43 lines
1.5 KiB
Diff
43 lines
1.5 KiB
Diff
Backported of:
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From 7035676c3daa4f1c3766095561f12e7a0e82c736 Mon Sep 17 00:00:00 2001
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From: Daniel Stenberg <daniel@haxx.se>
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Date: Mon, 16 May 2022 16:28:13 +0200
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Subject: [PATCH] content_encoding: return error on too many compression steps
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The max allowed steps is arbitrarily set to 5.
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diff --git a/lib/content_encoding.c b/lib/content_encoding.c
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index 82fcc2b..a89bb3e 100644
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--- a/lib/content_encoding.c
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+++ b/lib/content_encoding.c
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@@ -1027,6 +1027,9 @@ static const struct content_encoding *find_encoding(const char *name,
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return NULL;
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}
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+/* allow no more than 5 "chained" compression steps */
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+#define MAX_ENCODE_STACK 5
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+
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/* Set-up the unencoding stack from the Content-Encoding header value.
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* See RFC 7231 section 3.1.2.2. */
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CURLcode Curl_build_unencoding_stack(struct connectdata *conn,
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@@ -1034,6 +1037,7 @@ CURLcode Curl_build_unencoding_stack(struct connectdata *conn,
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{
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struct Curl_easy *data = conn->data;
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struct SingleRequest *k = &data->req;
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+ int counter = 0;
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do {
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const char *name;
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@@ -1068,6 +1072,11 @@ CURLcode Curl_build_unencoding_stack(struct connectdata *conn,
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if(!encoding)
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encoding = &error_encoding; /* Defer error at stack use. */
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+ if(++counter >= MAX_ENCODE_STACK) {
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+ failf(data, "Reject response due to %u content encodings",
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+ counter);
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+ return CURLE_BAD_CONTENT_ENCODING;
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+ }
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/* Stack the unencoding stage. */
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writer = new_unencoding_writer(conn, encoding, k->writer_stack);
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if(!writer)
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