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Detect flooding and tear down session

This commit is contained in:
Tatsuhiro Tsujikawa 2015-09-30 00:44:08 +09:00
parent f150f9aec4
commit 0cb8c82125
6 changed files with 136 additions and 3 deletions
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3
lib/nghttp2_int.h
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@ -52,7 +52,8 @@ typedef enum {
* Invalid HTTP header field was received but it can be treated as
* if it was not received because of compatibility reasons.
*/
NGHTTP2_ERR_IGN_HTTP_HEADER = -105
NGHTTP2_ERR_IGN_HTTP_HEADER = -105,
NGHTTP2_ERR_FLOODING_DETECTED = -106
} nghttp2_internal_error;
#endif /* NGHTTP2_INT_H */

46
lib/nghttp2_session.c
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@ -141,6 +141,15 @@ static int session_detect_idle_stream(nghttp2_session *session,
return 0;
}
static void session_on_flooding_detected(nghttp2_session *session) {
/* If we found flooding, we might not send GOAWAY since peer might
not read at all. So we just set these flags to pretend that
GOAWAY is sent, so that nghttp2_session_want_read() and
nghttp2_session_want_write() return 0. */
session->goaway_flags |= NGHTTP2_GOAWAY_TERM_ON_SEND |
NGHTTP2_GOAWAY_TERM_SENT | NGHTTP2_GOAWAY_SENT;
}
static int session_terminate_session(nghttp2_session *session,
int32_t last_stream_id,
uint32_t error_code, const char *reason) {
@ -1853,6 +1862,11 @@ static int session_prep_frame(nghttp2_session *session,
&frame->rst_stream);
break;
case NGHTTP2_SETTINGS: {
if (frame->hd.flags & NGHTTP2_FLAG_ACK) {
assert(session->obq_flood_counter_ > 0);
--session->obq_flood_counter_;
}
rv = nghttp2_frame_pack_settings(&session->aob.framebufs,
&frame->settings);
if (rv != 0) {
@ -1914,6 +1928,11 @@ static int session_prep_frame(nghttp2_session *session,
break;
}
case NGHTTP2_PING:
if (frame->hd.flags & NGHTTP2_FLAG_ACK) {
assert(session->obq_flood_counter_ > 0);
--session->obq_flood_counter_;
}
if (session_is_closing(session)) {
return NGHTTP2_ERR_SESSION_CLOSING;
}
@ -5908,6 +5927,13 @@ int nghttp2_session_add_ping(nghttp2_session *session, uint8_t flags,
nghttp2_mem *mem;
mem = &session->mem;
if ((flags & NGHTTP2_FLAG_ACK) &&
session->obq_flood_counter_ >= NGHTTP2_MAX_OBQ_FLOOD_ITEM) {
session_on_flooding_detected(session);
return NGHTTP2_ERR_FLOODING_DETECTED;
}
item = nghttp2_mem_malloc(mem, sizeof(nghttp2_outbound_item));
if (item == NULL) {
return NGHTTP2_ERR_NOMEM;
@ -5926,6 +5952,11 @@ int nghttp2_session_add_ping(nghttp2_session *session, uint8_t flags,
nghttp2_mem_free(mem, item);
return rv;
}
if (flags & NGHTTP2_FLAG_ACK) {
++session->obq_flood_counter_;
}
return 0;
}
@ -6044,8 +6075,15 @@ int nghttp2_session_add_settings(nghttp2_session *session, uint8_t flags,
mem = &session->mem;
if ((flags & NGHTTP2_FLAG_ACK) && niv != 0) {
return NGHTTP2_ERR_INVALID_ARGUMENT;
if (flags & NGHTTP2_FLAG_ACK) {
if (niv != 0) {
return NGHTTP2_ERR_INVALID_ARGUMENT;
}
if (session->obq_flood_counter_ >= NGHTTP2_MAX_OBQ_FLOOD_ITEM) {
session_on_flooding_detected(session);
return NGHTTP2_ERR_FLOODING_DETECTED;
}
}
if (!nghttp2_iv_check(iv, niv)) {
@ -6095,6 +6133,10 @@ int nghttp2_session_add_settings(nghttp2_session *session, uint8_t flags,
return rv;
}
if (flags & NGHTTP2_FLAG_ACK) {
++session->obq_flood_counter_;
}
session_append_inflight_settings(session, inflight_settings);
/* Extract NGHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS and ENABLE_PUSH

18
lib/nghttp2_session.h
View File

@ -74,6 +74,16 @@ typedef struct {
/* The default maximum number of incoming reserved streams */
#define NGHTTP2_MAX_INCOMING_RESERVED_STREAMS 200
/* The maximum number of items in outbound queue, which is considered
as flooding caused by peer. All frames are not considered here.
We only consider PING + ACK and SETTINGS + ACK. This is because
they both are response to the frame initiated by peer and peer can
send as many of them as they want. If peer does not read network,
response frames are stacked up, which leads to memory exhaustion.
The value selected here is arbitrary, but safe value and if we have
these frames in this number, it is considered suspicious. */
#define NGHTTP2_MAX_OBQ_FLOOD_ITEM 1000
/* Internal state when receiving incoming frame */
typedef enum {
/* Receiving frame header */
@ -227,6 +237,8 @@ struct nghttp2_session {
size_t num_idle_streams;
/* The number of bytes allocated for nvbuf */
size_t nvbuflen;
/* Counter for detecting flooding in outbound queue */
size_t obq_flood_counter_;
/* Next Stream ID. Made unsigned int to detect >= (1 << 31). */
uint32_t next_stream_id;
/* The largest stream ID received so far */
@ -355,6 +367,9 @@ int nghttp2_session_add_rst_stream(nghttp2_session *session, int32_t stream_id,
*
* NGHTTP2_ERR_NOMEM
* Out of memory.
* NGHTTP2_ERR_FLOODING_DETECTED
* There are too many items in outbound queue; this only happens
* if NGHTTP2_FLAG_ACK is set in |flags|
*/
int nghttp2_session_add_ping(nghttp2_session *session, uint8_t flags,
const uint8_t *opaque_data);
@ -402,6 +417,9 @@ int nghttp2_session_add_window_update(nghttp2_session *session, uint8_t flags,
*
* NGHTTP2_ERR_NOMEM
* Out of memory.
* NGHTTP2_ERR_FLOODING_DETECTED
* There are too many items in outbound queue; this only happens
* if NGHTTP2_FLAG_ACK is set in |flags|
*/
int nghttp2_session_add_settings(nghttp2_session *session, uint8_t flags,
const nghttp2_settings_entry *iv, size_t niv);

1
tests/main.c
View File

@ -277,6 +277,7 @@ int main(int argc _U_, char *argv[] _U_) {
test_nghttp2_session_defer_then_close) ||
!CU_add_test(pSuite, "session_detach_item_from_closed_stream",
test_nghttp2_session_detach_item_from_closed_stream) ||
!CU_add_test(pSuite, "session_flooding", test_nghttp2_session_flooding) ||
!CU_add_test(pSuite, "http_mandatory_headers",
test_nghttp2_http_mandatory_headers) ||
!CU_add_test(pSuite, "http_content_length",

70
tests/nghttp2_session_test.c
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@ -8090,6 +8090,76 @@ void test_nghttp2_session_detach_item_from_closed_stream(void) {
nghttp2_session_del(session);
}
void test_nghttp2_session_flooding(void) {
nghttp2_session *session;
nghttp2_session_callbacks callbacks;
nghttp2_bufs bufs;
nghttp2_buf *buf;
nghttp2_frame frame;
nghttp2_mem *mem;
mem = nghttp2_mem_default();
frame_pack_bufs_init(&bufs);
memset(&callbacks, 0, sizeof(callbacks));
/* PING ACK */
nghttp2_session_server_new(&session, &callbacks, NULL);
nghttp2_frame_ping_init(&frame.ping, NGHTTP2_FLAG_NONE, NULL);
nghttp2_frame_pack_ping(&bufs, &frame.ping);
nghttp2_frame_ping_free(&frame.ping);
buf = &bufs.head->buf;
for (int i = 0; i < NGHTTP2_MAX_OBQ_FLOOD_ITEM; ++i) {
CU_ASSERT(
(ssize_t)nghttp2_buf_len(buf) ==
nghttp2_session_mem_recv(session, buf->pos, nghttp2_buf_len(buf)));
}
CU_ASSERT(1 == nghttp2_session_want_read(session));
CU_ASSERT(1 == nghttp2_session_want_write(session));
CU_ASSERT((ssize_t)nghttp2_buf_len(buf) ==
nghttp2_session_mem_recv(session, buf->pos, nghttp2_buf_len(buf)));
CU_ASSERT(0 == nghttp2_session_want_read(session));
CU_ASSERT(0 == nghttp2_session_want_write(session));
nghttp2_session_del(session);
/* SETTINGS ACK */
nghttp2_bufs_reset(&bufs);
nghttp2_session_server_new(&session, &callbacks, NULL);
nghttp2_frame_settings_init(&frame.settings, NGHTTP2_FLAG_NONE, NULL, 0);
nghttp2_frame_pack_settings(&bufs, &frame.settings);
nghttp2_frame_settings_free(&frame.settings, mem);
buf = &bufs.head->buf;
for (int i = 0; i < NGHTTP2_MAX_OBQ_FLOOD_ITEM; ++i) {
CU_ASSERT(
(ssize_t)nghttp2_buf_len(buf) ==
nghttp2_session_mem_recv(session, buf->pos, nghttp2_buf_len(buf)));
}
CU_ASSERT(1 == nghttp2_session_want_read(session));
CU_ASSERT(1 == nghttp2_session_want_write(session));
CU_ASSERT((ssize_t)nghttp2_buf_len(buf) ==
nghttp2_session_mem_recv(session, buf->pos, nghttp2_buf_len(buf)));
CU_ASSERT(0 == nghttp2_session_want_read(session));
CU_ASSERT(0 == nghttp2_session_want_write(session));
nghttp2_session_del(session);
nghttp2_bufs_free(&bufs);
}
static void check_nghttp2_http_recv_headers_fail(
nghttp2_session *session, nghttp2_hd_deflater *deflater, int32_t stream_id,
int stream_state, const nghttp2_nv *nva, size_t nvlen) {

1
tests/nghttp2_session_test.h
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@ -131,6 +131,7 @@ void test_nghttp2_session_send_data_callback(void);
void test_nghttp2_session_on_begin_headers_temporal_failure(void);
void test_nghttp2_session_defer_then_close(void);
void test_nghttp2_session_detach_item_from_closed_stream(void);
void test_nghttp2_session_flooding(void);
void test_nghttp2_http_mandatory_headers(void);
void test_nghttp2_http_content_length(void);
void test_nghttp2_http_content_length_mismatch(void);