blob: 25f5b27cc729eee7ecfe68ce3cc792f32288a5f2 [file] [log] [blame]
Patrick Williamscb2a94c2022-07-29 10:24:38 -05001From e12531340b03d242d3f892aa8797faf12b56dddf Mon Sep 17 00:00:00 2001
2From: Daniel Stenberg <daniel@haxx.se>
3Date: Mon, 16 May 2022 16:28:13 +0200
4Subject: [PATCH] content_encoding: return error on too many compression steps
5
6The max allowed steps is arbitrarily set to 5.
7
8Bug: https://curl.se/docs/CVE-2022-32206.html
9CVE-2022-32206
10Reported-by: Harry Sintonen
11Closes #9049
12
13Upstream-Status: Backport [https://github.com/curl/curl/commit/3a09fbb7f264c67c43]
14Signed-off-by: Robert Joslyn <robert.joslyn@redrectangle.org>
15---
16 lib/content_encoding.c | 9 +++++++++
17 1 file changed, 9 insertions(+)
18
19diff --git a/lib/content_encoding.c b/lib/content_encoding.c
20index c03637a..6f994b3 100644
21--- a/lib/content_encoding.c
22+++ b/lib/content_encoding.c
23@@ -1026,12 +1026,16 @@ static const struct content_encoding *find_encoding(const char *name,
24 return NULL;
25 }
26
27+/* allow no more than 5 "chained" compression steps */
28+#define MAX_ENCODE_STACK 5
29+
30 /* Set-up the unencoding stack from the Content-Encoding header value.
31 * See RFC 7231 section 3.1.2.2. */
32 CURLcode Curl_build_unencoding_stack(struct Curl_easy *data,
33 const char *enclist, int maybechunked)
34 {
35 struct SingleRequest *k = &data->req;
36+ int counter = 0;
37
38 do {
39 const char *name;
40@@ -1066,6 +1070,11 @@ CURLcode Curl_build_unencoding_stack(struct Curl_easy *data,
41 if(!encoding)
42 encoding = &error_encoding; /* Defer error at stack use. */
43
44+ if(++counter >= MAX_ENCODE_STACK) {
45+ failf(data, "Reject response due to %u content encodings",
46+ counter);
47+ return CURLE_BAD_CONTENT_ENCODING;
48+ }
49 /* Stack the unencoding stage. */
50 writer = new_unencoding_writer(data, encoding, k->writer_stack);
51 if(!writer)