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[PATCH v2 0/7] harden unexpected object types checks

From
Taylor Blau <me@ttaylorr.com>
Date
Apr 10, 2019, 02:13 UTC
Message-ID
<cover.1554861974.git.me@ttaylorr.com>
In-Reply-To
<cover.1554435033.git.me@ttaylorr.com>
Hi everyone,

Here is 'v2' of mine and Peff's series to add tests for and fix some cases when object connections are malformed in various ways.

There aren't many major changes from the initial version, but what has changed is described briefly here, and in complete detail in the range-diff at the bottom of this message:

  - [2/7] was amended with Peff's suggestion to be a little clearer about
    what 'lone' and 'seen' mean
  - [2/7] was changed to replace all instances of:
      git cat-file ... | sed -e ... >broken-obj
    with:
      git cat-file ... >good-obj &&
      sed -e ... <good-obj >broken-obj
  - [4/7] was cleaned up to include the right test after a faulty
    rebase.
Thanks as always for your review :-).

Thanks, Taylor

Jeff King (3):
  get_commit_tree(): return NULL for broken tree
  rev-list: let traversal die when --missing is not in use
  rev-list: detect broken root trees
Taylor Blau (4):
  t: move 'hex2oct' into test-lib-functions.sh
  t: introduce tests for unexpected object types
  list-objects.c: handle unexpected non-blob entries
  list-objects.c: handle unexpected non-tree entries
 builtin/rev-list.c                     |   4 +-
 commit.c                               |   6 +-
 list-objects.c                         |  13 +++
 t/t1007-hash-object.sh                 |   4 -
 t/t1450-fsck.sh                        |   4 -
 t/t5601-clone.sh                       |   4 -
 t/t6102-rev-list-unexpected-objects.sh | 127 +++++++++++++++++++++++++
 t/test-lib-functions.sh                |   6 ++
 8 files changed, 152 insertions(+), 16 deletions(-)
 create mode 100755 t/t6102-rev-list-unexpected-objects.sh
Range-diff against v1:
1:  2104508e42 = 1:  f09c374557 t: move 'hex2oct' into test-lib-functions.sh
2:  909cbcd4a1 ! 2:  137e2df24d t: introduce tests for unexpected object types
    @@ -20,21 +20,19 @@
         cases that are not broken (i.e., they have NULL-ness checks or similar),
         mark these as expecting success.
    -    Let A be the object referenced with an unexpected type, and B be the
    -    object doing the referencing. Do the following:
    -
    -      - test 'git rev-list --objects A B'. This causes A to be "cached", and
    -        presents the above scenario.
    -
    -    Likewise, if we have a tree entry that claims to be a tree (for example)
    -    but points to another object type (say, a blob), there are two ways we
    -    might find out:
    +    We might hit an unexpected type in two different ways (imagine we have a
    +    tree entry that claims to be a tree but actually points to a blob):
           - when we call lookup_tree(), we might find that we've already seen
    -        the object referenced as another type, in which case we'd get NULL
    +        the object referenced as a blob, in which case we'd get NULL. We
    +        can exercise this with "git rev-list --objects $blob $tree", which
    +        guarantees that the blob will have been parsed before we look in
    +        the tree. These tests are marked as "seen" in the test script.
           - we call lookup_tree() successfully, but when we try to read the
    -        object, we find out it's something else.
    +        object, we find out it's something else. We construct our tests
    +        such that $blob is not otherwise mentioned in $tree. These tests
    +        are marked as "lone" in the script.
         We should check that we behave sensibly in both cases (especially
         because it is easy for a malicious actor to provoke one case or the
    @@ -58,7 +56,8 @@
     +test_expect_success 'setup well-formed objects' '
     +	blob="$(printf "foo" | git hash-object -w --stdin)" &&
     +	tree="$(printf "100644 blob $blob\tfoo" | git mktree)" &&
    -+	commit="$(git commit-tree $tree -m "first commit")"
    ++	commit="$(git commit-tree $tree -m "first commit")" &&
    ++	git cat-file commit $commit >good-commit
     +'
     +
     +test_expect_success 'setup unexpected non-blob entry' '
    @@ -84,12 +83,11 @@
     +'
     +
     +test_expect_failure 'traverse unexpected non-tree entry (seen)' '
    -+	test_must_fail git rev-list --objects $blob $broken_tree >output 2>&1
    ++	test_must_fail git rev-list --objects $blob $broken_tree
     +'
     +
     +test_expect_success 'setup unexpected non-commit parent' '
    -+	git cat-file commit $commit |
    -+		perl -lpe "/^author/ && print q(parent $blob)" \
    ++	sed "/^author/ { h; s/.*/parent $blob/; G; }" <good-commit \
     +		>broken-commit &&
     +	broken_commit="$(git hash-object -w --literally -t commit \
     +		broken-commit)"
    @@ -107,8 +105,7 @@
     +'
     +
     +test_expect_success 'setup unexpected non-tree root' '
    -+	git cat-file commit $commit |
    -+	sed -e "s/$tree/$blob/" >broken-commit &&
    ++	sed -e "s/$tree/$blob/" <good-commit >broken-commit &&
     +	broken_commit="$(git hash-object -w --literally -t commit \
     +		broken-commit)"
     +'
    @@ -123,8 +120,9 @@
     +
     +test_expect_success 'setup unexpected non-commit tag' '
     +	git tag -a -m "tagged commit" tag $commit &&
    ++	git cat-file tag tag >good-tag &&
     +	test_when_finished "git tag -d tag" &&
    -+	git cat-file -p tag | sed -e "s/$commit/$blob/" >broken-tag &&
    ++	sed -e "s/$commit/$blob/" <good-tag >broken-tag &&
     +	tag=$(git hash-object -w --literally -t tag broken-tag)
     +'
     +
    @@ -139,9 +137,9 @@
     +
     +test_expect_success 'setup unexpected non-tree tag' '
     +	git tag -a -m "tagged tree" tag $tree &&
    ++	git cat-file tag tag >good-tag &&
     +	test_when_finished "git tag -d tag" &&
    -+	git cat-file -p tag |
    -+	sed -e "s/$tree/$blob/" >broken-tag &&
    ++	sed -e "s/$tree/$blob/" <good-tag >broken-tag &&
     +	tag=$(git hash-object -w --literally -t tag broken-tag)
     +'
     +
    @@ -156,9 +154,9 @@
     +
     +test_expect_success 'setup unexpected non-blob tag' '
     +	git tag -a -m "tagged blob" tag $blob &&
    ++	git cat-file tag tag >good-tag &&
     +	test_when_finished "git tag -d tag" &&
    -+	git cat-file -p tag |
    -+	sed -e "s/$blob/$commit/" >broken-tag &&
    ++	sed -e "s/$blob/$commit/" <good-tag >broken-tag &&
     +	tag=$(git hash-object -w --literally -t tag broken-tag)
     +'
     +
3:  42f1b5d5fd = 3:  1d1ac9b7a7 list-objects.c: handle unexpected non-blob entries
4:  62c9a6f2e0 ! 4:  97c7e23ec9 list-objects.c: handle unexpected non-tree entries
    @@ -31,7 +31,7 @@
      '
     -test_expect_failure 'traverse unexpected non-tree entry (seen)' '
    --	test_must_fail git rev-list --objects $blob $broken_tree >output 2>&1
    +-	test_must_fail git rev-list --objects $blob $broken_tree
     +test_expect_success 'traverse unexpected non-tree entry (seen)' '
     +	test_must_fail git rev-list --objects $blob $broken_tree >output 2>&1 &&
     +	test_i18ngrep "is not a tree" output
5:  d0ae70542d = 5:  e9400a9f77 get_commit_tree(): return NULL for broken tree
6:  a0c23c8c16 = 6:  88ca5dfe68 rev-list: let traversal die when --missing is not in use
7:  2a25796147 = 7:  e0bd479e82 rev-list: detect broken root trees
--
2.21.0.203.g358da99528
Previous: Taylor BlauNext: Taylor Blau
Message 34 of 41 in “harden unexpected object types checks”
  1. 0/7 harden unexpected object types checksTaylor Blau, Apr 5, 2019
  2. 1/7 t: move 'hex2oct' into test-lib-functions.shTaylor Blau, Apr 5, 2019
  3. 2/7 t: introduce tests for unexpected object typesTaylor Blau, Apr 5, 2019
  4. SZEDER GáborApr 5, 2019
  5. Jeff KingApr 5, 2019
  6. SZEDER GáborApr 5, 2019
  7. Jeff KingApr 5, 2019
  8. Ævar Arnfjörð BjarmasonApr 7, 2019
  9. Taylor BlauApr 9, 2019
  10. Ævar Arnfjörð BjarmasonApr 9, 2019
  11. Taylor BlauApr 10, 2019
  12. Junio C HamanoApr 8, 2019
  13. Eric SunshineApr 5, 2019
  14. Jeff KingApr 5, 2019
  15. Taylor BlauApr 6, 2019
  16. Junio C HamanoApr 8, 2019
  17. Taylor BlauApr 9, 2019
  18. Eric SunshineApr 9, 2019
  19. Taylor BlauApr 9, 2019
  20. Eric SunshineApr 9, 2019
  21. Taylor BlauApr 10, 2019
  22. Taylor BlauApr 6, 2019
  23. Jeff KingApr 5, 2019
  24. Taylor BlauApr 6, 2019
  25. 3/7 list-objects.c: handle unexpected non-blob entriesTaylor Blau, Apr 5, 2019
  26. 4/7 list-objects.c: handle unexpected non-tree entriesTaylor Blau, Apr 5, 2019
  27. 5/7 get_commit_tree(): return NULL for broken treeTaylor Blau, Apr 5, 2019
  28. 6/7 rev-list: let traversal die when --missing is not in useTaylor Blau, Apr 5, 2019
  29. Jeff KingApr 5, 2019
  30. Taylor BlauApr 6, 2019
  31. Jeff KingApr 7, 2019
  32. Taylor BlauApr 9, 2019
  33. 7/7 rev-list: detect broken root treesTaylor Blau, Apr 5, 2019
  34. 0/7 harden unexpected object types checksTaylor Blau, Apr 10, 2019
  35. 1/7 t: move 'hex2oct' into test-lib-functions.shTaylor Blau, Apr 10, 2019
  36. 2/7 t: introduce tests for unexpected object typesTaylor Blau, Apr 10, 2019
  37. 3/7 list-objects.c: handle unexpected non-blob entriesTaylor Blau, Apr 10, 2019
  38. 4/7 list-objects.c: handle unexpected non-tree entriesTaylor Blau, Apr 10, 2019
  39. 5/7 get_commit_tree(): return NULL for broken treeTaylor Blau, Apr 10, 2019
  40. 6/7 rev-list: let traversal die when --missing is not in useTaylor Blau, Apr 10, 2019
  41. 7/7 rev-list: detect broken root treesTaylor Blau, Apr 10, 2019

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