diff options
Diffstat (limited to 'vendor/golang.org/x/crypto/openpgp/packet/reader.go')
-rw-r--r-- | vendor/golang.org/x/crypto/openpgp/packet/reader.go | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/vendor/golang.org/x/crypto/openpgp/packet/reader.go b/vendor/golang.org/x/crypto/openpgp/packet/reader.go new file mode 100644 index 0000000..34bc7c6 --- /dev/null +++ b/vendor/golang.org/x/crypto/openpgp/packet/reader.go | |||
@@ -0,0 +1,76 @@ | |||
1 | // Copyright 2011 The Go Authors. All rights reserved. | ||
2 | // Use of this source code is governed by a BSD-style | ||
3 | // license that can be found in the LICENSE file. | ||
4 | |||
5 | package packet | ||
6 | |||
7 | import ( | ||
8 | "golang.org/x/crypto/openpgp/errors" | ||
9 | "io" | ||
10 | ) | ||
11 | |||
12 | // Reader reads packets from an io.Reader and allows packets to be 'unread' so | ||
13 | // that they result from the next call to Next. | ||
14 | type Reader struct { | ||
15 | q []Packet | ||
16 | readers []io.Reader | ||
17 | } | ||
18 | |||
19 | // New io.Readers are pushed when a compressed or encrypted packet is processed | ||
20 | // and recursively treated as a new source of packets. However, a carefully | ||
21 | // crafted packet can trigger an infinite recursive sequence of packets. See | ||
22 | // http://mumble.net/~campbell/misc/pgp-quine | ||
23 | // https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2013-4402 | ||
24 | // This constant limits the number of recursive packets that may be pushed. | ||
25 | const maxReaders = 32 | ||
26 | |||
27 | // Next returns the most recently unread Packet, or reads another packet from | ||
28 | // the top-most io.Reader. Unknown packet types are skipped. | ||
29 | func (r *Reader) Next() (p Packet, err error) { | ||
30 | if len(r.q) > 0 { | ||
31 | p = r.q[len(r.q)-1] | ||
32 | r.q = r.q[:len(r.q)-1] | ||
33 | return | ||
34 | } | ||
35 | |||
36 | for len(r.readers) > 0 { | ||
37 | p, err = Read(r.readers[len(r.readers)-1]) | ||
38 | if err == nil { | ||
39 | return | ||
40 | } | ||
41 | if err == io.EOF { | ||
42 | r.readers = r.readers[:len(r.readers)-1] | ||
43 | continue | ||
44 | } | ||
45 | if _, ok := err.(errors.UnknownPacketTypeError); !ok { | ||
46 | return nil, err | ||
47 | } | ||
48 | } | ||
49 | |||
50 | return nil, io.EOF | ||
51 | } | ||
52 | |||
53 | // Push causes the Reader to start reading from a new io.Reader. When an EOF | ||
54 | // error is seen from the new io.Reader, it is popped and the Reader continues | ||
55 | // to read from the next most recent io.Reader. Push returns a StructuralError | ||
56 | // if pushing the reader would exceed the maximum recursion level, otherwise it | ||
57 | // returns nil. | ||
58 | func (r *Reader) Push(reader io.Reader) (err error) { | ||
59 | if len(r.readers) >= maxReaders { | ||
60 | return errors.StructuralError("too many layers of packets") | ||
61 | } | ||
62 | r.readers = append(r.readers, reader) | ||
63 | return nil | ||
64 | } | ||
65 | |||
66 | // Unread causes the given Packet to be returned from the next call to Next. | ||
67 | func (r *Reader) Unread(p Packet) { | ||
68 | r.q = append(r.q, p) | ||
69 | } | ||
70 | |||
71 | func NewReader(r io.Reader) *Reader { | ||
72 | return &Reader{ | ||
73 | q: nil, | ||
74 | readers: []io.Reader{r}, | ||
75 | } | ||
76 | } | ||