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Reject tickets from the future.

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This shouldn't happen, but it is good to check to avoid the potential
underflow in ssl_session_is_time_valid.

This required tweaking the mock clock in bssl_shim to stop going back in
time.

Change-Id: Id3ab8755139e989190d0b53d4bf90fe1ac203022
Reviewed-on: https://boringssl-review.googlesource.com/11841
Reviewed-by: David Benjamin <davidben@google.com>
This commit is contained in:
David Benjamin 2016-10-27 16:36:32 -04:00
parent b6b6ff3bef
commit 1b22f85a56
5 changed files with 45 additions and 34 deletions
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6
ssl/ssl_session.c
View File

@ -599,6 +599,12 @@ int ssl_session_is_time_valid(const SSL *ssl, const SSL_SESSION *session) {
struct timeval now;
ssl_get_current_time(ssl, &now);
/* Reject tickets from the future to avoid underflow. */
if ((long)now.tv_sec < session->time) {
return 0;
}
return session->timeout >= (long)now.tv_sec - session->time;
}

12
ssl/ssl_test.cc
View File

@ -2047,6 +2047,9 @@ static bool TestSessionTimeout() {
}
for (uint16_t version : kTLSVersions) {
static const int kStartTime = 1000;
g_current_time.tv_sec = kStartTime;
bssl::UniquePtr<SSL_CTX> server_ctx(SSL_CTX_new(TLS_method()));
bssl::UniquePtr<SSL_CTX> client_ctx(SSL_CTX_new(TLS_method()));
if (!server_ctx || !client_ctx ||
@ -2088,6 +2091,15 @@ static bool TestSessionTimeout() {
fprintf(stderr, "Error resuming session (version = %04x).\n", version);
return false;
}
// Rewind the clock to before the session was minted.
g_current_time.tv_sec = kStartTime - 1;
if (!ExpectSessionReused(client_ctx.get(), server_ctx.get(), session.get(),
false /* expect session not reused */)) {
fprintf(stderr, "Error resuming session (version = %04x).\n", version);
return false;
}
}
return true;

15
ssl/test/bssl_shim.cc
View File

@ -594,8 +594,10 @@ static unsigned PskServerCallback(SSL *ssl, const char *identity,
return config->psk.size();
}
static timeval g_clock;
static void CurrentTimeCallback(const SSL *ssl, timeval *out_clock) {
*out_clock = PacketedBioGetClock(GetTestState(ssl)->packeted_bio);
*out_clock = g_clock;
}
static void ChannelIdCallback(SSL *ssl, EVP_PKEY **out_pkey) {
@ -923,9 +925,7 @@ static bssl::UniquePtr<SSL_CTX> SetupCtx(const TestConfig *config) {
SSL_CTX_enable_tls_channel_id(ssl_ctx.get());
SSL_CTX_set_channel_id_cb(ssl_ctx.get(), ChannelIdCallback);
if (config->is_dtls) {
SSL_CTX_set_current_time_cb(ssl_ctx.get(), CurrentTimeCallback);
}
SSL_CTX_set_current_time_cb(ssl_ctx.get(), CurrentTimeCallback);
SSL_CTX_set_info_callback(ssl_ctx.get(), InfoCallback);
SSL_CTX_sess_set_new_cb(ssl_ctx.get(), NewSessionCallback);
@ -1473,7 +1473,7 @@ static bool DoExchange(bssl::UniquePtr<SSL_SESSION> *out_session,
return false;
}
if (config->is_dtls) {
bssl::UniquePtr<BIO> packeted = PacketedBioCreate(!config->async);
bssl::UniquePtr<BIO> packeted = PacketedBioCreate(&g_clock, !config->async);
if (!packeted) {
return false;
}
@ -1748,6 +1748,11 @@ static int Main(int argc, char **argv) {
return Usage(argv[0]);
}
// Some code treats the zero time special, so initialize the clock to a
// non-zero time.
g_clock.tv_sec = 1234;
g_clock.tv_usec = 1234;
bssl::UniquePtr<SSL_CTX> ssl_ctx = SetupCtx(&config);
if (!ssl_ctx) {
ERR_print_errors_fp(stderr);

33
ssl/test/packeted_bio.cc
View File

@ -31,10 +31,9 @@ const uint8_t kOpcodeTimeout = 'T';
const uint8_t kOpcodeTimeoutAck = 't';
struct PacketedBio {
explicit PacketedBio(bool advance_clock_arg)
: advance_clock(advance_clock_arg) {
PacketedBio(timeval *clock_arg, bool advance_clock_arg)
: clock(clock_arg), advance_clock(advance_clock_arg) {
memset(&timeout, 0, sizeof(timeout));
memset(&clock, 0, sizeof(clock));
memset(&read_deadline, 0, sizeof(read_deadline));
}
@ -47,14 +46,14 @@ struct PacketedBio {
return true;
}
if (clock.tv_sec == read_deadline.tv_sec) {
return clock.tv_usec < read_deadline.tv_usec;
if (clock->tv_sec == read_deadline.tv_sec) {
return clock->tv_usec < read_deadline.tv_usec;
}
return clock.tv_sec < read_deadline.tv_sec;
return clock->tv_sec < read_deadline.tv_sec;
}
timeval timeout;
timeval clock;
timeval *clock;
timeval read_deadline;
bool advance_clock;
};
@ -66,10 +65,6 @@ PacketedBio *GetData(BIO *bio) {
return (PacketedBio *)bio->ptr;
}
const PacketedBio *GetData(const BIO *bio) {
return GetData(const_cast<BIO*>(bio));
}
// ReadAll reads |len| bytes from |bio| into |out|. It returns 1 on success and
// 0 or -1 on error.
static int ReadAll(BIO *bio, uint8_t *out, size_t len) {
@ -272,19 +267,15 @@ const BIO_METHOD g_packeted_bio_method = {
} // namespace
bssl::UniquePtr<BIO> PacketedBioCreate(bool advance_clock) {
bssl::UniquePtr<BIO> PacketedBioCreate(timeval *clock, bool advance_clock) {
bssl::UniquePtr<BIO> bio(BIO_new(&g_packeted_bio_method));
if (!bio) {
return nullptr;
}
bio->ptr = new PacketedBio(advance_clock);
bio->ptr = new PacketedBio(clock, advance_clock);
return bio;
}
timeval PacketedBioGetClock(const BIO *bio) {
return GetData(bio)->clock;
}
bool PacketedBioAdvanceClock(BIO *bio) {
PacketedBio *data = GetData(bio);
if (data == nullptr) {
@ -295,10 +286,10 @@ bool PacketedBioAdvanceClock(BIO *bio) {
return false;
}
data->clock.tv_usec += data->timeout.tv_usec;
data->clock.tv_sec += data->clock.tv_usec / 1000000;
data->clock.tv_usec %= 1000000;
data->clock.tv_sec += data->timeout.tv_sec;
data->clock->tv_usec += data->timeout.tv_usec;
data->clock->tv_sec += data->clock->tv_usec / 1000000;
data->clock->tv_usec %= 1000000;
data->clock->tv_sec += data->timeout.tv_sec;
memset(&data->timeout, 0, sizeof(data->timeout));
return true;
}

13
ssl/test/packeted_bio.h
View File

@ -28,21 +28,18 @@ OPENSSL_MSVC_PRAGMA(warning(pop))
// PacketedBioCreate creates a filter BIO which implements a reliable in-order
// blocking datagram socket. It internally maintains a clock and honors
// |BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT| based on it.
// blocking datagram socket. It uses the value of |*clock| as the clock and
// honors |BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT| based on it.
//
// During a |BIO_read|, the peer may signal the filter BIO to simulate a
// timeout. If |advance_clock| is true, it automatically advances the clock and
// continues reading, subject to the read deadline. Otherwise, it fails
// immediately. The caller must then call |PacketedBioAdvanceClock| before
// retrying |BIO_read|.
bssl::UniquePtr<BIO> PacketedBioCreate(bool advance_clock);
bssl::UniquePtr<BIO> PacketedBioCreate(timeval *clock, bool advance_clock);
// PacketedBioGetClock returns the current time for |bio|.
timeval PacketedBioGetClock(const BIO *bio);
// PacketedBioAdvanceClock advances |bio|'s internal clock and returns true if
// there is a pending timeout. Otherwise, it returns false.
// PacketedBioAdvanceClock advances |bio|'s clock and returns true if there is a
// pending timeout. Otherwise, it returns false.
bool PacketedBioAdvanceClock(BIO *bio);