From 119fb187192a9ea13dc90d9d20c215fc82799ab9 Mon Sep 17 00:00:00 2001
From: Patrick Monnerat <patrick@monnerat.net>
Date: Mon, 13 Feb 2023 08:33:09 +0100
Subject: [PATCH] content_encoding: do not reset stage counter for each header

Test 418 verifies

Closes #10492

Upstream-Status: Backport [https://github.com/curl/curl/commit/119fb187192a9ea13dc90d9d20c215fc82799ab9]
CVE: CVE-2023-23916
Signed-off-by: Hitendra Prajapati <hprajapati@mvista.com>
---
 lib/content_encoding.c  |   7 +-
 lib/urldata.h           |   1 +
 tests/data/Makefile.inc |   2 +-
 tests/data/test418      | 152 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 157 insertions(+), 5 deletions(-)
 create mode 100644 tests/data/test418

diff --git a/lib/content_encoding.c b/lib/content_encoding.c
index 91e621f..7e098a5 100644
--- a/lib/content_encoding.c
+++ b/lib/content_encoding.c
@@ -944,7 +944,6 @@ 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;
@@ -979,9 +978,9 @@ 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);
+      if(k->writer_stack_depth++ >= MAX_ENCODE_STACK) {
+        failf(data, "Reject response due to more than %u content encodings",
+              MAX_ENCODE_STACK);
         return CURLE_BAD_CONTENT_ENCODING;
       }    
       /* Stack the unencoding stage. */
diff --git a/lib/urldata.h b/lib/urldata.h
index ad0ef8f..168f874 100644
--- a/lib/urldata.h
+++ b/lib/urldata.h
@@ -648,6 +648,7 @@ struct SingleRequest {
 #ifndef CURL_DISABLE_DOH
   struct dohdata doh; /* DoH specific data for this request */
 #endif
+  unsigned char writer_stack_depth; /* Unencoding stack depth. */
   BIT(header);       /* incoming data has HTTP header */
   BIT(content_range); /* set TRUE if Content-Range: was found */
   BIT(upload_done);  /* set to TRUE when doing chunked transfer-encoding
diff --git a/tests/data/Makefile.inc b/tests/data/Makefile.inc
index 60e8176..40de8bc 100644
--- a/tests/data/Makefile.inc
+++ b/tests/data/Makefile.inc
@@ -63,7 +63,7 @@ test350 test351 test352 test353 test354 test355 test356 test357 \
 test393 test394 test395 \
 \
 test400 test401 test402 test403 test404 test405 test406 test407 test408 \
-test409 \
+test409 test418 \
 \
 test490 test491 test492 \
 \
diff --git a/tests/data/test418 b/tests/data/test418
new file mode 100644
index 0000000..50e974e
--- /dev/null
+++ b/tests/data/test418
@@ -0,0 +1,152 @@
+<testcase>
+<info>
+<keywords>
+HTTP
+gzip
+</keywords>
+</info>
+
+#
+# Server-side
+<reply>
+<data nocheck="yes">
+HTTP/1.1 200 OK
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+
+-foo-
+</data>
+</reply>
+
+#
+# Client-side
+<client>
+<server>
+http
+</server>
+ <name>
+Response with multiple Transfer-Encoding headers
+ </name>
+ <command>
+http://%HOSTIP:%HTTPPORT/%TESTNUMBER -sS
+</command>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+<protocol crlf="yes">
+GET /%TESTNUMBER HTTP/1.1
+Host: %HOSTIP:%HTTPPORT
+User-Agent: curl/%VERSION
+Accept: */*
+
+</protocol>
+
+# CURLE_BAD_CONTENT_ENCODING is 61
+<errorcode>
+61
+</errorcode>
+<stderr mode="text">
+curl: (61) Reject response due to more than 5 content encodings
+</stderr>
+</verify>
+</testcase>
-- 
2.25.1