From: Vijay Anusuri <vanus...@mvista.com> A malicious HTTP sender can use chunk extensions to cause a receiver reading from a request or response body to read many more bytes from the network than are in the body. A malicious HTTP client can further exploit this to cause a server to automatically read a large amount of data (up to about 1GiB) when a handler fails to read the entire body of a request. Chunk extensions are a little-used HTTP feature which permit including additional metadata in a request or response body sent using the chunked encoding. The net/http chunked encoding reader discards this metadata. A sender can exploit this by inserting a large metadata segment with each byte transferred. The chunk reader now produces an error if the ratio of real body to encoded bytes grows too small.
References: https://nvd.nist.gov/vuln/detail/CVE-2023-39326 https://security-tracker.debian.org/tracker/CVE-2023-39326 Signed-off-by: Vijay Anusuri <vanus...@mvista.com> Signed-off-by: Steve Sakoman <st...@sakoman.com> --- meta/recipes-devtools/go/go-1.14.inc | 1 + .../go/go-1.14/CVE-2023-39326.patch | 181 ++++++++++++++++++ 2 files changed, 182 insertions(+) create mode 100644 meta/recipes-devtools/go/go-1.14/CVE-2023-39326.patch diff --git a/meta/recipes-devtools/go/go-1.14.inc b/meta/recipes-devtools/go/go-1.14.inc index 091b778de8..b827a3606d 100644 --- a/meta/recipes-devtools/go/go-1.14.inc +++ b/meta/recipes-devtools/go/go-1.14.inc @@ -82,6 +82,7 @@ SRC_URI += "\ file://CVE-2023-24536_3.patch \ file://CVE-2023-39318.patch \ file://CVE-2023-39319.patch \ + file://CVE-2023-39326.patch \ " SRC_URI_append_libc-musl = " file://0009-ld-replace-glibc-dynamic-linker-with-musl.patch" diff --git a/meta/recipes-devtools/go/go-1.14/CVE-2023-39326.patch b/meta/recipes-devtools/go/go-1.14/CVE-2023-39326.patch new file mode 100644 index 0000000000..998af361e8 --- /dev/null +++ b/meta/recipes-devtools/go/go-1.14/CVE-2023-39326.patch @@ -0,0 +1,181 @@ +From 6446af942e2e2b161c4ec1b60d9703a2b55dc4dd Mon Sep 17 00:00:00 2001 +From: Damien Neil <dn...@google.com> +Date: Tue, 7 Nov 2023 10:47:56 -0800 +Subject: [PATCH] [release-branch.go1.20] net/http: limit chunked data overhead + +The chunked transfer encoding adds some overhead to +the content transferred. When writing one byte per +chunk, for example, there are five bytes of overhead +per byte of data transferred: "1\r\nX\r\n" to send "X". + +Chunks may include "chunk extensions", +which we skip over and do not use. +For example: "1;chunk extension here\r\nX\r\n". + +A malicious sender can use chunk extensions to add +about 4k of overhead per byte of data. +(The maximum chunk header line size we will accept.) + +Track the amount of overhead read in chunked data, +and produce an error if it seems excessive. + +Updates #64433 +Fixes #64434 +Fixes CVE-2023-39326 + +Change-Id: I40f8d70eb6f9575fb43f506eb19132ccedafcf39 +Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/2076135 +Reviewed-by: Tatiana Bradley <tatianabrad...@google.com> +Reviewed-by: Roland Shoemaker <bracew...@google.com> +(cherry picked from commit 3473ae72ee66c60744665a24b2fde143e8964d4f) +Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/2095407 +Run-TryBot: Roland Shoemaker <bracew...@google.com> +TryBot-Result: Security TryBots <security-tryb...@go-security-trybots.iam.gserviceaccount.com> +Reviewed-by: Damien Neil <dn...@google.com> +Reviewed-on: https://go-review.googlesource.com/c/go/+/547355 +Reviewed-by: Dmitri Shuralyov <dmits...@google.com> +LUCI-TryBot-Result: Go LUCI <golang-sco...@luci-project-accounts.iam.gserviceaccount.com> + +Upstream-Status: Backport [https://github.com/golang/go/commit/6446af942e2e2b161c4ec1b60d9703a2b55dc4dd] +CVE: CVE-2023-39326 +Signed-off-by: Vijay Anusuri <vanus...@mvista.com> +--- + src/net/http/internal/chunked.go | 36 +++++++++++++--- + src/net/http/internal/chunked_test.go | 59 +++++++++++++++++++++++++++ + 2 files changed, 89 insertions(+), 6 deletions(-) + +diff --git a/src/net/http/internal/chunked.go b/src/net/http/internal/chunked.go +index f06e572..ddbaacb 100644 +--- a/src/net/http/internal/chunked.go ++++ b/src/net/http/internal/chunked.go +@@ -39,7 +39,8 @@ type chunkedReader struct { + n uint64 // unread bytes in chunk + err error + buf [2]byte +- checkEnd bool // whether need to check for \r\n chunk footer ++ checkEnd bool // whether need to check for \r\n chunk footer ++ excess int64 // "excessive" chunk overhead, for malicious sender detection + } + + func (cr *chunkedReader) beginChunk() { +@@ -49,10 +50,38 @@ func (cr *chunkedReader) beginChunk() { + if cr.err != nil { + return + } ++ cr.excess += int64(len(line)) + 2 // header, plus \r\n after the chunk data ++ line = trimTrailingWhitespace(line) ++ line, cr.err = removeChunkExtension(line) ++ if cr.err != nil { ++ return ++ } + cr.n, cr.err = parseHexUint(line) + if cr.err != nil { + return + } ++ // A sender who sends one byte per chunk will send 5 bytes of overhead ++ // for every byte of data. ("1\r\nX\r\n" to send "X".) ++ // We want to allow this, since streaming a byte at a time can be legitimate. ++ // ++ // A sender can use chunk extensions to add arbitrary amounts of additional ++ // data per byte read. ("1;very long extension\r\nX\r\n" to send "X".) ++ // We don't want to disallow extensions (although we discard them), ++ // but we also don't want to allow a sender to reduce the signal/noise ratio ++ // arbitrarily. ++ // ++ // We track the amount of excess overhead read, ++ // and produce an error if it grows too large. ++ // ++ // Currently, we say that we're willing to accept 16 bytes of overhead per chunk, ++ // plus twice the amount of real data in the chunk. ++ cr.excess -= 16 + (2 * int64(cr.n)) ++ if cr.excess < 0 { ++ cr.excess = 0 ++ } ++ if cr.excess > 16*1024 { ++ cr.err = errors.New("chunked encoding contains too much non-data") ++ } + if cr.n == 0 { + cr.err = io.EOF + } +@@ -133,11 +162,6 @@ func readChunkLine(b *bufio.Reader) ([]byte, error) { + if len(p) >= maxLineLength { + return nil, ErrLineTooLong + } +- p = trimTrailingWhitespace(p) +- p, err = removeChunkExtension(p) +- if err != nil { +- return nil, err +- } + return p, nil + } + +diff --git a/src/net/http/internal/chunked_test.go b/src/net/http/internal/chunked_test.go +index d067165..b20747d 100644 +--- a/src/net/http/internal/chunked_test.go ++++ b/src/net/http/internal/chunked_test.go +@@ -212,3 +212,62 @@ func TestChunkReadPartial(t *testing.T) { + } + + } ++ ++func TestChunkReaderTooMuchOverhead(t *testing.T) { ++ // If the sender is sending 100x as many chunk header bytes as chunk data, ++ // we should reject the stream at some point. ++ chunk := []byte("1;") ++ for i := 0; i < 100; i++ { ++ chunk = append(chunk, 'a') // chunk extension ++ } ++ chunk = append(chunk, "\r\nX\r\n"...) ++ const bodylen = 1 << 20 ++ r := NewChunkedReader(&funcReader{f: func(i int) ([]byte, error) { ++ if i < bodylen { ++ return chunk, nil ++ } ++ return []byte("0\r\n"), nil ++ }}) ++ _, err := io.ReadAll(r) ++ if err == nil { ++ t.Fatalf("successfully read body with excessive overhead; want error") ++ } ++} ++ ++func TestChunkReaderByteAtATime(t *testing.T) { ++ // Sending one byte per chunk should not trip the excess-overhead detection. ++ const bodylen = 1 << 20 ++ r := NewChunkedReader(&funcReader{f: func(i int) ([]byte, error) { ++ if i < bodylen { ++ return []byte("1\r\nX\r\n"), nil ++ } ++ return []byte("0\r\n"), nil ++ }}) ++ got, err := io.ReadAll(r) ++ if err != nil { ++ t.Errorf("unexpected error: %v", err) ++ } ++ if len(got) != bodylen { ++ t.Errorf("read %v bytes, want %v", len(got), bodylen) ++ } ++} ++ ++type funcReader struct { ++ f func(iteration int) ([]byte, error) ++ i int ++ b []byte ++ err error ++} ++ ++func (r *funcReader) Read(p []byte) (n int, err error) { ++ if len(r.b) == 0 && r.err == nil { ++ r.b, r.err = r.f(r.i) ++ r.i++ ++ } ++ n = copy(p, r.b) ++ r.b = r.b[n:] ++ if len(r.b) > 0 { ++ return n, nil ++ } ++ return n, r.err ++} +-- +2.25.1 + -- 2.34.1
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