[PATCH 0/5] tree-walk object_id refactor
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git@vger.kernel.org
Cc
Martin Ă…gren
Junio C Hamano
From
brian m. carlson
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Date
2019-01-10 04:25:46 UTC
There are a small number of places in our codebase where we cast a
buffer of unsigned char to a struct object_id pointer. When we have
GIT_MAX_RAWSZ set to 32 (because we have SHA-256), one of these places
(the buffer for tree objects) can lead to us copying too much data when
using SHA-1 as the hash, since there are only 20 bytes to read.

This was not expected to be a problem before future code was introduced,
but due to a combination of series the issue became noticeable.

This series introduces a refactor to avoid referencing the struct
object_id directly from a buffer and instead storing an additional
struct object_id (and an int) in struct name_entry and referring to
that.

This series, while based on master, addresses the interactions seen on
pu between the SHA-256 series and the oidset series. There are a small
number of conflicts, both textual and logical, when merging this series
and pu, but they should be easily resolved.

This series contains a final patch which will become necessary at some
point for hygienic code, but which could be deferred until later if
desired.

The testsuite passes with AddressSanitizer at each stage and when merged
into pu.

brian m. carlson (5):
  tree-walk: copy object ID before use
  match-trees: compute buffer offset correctly when splicing
  match-trees: use hashcpy to splice trees
  tree-walk: store object_id in a separate member
  cache: make oidcpy always copy GIT_MAX_RAWSZ bytes

 builtin/grep.c                     |  8 ++++----
 builtin/merge-tree.c               | 20 ++++++++++----------
 builtin/pack-objects.c             |  4 ++--
 builtin/reflog.c                   |  4 ++--
 cache-tree.c                       |  4 ++--
 cache.h                            |  2 +-
 contrib/coccinelle/object_id.cocci | 30 ------------------------------
 delta-islands.c                    |  2 +-
 fsck.c                             |  4 ++--
 http-push.c                        |  4 ++--
 list-objects.c                     |  6 +++---
 match-trees.c                      | 11 ++++++-----
 notes.c                            |  4 ++--
 packfile.c                         |  2 +-
 revision.c                         |  4 ++--
 tree-diff.c                        |  6 +++---
 tree-walk.c                        | 21 ++++++++++++---------
 tree-walk.h                        |  9 ++++++---
 tree.c                             | 10 +++++-----
 unpack-trees.c                     |  6 +++---
 walker.c                           |  4 ++--
 21 files changed, 71 insertions(+), 94 deletions(-)