From e12531340b03d242d3f892aa8797faf12b56dddf Mon Sep 17 00:00:00 2001 From: Daniel Stenberg Date: Mon, 16 May 2022 16:28:13 +0200 Subject: [PATCH] content_encoding: return error on too many compression steps The max allowed steps is arbitrarily set to 5. Bug: https://curl.se/docs/CVE-2022-32206.html CVE-2022-32206 Reported-by: Harry Sintonen Closes #9049 Upstream-Status: Backport [https://github.com/curl/curl/commit/3a09fbb7f264c67c43] Signed-off-by: Robert Joslyn --- lib/content_encoding.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/lib/content_encoding.c b/lib/content_encoding.c index c03637a..6f994b3 100644 --- a/lib/content_encoding.c +++ b/lib/content_encoding.c @@ -1026,12 +1026,16 @@ static const struct content_encoding *find_encoding(const char *name, return NULL; } +/* allow no more than 5 "chained" compression steps */ +#define MAX_ENCODE_STACK 5 + /* Set-up the unencoding stack from the Content-Encoding header value. * See RFC 7231 section 3.1.2.2. */ CURLcode Curl_build_unencoding_stack(struct Curl_easy *data, const char *enclist, int maybechunked) { struct SingleRequest *k = &data->req; + int counter = 0; do { const char *name; @@ -1066,6 +1070,11 @@ CURLcode Curl_build_unencoding_stack(struct Curl_easy *data, if(!encoding) encoding = &error_encoding; /* Defer error at stack use. */ + if(++counter >= MAX_ENCODE_STACK) { + failf(data, "Reject response due to %u content encodings", + counter); + return CURLE_BAD_CONTENT_ENCODING; + } /* Stack the unencoding stage. */ writer = new_unencoding_writer(data, encoding, k->writer_stack); if(!writer)