From 24dedf9b260eebb7feae6fc273208b551fe54a79 Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Mon, 16 May 2022 16:28:13 +0200
Subject: [PATCH 1/2] 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-commit: 3a09fbb7f264c67c438d01a30669ce325aa508e2
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
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
@@ -934,6 +934,9 @@ static const content_encoding *find_encoding(const char *name, size_t len)
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 connectdata *conn,
@@ -941,6 +944,7 @@ CURLcode Curl_build_unencoding_stack(struct connectdata *conn,
{
struct Curl_easy *data = conn->data;
struct SingleRequest *k = &data->req;
+ int counter = 0;
do {
const char *name;
@@ -975,6 +979,11 @@ CURLcode Curl_build_unencoding_stack(struct connectdata *conn,
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(conn, encoding, k->writer_stack);
if(!writer)
--
2.35.3
From b3cd74f01871281f0989860e04c546d896f0e72f Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Mon, 16 May 2022 16:29:07 +0200
Subject: [PATCH 2/2] test387: verify rejection of compression chain attack
Upstream-commit: 7230b19a2e17a164f61f82e4e409a9777ea2421a
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
tests/data/Makefile.inc | 1 +
tests/data/test387 | 53 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 54 insertions(+)
create mode 100644 tests/data/test387
diff --git a/tests/data/Makefile.inc b/tests/data/Makefile.inc
index 98d5516..9b5f4fb 100644
--- a/tests/data/Makefile.inc
+++ b/tests/data/Makefile.inc
@@ -61,6 +61,7 @@ test325 test326 test330 \
test340 \
\
test350 test351 test352 test353 test354 \
+test387 \
test393 test394 test395 \
\
test400 test401 test402 test403 test404 test405 test406 test407 test408 \
diff --git a/tests/data/test387 b/tests/data/test387
new file mode 100644
index 0000000..015ec25
--- /dev/null
+++ b/tests/data/test387
@@ -0,0 +1,53 @@
+<testcase>
+<info>
+<keywords>
+HTTP
+gzip
+</keywords>
+</info>
+
+#
+# Server-side
+<reply>
+<data nocheck="yes">
+HTTP/1.1 200 OK
+Transfer-Encoding: gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip,gzip
+
+-foo-
+</data>
+</reply>
+
+#
+# Client-side
+<client>
+<server>
+http
+</server>
+ <name>
+Response with overly long compression chain
+ </name>
+ <command>
+http://%HOSTIP:%HTTPPORT/%TESTNUMBER -sS
+</command>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+<protocol>
+GET /%TESTNUMBER HTTP/1.1
+Host: %HOSTIP:%HTTPPORT
+User-Agent: curl/7.61.1
+Accept: */*
+
+</protocol>
+
+# CURLE_BAD_CONTENT_ENCODING is 61
+<errorcode>
+61
+</errorcode>
+<stderr mode="text">
+curl: (61) Reject response due to 5 content encodings
+</stderr>
+</verify>
+</testcase>
--
2.35.3