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From 00201ecd8f982da3b67d4f6868af72a1b03b14e0 Mon Sep 17 00:00:00 2001
From: Tatsuhiro Tsujikawa <tatsuhiro.t@gmail.com>
Date: Sat, 9 Mar 2024 16:26:42 +0900
Subject: [PATCH] Limit CONTINUATION frames following an incoming HEADER frame
CVE: CVE-2024-28182
Upstream-Status: Backport [https://github.com/nghttp2/nghttp2/commit/00201ecd8f982da3b67d4f6868af72a1b03b14e0]
Signed-off-by: Soumya Sambu <soumya.sambu@windriver.com>
---
lib/includes/nghttp2/nghttp2.h | 7 ++++++-
lib/nghttp2_helper.c | 2 ++
lib/nghttp2_session.c | 7 +++++++
lib/nghttp2_session.h | 10 ++++++++++
4 files changed, 25 insertions(+), 1 deletion(-)
diff --git a/lib/includes/nghttp2/nghttp2.h b/lib/includes/nghttp2/nghttp2.h
index 2bd35f4..6cc8c0c 100644
--- a/lib/includes/nghttp2/nghttp2.h
+++ b/lib/includes/nghttp2/nghttp2.h
@@ -440,7 +440,12 @@ typedef enum {
* exhaustion on server side to send these frames forever and does
* not read network.
*/
- NGHTTP2_ERR_FLOODED = -904
+ NGHTTP2_ERR_FLOODED = -904,
+ /**
+ * When a local endpoint receives too many CONTINUATION frames
+ * following a HEADER frame.
+ */
+ NGHTTP2_ERR_TOO_MANY_CONTINUATIONS = -905,
} nghttp2_error;
/**
diff --git a/lib/nghttp2_helper.c b/lib/nghttp2_helper.c
index 588e269..98989f6 100644
--- a/lib/nghttp2_helper.c
+++ b/lib/nghttp2_helper.c
@@ -336,6 +336,8 @@ const char *nghttp2_strerror(int error_code) {
"closed";
case NGHTTP2_ERR_TOO_MANY_SETTINGS:
return "SETTINGS frame contained more than the maximum allowed entries";
+ case NGHTTP2_ERR_TOO_MANY_CONTINUATIONS:
+ return "Too many CONTINUATION frames following a HEADER frame";
default:
return "Unknown error code";
}
diff --git a/lib/nghttp2_session.c b/lib/nghttp2_session.c
index 5c834fa..537127c 100644
--- a/lib/nghttp2_session.c
+++ b/lib/nghttp2_session.c
@@ -464,6 +464,7 @@ static int session_new(nghttp2_session **session_ptr,
(*session_ptr)->max_send_header_block_length = NGHTTP2_MAX_HEADERSLEN;
(*session_ptr)->max_outbound_ack = NGHTTP2_DEFAULT_MAX_OBQ_FLOOD_ITEM;
(*session_ptr)->max_settings = NGHTTP2_DEFAULT_MAX_SETTINGS;
+ (*session_ptr)->max_continuations = NGHTTP2_DEFAULT_MAX_CONTINUATIONS;
if (option) {
if ((option->opt_set_mask & NGHTTP2_OPT_NO_AUTO_WINDOW_UPDATE) &&
@@ -6307,6 +6308,8 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
}
}
session_inbound_frame_reset(session);
+
+ session->num_continuations = 0;
}
break;
}
@@ -6428,6 +6431,10 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
}
#endif /* DEBUGBUILD */
+ if (++session->num_continuations > session->max_continuations) {
+ return NGHTTP2_ERR_TOO_MANY_CONTINUATIONS;
+ }
+
readlen = inbound_frame_buf_read(iframe, in, last);
in += readlen;
diff --git a/lib/nghttp2_session.h b/lib/nghttp2_session.h
index 5f71a16..9a00b0e 100644
--- a/lib/nghttp2_session.h
+++ b/lib/nghttp2_session.h
@@ -107,6 +107,10 @@ typedef struct {
#define NGHTTP2_DEFAULT_STREAM_RESET_BURST 1000
#define NGHTTP2_DEFAULT_STREAM_RESET_RATE 33
+/* The default max number of CONTINUATION frames following an incoming
+ HEADER frame. */
+#define NGHTTP2_DEFAULT_MAX_CONTINUATIONS 8
+
/* Internal state when receiving incoming frame */
typedef enum {
/* Receiving frame header */
@@ -279,6 +283,12 @@ struct nghttp2_session {
size_t max_send_header_block_length;
/* The maximum number of settings accepted per SETTINGS frame. */
size_t max_settings;
+ /* The maximum number of CONTINUATION frames following an incoming
+ HEADER frame. */
+ size_t max_continuations;
+ /* The number of CONTINUATION frames following an incoming HEADER
+ frame. This variable is reset when END_HEADERS flag is seen. */
+ size_t num_continuations;
/* Next Stream ID. Made unsigned int to detect >= (1 << 31). */
uint32_t next_stream_id;
/* The last stream ID this session initiated. For client session,
--
2.40.0
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