go1.19.6 (released 2023-02-14) includes security fixes to the crypto/tls,
mime/multipart, net/http, and path/filepath packages, as well as bug fixes to
the go command, the linker, the runtime, and the crypto/x509, net/http, and
time packages. See the Go 1.19.6 milestone on our issue tracker for details:
https://github.com/golang/go/issues?q=milestone%3AGo1.19.6+label%3ACherryPickApproved
From the announcement on the security mailing:
We have just released Go versions 1.20.1 and 1.19.6, minor point releases.
These minor releases include 4 security fixes following the security policy:
- path/filepath: path traversal in filepath.Clean on Windows
On Windows, the filepath.Clean function could transform an invalid path such
as a/../c:/b into the valid path c:\b. This transformation of a relative (if
invalid) path into an absolute path could enable a directory traversal attack.
The filepath.Clean function will now transform this path into the relative
(but still invalid) path .\c:\b.
This is CVE-2022-41722 and Go issue https://go.dev/issue/57274.
- net/http, mime/multipart: denial of service from excessive resource
consumption
Multipart form parsing with mime/multipart.Reader.ReadForm can consume largely
unlimited amounts of memory and disk files. This also affects form parsing in
the net/http package with the Request methods FormFile, FormValue,
ParseMultipartForm, and PostFormValue.
ReadForm takes a maxMemory parameter, and is documented as storing "up to
maxMemory bytes +10MB (reserved for non-file parts) in memory". File parts
which cannot be stored in memory are stored on disk in temporary files. The
unconfigurable 10MB reserved for non-file parts is excessively large and can
potentially open a denial of service vector on its own. However, ReadForm did
not properly account for all memory consumed by a parsed form, such as map
ntry overhead, part names, and MIME headers, permitting a maliciously crafted
form to consume well over 10MB. In addition, ReadForm contained no limit on
the number of disk files created, permitting a relatively small request body
to create a large number of disk temporary files.
ReadForm now properly accounts for various forms of memory overhead, and
should now stay within its documented limit of 10MB + maxMemory bytes of
memory consumption. Users should still be aware that this limit is high and
may still be hazardous.
ReadForm now creates at most one on-disk temporary file, combining multiple
form parts into a single temporary file. The mime/multipart.File interface
type's documentation states, "If stored on disk, the File's underlying
concrete type will be an *os.File.". This is no longer the case when a form
contains more than one file part, due to this coalescing of parts into a
single file. The previous behavior of using distinct files for each form part
may be reenabled with the environment variable
GODEBUG=multipartfiles=distinct.
Users should be aware that multipart.ReadForm and the http.Request methods
that call it do not limit the amount of disk consumed by temporary files.
Callers can limit the size of form data with http.MaxBytesReader.
This is CVE-2022-41725 and Go issue https://go.dev/issue/58006.
- crypto/tls: large handshake records may cause panics
Both clients and servers may send large TLS handshake records which cause
servers and clients, respectively, to panic when attempting to construct
responses.
This affects all TLS 1.3 clients, TLS 1.2 clients which explicitly enable
session resumption (by setting Config.ClientSessionCache to a non-nil value),
and TLS 1.3 servers which request client certificates (by setting
Config.ClientAuth
> = RequestClientCert).
This is CVE-2022-41724 and Go issue https://go.dev/issue/58001.
- net/http: avoid quadratic complexity in HPACK decoding
A maliciously crafted HTTP/2 stream could cause excessive CPU consumption
in the HPACK decoder, sufficient to cause a denial of service from a small
number of small requests.
This issue is also fixed in golang.org/x/net/http2 v0.7.0, for users manually
configuring HTTP/2.
This is CVE-2022-41723 and Go issue https://go.dev/issue/57855.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Includes security fixes for net/http (CVE-2022-41717, CVE-2022-41720),
and os (CVE-2022-41720).
These minor releases include 2 security fixes following the security policy:
- os, net/http: avoid escapes from os.DirFS and http.Dir on Windows
The os.DirFS function and http.Dir type provide access to a tree of files
rooted at a given directory. These functions permitted access to Windows
device files under that root. For example, os.DirFS("C:/tmp").Open("COM1")
would open the COM1 device.
Both os.DirFS and http.Dir only provide read-only filesystem access.
In addition, on Windows, an os.DirFS for the directory \(the root of the
current drive) can permit a maliciously crafted path to escape from the
drive and access any path on the system.
The behavior of os.DirFS("") has changed. Previously, an empty root was
treated equivalently to "/", so os.DirFS("").Open("tmp") would open the
path "/tmp". This now returns an error.
This is CVE-2022-41720 and Go issue https://go.dev/issue/56694.
- net/http: limit canonical header cache by bytes, not entries
An attacker can cause excessive memory growth in a Go server accepting
HTTP/2 requests.
HTTP/2 server connections contain a cache of HTTP header keys sent by
the client. While the total number of entries in this cache is capped,
an attacker sending very large keys can cause the server to allocate
approximately 64 MiB per open connection.
This issue is also fixed in golang.org/x/net/http2 vX.Y.Z, for users
manually configuring HTTP/2.
Thanks to Josselin Costanzi for reporting this issue.
This is CVE-2022-41717 and Go issue https://go.dev/issue/56350.
View the release notes for more information:
https://go.dev/doc/devel/release#go1.19.4
And the milestone on the issue tracker:
https://github.com/golang/go/issues?q=milestone%3AGo1.19.4+label%3ACherryPickApproved
Full diff: https://github.com/golang/go/compare/go1.19.3...go1.19.4
The golang.org/x/net fix is in 1e63c2f08a
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
On Windows, syscall.StartProcess and os/exec.Cmd did not properly
check for invalid environment variable values. A malicious
environment variable value could exploit this behavior to set a
value for a different environment variable. For example, the
environment variable string "A=B\x00C=D" set the variables "A=B" and
"C=D".
Thanks to RyotaK (https://twitter.com/ryotkak) for reporting this
issue.
This is CVE-2022-41716 and Go issue https://go.dev/issue/56284.
This Go release also fixes https://github.com/golang/go/issues/56309, a
runtime bug which can cause random memory corruption when a goroutine
exits with runtime.LockOSThread() set. This fix is necessary to unblock
work to replace certain uses of pkg/reexec with unshared OS threads.
Signed-off-by: Cory Snider <csnider@mirantis.com>
From the mailing list:
We have just released Go versions 1.19.2 and 1.18.7, minor point releases.
These minor releases include 3 security fixes following the security policy:
- archive/tar: unbounded memory consumption when reading headers
Reader.Read did not set a limit on the maximum size of file headers.
A maliciously crafted archive could cause Read to allocate unbounded
amounts of memory, potentially causing resource exhaustion or panics.
Reader.Read now limits the maximum size of header blocks to 1 MiB.
Thanks to Adam Korczynski (ADA Logics) and OSS-Fuzz for reporting this issue.
This is CVE-2022-2879 and Go issue https://go.dev/issue/54853.
- net/http/httputil: ReverseProxy should not forward unparseable query parameters
Requests forwarded by ReverseProxy included the raw query parameters from the
inbound request, including unparseable parameters rejected by net/http. This
could permit query parameter smuggling when a Go proxy forwards a parameter
with an unparseable value.
ReverseProxy will now sanitize the query parameters in the forwarded query
when the outbound request's Form field is set after the ReverseProxy.Director
function returns, indicating that the proxy has parsed the query parameters.
Proxies which do not parse query parameters continue to forward the original
query parameters unchanged.
Thanks to Gal Goldstein (Security Researcher, Oxeye) and
Daniel Abeles (Head of Research, Oxeye) for reporting this issue.
This is CVE-2022-2880 and Go issue https://go.dev/issue/54663.
- regexp/syntax: limit memory used by parsing regexps
The parsed regexp representation is linear in the size of the input,
but in some cases the constant factor can be as high as 40,000,
making relatively small regexps consume much larger amounts of memory.
Each regexp being parsed is now limited to a 256 MB memory footprint.
Regular expressions whose representation would use more space than that
are now rejected. Normal use of regular expressions is unaffected.
Thanks to Adam Korczynski (ADA Logics) and OSS-Fuzz for reporting this issue.
This is CVE-2022-41715 and Go issue https://go.dev/issue/55949.
View the release notes for more information: https://go.dev/doc/devel/release#go1.19.2
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
From the mailing list:
We have just released Go versions 1.19.1 and 1.18.6, minor point releases.
These minor releases include 2 security fixes following the security policy:
- net/http: handle server errors after sending GOAWAY
A closing HTTP/2 server connection could hang forever waiting for a clean
shutdown that was preempted by a subsequent fatal error. This failure mode
could be exploited to cause a denial of service.
Thanks to Bahruz Jabiyev, Tommaso Innocenti, Anthony Gavazzi, Steven Sprecher,
and Kaan Onarlioglu for reporting this.
This is CVE-2022-27664 and Go issue https://go.dev/issue/54658.
- net/url: JoinPath does not strip relative path components in all circumstances
JoinPath and URL.JoinPath would not remove `../` path components appended to a
relative path. For example, `JoinPath("https://go.dev", "../go")` returned the
URL `https://go.dev/../go`, despite the JoinPath documentation stating that
`../` path elements are cleaned from the result.
Thanks to q0jt for reporting this issue.
This is CVE-2022-32190 and Go issue https://go.dev/issue/54385.
Release notes:
go1.19.1 (released 2022-09-06) includes security fixes to the net/http and
net/url packages, as well as bug fixes to the compiler, the go command, the pprof
command, the linker, the runtime, and the crypto/tls and crypto/x509 packages.
See the Go 1.19.1 milestone on the issue tracker for details.
https://github.com/golang/go/issues?q=milestone%3AGo1.19.1+label%3ACherryPickApproved
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
From the mailing list:
We have just released Go versions 1.19.1 and 1.18.6, minor point releases.
These minor releases include 2 security fixes following the security policy:
- net/http: handle server errors after sending GOAWAY
A closing HTTP/2 server connection could hang forever waiting for a clean
shutdown that was preempted by a subsequent fatal error. This failure mode
could be exploited to cause a denial of service.
Thanks to Bahruz Jabiyev, Tommaso Innocenti, Anthony Gavazzi, Steven Sprecher,
and Kaan Onarlioglu for reporting this.
This is CVE-2022-27664 and Go issue https://go.dev/issue/54658.
- net/url: JoinPath does not strip relative path components in all circumstances
JoinPath and URL.JoinPath would not remove `../` path components appended to a
relative path. For example, `JoinPath("https://go.dev", "../go")` returned the
URL `https://go.dev/../go`, despite the JoinPath documentation stating that
`../` path elements are cleaned from the result.
Thanks to q0jt for reporting this issue.
This is CVE-2022-32190 and Go issue https://go.dev/issue/54385.
Release notes:
go1.18.6 (released 2022-09-06) includes security fixes to the net/http package,
as well as bug fixes to the compiler, the go command, the pprof command, the
runtime, and the crypto/tls, encoding/xml, and net packages. See the Go 1.18.6
milestone on the issue tracker for details;
https://github.com/golang/go/issues?q=milestone%3AGo1.18.6+label%3ACherryPickApproved
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Update Go runtime to 1.18.5 to address CVE-2022-32189.
Full diff: https://github.com/golang/go/compare/go1.18.4...go1.18.5
--------------------------------------------------------
From the security announcement:
https://groups.google.com/g/golang-announce/c/YqYYG87xB10
We have just released Go versions 1.18.5 and 1.17.13, minor point
releases.
These minor releases include 1 security fixes following the security
policy:
encoding/gob & math/big: decoding big.Float and big.Rat can panic
Decoding big.Float and big.Rat types can panic if the encoded message is
too short.
This is CVE-2022-32189 and Go issue https://go.dev/issue/53871.
View the release notes for more information:
https://go.dev/doc/devel/release#go1.18.5
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
go1.18.4 (released 2022-07-12) includes security fixes to the compress/gzip,
encoding/gob, encoding/xml, go/parser, io/fs, net/http, and path/filepath
packages, as well as bug fixes to the compiler, the go command, the linker,
the runtime, and the runtime/metrics package. See the Go 1.18.4 milestone on the
issue tracker for details:
https://github.com/golang/go/issues?q=milestone%3AGo1.18.4+label%3ACherryPickApproved
This update addresses:
CVE-2022-1705, CVE-2022-1962, CVE-2022-28131, CVE-2022-30630, CVE-2022-30631,
CVE-2022-30632, CVE-2022-30633, CVE-2022-30635, and CVE-2022-32148.
Full diff: https://github.com/golang/go/compare/go1.18.3...go1.18.4
From the security announcement;
https://groups.google.com/g/golang-announce/c/nqrv9fbR0zE
We have just released Go versions 1.18.4 and 1.17.12, minor point releases. These
minor releases include 9 security fixes following the security policy:
- net/http: improper sanitization of Transfer-Encoding header
The HTTP/1 client accepted some invalid Transfer-Encoding headers as indicating
a "chunked" encoding. This could potentially allow for request smuggling, but
only if combined with an intermediate server that also improperly failed to
reject the header as invalid.
This is CVE-2022-1705 and https://go.dev/issue/53188.
- When `httputil.ReverseProxy.ServeHTTP` was called with a `Request.Header` map
containing a nil value for the X-Forwarded-For header, ReverseProxy would set
the client IP as the value of the X-Forwarded-For header, contrary to its
documentation. In the more usual case where a Director function set the
X-Forwarded-For header value to nil, ReverseProxy would leave the header
unmodified as expected.
This is https://go.dev/issue/53423 and CVE-2022-32148.
Thanks to Christian Mehlmauer for reporting this issue.
- compress/gzip: stack exhaustion in Reader.Read
Calling Reader.Read on an archive containing a large number of concatenated
0-length compressed files can cause a panic due to stack exhaustion.
This is CVE-2022-30631 and Go issue https://go.dev/issue/53168.
- encoding/xml: stack exhaustion in Unmarshal
Calling Unmarshal on a XML document into a Go struct which has a nested field
that uses the any field tag can cause a panic due to stack exhaustion.
This is CVE-2022-30633 and Go issue https://go.dev/issue/53611.
- encoding/xml: stack exhaustion in Decoder.Skip
Calling Decoder.Skip when parsing a deeply nested XML document can cause a
panic due to stack exhaustion. The Go Security team discovered this issue, and
it was independently reported by Juho Nurminen of Mattermost.
This is CVE-2022-28131 and Go issue https://go.dev/issue/53614.
- encoding/gob: stack exhaustion in Decoder.Decode
Calling Decoder.Decode on a message which contains deeply nested structures
can cause a panic due to stack exhaustion.
This is CVE-2022-30635 and Go issue https://go.dev/issue/53615.
- path/filepath: stack exhaustion in Glob
Calling Glob on a path which contains a large number of path separators can
cause a panic due to stack exhaustion.
Thanks to Juho Nurminen of Mattermost for reporting this issue.
This is CVE-2022-30632 and Go issue https://go.dev/issue/53416.
- io/fs: stack exhaustion in Glob
Calling Glob on a path which contains a large number of path separators can
cause a panic due to stack exhaustion.
This is CVE-2022-30630 and Go issue https://go.dev/issue/53415.
- go/parser: stack exhaustion in all Parse* functions
Calling any of the Parse functions on Go source code which contains deeply
nested types or declarations can cause a panic due to stack exhaustion.
Thanks to Juho Nurminen of Mattermost for reporting this issue.
This is CVE-2022-1962 and Go issue https://go.dev/issue/53616.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
go1.18.3 (released 2022-06-01) includes security fixes to the crypto/rand,
crypto/tls, os/exec, and path/filepath packages, as well as bug fixes to the
compiler, and the crypto/tls and text/template/parse packages. See the Go
1.18.3 milestone on our issue tracker for details:
https://github.com/golang/go/issues?q=milestone%3AGo1.18.3+label%3ACherryPickApproved
Hello gophers,
We have just released Go versions 1.18.3 and 1.17.11, minor point releases.
These minor releases include 4 security fixes following the security policy:
- crypto/rand: rand.Read hangs with extremely large buffers
On Windows, rand.Read will hang indefinitely if passed a buffer larger than
1 << 32 - 1 bytes.
Thanks to Davis Goodin and Quim Muntal, working at Microsoft on the Go toolset,
for reporting this issue.
This is [CVE-2022-30634][CVE-2022-30634] and Go issue https://go.dev/issue/52561.
- crypto/tls: session tickets lack random ticket_age_add
Session tickets generated by crypto/tls did not contain a randomly generated
ticket_age_add. This allows an attacker that can observe TLS handshakes to
correlate successive connections by comparing ticket ages during session
resumption.
Thanks to GitHub user nervuri for reporting this.
This is [CVE-2022-30629][CVE-2022-30629] and Go issue https://go.dev/issue/52814.
- `os/exec`: empty `Cmd.Path` can result in running unintended binary on Windows
If, on Windows, `Cmd.Run`, `cmd.Start`, `cmd.Output`, or `cmd.CombinedOutput`
are executed when Cmd.Path is unset and, in the working directory, there are
binaries named either "..com" or "..exe", they will be executed.
Thanks to Chris Darroch, brian m. carlson, and Mikhail Shcherbakov for reporting
this.
This is [CVE-2022-30580][CVE-2022-30580] and Go issue https://go.dev/issue/52574.
- `path/filepath`: Clean(`.\c:`) returns `c:` on Windows
On Windows, the `filepath.Clean` function could convert an invalid path to a
valid, absolute path. For example, Clean(`.\c:`) returned `c:`.
Thanks to Unrud for reporting this issue.
This is [CVE-2022-29804][CVE-2022-29804] and Go issue https://go.dev/issue/52476.
[CVE-2022-30634]: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-30634
[CVE-2022-30629]: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-30629
[CVE-2022-30580]: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-30580
[CVE-2022-29804]: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-29804
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Includes security fixes for crypto/elliptic (CVE-2022-23806), math/big (CVE-2022-23772),
and cmd/go (CVE-2022-23773).
go1.17.7 (released 2022-02-10) includes security fixes to the crypto/elliptic,
math/big packages and to the go command, as well as bug fixes to the compiler,
linker, runtime, the go command, and the debug/macho, debug/pe, and net/http/httptest
packages. See the Go 1.17.7 milestone on our issue tracker for details:
https://github.com/golang/go/issues?q=milestone%3AGo1.17.7+label%3ACherryPickApproved
full diff: https://github.com/golang/go/compare/go1.17.6...go1.17.7
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
go1.17.3 (released 2021-11-04) includes security fixes to the archive/zip and
debug/macho packages, as well as bug fixes to the compiler, linker, runtime, the
go command, the misc/wasm directory, and to the net/http and syscall packages.
See the Go 1.17.3 milestone on our issue tracker for details.
From the announcement e-mail:
[security] Go 1.17.3 and Go 1.16.10 are released
We have just released Go versions 1.17.3 and 1.16.10, minor point releases.
These minor releases include two security fixes following the security policy:
- archive/zip: don't panic on (*Reader).Open
Reader.Open (the API implementing io/fs.FS introduced in Go 1.16) can be made
to panic by an attacker providing either a crafted ZIP archive containing
completely invalid names or an empty filename argument.
Thank you to Colin Arnott, SiteHost and Noah Santschi-Cooney, Sourcegraph Code
Intelligence Team for reporting this issue. This is CVE-2021-41772 and Go issue
golang.org/issue/48085.
- debug/macho: invalid dynamic symbol table command can cause panic
Malformed binaries parsed using Open or OpenFat can cause a panic when calling
ImportedSymbols, due to an out-of-bounds slice operation.
Thanks to Burak Çarıkçı - Yunus Yıldırım (CT-Zer0 Crypttech) for reporting this
issue. This is CVE-2021-41771 and Go issue golang.org/issue/48990.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
go1.17.2 (released 2021-10-07) includes a security fix to the linker and misc/wasm
directory, as well as bug fixes to the compiler, the runtime, the go command, and
to the time and text/template packages. See the Go 1.17.2 milestone on our issue
tracker for details:
https://github.com/golang/go/issues?q=milestone%3AGo1.17.2+label%3ACherryPickApproved
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This includes additional fixes for CVE-2021-39293.
go1.17.1 (released 2021-09-09) includes a security fix to the archive/zip package,
as well as bug fixes to the compiler, linker, the go command, and to the crypto/rand,
embed, go/types, html/template, and net/http packages. See the Go 1.17.1 milestone
on the issue tracker for details:
https://github.com/golang/go/issues?q=milestone%3AGo1.17.1+label%3ACherryPickApproved
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
go1.16.7 (released 2021-08-05) includes a security fix to the net/http/httputil
package, as well as bug fixes to the compiler, the linker, the runtime, the go
command, and the net/http package. See the Go 1.16.7 milestone on the issue
tracker for details:
https://github.com/golang/go/issues?q=milestone%3AGo1.16.7+label%3ACherryPickApproved
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Use the image build from Dockerfile.simple to build docker binary failed
with not find <brtfs/ioctl.h>, we need to install libbtrfs-dev to fix this.
```
Building: bundles/dynbinary-daemon/dockerd-dev
GOOS="" GOARCH="" GOARM=""
.gopath/src/github.com/docker/docker/daemon/graphdriver/btrfs/btrfs.go:8:10: fatal error: btrfs/ioctl.h: No such file or directory
#include <btrfs/ioctl.h>
```
Signed-off-by: Lei Jitang <leijitang@outlook.com>
Commit 4e3ab9e9fb switched the
main Dockerfile to the "buster" variant, but did not update
some of the other Dockerfiles.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
full diff: https://github.com/golang/go/compare/go1.13.6...go1.13.7
go1.13.7 (released 2020/01/28) includes two security fixes. One mitigates
the CVE-2020-0601 certificate verification bypass on Windows. The other affects
only 32-bit architectures.
https://github.com/golang/go/issues?q=milestone%3AGo1.13.7+label%3ACherryPickApproved
- X.509 certificate validation bypass on Windows 10
A Windows vulnerability allows attackers to spoof valid certificate chains when
the system root store is in use. These releases include a mitigation for Go
applications, but it’s strongly recommended that affected users install the
Windows security update to protect their system.
This issue is CVE-2020-0601 and Go issue golang.org/issue/36834.
- Panic in crypto/x509 certificate parsing and golang.org/x/crypto/cryptobyte
On 32-bit architectures, a malformed input to crypto/x509 or the ASN.1 parsing
functions of golang.org/x/crypto/cryptobyte can lead to a panic.
The malformed certificate can be delivered via a crypto/tls connection to a
client, or to a server that accepts client certificates. net/http clients can
be made to crash by an HTTPS server, while net/http servers that accept client
certificates will recover the panic and are unaffected.
Thanks to Project Wycheproof for providing the test cases that led to the
discovery of this issue. The issue is CVE-2020-7919 and Go issue golang.org/issue/36837.
This is also fixed in version v0.0.0-20200124225646-8b5121be2f68 of golang.org/x/crypto/cryptobyte.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
full diff: https://github.com/golang/go/compare/go1.13...go1.13.1
```
Hi gophers,
We have just released Go 1.13.1 and Go 1.12.10 to address a recently reported security issue. We recommend that all affected users update to one of these releases (if you're not sure which, choose Go 1.13.1).
net/http (through net/textproto) used to accept and normalize invalid HTTP/1.1 headers with a space before the colon, in violation of RFC 7230. If a Go server is used behind an uncommon reverse proxy that accepts and forwards but doesn't normalize such invalid headers, the reverse proxy and the server can interpret the headers differently. This can lead to filter bypasses or request smuggling, the latter if requests from separate clients are multiplexed onto the same upstream connection by the proxy. Such invalid headers are now rejected by Go servers, and passed without normalization to Go client applications.
The issue is CVE-2019-16276 and Go issue golang.org/issue/34540.
Thanks to Andrew Stucki, Adam Scarr (99designs.com), and Jan Masarik (masarik.sh) for discovering and reporting this issue.
Downloads are available at https://golang.org/dl for all supported platforms.
Alla prossima,
Filippo on behalf of the Go team
```
From the patch: 6e6f4aaf70
```
net/textproto: don't normalize headers with spaces before the colon
RFC 7230 is clear about headers with a space before the colon, like
X-Answer : 42
being invalid, but we've been accepting and normalizing them for compatibility
purposes since CL 5690059 in 2012.
On the client side, this is harmless and indeed most browsers behave the same
to this day. On the server side, this becomes a security issue when the
behavior doesn't match that of a reverse proxy sitting in front of the server.
For example, if a WAF accepts them without normalizing them, it might be
possible to bypass its filters, because the Go server would interpret the
header differently. Worse, if the reverse proxy coalesces requests onto a
single HTTP/1.1 connection to a Go server, the understanding of the request
boundaries can get out of sync between them, allowing an attacker to tack an
arbitrary method and path onto a request by other clients, including
authentication headers unknown to the attacker.
This was recently presented at multiple security conferences:
https://portswigger.net/blog/http-desync-attacks-request-smuggling-reborn
net/http servers already reject header keys with invalid characters.
Simply stop normalizing extra spaces in net/textproto, let it return them
unchanged like it does for other invalid headers, and let net/http enforce
RFC 7230, which is HTTP specific. This loses us normalization on the client
side, but there's no right answer on the client side anyway, and hiding the
issue sounds worse than letting the application decide.
```
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
