From: Zhouyihai Ding Date: Wed, 10 Jan 2018 18:12:18 +0000 (-0800) Subject: http2: fix incorrect trailer buffer size X-Git-Tag: curl-7_58_0~33 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=fa3dbb9a147488a2943bda809c66fc497efe06cb;p=curl http2: fix incorrect trailer buffer size Prior to this change the stored byte count of each trailer was miscalculated and 1 less than required. It appears any trailer after the first that was passed to Curl_client_write would be truncated or corrupted as well as the size. Potentially the size of some subsequent trailer could be erroneously extracted from the contents of that trailer, and since that size is used by client write an out-of-bounds read could occur and cause a crash or be otherwise processed by client write. The bug appears to have been born in 0761a51 (precedes 7.49.0). Closes https://github.com/curl/curl/pull/2231 --- diff --git a/lib/http2.c b/lib/http2.c index 8e2fc7199..699287940 100644 --- a/lib/http2.c +++ b/lib/http2.c @@ -925,8 +925,8 @@ static int on_header(nghttp2_session *session, const nghttp2_frame *frame, if(stream->bodystarted) { /* This is trailer fields. */ - /* 3 is for ":" and "\r\n". */ - uint32_t n = (uint32_t)(namelen + valuelen + 3); + /* 4 is for ": " and "\r\n". */ + uint32_t n = (uint32_t)(namelen + valuelen + 4); DEBUGF(infof(data_s, "h2 trailer: %.*s: %.*s\n", namelen, name, valuelen, value));