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  1. Aug 04, 2020
    • Hans Wennborg's avatar
      [zlib] Add streaming inflate fuzzer · 493d4299
      Hans Wennborg authored 
      This adds a new fuzzer which first deflates and then inflates some data
one chunk at a time and verifies that it round-trips correctly. It's
targeted at the recent bug where inffast_chunk was called with
overlapping from and out buffers.

I've verified that the fuzzer detects the incorrect inflate results when
using Clang's -basic-aa-recphi option before the bug fix in e0f88a9.

Furthermore, this patch adds asserts in inffast_chunk and other
functions that verify there's no overlap of restrict-qualified buffers.
(I've checked that the fuzzer hits the inffast_chunk assert before
e0f88a9).

To make those asserts work, this changes the build config to define
ZLIB_DEBUG in debug and fuzzer builds.

Bug: 1103818, 708726
Change-Id: Ia3d5e7906b8b1a65d56a589d8a81d17661e638c2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2332705


Commit-Queue: Hans Wennborg <hans@chromium.org>
Reviewed-by: default avatarNico Weber <thakis@chromium.org>
Reviewed-by: default avatarAdenilson Cavalcanti <cavalcantii@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#794482}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 3eda17e22e6a3c4e44fdfa778b7d55f0a7c82e75
      493d4299
  3. Jul 30, 2020
    • Adenilson Cavalcanti's avatar
      Handling undefined behavior in inffast_chunk · a21a4e8f
      Adenilson Cavalcanti authored 
      It was revealed by a new clang flag (i.e. basic-aa-recphi) that chunkcopy_safe
could hit a scenario of undefined behavior with the use of 'restrict' modifier when
the 'from' and 'out' pointers overlapped during decompression.

This patch targets to address this issue and unblock the enablement of the
aforementioned compiler flag.

Credit for the original investigation and the new unit test stressing the
failure scenario goes to Hans Wennborg.

Performance implications: initial numbers point to
a slight improvement for ARM big cores@64bit (i.e. 2% to 3.6%) and x86-64
(i.e. up to 7.5% for Intel i7) but a regression otherwise for 32bit
(i.e. between 2.3% to 3% big.LITTLE respectively).

Bug: 1103818
Change-Id: I9b7d2c1e47caaf498cd539fd6b77c4b949cb0dac
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2309041


Reviewed-by: default avatarHans Wennborg <hans@chromium.org>
Reviewed-by: default avatarAdenilson Cavalcanti <cavalcantii@chromium.org>
Commit-Queue: Adenilson Cavalcanti <cavalcantii@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#793239}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: e0f88a903fdcb6c772de1929834a73d1662d509a
      a21a4e8f
  5. Jul 29, 2020
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  33. Apr 30, 2020
  35. Apr 29, 2020
    • Noel Gordon's avatar
      [zlib] Fix gcc parenthesis warning in crc_folding.c from V8 roll · 438cb5c0
      Noel Gordon authored 
      V8 roll uses gcc and [-Werror=parentheses], and started reporting code
errors in crc_folding.c recently, issue 1076360

  third_party/zlib/crc_folding.c:288:19: error: suggest parentheses
  around ‘-’ in operand of ‘&’ [-Werror=parentheses]
  288 |     algn_diff = 0 - (uintptr_t)src & 0xF;
      |                 ~~^~~~~~~~~~~~~~~~
  cc1: all warnings being treated as errors

Operator - has higher precedence than &, per C rules but help gcc work
out that that is the code intent by bracketing the expression:

  algn_diff = (0 - (uintptr_t)src) & 0xF;

[-Werror=parentheses] is happy with that change, and so is zlib_bench,
at zlib@1,3,6,9. No change in behavior: covered by many, many existing
integration, unit and blink layout tests.

Tbr: cblume, cavalcantii
Bug: 1076360, 1072308
Change-Id: Id9411dc96b638ca44ca9c67f6c411bf7c4bec519
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2172191


Reviewed-by: default avatarNoel Gordon <noel@chromium.org>
Reviewed-by: default avatarMichael Achenbach <machenbach@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#763787}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 7453f9f2d7adcdb5c30aa9d802d0a19d6c085bb7
      438cb5c0
    • Adenilson Cavalcanti's avatar
      [zlib] Re-land import canonical zlib inflate cover tests · 699e86dc
      Adenilson Cavalcanti authored 
      There is a test suite in Canonical zlib that ensures correctness and
coverage of inflate/deflate: the inflate cover (infcover.c) suite.

This patch imports the inflate cover suite with the necessary changes
to make it build and run under Chromes's C++11 GTEST test system.

There are minimal changes (i.e. undefined 'local', miscellaneous C
casts to use C++ casts, etc) so we can build it as C++ code and hook
into GTEST e.g. use EXPECT_TRUE instead of C assert from <assert.h>.

Adds a patch file for these changes, that can be applied on Canonical
infcover should we need to sync with a new Canonical zlib release.

TODO: there's one test accessing a symbol that causes link errors so
comment that code out for now.

Bug: 1032721
Change-Id: I004a1357d46d909ad3a5a5bacc5f9ab9bfcb7809
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2168792


Reviewed-by: default avatarAdenilson Cavalcanti <cavalcantii@chromium.org>
Reviewed-by: default avatarNoel Gordon <noel@chromium.org>
Commit-Queue: Adenilson Cavalcanti <cavalcantii@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#763696}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 26b3182d7a40f33da10a95bc69199af925dedbcc
      699e86dc
  37. Apr 23, 2020
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