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Austin Clements 04017ffadf [release-branch.go1.8] reflect: fix out-of-bounds pointers calling no-result method
reflect.callReflect heap-allocates a stack frame and then constructs
pointers to the arguments and result areas of that frame. However, if
there are no results, the results pointer will point past the end of
the frame allocation. If there are also no arguments, the arguments
pointer will also point past the end of the frame allocation. If the
GC observes either these pointers, it may panic.

Fix this by not constructing these pointers if these areas of the
frame are empty.

This adds a test of calling no-argument/no-result methods via reflect,
since nothing in std did this before. However, it's quite difficult to
demonstrate the actual failure because it depends on both exact
allocation patterns and on GC scanning the goroutine's stack while
inside one of the typedmemmovepartial calls.

I also audited other uses of typedmemmovepartial and
memclrNoHeapPointers in reflect, since these are the most susceptible
to this. These appear to be the only two cases that can construct
out-of-bounds arguments to these functions.

Fixes #19724.
Fixes #19768 (backport).

Change-Id: I4b83c596b5625dc4ad0567b1e281bad4faef972b
Reviewed-on: https://go-review.googlesource.com/39604
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Russ Cox <rsc@golang.org>
2017-04-05 16:58:37 +00:00
.github doc: improve issue template 2016-08-29 03:33:28 +00:00
api Revert "cmd/go: note when some Go files were ignored on no-Go-files errors" 2016-12-21 05:25:57 +00:00
doc [release-branch.go1.8] doc: reorganize the contribution guidelines into a guide 2017-03-16 21:47:46 +00:00
lib/time lib/time: update tzdata to 2016j 2017-01-05 01:00:53 +00:00
misc [release-branch.go1.8] cmd/link: make mach-o dwarf segment properly aligned 2017-04-05 16:58:33 +00:00
src [release-branch.go1.8] reflect: fix out-of-bounds pointers calling no-result method 2017-04-05 16:58:37 +00:00
test [release-branch.go1.8] cmd/compile: don't crash when slicing non-slice 2017-04-05 16:58:29 +00:00
.gitattributes
.gitignore .gitignore: fix attempt at rooted paths 2017-01-05 01:29:25 +00:00
AUTHORS A+C: automated update 2016-12-21 03:22:22 +00:00
CONTRIBUTING.md doc: update CONTRIBUTING.md a bit, mention proposal process 2017-01-06 23:19:01 +00:00
CONTRIBUTORS A+C: automated update 2016-12-21 03:22:22 +00:00
LICENSE doc: revert copyright date to 2009 2016-06-01 22:40:04 +00:00
PATENTS
README.md README.md: update and simplify 2017-01-17 21:26:43 +00:00
VERSION [release-branch.go1.8] go1.8 2017-02-16 17:12:24 +00:00
favicon.ico website: recreate 16px and 32px favicon 2016-08-25 15:43:32 +00:00
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