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am 7f46cf9a: Merge "Pass around struct android_net_context for better behaviour"

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* commit '7f46cf9a5f0b3e54d97fc94a83b955ae4c335a31':
  Pass around struct android_net_context for better behaviour
This commit is contained in:
Erik Kline 2015-06-30 02:42:17 +00:00 committed by Android Git Automerger
commit 2ce0969b83
3 changed files with 73 additions and 48 deletions
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29
libc/dns/include/resolv_netid.h
View file

@ -53,10 +53,37 @@ struct addrinfo;
#define __used_in_netd __attribute__((visibility ("default")))
/*
* A struct to capture context relevant to network operations.
*
* Application and DNS netids/marks can differ from one another under certain
* circumstances, notably when a VPN applies to the given uid's traffic but the
* VPN network does not have its own DNS servers explicitly provisioned.
*
* The introduction of per-UID routing means the uid is also an essential part
* of the evaluation context. Its proper uninitialized value is
* NET_CONTEXT_INVALID_UID.
*/
struct android_net_context {
unsigned app_netid;
unsigned app_mark;
unsigned dns_netid;
unsigned dns_mark;
uid_t uid;
} __attribute__((packed));
#define NET_CONTEXT_INVALID_UID ((uid_t)-1)
struct hostent *android_gethostbyaddrfornet(const void *, socklen_t, int, unsigned, unsigned) __used_in_netd;
struct hostent *android_gethostbynamefornet(const char *, int, unsigned, unsigned) __used_in_netd;
int android_getaddrinfofornet(const char *, const char *, const struct addrinfo *, unsigned,
unsigned, struct addrinfo **) __used_in_netd;
unsigned, struct addrinfo **) __used_in_netd;
/*
* TODO: consider refactoring android_getaddrinfo_proxy() to serve as an
* explore_fqdn() dispatch table method, with the below function only making DNS calls.
*/
int android_getaddrinfofornetcontext(const char *, const char *, const struct addrinfo *,
const struct android_net_context *, struct addrinfo **) __used_in_netd;
/* set name servers for a network */
extern void _resolv_set_nameservers_for_net(unsigned netid,

91
libc/dns/net/getaddrinfo.c
View file

@ -218,7 +218,7 @@ struct res_target {
static int str2number(const char *);
static int explore_fqdn(const struct addrinfo *, const char *,
const char *, struct addrinfo **, unsigned netid, unsigned mark);
const char *, struct addrinfo **, const struct android_net_context *);
static int explore_null(const struct addrinfo *,
const char *, struct addrinfo **);
static int explore_numeric(const struct addrinfo *, const char *,
@ -244,6 +244,7 @@ static void _endhtent(FILE **);
static struct addrinfo *_gethtent(FILE **, const char *,
const struct addrinfo *);
static int _files_getaddrinfo(void *, void *, va_list);
static int _find_src_addr(const struct sockaddr *, struct sockaddr *, unsigned , uid_t);
static int res_queryN(const char *, struct res_target *, res_state);
static int res_searchN(const char *, struct res_target *, res_state);
@ -359,29 +360,6 @@ str2number(const char *p)
return -1;
}
/*
* Connect a UDP socket to a given unicast address. This will cause no network
* traffic, but will fail fast if the system has no or limited reachability to
* the destination (e.g., no IPv4 address, no IPv6 default route, ...).
*/
static int
_test_connect(int pf, struct sockaddr *addr, size_t addrlen, unsigned mark) {
int s = socket(pf, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
if (s < 0)
return 0;
if (mark != MARK_UNSET && setsockopt(s, SOL_SOCKET, SO_MARK, &mark, sizeof(mark)) < 0)
return 0;
int ret;
do {
ret = __connect(s, addr, addrlen);
} while (ret < 0 && errno == EINTR);
int success = (ret == 0);
do {
ret = close(s);
} while (ret < 0 && errno == EINTR);
return success;
}
/*
* The following functions determine whether IPv4 or IPv6 connectivity is
* available in order to implement AI_ADDRCONFIG.
@ -392,24 +370,24 @@ _test_connect(int pf, struct sockaddr *addr, size_t addrlen, unsigned mark) {
* so checking for connectivity is the next best thing.
*/
static int
_have_ipv6(unsigned mark) {
_have_ipv6(unsigned mark, uid_t uid) {
static const struct sockaddr_in6 sin6_test = {
.sin6_family = AF_INET6,
.sin6_addr.s6_addr = { // 2000::
0x20, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
};
sockaddr_union addr = { .in6 = sin6_test };
return _test_connect(PF_INET6, &addr.generic, sizeof(addr.in6), mark);
return _find_src_addr(&addr.generic, NULL, mark, uid) == 1;
}
static int
_have_ipv4(unsigned mark) {
_have_ipv4(unsigned mark, uid_t uid) {
static const struct sockaddr_in sin_test = {
.sin_family = AF_INET,
.sin_addr.s_addr = __constant_htonl(0x08080808L) // 8.8.8.8
};
sockaddr_union addr = { .in = sin_test };
return _test_connect(PF_INET, &addr.generic, sizeof(addr.in), mark);
return _find_src_addr(&addr.generic, NULL, mark, uid) == 1;
}
bool readBE32(FILE* fp, int32_t* result) {
@ -474,7 +452,7 @@ android_getaddrinfo_proxy(
int result_code = (int)strtol(buf, NULL, 10);
// verify the code itself
if (result_code != DnsProxyQueryResult ) {
if (result_code != DnsProxyQueryResult) {
fread(buf, 1, sizeof(buf), proxy);
goto exit;
}
@ -588,6 +566,21 @@ getaddrinfo(const char *hostname, const char *servname,
int
android_getaddrinfofornet(const char *hostname, const char *servname,
const struct addrinfo *hints, unsigned netid, unsigned mark, struct addrinfo **res)
{
struct android_net_context netcontext = {
.app_netid = netid,
.app_mark = mark,
.dns_netid = netid,
.dns_mark = mark,
.uid = NET_CONTEXT_INVALID_UID,
};
return android_getaddrinfofornetcontext(hostname, servname, hints, &netcontext, res);
}
int
android_getaddrinfofornetcontext(const char *hostname, const char *servname,
const struct addrinfo *hints, const struct android_net_context *netcontext,
struct addrinfo **res)
{
struct addrinfo sentinel;
struct addrinfo *cur;
@ -601,6 +594,7 @@ android_getaddrinfofornet(const char *hostname, const char *servname,
/* servname is allowed to be NULL */
/* hints is allowed to be NULL */
assert(res != NULL);
assert(netcontext != NULL);
memset(&sentinel, 0, sizeof(sentinel));
cur = &sentinel;
pai = &ai;
@ -731,7 +725,8 @@ android_getaddrinfofornet(const char *hostname, const char *servname,
ERR(EAI_NONAME);
#if defined(__ANDROID__)
int gai_error = android_getaddrinfo_proxy(hostname, servname, hints, res, netid);
int gai_error = android_getaddrinfo_proxy(
hostname, servname, hints, res, netcontext->app_netid);
if (gai_error != EAI_SYSTEM) {
return gai_error;
}
@ -763,8 +758,8 @@ android_getaddrinfofornet(const char *hostname, const char *servname,
if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
pai->ai_protocol = ex->e_protocol;
error = explore_fqdn(pai, hostname, servname,
&cur->ai_next, netid, mark);
error = explore_fqdn(
pai, hostname, servname, &cur->ai_next, netcontext);
while (cur && cur->ai_next)
cur = cur->ai_next;
@ -797,7 +792,8 @@ android_getaddrinfofornet(const char *hostname, const char *servname,
*/
static int
explore_fqdn(const struct addrinfo *pai, const char *hostname,
const char *servname, struct addrinfo **res, unsigned netid, unsigned mark)
const char *servname, struct addrinfo **res,
const struct android_net_context *netcontext)
{
struct addrinfo *result;
struct addrinfo *cur;
@ -823,7 +819,7 @@ explore_fqdn(const struct addrinfo *pai, const char *hostname,
return 0;
switch (nsdispatch(&result, dtab, NSDB_HOSTS, "getaddrinfo",
default_dns_files, hostname, pai, netid, mark)) {
default_dns_files, hostname, pai, netcontext)) {
case NS_TRYAGAIN:
error = EAI_AGAIN;
goto free;
@ -1763,13 +1759,13 @@ _rfc6724_compare(const void *ptr1, const void* ptr2)
* address. src_addr must be large enough to hold a struct sockaddr_in6.
*
* Returns 1 if a source address was found, 0 if the address is unreachable,
* and -1 if a fatal error occurred. If 0 or 1, the contents of src_addr are
* and -1 if a fatal error occurred. If 0 or -1, the contents of src_addr are
* undefined.
*/
/*ARGSUSED*/
static int
_find_src_addr(const struct sockaddr *addr, struct sockaddr *src_addr, unsigned mark)
_find_src_addr(const struct sockaddr *addr, struct sockaddr *src_addr, unsigned mark, uid_t uid)
{
int sock;
int ret;
@ -1797,6 +1793,8 @@ _find_src_addr(const struct sockaddr *addr, struct sockaddr *src_addr, unsigned
}
if (mark != MARK_UNSET && setsockopt(sock, SOL_SOCKET, SO_MARK, &mark, sizeof(mark)) < 0)
return 0;
if (uid > 0 && uid != NET_CONTEXT_INVALID_UID && fchown(sock, uid, (gid_t)-1) < 0)
return 0;
do {
ret = __connect(sock, addr, len);
} while (ret == -1 && errno == EINTR);
@ -1806,7 +1804,7 @@ _find_src_addr(const struct sockaddr *addr, struct sockaddr *src_addr, unsigned
return 0;
}
if (getsockname(sock, src_addr, &len) == -1) {
if (src_addr && getsockname(sock, src_addr, &len) == -1) {
close(sock);
return -1;
}
@ -1821,7 +1819,7 @@ _find_src_addr(const struct sockaddr *addr, struct sockaddr *src_addr, unsigned
/*ARGSUSED*/
static void
_rfc6724_sort(struct addrinfo *list_sentinel, unsigned mark)
_rfc6724_sort(struct addrinfo *list_sentinel, unsigned mark, uid_t uid)
{
struct addrinfo *cur;
int nelem = 0, i;
@ -1848,7 +1846,7 @@ _rfc6724_sort(struct addrinfo *list_sentinel, unsigned mark)
elems[i].ai = cur;
elems[i].original_order = i;
has_src_addr = _find_src_addr(cur->ai_addr, &elems[i].src_addr.generic, mark);
has_src_addr = _find_src_addr(cur->ai_addr, &elems[i].src_addr.generic, mark, uid);
if (has_src_addr == -1) {
goto error;
}
@ -1879,12 +1877,11 @@ _dns_getaddrinfo(void *rv, void *cb_data, va_list ap)
struct addrinfo sentinel, *cur;
struct res_target q, q2;
res_state res;
unsigned netid, mark;
const struct android_net_context *netcontext;
name = va_arg(ap, char *);
pai = va_arg(ap, const struct addrinfo *);
netid = va_arg(ap, unsigned);
mark = va_arg(ap, unsigned);
netcontext = va_arg(ap, const struct android_net_context *);
//fprintf(stderr, "_dns_getaddrinfo() name = '%s'\n", name);
memset(&q, 0, sizeof(q));
@ -1913,8 +1910,8 @@ _dns_getaddrinfo(void *rv, void *cb_data, va_list ap)
q.anslen = sizeof(buf->buf);
int query_ipv6 = 1, query_ipv4 = 1;
if (pai->ai_flags & AI_ADDRCONFIG) {
query_ipv6 = _have_ipv6(mark);
query_ipv4 = _have_ipv4(mark);
query_ipv6 = _have_ipv6(netcontext->app_mark, netcontext->uid);
query_ipv4 = _have_ipv4(netcontext->app_mark, netcontext->uid);
}
if (query_ipv6) {
q.qtype = T_AAAA;
@ -1966,8 +1963,8 @@ _dns_getaddrinfo(void *rv, void *cb_data, va_list ap)
* fully populate the thread private data here, but if we get down there
* and have a cache hit that would be wasted, so we do the rest there on miss
*/
res_setnetid(res, netid);
res_setmark(res, mark);
res_setnetid(res, netcontext->dns_netid);
res_setmark(res, netcontext->dns_mark);
if (res_searchN(name, &q, res) < 0) {
__res_put_state(res);
free(buf);
@ -1999,7 +1996,7 @@ _dns_getaddrinfo(void *rv, void *cb_data, va_list ap)
}
}
_rfc6724_sort(&sentinel, netid);
_rfc6724_sort(&sentinel, netcontext->app_mark, netcontext->uid);
__res_put_state(res);

1
libc/libc.map
View file

@ -306,6 +306,7 @@ LIBC {
alphasort;
alphasort64;
android_getaddrinfofornet;
android_getaddrinfofornetcontext;
android_gethostbyaddrfornet;
android_gethostbynamefornet;
android_set_abort_message;