BUG/MAJOR: mux_h2: Don't consume more payload than received for skipped frames
When a frame is received for a unknown or already closed stream, it must be
skipped. This also happens when a stream error is reported. But we must be sure
to only skip received data. In the loop in h2_process_demux(), when such frames
are handled, all the frame lenght is systematically skipped. If the frame
payload is partially received, it leaves the demux buffer in an undefined
state. Because of this bug, all sort of errors may be observed, like crash or
intermittent freeze.
This patch must be backported to 2.0, 1.9 and 1.8.
diff --git a/src/mux_h2.c b/src/mux_h2.c
index b59c7fa..41c41de 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -3103,10 +3103,15 @@
}
if (h2c->st0 != H2_CS_FRAME_H) {
- b_del(&h2c->dbuf, h2c->dfl);
- h2c->dsi = -1;
- TRACE_STATE("switching to FRAME_H", H2_EV_RX_FRAME|H2_EV_RX_FHDR, h2c->conn);
- h2c->st0 = H2_CS_FRAME_H;
+ TRACE_DEVEL("stream error, skip frame payload", H2_EV_RX_FRAME, h2c->conn, h2s);
+ ret = MIN(b_data(&h2c->dbuf), h2c->dfl);
+ b_del(&h2c->dbuf, ret);
+ h2c->dfl -= ret;
+ if (!h2c->dfl) {
+ TRACE_STATE("switching to FRAME_H", H2_EV_RX_FRAME|H2_EV_RX_FHDR, h2c->conn);
+ h2c->st0 = H2_CS_FRAME_H;
+ h2c->dsi = -1;
+ }
}
}