The Go implementation of gzip is the only known to produce compressed
layers with the expected digest hashes.
This change allows compressed tar layer files to be produced, which is
useful for exporting layers from non-Go tools.
Now when golang 1.11 is out, 1.9 and older versions are no longer
supported. More to say, since the archive/tar is from go-1.11, it
uses some features from new Go versions (strings.Builder and sync.Map)
not supported by anything older than Go 1.10.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This is a port of commits adding RawHeader() to go-1.11 archive/tar.
In addition:
* simplify the rawBytes.Write() code in readHeader()
* ignore errors from rawBytes.Write(), as (at least for go-1.11)
it never returns an error, only panics (if the buffer grew too large)
Also, remove the internal/testenv from tar_tar.go to enable go test.
As working symlink detection is non-trivial on Windows, just skip
the test on that platform.
In addition to `go test`, I did some minimal manual testing, and
it seems this code creates tar-data.json.gz which is identical
to the one made by the old version.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
To ensure we don't have regressions in our padding fix, add a test case
that attempts to crash the test by creating 20GB of random junk padding.
Signed-off-by: Aleksa Sarai <asarai@suse.de>
Previously, we would read the entire padding in a given archive into
memory in order to store it in the packer. This would cause memory
exhaustion if a malicious archive was crafted with very large amounts of
padding. Since a given SegmentType is reconstructed losslessly, we can
simply chunk up any padding into large segments to avoid this problem.
Use a reasonable default of 1MiB to avoid changing the tar-split.json of
existing archives that are not malformed.
Fixes: CVE-2017-14992
Signed-off-by: Aleksa Sarai <asarai@suse.de>
This fixes a new go-vet(1) error which has surfaced in Go HEAD.
$ go vet ./...
go build github.com/vbatts/tar-split: no non-test Go files in
/home/travis/gopath/src/github.com/vbatts/tar-split
Signed-off-by: Aleksa Sarai <asarai@suse.de>
Since this project has forked logic of upstream 'archive/tar', this does
a brief comparison including the RawBytes usage.
```bash
$ go test -run="XXX" -bench=.
testing: warning: no tests to run
BenchmarkUpstreamTar-4 2000 700809 ns/op
BenchmarkOurTarNoAccounting-4 2000 692055 ns/op
BenchmarkOurTarYesAccounting-4 2000 723184 ns/op
PASS
ok vb/tar-split 4.461s
```
From this, the difference is negligible.
Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>
This is not saying that tar-split no longer works on go1.3 or go1.4, but
rather that the headache of `go vet` having a version dependent ability
to install it, makes it a headache in travis.
Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>
Commit dd5e14a7511465d20c6e95bf54c9b8f999abbbf6 ensured that no data
could be read for header-only files regardless of what the Header.Size
said. We should document this fact in Reader.Read.
Updates #13647
Change-Id: I4df9a2892bc66b49e0279693d08454bf696cfa31
Reviewed-on: https://go-review.googlesource.com/17913
Reviewed-by: Russ Cox <rsc@golang.org>
Motivation:
* Previous implementation did not detect integer overflow when
parsing a base-256 encoded field.
* Previous implementation did not treat the integer as a two's
complement value as specified by GNU.
The relevant GNU specification says:
<<<
GNU format uses two's-complement base-256 notation to store values
that do not fit into standard ustar range.
>>>
Fixes#12435
Change-Id: I4639bcffac8d12e1cb040b76bd05c9d7bc6c23a8
Reviewed-on: https://go-review.googlesource.com/17424
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Motivation:
* Previous implementation silently failed when an integer overflow
occurred. Now, we report an ErrFieldTooLong.
* Previous implementation did not encode in two's complement format and was
unable to encode negative numbers.
The relevant GNU specification says:
<<<
GNU format uses two's-complement base-256 notation to store values
that do not fit into standard ustar range.
>>>
Fixes#12436
Change-Id: I09c20602eabf8ae3a7e0db35b79440a64bfaf807
Reviewed-on: https://go-review.googlesource.com/17425
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Motivation for change:
* Recursive logic is hard to follow, since it tends to apply
things in reverse. On the other hand, the tar formats tend to
describe meta headers as affecting the next entry.
* Recursion also applies changes in the wrong order. Two test
files are attached that use multiple headers. The previous Go
behavior differs from what GNU and BSD tar do.
Change-Id: Ic1557256fc1363c5cb26570e5d0b9f65a9e57341
Reviewed-on: https://go-review.googlesource.com/14624
Run-TryBot: Joe Tsai <joetsai@digital-static.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Motivations for this change:
* It allows these functions to be used outside of Reader/Writer.
* It allows these functions to be more easily unit tested.
Change-Id: Iebe2b70bdb8744371c9ffa87c24316cbbf025b59
Reviewed-on: https://go-review.googlesource.com/15113
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Joe Tsai <joetsai@digital-static.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Motivations:
* Use of strconv.ParseInt does not properly treat integers as 64bit,
preventing this function from working properly on 32bit machines.
* Use of io.ReadFull does not properly detect truncated streams
when the file suddenly ends on a block boundary.
* The function blindly trusts user input for numEntries and allocates
memory accordingly.
* The function does not validate that numEntries is not negative,
allowing a malicious sparse file to cause a panic during make.
In general, this function was overly complicated for what it was
accomplishing and it was hard to reason that it was free from
bounds errors. Instead, it has been rewritten and relies on
bytes.Buffer.ReadString to do the main work. So long as invariants
about the number of '\n' in the buffer are maintained, it is much
easier to see why this approach is correct.
Change-Id: Ibb12c4126c26e0ea460ea063cd17af68e3cf609e
Reviewed-on: https://go-review.googlesource.com/15174
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Certain special type-flags, specifically 1, 2, 3, 4, 5, 6,
do not have a data section. Thus, regardless of what the size field
says, we should not attempt to read any data for these special types.
The relevant PAX and USTAR specification says:
<<<
If the typeflag field is set to specify a file to be of type 1 (a link)
or 2 (a symbolic link), the size field shall be specified as zero.
If the typeflag field is set to specify a file of type 5 (directory),
the size field shall be interpreted as described under the definition
of that record type. No data logical records are stored for types 1, 2, or 5.
If the typeflag field is set to 3 (character special file),
4 (block special file), or 6 (FIFO), the meaning of the size field is
unspecified by this volume of POSIX.1-2008, and no data logical records shall
be stored on the medium.
Additionally, for type 6, the size field shall be ignored when reading.
If the typeflag field is set to any other value, the number of logical
records written following the header shall be (size+511)/512, ignoring
any fraction in the result of the division.
>>>
Contrary to the specification, we do not assert that the size field
is zero for type 1 and 2 since we liberally accept non-conforming formats.
Change-Id: I666b601597cb9d7a50caa081813d90ca9cfc52ed
Reviewed-on: https://go-review.googlesource.com/16614
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Replaces PID in PaxHeaders with 0. Sorts PAX header keys before writing
them to the archive.
Fixes#12358
Change-Id: If239f89c85f1c9d9895a253fb06a47ad44960124
Reviewed-on: https://go-review.googlesource.com/13975
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Joe Tsai <joetsai@digital-static.net>
Motivation:
* Reader.skipUnread never reports io.ErrUnexpectedEOF. This is strange
given that io.ErrUnexpectedEOF is given through Reader.Read if the
user manually reads the file.
* Reader.skipUnread fails to detect truncated files since io.Seeker
is lazy about reporting errors. Thus, the behavior of Reader differs
whether the input io.Reader also satisfies io.Seeker or not.
To solve this, we seek to one before the end of the data section and
always rely on at least one call to io.CopyN. If the tr.r satisfies
io.Seeker, this is guarunteed to never read more than blockSize.
Fixes#12557
Change-Id: I0ddddfc6bed0d74465cb7e7a02b26f1de7a7a279
Reviewed-on: https://go-review.googlesource.com/15175
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Motivation:
* The logic to verify the numEntries can overflow and incorrectly
pass, allowing a malicious file to allocate arbitrary memory.
* The use of strconv.ParseInt does not set the integer precision
to 64bit, causing this code to work incorrectly on 32bit machines.
Change-Id: I1b1571a750a84f2dde97cc329ed04fe2342aaa60
Reviewed-on: https://go-review.googlesource.com/15173
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
A recursive call to Reader.Next did not check the error before
trying to use the result, leading to a nil pointer panic.
This specific CL addresses the immediate issue, which is the panic,
but does not solve the root issue, which is due to an integer
overflow in the base-256 parser.
Updates #12435
Change-Id: Ia908671f0f411a409a35e24f2ebf740d46734072
Reviewed-on: https://go-review.googlesource.com/15437
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
