A new attack on CBC padding in SSLv3 was released yesterday[1]. Go only
supports SSLv3 as a server, not as a client. An easy fix is to change
the default minimum version to TLS 1.0 but that seems a little much
this late in the 1.4 process as it may break some things.
Thus this patch adds server support for TLS_FALLBACK_SCSV[2] -- a
mechanism for solving the fallback problem overall. Chrome has
implemented this since February and Google has urged others to do so in
light of yesterday's news.
With this change, clients can indicate that they are doing a fallback
connection and Go servers will be able to correctly reject them.
[1] http://googleonlinesecurity.blogspot.com/2014/10/this-poodle-bites-exploiting-ssl-30.html
[2] https://tools.ietf.org/html/draft-ietf-tls-downgrade-scsv-00
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/157090043
Among other things, *x = T{} does not need a write barrier.
The changes here avoid an unnecessary copy even when
no pointers are involved, so it may have larger effects.
In 6g and 8g, avoid manually repeated STOSQ in favor of
writing explicit MOVs, under the theory that the MOVs
should have fewer dependencies and pipeline better.
Benchmarks compare best of 5 on a 2012 MacBook Pro Core i5
with TurboBoost disabled. Most improvements can be explained
by the changes in this CL.
The effect in Revcomp is real but harder to explain: none of
the instructions in the inner loop changed. I suspect loop
alignment but really have no idea.
benchmark old new delta
BenchmarkBinaryTree17 3809027371 3819907076 +0.29%
BenchmarkFannkuch11 3607547556 3686983012 +2.20%
BenchmarkFmtFprintfEmpty 118 103 -12.71%
BenchmarkFmtFprintfString 289 277 -4.15%
BenchmarkFmtFprintfInt 304 290 -4.61%
BenchmarkFmtFprintfIntInt 507 458 -9.66%
BenchmarkFmtFprintfPrefixedInt 425 408 -4.00%
BenchmarkFmtFprintfFloat 555 555 +0.00%
BenchmarkFmtManyArgs 1835 1733 -5.56%
BenchmarkGobDecode 14738209 14639331 -0.67%
BenchmarkGobEncode 14239039 13703571 -3.76%
BenchmarkGzip 538211054 538701315 +0.09%
BenchmarkGunzip 135430877 134818459 -0.45%
BenchmarkHTTPClientServer 116488 116618 +0.11%
BenchmarkJSONEncode 28923406 29294334 +1.28%
BenchmarkJSONDecode 105779820 104289543 -1.41%
BenchmarkMandelbrot200 5791758 5771964 -0.34%
BenchmarkGoParse 5376642 5310943 -1.22%
BenchmarkRegexpMatchEasy0_32 195 190 -2.56%
BenchmarkRegexpMatchEasy0_1K 477 455 -4.61%
BenchmarkRegexpMatchEasy1_32 170 165 -2.94%
BenchmarkRegexpMatchEasy1_1K 1410 1394 -1.13%
BenchmarkRegexpMatchMedium_32 336 329 -2.08%
BenchmarkRegexpMatchMedium_1K 108979 106328 -2.43%
BenchmarkRegexpMatchHard_32 5854 5821 -0.56%
BenchmarkRegexpMatchHard_1K 185089 182838 -1.22%
BenchmarkRevcomp 834920364 780202624 -6.55%
BenchmarkTemplate 137046937 129728756 -5.34%
BenchmarkTimeParse 600 594 -1.00%
BenchmarkTimeFormat 559 539 -3.58%
LGTM=r
R=r
CC=golang-codereviews, iant, khr, rlh
https://golang.org/cl/157910047
A Go prototype can be used instead now, and the compiler
will do a better job than we will doing it by hand.
(We got it wrong in amd64p32, causing the current build
breakage.)
The auto-prototype-matching only applies to functions
without an explicit package path, so the TEXT lines for
reflectcall and callXX are s/runtime·/·/.
LGTM=khr
R=khr
CC=golang-codereviews, iant, r
https://golang.org/cl/153600043
The http package by default adds "Accept-Encoding: gzip" to outgoing
requests, unless it's a bad idea, or the user requested otherwise.
Only when the http package adds its own implicit Accept-Encoding header
does the http package also transparently un-gzip the response.
If the user requested part of a document (e.g. bytes 40 to 50), it appears
that Github/Varnish send:
range(gzip(content), 40, 50)
And not:
gzip(range(content, 40, 50))
The RFC 2616 set of replacements (with the purpose of
clarifying ambiguities since 1999) has an RFC about Range
requests (http://tools.ietf.org/html/rfc7233) but does not
mention the interaction with encodings.
Regardless of whether range(gzip(content)) or gzip(range(content)) is
correct, this change prevents the Go package from asking for gzip
in requests if we're also asking for Range, avoiding the issue.
If the user cared, they can do it themselves. But Go transparently
un-gzipping a fragment of gzip is never useful.
Fixes#8923
LGTM=adg
R=adg
CC=golang-codereviews
https://golang.org/cl/155420044
The assembler could give a better error, but this one
is good enough for now.
Fixes#8880.
LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/153610043
When the Import function in go/build encounters a directory
without any buildable Go source files, it returns a handy
NoGoError. Now if, instead it encounters multiple Go source files
from multiple packages, it returns a handy MultiplePackageError.
A new test for NoGoError and MultiplePackageError is also provided.
Fixes#8286.
LGTM=adg, rsc
R=bradfitz, rsc, adg
CC=golang-codereviews
https://golang.org/cl/155050043
The racewalk code was not updated for the new write barriers.
Make it more future-proof.
The new write barrier code assumed that +1 pointer would
be aligned properly for any type that might follow, but that's
not true on 32-bit systems where some types are 64-bit aligned.
The only system like that today is nacl/amd64p32.
Insert a dummy pointer so that the ambiguously typed
value is at +2 pointers, which is always max-aligned.
LGTM=r
R=r
CC=golang-codereviews, iant, khr
https://golang.org/cl/158890046
FieldByIndex never returns an invalid Value, so the validity
test can be avoided if the field is not indirect.
BenchmarkGobEncode 12768642 12424022 -2.70%
BenchmarkGobEncode 60.11 61.78 1.03x
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/158890045
includes undo of 22318cd31d7d and also:
- always use SetUnhandledExceptionFilter on windows-386;
- crash when receive EXCEPTION_BREAKPOINT in exception handler.
Fixes#8006.
LGTM=rsc
R=golang-codereviews, rsc
CC=golang-codereviews
https://golang.org/cl/155360043
The inverse is defined whenever the element and the
modulus are relatively prime. The code already handles
this situation, but the spec does not.
Test that it does indeed work.
Fixes#8875
LGTM=agl
R=agl
CC=golang-codereviews
https://golang.org/cl/155010043
Assignments of 2-, 3-, and 4-word values were handled
by individual MOV instructions (and for scalars still are).
But if there are pointers involved, those assignments now
go through the write barrier routine. Before this CL, they
went to writebarrierfat, which calls memmove.
Memmove is too much overhead for these small
amounts of data.
Instead, call writebarrierfat{2,3,4}, which are specialized
for the specific amount of data being copied.
Today the write barrier does not care which words are
pointers, so size alone is enough to distinguish the cases.
If we keep these distinctions in Go 1.5 we will need to
expand them for all the pointer-vs-scalar possibilities,
so the current 3 functions will become 3+7+15 = 25,
still not a large burden (we deleted more morestack
functions than that when we dropped segmented stacks).
BenchmarkBinaryTree17 3250972583 3123910344 -3.91%
BenchmarkFannkuch11 3067605223 2964737839 -3.35%
BenchmarkFmtFprintfEmpty 101 96.0 -4.95%
BenchmarkFmtFprintfString 267 235 -11.99%
BenchmarkFmtFprintfInt 261 253 -3.07%
BenchmarkFmtFprintfIntInt 444 402 -9.46%
BenchmarkFmtFprintfPrefixedInt 374 346 -7.49%
BenchmarkFmtFprintfFloat 472 449 -4.87%
BenchmarkFmtManyArgs 1537 1476 -3.97%
BenchmarkGobDecode 13986528 12432985 -11.11%
BenchmarkGobEncode 13120323 12537420 -4.44%
BenchmarkGzip 451925758 437500578 -3.19%
BenchmarkGunzip 113267612 110053644 -2.84%
BenchmarkHTTPClientServer 103151 77100 -25.26%
BenchmarkJSONEncode 25002733 23435278 -6.27%
BenchmarkJSONDecode 94213717 82568789 -12.36%
BenchmarkMandelbrot200 4804246 4713070 -1.90%
BenchmarkGoParse 4646114 4379456 -5.74%
BenchmarkRegexpMatchEasy0_32 163 158 -3.07%
BenchmarkRegexpMatchEasy0_1K 433 391 -9.70%
BenchmarkRegexpMatchEasy1_32 154 138 -10.39%
BenchmarkRegexpMatchEasy1_1K 1481 1132 -23.57%
BenchmarkRegexpMatchMedium_32 282 270 -4.26%
BenchmarkRegexpMatchMedium_1K 92421 86149 -6.79%
BenchmarkRegexpMatchHard_32 5209 4718 -9.43%
BenchmarkRegexpMatchHard_1K 158141 147921 -6.46%
BenchmarkRevcomp 699818791 642222464 -8.23%
BenchmarkTemplate 132402383 108269713 -18.23%
BenchmarkTimeParse 509 478 -6.09%
BenchmarkTimeFormat 462 456 -1.30%
LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/156200043
In [1] the behaviour of encoding/asn1 with respect to marshaling
optional integers was changed. Previously, a zero valued integer would
be omitted when marshaling. After the change, if a default value was
set then the integer would only be omitted if it was the default value.
This changed the behaviour of crypto/x509 because
Certificate.MaxPathLen has a default value of -1 and thus zero valued
MaxPathLens would no longer be omitted when marshaling. This is
arguably a bug-fix -- a value of zero for MaxPathLen is valid and
meaningful and now could be expressed. However it broke users
(including Docker) who were not setting MaxPathLen at all.
This change again causes a zero-valued MaxPathLen to be omitted and
introduces a ZeroMathPathLen member that indicates that, yes, one
really does want a zero. This is ugly, but we value not breaking users.
[1] https://code.google.com/p/go/source/detail?r=4218b3544610e8d9771b89126553177e32687adf
LGTM=rsc
R=rsc
CC=golang-codereviews, golang-dev
https://golang.org/cl/153420045
This error is returned by lib9p when removing a file
without parent. It should fix TestRemoveAllRace
when running on ramfs.
LGTM=bradfitz, aram
R=rsc, bradfitz, aram
CC=golang-codereviews, mischief
https://golang.org/cl/153410044
The code for a generated type is already generating an
unrolled GC bitmask. Rather than unrolling the the source
type bitmasks and copying them, just generate the required
bitmask directly. Don't mark it as an unrolled GC program,
since there is no need to do so.
Fixes#8917.
LGTM=rsc
R=dvyukov, rsc
CC=golang-codereviews
https://golang.org/cl/156930044
Our current pe object reader assumes that every symbol starting with
'.' is section. It appeared to be true, until now gcc 4.9.1 generates
some symbols with '.' at the front. Change that logic to check other
symbol fields in addition to checking for '.'. I am not an expert
here, but it seems reasonable to me.
Added test, but it is only good, if tested with gcc 4.9.1. Otherwise
the test PASSes regardless.
Fixes#8811.
Fixes#8856.
LGTM=jfrederich, iant, stephen.gutekanst
R=golang-codereviews, jfrederich, stephen.gutekanst, iant
CC=alex.brainman, golang-codereviews
https://golang.org/cl/152410043
gcc 4.9.1 generates pe sections with names longer then 8 charters.
From IMAGE_SECTION_HEADER definition:
Name
An 8-byte, null-padded UTF-8 string. There is no terminating null character
if the string is exactly eight characters long. For longer names, this
member contains a forward slash (/) followed by an ASCII representation
of a decimal number that is an offset into the string table.
Our current pe object file reader does not read string table when section
names starts with /. Do that, so (issue 8811 example)
c:\go\path\src\isssue8811>go build
# isssue8811
isssue8811/glfw(.text): isssue8811/glfw(/76): not defined
isssue8811/glfw(.text): undefined: isssue8811/glfw(/76)
becomes
c:\go\path\src\isssue8811>go build
# isssue8811
isssue8811/glfw(.text): isssue8811/glfw(.rdata$.refptr._glfwInitialized): not defined
isssue8811/glfw(.text): undefined: isssue8811/glfw(.rdata$.refptr._glfwInitialized)
Small progress to
Update #8811
LGTM=iant, jfrederich
R=golang-codereviews, iant, jfrederich
CC=golang-codereviews
https://golang.org/cl/154210044
I diffed the output of `nm -n gofmt' before and after this change,
and verified that all changes are correct and all corrupted symbol
names are fixed.
Fixes#8906.
LGTM=iant, cookieo9
R=golang-codereviews, iant, cookieo9
CC=golang-codereviews
https://golang.org/cl/159750043
https://golang.org/cl/153770043/ tried to fix the case where a
implicitly tagged Time, that happened to have the same tag as
GENERALIZEDTIME, shouldn't be parsed as a GENERALIZEDTIME.
It did so, mistakenly, by testing whether params.tag != nil. But
explicitly tagged values also have a non-nil tag and there the inner
tag actually does encode the type of the value.
This change instead tests whether the tag class is UNIVERSAL before
assuming that the tag contains type information.
LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/152380044
That was complete failure - builders are broken,
but original cl worked fine on my system.
I will need access to builders
to test this change properly.
««« original CL description
runtime: handle all windows exception
Fixes#8006.
LGTM=rsc
R=golang-codereviews, rsc
CC=golang-codereviews
https://golang.org/cl/145150043
»»»
TBR=rsc
R=golang-codereviews
CC=golang-codereviews
https://golang.org/cl/154180043
In channels, zeroing of gp.waiting is missed on a closed channel panic.
m.morebuf.g is not zeroed.
I don't expect the latter causes any problems, but just in case.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/151610043
TestMakeFuncVariadic only called the variadic function via Call and
CallSlice, not via a direct function call.
I thought these tests would fail under gccgo tip, but they don't. Still seems worth having though.
LGTM=iant
R=golang-codereviews, gobot, iant
CC=golang-codereviews
https://golang.org/cl/152060043
This change prevents confusion in the garbage collector.
The collector wants to make sure that every pointer it finds
isn't junk. Its criteria for junk is (among others) points
to a "free" span.
Because the stack shrinker modifies pointers in the heap,
there is a race condition between the GC scanner and the
shrinker. The GC scanner can see old pointers (pointers to
freed stacks). In particular this happens with SudoG.elem
pointers.
Normally this is not a problem, as pointers into stack spans
are ok. But if the freed stack is the last one in its span,
the span is marked as "free" instead of "contains stacks".
This change makes sure that even if the GC scanner sees
an old pointer, the span into which it points is still
marked as "contains stacks", and thus the GC doesn't
complain about it.
This change will make the GC pause a tiny bit slower, as
the stack freeing now happens in serial with the mark pause.
We could delay the freeing until the mutators start back up,
but this is the simplest change for now.
TBR=dvyukov
CC=golang-codereviews
https://golang.org/cl/158750043
