wg-quick: android: use Binder for setting DNS on Android 10

Signed-off-by: Nicolas Douma <nicolas@serveur.io>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Nicolas Douma 2019-10-02 21:10:51 +02:00 committed by Jason A. Donenfeld
parent 959937672a
commit 792727cf64
1 changed files with 429 additions and 7 deletions

View File

@ -20,6 +20,7 @@
#include <unistd.h> #include <unistd.h>
#include <errno.h> #include <errno.h>
#include <regex.h> #include <regex.h>
#include <dlfcn.h>
#include <sys/types.h> #include <sys/types.h>
#include <sys/stat.h> #include <sys/stat.h>
#include <sys/wait.h> #include <sys/wait.h>
@ -37,6 +38,7 @@
#define ARRAY_SIZE(x) (sizeof(x) / sizeof(x[0])) #define ARRAY_SIZE(x) (sizeof(x) / sizeof(x[0]))
static bool is_exiting = false; static bool is_exiting = false;
static bool binder_available = false;
static void *xmalloc(size_t size) static void *xmalloc(size_t size)
{ {
@ -235,6 +237,373 @@ _printf_(1, 2) static void cndc(const char *cmd_fmt, ...)
} }
} }
/* Values are from AOSP repository platform/frameworks/native in libs/binder/ndk/include_ndk/android/binder_status.h. */
enum {
STATUS_OK = 0,
STATUS_UNKNOWN_ERROR = -2147483647 - 1,
STATUS_NO_MEMORY = -ENOMEM,
STATUS_INVALID_OPERATION = -ENOSYS,
STATUS_BAD_VALUE = -EINVAL,
STATUS_BAD_TYPE = STATUS_UNKNOWN_ERROR + 1,
STATUS_NAME_NOT_FOUND = -ENOENT,
STATUS_PERMISSION_DENIED = -EPERM,
STATUS_NO_INIT = -ENODEV,
STATUS_ALREADY_EXISTS = -EEXIST,
STATUS_DEAD_OBJECT = -EPIPE,
STATUS_FAILED_TRANSACTION = STATUS_UNKNOWN_ERROR + 2,
STATUS_BAD_INDEX = -EOVERFLOW,
STATUS_NOT_ENOUGH_DATA = -ENODATA,
STATUS_WOULD_BLOCK = -EWOULDBLOCK,
STATUS_TIMED_OUT = -ETIMEDOUT,
STATUS_UNKNOWN_TRANSACTION = -EBADMSG,
STATUS_FDS_NOT_ALLOWED = STATUS_UNKNOWN_ERROR + 7,
STATUS_UNEXPECTED_NULL = STATUS_UNKNOWN_ERROR + 8
};
enum {
EX_NONE = 0,
EX_SECURITY = -1,
EX_BAD_PARCELABLE = -2,
EX_ILLEGAL_ARGUMENT = -3,
EX_NULL_POINTER = -4,
EX_ILLEGAL_STATE = -5,
EX_NETWORK_MAIN_THREAD = -6,
EX_UNSUPPORTED_OPERATION = -7,
EX_SERVICE_SPECIFIC = -8,
EX_PARCELABLE = -9,
EX_TRANSACTION_FAILED = -129
};
enum {
FLAG_ONEWAY = 0x01,
};
enum {
FIRST_CALL_TRANSACTION = 0x00000001,
LAST_CALL_TRANSACTION = 0x00ffffff
};
struct AIBinder;
struct AParcel;
struct AStatus;
struct AIBinder_Class;
typedef struct AIBinder AIBinder;
typedef struct AParcel AParcel;
typedef struct AStatus AStatus;
typedef struct AIBinder_Class AIBinder_Class;
typedef int32_t binder_status_t;
typedef int32_t binder_exception_t;
typedef uint32_t transaction_code_t;
typedef uint32_t binder_flags_t;
typedef void *(*AIBinder_Class_onCreate)(void *args);
typedef void (*AIBinder_Class_onDestroy)(void *userData);
typedef binder_status_t (*AIBinder_Class_onTransact)(AIBinder *binder, transaction_code_t code, const AParcel *in, AParcel *out);
typedef const char *(*AParcel_stringArrayElementGetter)(const void *arrayData, size_t index, int32_t *outLength);
static AIBinder_Class *(*AIBinder_Class_define)(const char *interfaceDescriptor, AIBinder_Class_onCreate onCreate, AIBinder_Class_onDestroy onDestroy, AIBinder_Class_onTransact onTransact) __attribute__((warn_unused_result));
static bool (*AIBinder_associateClass)(AIBinder *binder, const AIBinder_Class *clazz);
static void (*AIBinder_decStrong)(AIBinder *binder);
static binder_status_t (*AIBinder_prepareTransaction)(AIBinder *binder, AParcel **in);
static binder_status_t (*AIBinder_transact)(AIBinder *binder, transaction_code_t code, AParcel **in, AParcel **out, binder_flags_t flags);
static binder_status_t (*AIBinder_ping)(AIBinder *binder);
static binder_status_t (*AIBinder_dump)(AIBinder *binder, int fd, const char **args, uint32_t numArgs);
static binder_status_t (*AParcel_readStatusHeader)(const AParcel *parcel, AStatus **status);
static binder_status_t (*AParcel_readBool)(const AParcel *parcel, bool *value);
static void (*AParcel_delete)(AParcel *parcel);
static binder_status_t (*AParcel_setDataPosition)(const AParcel *parcel, int32_t position);
static int32_t (*AParcel_getDataPosition)(const AParcel *parcel);
static binder_status_t (*AParcel_writeInt32)(AParcel *parcel, int32_t value);
static binder_status_t (*AParcel_writeStringArray)(AParcel *parcel, const void *arrayData, int32_t length, AParcel_stringArrayElementGetter getter);
static binder_status_t (*AParcel_writeString)(AParcel *parcel, const char *string, int32_t length);
static bool (*AStatus_isOk)(const AStatus *status);
static void (*AStatus_delete)(AStatus *status);
static binder_exception_t (*AStatus_getExceptionCode)(const AStatus *status);
static int32_t (*AStatus_getServiceSpecificError)(const AStatus *status);
static const char* (*AStatus_getMessage)(const AStatus *status);
static binder_status_t (*AStatus_getStatus)(const AStatus *status);
static AIBinder *(*AServiceManager_getService)(const char *instance) __attribute__((__warn_unused_result__));
static __attribute__((__constructor__(65535))) void load_symbols(void)
{
void *handle = dlopen("libbinder_ndk.so", RTLD_LAZY);
binder_available = !!handle;
if (!binder_available)
return;
#define X(symb) do { \
if (!((symb) = (typeof(symb))dlsym(handle, #symb))) { \
fprintf(stderr, "Error: unable to import " #symb " from libbinder_ndk.so\n"); \
exit(ELIBACC); \
} \
} while (0)
X(AIBinder_Class_define);
X(AIBinder_associateClass);
X(AIBinder_decStrong);
X(AIBinder_prepareTransaction);
X(AIBinder_transact);
X(AIBinder_ping);
X(AIBinder_dump);
X(AParcel_readStatusHeader);
X(AParcel_readBool);
X(AParcel_delete);
X(AParcel_setDataPosition);
X(AParcel_getDataPosition);
X(AParcel_writeInt32);
X(AParcel_writeStringArray);
X(AParcel_writeString);
X(AStatus_isOk);
X(AStatus_delete);
X(AStatus_getExceptionCode);
X(AStatus_getServiceSpecificError);
X(AStatus_getMessage);
X(AStatus_getStatus);
X(AServiceManager_getService);
#undef X
}
static void cleanup_binder(AIBinder **binder)
{
AIBinder_decStrong(*binder);
}
static void cleanup_status(AStatus **status)
{
AStatus_delete(*status);
}
static void cleanup_parcel(AParcel **parcel)
{
AParcel_delete(*parcel);
}
#define _cleanup_status_ __attribute__((__cleanup__(cleanup_status)))
#define _cleanup_parcel_ __attribute__((__cleanup__(cleanup_parcel)))
#define _cleanup_binder_ __attribute__((__cleanup__(cleanup_binder)))
static int32_t string_size(const char *str)
{
return str ? strlen(str) : -1;
}
static int32_t string_array_size(char *const *array)
{
int32_t size = -1;
if (!array)
return size;
for (size = 0; array[size]; ++size);
return size;
}
static const char *string_array_getter(const void *array_data, size_t index, int32_t *outlength)
{
const char **array = (const char **)array_data;
*outlength = array[index] ? strlen(array[index]) : -1;
return array[index];
}
static binder_status_t meaningful_binder_status(const AStatus *status_out)
{
binder_status_t status = STATUS_OK;
binder_exception_t exc_code;
int32_t exc_code_service;
const char *message;
if (!AStatus_isOk(status_out)) {
exc_code = AStatus_getExceptionCode(status_out);
if (exc_code == EX_TRANSACTION_FAILED) {
status = AStatus_getStatus(status_out);
fprintf(stderr, "Error: transaction failed: %d\n", status);
}
else {
message = AStatus_getMessage(status_out);
if (exc_code == EX_SERVICE_SPECIFIC) {
exc_code_service = AStatus_getServiceSpecificError(status_out);
fprintf(stderr, "Error: service specific exception code: %d%s%s\n", exc_code_service, message ? ": " : "", message ?: "");
}
else
fprintf(stderr, "Error: exception code: %d%s%s\n", exc_code, message ? ": " : "", message ?: "");
status = STATUS_FAILED_TRANSACTION;
}
}
return status;
}
/* These values are default values observed in AOSP. */
enum {
DNSRESOLVER_SAMPLE_VALIDITY = 1800 /* sec */,
DNSRESOLVER_SUCCESS_THRESHOLD = 25,
DNSRESOLVER_MIN_SAMPLES = 8,
DNSRESOLVER_MAX_SAMPLES = 8,
DNSRESOLVER_BASE_TIMEOUT = 5000 /* msec */,
DNSRESOLVER_RETRY_COUNT = 2
};
struct dnsresolver_params {
int32_t netid;
int32_t sample_validity_seconds;
int32_t success_threshold;
int32_t min_samples;
int32_t max_samples;
int32_t base_timeout_msec;
int32_t retry_count;
char **servers; /* NULL terminated array of zero-terminated UTF-8 strings */
char **domains; /* NULL terminated array of zero-terminated UTF-8 strings */
char *tls_name; /* zero-terminated UTF-8 string */
char **tls_servers; /* NULL terminated array of zero-terminated UTF-8 strings */
char **tls_fingerprints; /* NULL terminated array of zero-terminated UTF-8 strings */
};
static void *on_create()
{
fprintf(stderr, "Error: on_create called on proxy object\n");
exit(ENOTSUP);
return NULL;
}
static void on_destroy()
{
fprintf(stderr, "Error: on_destroy called on proxy object\n");
exit(ENOTSUP);
}
static binder_status_t on_transact()
{
fprintf(stderr, "Error: on_transact called on a proxy object\n");
exit(ENOTSUP);
return 0;
}
static AIBinder *dnsresolver_get_handle(void)
{
AIBinder *binder;
AIBinder_Class *clazz;
if (!binder_available)
return NULL;
binder = AServiceManager_getService("dnsresolver");
if (!binder)
return NULL;
clazz = AIBinder_Class_define("android.net.IDnsResolver", &on_create, &on_destroy, &on_transact);
if (!clazz)
goto error;
if (!AIBinder_associateClass(binder, clazz))
goto error;
return binder;
error:
AIBinder_decStrong(binder);
return NULL;
}
static int32_t dnsresolver_create_network_cache(void *handle, int32_t netid)
{
AIBinder *const binder = handle;
binder_status_t status;
_cleanup_parcel_ AParcel *parcel_in = NULL;
_cleanup_parcel_ AParcel *parcel_out = NULL;
_cleanup_status_ AStatus *status_out = NULL;
status = AIBinder_prepareTransaction(binder, &parcel_in);
if (status != STATUS_OK)
return status;
status = AParcel_writeInt32(parcel_in, netid);
if (status != STATUS_OK)
return status;
status = AIBinder_transact(binder, FIRST_CALL_TRANSACTION + 7 /* createNetworkCache */, &parcel_in, &parcel_out, 0);
if (status != STATUS_OK)
return status;
status = AParcel_readStatusHeader(parcel_out, &status_out);
if (status != STATUS_OK)
return status;
if (!AStatus_isOk(status_out))
return meaningful_binder_status(status_out);
return STATUS_OK;
}
static int32_t dnsresolver_set_resolver_configuration(void *handle, const struct dnsresolver_params *params)
{
AIBinder *const binder = handle;
binder_status_t status;
_cleanup_parcel_ AParcel *parcel_in = NULL;
_cleanup_parcel_ AParcel *parcel_out = NULL;
_cleanup_status_ AStatus *status_out = NULL;
int32_t start_position, end_position;
status = AIBinder_prepareTransaction(binder, &parcel_in);
if (status != STATUS_OK)
return status;
status = AParcel_writeInt32(parcel_in, 1);
if (status != STATUS_OK)
return status;
start_position = AParcel_getDataPosition(parcel_in);
status = AParcel_writeInt32(parcel_in, 0);
if (status != STATUS_OK)
return status;
status = AParcel_writeInt32(parcel_in, params->netid);
if (status != STATUS_OK)
return status;
status = AParcel_writeInt32(parcel_in, params->sample_validity_seconds);
if (status != STATUS_OK)
return status;
status = AParcel_writeInt32(parcel_in, params->success_threshold);
if (status != STATUS_OK)
return status;
status = AParcel_writeInt32(parcel_in, params->min_samples);
if (status != STATUS_OK)
return status;
status = AParcel_writeInt32(parcel_in, params->max_samples);
if (status != STATUS_OK)
return status;
status = AParcel_writeInt32(parcel_in, params->base_timeout_msec);
if (status != STATUS_OK)
return status;
status = AParcel_writeInt32(parcel_in, params->retry_count);
if (status != STATUS_OK)
return status;
status = AParcel_writeStringArray(parcel_in, params->servers, string_array_size(params->servers), &string_array_getter);
if (status != STATUS_OK)
return status;
status = AParcel_writeStringArray(parcel_in, params->domains, string_array_size(params->domains), &string_array_getter);
if (status != STATUS_OK)
return status;
status = AParcel_writeString(parcel_in, params->tls_name, string_size(params->tls_name));
if (status != STATUS_OK)
return status;
status = AParcel_writeStringArray(parcel_in, params->tls_servers, string_array_size(params->tls_servers), &string_array_getter);
if (status != STATUS_OK)
return status;
status = AParcel_writeStringArray(parcel_in, params->tls_fingerprints, string_array_size(params->tls_fingerprints), &string_array_getter);
if (status != STATUS_OK)
return status;
end_position = AParcel_getDataPosition(parcel_in);
status = AParcel_setDataPosition(parcel_in, start_position);
if (status != STATUS_OK)
return status;
status = AParcel_writeInt32(parcel_in, end_position - start_position);
if (status != STATUS_OK)
return status;
status = AParcel_setDataPosition(parcel_in, end_position);
if (status != STATUS_OK)
return status;
status = AIBinder_transact(binder, FIRST_CALL_TRANSACTION + 2 /* setResolverConfiguration */, &parcel_in, &parcel_out, 0);
if (status != STATUS_OK)
return status;
status = AParcel_readStatusHeader(parcel_out, &status_out);
if (status != STATUS_OK)
return status;
return meaningful_binder_status(status_out);
}
static void auto_su(int argc, char *argv[]) static void auto_su(int argc, char *argv[])
{ {
char *args[argc + 4]; char *args[argc + 4];
@ -440,22 +809,75 @@ static void set_dnses(unsigned int netid, const char *dnses)
if (len > (1<<16)) if (len > (1<<16))
return; return;
_cleanup_free_ char *mutable = xstrdup(dnses); _cleanup_free_ char *mutable = xstrdup(dnses);
_cleanup_free_ char *arglist = xmalloc(len * 4 + 1); _cleanup_free_ char *shell_arglist = xmalloc(len * 4 + 1);
_cleanup_free_ char *function_arglist = xmalloc(len * 4 + 1);
_cleanup_free_ char *arg = xmalloc(len + 4); _cleanup_free_ char *arg = xmalloc(len + 4);
_cleanup_free_ char **dns_list = NULL;
_cleanup_binder_ AIBinder *handle = NULL;
size_t dns_list_size = 0;
if (!len) if (!len)
return; return;
arglist[0] = '\0'; for (char *dns = strtok(mutable, ", \t\n"); dns; dns = strtok(NULL, ", \t\n")) {
if (strchr(dns, '\'') || strchr(dns, '\\'))
continue;
++dns_list_size;
}
if (!dns_list_size)
return;
dns_list = xcalloc(dns_list_size + 1, sizeof(*dns_list));
free(mutable);
mutable = xstrdup(dnses);
shell_arglist[0] = '\0';
function_arglist[0] = '\0';
dns_list_size = 0;
for (char *dns = strtok(mutable, ", \t\n"); dns; dns = strtok(NULL, ", \t\n")) { for (char *dns = strtok(mutable, ", \t\n"); dns; dns = strtok(NULL, ", \t\n")) {
if (strchr(dns, '\'') || strchr(dns, '\\')) if (strchr(dns, '\'') || strchr(dns, '\\'))
continue; continue;
snprintf(arg, len + 3, "'%s' ", dns); snprintf(arg, len + 3, "'%s' ", dns);
strncat(arglist, arg, len * 4 - 1); strncat(shell_arglist, arg, len * 4 - 1);
snprintf(arg, len + 2, function_arglist[0] == '\0' ? "%s" : ", %s", dns);
strncat(function_arglist, arg, len * 4 - 1);
dns_list[dns_list_size++] = dns;
} }
if (!strlen(arglist))
return; if ((handle = dnsresolver_get_handle())) {
cndc("resolver setnetdns %u '' %s", netid, arglist); binder_status_t status;
printf("[#] <binder>::dnsResolver->createNetworkCache(%u)\n", netid);
status = dnsresolver_create_network_cache(handle, netid);
if (status != 0) {
fprintf(stderr, "Error: unable to create network cache\n");
exit(ENONET);
}
struct dnsresolver_params params = {
.netid = netid,
.sample_validity_seconds = DNSRESOLVER_SAMPLE_VALIDITY,
.success_threshold = DNSRESOLVER_SUCCESS_THRESHOLD,
.min_samples = DNSRESOLVER_MIN_SAMPLES,
.max_samples = DNSRESOLVER_MAX_SAMPLES,
.base_timeout_msec = DNSRESOLVER_BASE_TIMEOUT,
.retry_count = DNSRESOLVER_RETRY_COUNT,
.servers = dns_list,
.domains = (char *[]){NULL},
.tls_name = "",
.tls_servers = (char *[]){NULL},
.tls_fingerprints = (char *[]){NULL}
};
printf("[#] <binder>::dnsResolver->setResolverConfiguration(%u, [%s], [], %d, %d, %d, %d, %d, %d, [], [])\n",
netid, function_arglist, DNSRESOLVER_SAMPLE_VALIDITY, DNSRESOLVER_SUCCESS_THRESHOLD,
DNSRESOLVER_MIN_SAMPLES, DNSRESOLVER_MAX_SAMPLES, DNSRESOLVER_BASE_TIMEOUT, DNSRESOLVER_RETRY_COUNT);
status = dnsresolver_set_resolver_configuration(handle, &params);
if (status != 0) {
fprintf(stderr, "Error: unable to set DNS servers through Binder: %d\n", status);
exit(ENONET);
}
} else
cndc("resolver setnetdns %u '' %s", netid, shell_arglist);
} }
static void add_addr(const char *iface, const char *addr) static void add_addr(const char *iface, const char *addr)
@ -662,8 +1084,8 @@ static void cmd_up(const char *iface, const char *config, unsigned int mtu, cons
add_if(iface); add_if(iface);
set_config(iface, config); set_config(iface, config);
listen_port = determine_listen_port(iface); listen_port = determine_listen_port(iface);
set_addr(iface, addrs);
up_if(&netid, iface, listen_port); up_if(&netid, iface, listen_port);
set_addr(iface, addrs);
set_dnses(netid, dnses); set_dnses(netid, dnses);
set_routes(iface, netid); set_routes(iface, netid);
set_mtu(iface, mtu); set_mtu(iface, mtu);