From d6fb7a0e0f3a79afa1f4b6fc7b62053c3955dc4a Mon Sep 17 00:00:00 2001 From: Amaury Denoyelle Date: Wed, 7 Dec 2022 14:31:42 +0100 Subject: [PATCH] BUG/MEDIUM: h3: reject request with invalid header name Reject request containing invalid header name. This concerns every header containing uppercase letter or a non HTTP token such as a space. For the moment, this kind of errors triggers a connection close. In the future, it should be handled only with a stream reset. To reduce backport surface, this will be implemented in another commit. Thanks to Yuki Mogi from FFRI Security, Inc. for having reported this. This must be backported up to 2.6. --- src/h3.c | 30 +++++++++++++++++++++++++++++- 1 file changed, 29 insertions(+), 1 deletion(-) diff --git a/src/h3.c b/src/h3.c index 97e821efe..5f1c68a29 100644 --- a/src/h3.c +++ b/src/h3.c @@ -352,7 +352,27 @@ static ssize_t h3_headers_to_htx(struct qcs *qcs, const struct buffer *buf, //struct ist scheme = IST_NULL, authority = IST_NULL; struct ist authority = IST_NULL; int hdr_idx, ret; - int cookie = -1, last_cookie = -1; + int cookie = -1, last_cookie = -1, i; + + /* RFC 9114 4.1.2. Malformed Requests and Responses + * + * A malformed request or response is one that is an otherwise valid + * sequence of frames but is invalid due to: + * - the presence of prohibited fields or pseudo-header fields, + * - the absence of mandatory pseudo-header fields, + * - invalid values for pseudo-header fields, + * - pseudo-header fields after fields, + * - an invalid sequence of HTTP messages, + * - the inclusion of uppercase field names, or + * - the inclusion of invalid characters in field names or values. + * + * [...] + * + * Intermediaries that process HTTP requests or responses (i.e., any + * intermediary not acting as a tunnel) MUST NOT forward a malformed + * request or response. Malformed requests or responses that are + * detected MUST be treated as a stream error of type H3_MESSAGE_ERROR. + */ TRACE_ENTER(H3_EV_RX_FRAME|H3_EV_RX_HDR, qcs->qcc->conn, qcs); @@ -416,6 +436,14 @@ static ssize_t h3_headers_to_htx(struct qcs *qcs, const struct buffer *buf, if (isteq(list[hdr_idx].n, ist(""))) break; + for (i = 0; i < list[hdr_idx].n.len; ++i) { + const char c = list[hdr_idx].n.ptr[i]; + if ((uint8_t)(c - 'A') < 'Z' - 'A' || !HTTP_IS_TOKEN(c)) { + TRACE_ERROR("invalid characters in field name", H3_EV_RX_FRAME|H3_EV_RX_HDR, qcs->qcc->conn, qcs); + return -1; + } + } + if (isteq(list[hdr_idx].n, ist("cookie"))) { http_cookie_register(list, hdr_idx, &cookie, &last_cookie); continue; -- 2.47.3