol && strcmp(current_service->s_name, name) == 0)
break;
else if (strcmp(current_service->s_name, name) == 0 && strcmp(current_service->s_proto, protocol) == 0)
break;
}
return current_service;
}
struct servent* getservbyport(int port, char const* protocol)
{
bool previous_file_open_setting = keep_service_file_open;
setservent(1);
struct servent* current_service = nullptr;
auto service_file_handler = ScopeGuard([previous_file_open_setting] {
if (!previous_file_open_setting) {
endservent();
}
});
while (true) {
current_service = getservent();
if (current_service == nullptr)
break;
else if (!protocol && current_service->s_port == port)
break;
else if (current_service->s_port == port && (strcmp(current_service->s_proto, protocol) == 0))
break;
}
return current_service;
}
void setservent(int stay_open)
{
if (!services_file) {
services_file = fopen(services_path, "r");
if (!services_file) {
perror("error opening services file");
return;
}
}
rewind(services_file);
keep_service_file_open = stay_open;
service_file_offset = 0;
}
void endservent()
{
if (!services_file) {
return;
}
fclose(services_file);
services_file = nullptr;
}
// Fill the service entry buffer with the information contained
// in the currently read line, returns true if successful,
// false if failure occurs.
static bool fill_getserv_buffers(char const* line, ssize_t read)
{
// Splitting the line by tab delimiter and filling the servent buffers name, port, and protocol members.
auto split_line = StringView(line, read).replace(" ", "\t", ReplaceMode::All).split('\t');
// This indicates an incorrect file format.
// Services file entries should always at least contain
// name and port/protocol, separated by tabs.
if (split_line.size() < 2) {
warnln("getservent(): malformed services file");
return false;
}
__getserv_name_buffer = split_line[0];
auto port_protocol_split = String(split_line[1]).split('/');
if (port_protocol_split.size() < 2) {
warnln("getservent(): malformed services file");
return false;
}
auto number = port_protocol_split[0].to_int();
if (!number.has_value())
return false;
__getserv_port_buffer = number.value();
// Remove any annoying whitespace at the end of the protocol.
__getserv_protocol_buffer = port_protocol_split[1].replace(" ", "", ReplaceMode::All).replace("\t", "", ReplaceMode::All).replace("\n", "", ReplaceMode::All);
__getserv_alias_list_buffer.clear();
// If there are aliases for the service, we will fill the alias list buffer.
if (split_line.size() > 2 && !split_line[2].starts_with('#')) {
for (size_t i = 2; i < split_line.size(); i++) {
if (split_line[i].starts_with('#')) {
break;
}
auto alias = split_line[i].to_byte_buffer();
if (alias.try_append("\0", sizeof(char)).is_error())
return false;
__getserv_alias_list_buffer.append(move(alias));
}
}
return true;
}
struct protoent* getprotoent()
{
// If protocols file isn't open, attempt to open and return null on failure.
if (!protocols_file) {
protocols_file = fopen(protocols_path, "r");
if (!protocols_file) {
perror("error opening protocols file");
return nullptr;
}
}
if (fseek(protocols_file, protocol_file_offset, SEEK_SET) != 0) {
perror("error seeking protocols file");
fclose(protocols_file);
return nullptr;
}
char* line = nullptr;
size_t len = 0;
ssize_t read;
auto free_line_on_exit = ScopeGuard([line] {
if (line) {
free(line);
}
});
do {
read = getline(&line, &len, protocols_file);
protocol_file_offset += read;
if (read > 0 && (line[0] >= 65 && line[0] <= 122)) {
break;
}
} while (read != -1);
if (read == -1) {
fclose(protocols_file);
protocols_file = nullptr;
protocol_file_offset = 0;
return nullptr;
}
struct protoent* protocol_entry = nullptr;
if (!fill_getproto_buffers(line, read))
return nullptr;
__getproto_buffer.p_name = const_cast<char*>(__getproto_name_buffer.characters());
__getproto_buffer.p_proto = __getproto_protocol_buffer;
__getproto_alias_list.clear_with_capacity();
__getproto_alias_list.ensure_capacity(__getproto_alias_list_buffer.size() + 1);
for (auto& alias : __getproto_alias_list_buffer)
__getproto_alias_list.unchecked_append(reinterpret_cast<char*>(alias.data()));
__getserv_alias_list.unchecked_append(nullptr);
__getproto_buffer.p_aliases = __getproto_alias_list.data();
protocol_entry = &__getproto_buffer;
if (!keep_protocols_file_open)
endprotoent();
return protocol_entry;
}
struct protoent* getprotobyname(char const* name)
{
bool previous_file_open_setting = keep_protocols_file_open;
setprotoent(1);
struct protoent* current_protocol = nullptr;
auto protocol_file_handler = ScopeGuard([previous_file_open_setting] {
if (!previous_file_open_setting) {
endprotoent();
}
});
while (true) {
current_protocol = getprotoent();
if (current_protocol == nullptr)
break;
else if (strcmp(current_protocol->p_name, name) == 0)
break;
}
return current_protocol;
}
struct protoent* getprotobynumber(int proto)
{
bool previous_file_open_setting = keep_protocols_file_open;
setprotoent(1);
struct protoent* current_protocol = nullptr;
auto protocol_file_handler = ScopeGuard([previous_file_open_setting] {
if (!previous_file_open_setting) {
endprotoent();
}
});
while (true) {
current_protocol = getprotoent();
if (current_protocol == nullptr)
break;
else if (current_protocol->p_proto == proto)
break;
}
return current_protocol;
}
void setprotoent(int stay_open)
{
if (!protocols_file) {
protocols_file = fopen(protocols_path, "r");
if (!protocols_file) {
perror("setprotoent(): error opening protocols file");
return;
}
}
rewind(protocols_file);
keep_protocols_file_open = stay_open;
protocol_file_offset = 0;
}
void endprotoent()
{
if (!protocols_file) {
return;
}
fclose(protocols_file);
protocols_file = nullptr;
}
static bool fill_getproto_buffers(char const* line, ssize_t read)
{
String string_line = String(line, read);
auto split_line = string_line.replace(" ", "\t", ReplaceMode::All).split('\t');
// This indicates an incorrect file format. Protocols file entries should
// always have at least a name and a protocol.
if (split_line.size() < 2) {
warnln("getprotoent(): malformed protocols file");
return false;
}
__getproto_name_buffer = split_line[0];
auto number = split_line[1].to_int();
if (!number.has_value())
return false;
__getproto_protocol_buffer = number.value();
__getproto_alias_list_buffer.clear();
// If there are aliases for the protocol, we will fill the alias list buffer.
if (split_line.size() > 2 && !split_line[2].starts_with('#')) {
for (size_t i = 2; i < split_line.size(); i++) {
if (split_line[i].starts_with('#'))
break;
auto alias = split_line[i].to_byte_buffer();
if (alias.try_append("\0", sizeof(char)).is_error())
return false;
__getproto_alias_list_buffer.append(move(alias));
}
}
return true;
}
int getaddrinfo(char const* __restrict node, char const* __restrict service, const struct addrinfo* __restrict hints, struct addrinfo** __restrict res)
{
*res = nullptr;
if (hints && hints->ai_family != AF_INET && hints->ai_family != AF_UNSPEC)
return EAI_FAMILY;
if (!node) {
if (hints && hints->ai_flags & AI_PASSIVE)
node = "0.0.0.0";
else
node = "127.0.0.1";
}
auto host_ent = gethostbyname(node);
if (!host_ent)
return EAI_FAIL;
char const* proto = nullptr;
if (hints && hints->ai_socktype) {
switch (hints->ai_socktype) {
case SOCK_STREAM:
proto = "tcp";
break;
case SOCK_DGRAM:
proto = "udp";
break;
default:
return EAI_SOCKTYPE;
}
}
long port;
int socktype;
servent* svc_ent = nullptr;
if (!hints || (hints->ai_flags & AI_NUMERICSERV) == 0) {
svc_ent = getservbyname(service, proto);
}
if (!svc_ent) {
if (service) {
char* end;
port = htons(strtol(service, &end, 10));
if (*end)
return EAI_FAIL;
} else {
port = htons(0);
}
if (hints && hints->ai_socktype != 0)
socktype = hints->ai_socktype;
else
socktype = SOCK_STREAM;
} else {
port = svc_ent->s_port;
socktype = strcmp(svc_ent->s_proto, "tcp") ? SOCK_STREAM : SOCK_DGRAM;
}
addrinfo* first_info = nullptr;
addrinfo* prev_info = nullptr;
for (int host_index = 0; host_ent->h_addr_list[host_index]; host_index++) {
sockaddr_in* sin = new sockaddr_in;
sin->sin_family = AF_INET;
sin->sin_port = port;
memcpy(&sin->sin_addr.s_addr, host_ent->h_addr_list[host_index], host_ent->h_length);
addrinfo* info = new addrinfo;
info->ai_flags = 0;
info->ai_family = AF_INET;
info->ai_socktype = socktype;
info->ai_protocol = PF_INET;
info->ai_addrlen = sizeof(*sin);
info->ai_addr = reinterpret_cast<sockaddr*>(sin);
if (hints && hints->ai_flags & AI_CANONNAME)
info->ai_canonname = strdup(host_ent->h_name);
else
info->ai_canonname = nullptr;
info->ai_next = nullptr;
if (!first_info)
first_info = info;
if (prev_info)
prev_info->ai_next = info;
prev_info = info;
}
if (first_info) {
*res = first_info;
return 0;
} else
return EAI_NONAME;
}
void freeaddrinfo(struct addrinfo* res)
{
if (res) {
delete reinterpret_cast<sockaddr_in*>(res->ai_addr);
free(res->ai_canonname);
freeaddrinfo(res->ai_next);
delete res;
}
}
char const* gai_strerror(int errcode)
{
switch (errcode) {
case EAI_ADDRFAMILY:
return "no address for this address family available";
case EAI_AGAIN:
return "name server returned temporary failure";
case EAI_BADFLAGS:
return "invalid flags";
case EAI_FAIL:
return "name server returned permanent failure";
case EAI_FAMILY:
return "unsupported address family";
case EAI_MEMORY:
return "out of memory";
case EAI_NODATA:
return "no address available";
case EAI_NONAME:
return "node or service is not known";
case EAI_SERVICE:
return "service not available";
case EAI_SOCKTYPE:
return "unsupported socket type";
case EAI_SYSTEM:
return "system error";
case EAI_OVERFLOW:
return "buffer too small";
default:
return "invalid error code";
}
}
int getnameinfo(const struct sockaddr* __restrict addr, socklen_t addrlen, char* __restrict host, socklen_t hostlen, char* __restrict serv, socklen_t servlen, int flags)
{
if (addr->sa_family != AF_INET || addrlen < sizeof(sockaddr_in))
return EAI_FAMILY;
sockaddr_in const* sin = reinterpret_cast<sockaddr_in const*>(addr);
if (host && hostlen > 0) {
if (flags != 0)
dbgln("getnameinfo flags are not implemented: {:#x}", flags);
if (!inet_ntop(AF_INET, &sin->sin_addr, host, hostlen)) {
if (errno == ENOSPC)
return EAI_OVERFLOW;
else
return EAI_SYSTEM;
}
}
if (serv && servlen > 0) {
if (snprintf(serv, servlen, "%d", (int)ntohs(sin->sin_port)) > (int)servlen)
return EAI_OVERFLOW;
}
return 0;
}
void herror(char const* s)
{
dbgln("herror(): {}: {}", s, hstrerror(h_errno));
warnln("{}: {}", s, hstrerror(h_errno));
}
char const* hstrerror(int err)
{
switch (err) {
case HOST_NOT_FOUND:
return "The specified host is unknown.";
case NO_DATA:
return "The requested name is valid but does not have an IP address.";
case NO_RECOVERY:
return "A nonrecoverable name server error occurred.";
case TRY_AGAIN:
return "A temporary error occurred on an authoritative name server. Try again later.";
default:
return "Unknown error.";
}
}
}
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