git-commit-vandalism/t/t1007-hash-object.sh
Jeff King 69bbbe484b hash-object: use fsck for object checks
Since c879daa237 (Make hash-object more robust against malformed
objects, 2011-02-05), we've done some rudimentary checks against objects
we're about to write by running them through our usual parsers for
trees, commits, and tags.

These parsers catch some problems, but they are not nearly as careful as
the fsck functions (which make sense; the parsers are designed to be
fast and forgiving, bailing only when the input is unintelligible). We
are better off doing the more thorough fsck checks when writing objects.
Doing so at write time is much better than writing garbage only to find
out later (after building more history atop it!) that fsck complains
about it, or hosts with transfer.fsckObjects reject it.

This is obviously going to be a user-visible behavior change, and the
test changes earlier in this series show the scope of the impact. But
I'd argue that this is OK:

  - the documentation for hash-object is already vague about which
    checks we might do, saying that --literally will allow "any
    garbage[...] which might not otherwise pass standard object parsing
    or git-fsck checks". So we are already covered under the documented
    behavior.

  - users don't generally run hash-object anyway. There are a lot of
    spots in the tests that needed to be updated because creating
    garbage objects is something that Git's tests disproportionately do.

  - it's hard to imagine anyone thinking the new behavior is worse. Any
    object we reject would be a potential problem down the road for the
    user. And if they really want to create garbage, --literally is
    already the escape hatch they need.

Note that the change here is actually in index_mem(), which handles the
HASH_FORMAT_CHECK flag passed by hash-object. That flag is also used by
"git-replace --edit" to sanity-check the result. Covering that with more
thorough checks likewise seems like a good thing.

Besides being more thorough, there are a few other bonuses:

  - we get rid of some questionable stack allocations of object structs.
    These don't seem to currently cause any problems in practice, but
    they subtly violate some of the assumptions made by the rest of the
    code (e.g., the "struct commit" we put on the stack and
    zero-initialize will not have a proper index from
    alloc_comit_index().

  - likewise, those parsed object structs are the source of some small
    memory leaks

  - the resulting messages are much better. For example:

      [before]
      $ echo 'tree 123' | git hash-object -t commit --stdin
      error: bogus commit object 0000000000000000000000000000000000000000
      fatal: corrupt commit

      [after]
      $ echo 'tree 123' | git.compile hash-object -t commit --stdin
      error: object fails fsck: badTreeSha1: invalid 'tree' line format - bad sha1
      fatal: refusing to create malformed object

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-01-18 12:59:45 -08:00

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#!/bin/sh
test_description="git hash-object"
TEST_PASSES_SANITIZE_LEAK=true
. ./test-lib.sh
echo_without_newline() {
printf '%s' "$*"
}
test_blob_does_not_exist() {
test_expect_success 'blob does not exist in database' "
test_must_fail git cat-file blob $1
"
}
test_blob_exists() {
test_expect_success 'blob exists in database' "
git cat-file blob $1
"
}
hello_content="Hello World"
example_content="This is an example"
setup_repo() {
echo_without_newline "$hello_content" > hello
echo_without_newline "$example_content" > example
}
test_repo=test
push_repo() {
test_create_repo $test_repo
cd $test_repo
setup_repo
}
pop_repo() {
cd ..
rm -rf $test_repo
}
test_expect_success 'setup' '
setup_repo &&
test_oid_cache <<-EOF
hello sha1:5e1c309dae7f45e0f39b1bf3ac3cd9db12e7d689
hello sha256:1e3b6c04d2eeb2b3e45c8a330445404c0b7cc7b257e2b097167d26f5230090c4
example sha1:ddd3f836d3e3fbb7ae289aa9ae83536f76956399
example sha256:b44fe1fe65589848253737db859bd490453510719d7424daab03daf0767b85ae
EOF
'
# Argument checking
test_expect_success "multiple '--stdin's are rejected" '
echo example | test_must_fail git hash-object --stdin --stdin
'
test_expect_success "Can't use --stdin and --stdin-paths together" '
echo example | test_must_fail git hash-object --stdin --stdin-paths &&
echo example | test_must_fail git hash-object --stdin-paths --stdin
'
test_expect_success "Can't pass filenames as arguments with --stdin-paths" '
echo example | test_must_fail git hash-object --stdin-paths hello
'
test_expect_success "Can't use --path with --stdin-paths" '
echo example | test_must_fail git hash-object --stdin-paths --path=foo
'
test_expect_success "Can't use --path with --no-filters" '
test_must_fail git hash-object --no-filters --path=foo
'
# Behavior
push_repo
test_expect_success 'hash a file' '
test "$(test_oid hello)" = $(git hash-object hello)
'
test_blob_does_not_exist "$(test_oid hello)"
test_expect_success 'hash from stdin' '
test "$(test_oid example)" = $(git hash-object --stdin < example)
'
test_blob_does_not_exist "$(test_oid example)"
test_expect_success 'hash a file and write to database' '
test "$(test_oid hello)" = $(git hash-object -w hello)
'
test_blob_exists "$(test_oid hello)"
test_expect_success 'git hash-object --stdin file1 <file0 first operates on file0, then file1' '
echo foo > file1 &&
obname0=$(echo bar | git hash-object --stdin) &&
obname1=$(git hash-object file1) &&
obname0new=$(echo bar | git hash-object --stdin file1 | sed -n -e 1p) &&
obname1new=$(echo bar | git hash-object --stdin file1 | sed -n -e 2p) &&
test "$obname0" = "$obname0new" &&
test "$obname1" = "$obname1new"
'
test_expect_success 'set up crlf tests' '
echo fooQ | tr Q "\\015" >file0 &&
cp file0 file1 &&
echo "file0 -crlf" >.gitattributes &&
echo "file1 crlf" >>.gitattributes &&
git config core.autocrlf true &&
file0_sha=$(git hash-object file0) &&
file1_sha=$(git hash-object file1) &&
test "$file0_sha" != "$file1_sha"
'
test_expect_success 'check that appropriate filter is invoke when --path is used' '
path1_sha=$(git hash-object --path=file1 file0) &&
path0_sha=$(git hash-object --path=file0 file1) &&
test "$file0_sha" = "$path0_sha" &&
test "$file1_sha" = "$path1_sha" &&
path1_sha=$(cat file0 | git hash-object --path=file1 --stdin) &&
path0_sha=$(cat file1 | git hash-object --path=file0 --stdin) &&
test "$file0_sha" = "$path0_sha" &&
test "$file1_sha" = "$path1_sha"
'
test_expect_success 'gitattributes also work in a subdirectory' '
mkdir subdir &&
(
cd subdir &&
subdir_sha0=$(git hash-object ../file0) &&
subdir_sha1=$(git hash-object ../file1) &&
test "$file0_sha" = "$subdir_sha0" &&
test "$file1_sha" = "$subdir_sha1"
)
'
test_expect_success '--path works in a subdirectory' '
(
cd subdir &&
path1_sha=$(git hash-object --path=../file1 ../file0) &&
path0_sha=$(git hash-object --path=../file0 ../file1) &&
test "$file0_sha" = "$path0_sha" &&
test "$file1_sha" = "$path1_sha"
)
'
test_expect_success 'check that --no-filters option works' '
nofilters_file1=$(git hash-object --no-filters file1) &&
test "$file0_sha" = "$nofilters_file1" &&
nofilters_file1=$(cat file1 | git hash-object --stdin) &&
test "$file0_sha" = "$nofilters_file1"
'
test_expect_success 'check that --no-filters option works with --stdin-paths' '
nofilters_file1=$(echo "file1" | git hash-object --stdin-paths --no-filters) &&
test "$file0_sha" = "$nofilters_file1"
'
pop_repo
for args in "-w --stdin" "--stdin -w"; do
push_repo
test_expect_success "hash from stdin and write to database ($args)" '
test "$(test_oid example)" = $(git hash-object $args < example)
'
test_blob_exists "$(test_oid example)"
pop_repo
done
filenames="hello
example"
oids="$(test_oid hello)
$(test_oid example)"
test_expect_success "hash two files with names on stdin" '
test "$oids" = "$(echo_without_newline "$filenames" | git hash-object --stdin-paths)"
'
for args in "-w --stdin-paths" "--stdin-paths -w"; do
push_repo
test_expect_success "hash two files with names on stdin and write to database ($args)" '
test "$oids" = "$(echo_without_newline "$filenames" | git hash-object $args)"
'
test_blob_exists "$(test_oid hello)"
test_blob_exists "$(test_oid example)"
pop_repo
done
test_expect_success 'too-short tree' '
echo abc >malformed-tree &&
test_must_fail git hash-object -t tree malformed-tree 2>err &&
grep "too-short tree object" err
'
test_expect_success 'malformed mode in tree' '
hex_oid=$(echo foo | git hash-object --stdin -w) &&
bin_oid=$(echo $hex_oid | hex2oct) &&
printf "9100644 \0$bin_oid" >tree-with-malformed-mode &&
test_must_fail git hash-object -t tree tree-with-malformed-mode 2>err &&
grep "malformed mode in tree entry" err
'
test_expect_success 'empty filename in tree' '
hex_oid=$(echo foo | git hash-object --stdin -w) &&
bin_oid=$(echo $hex_oid | hex2oct) &&
printf "100644 \0$bin_oid" >tree-with-empty-filename &&
test_must_fail git hash-object -t tree tree-with-empty-filename 2>err &&
grep "empty filename in tree entry" err
'
test_expect_success 'duplicate filename in tree' '
hex_oid=$(echo foo | git hash-object --stdin -w) &&
bin_oid=$(echo $hex_oid | hex2oct) &&
{
printf "100644 file\0$bin_oid" &&
printf "100644 file\0$bin_oid"
} >tree-with-duplicate-filename &&
test_must_fail git hash-object -t tree tree-with-duplicate-filename 2>err &&
grep "duplicateEntries" err
'
test_expect_success 'corrupt commit' '
test_must_fail git hash-object -t commit --stdin </dev/null
'
test_expect_success 'corrupt tag' '
test_must_fail git hash-object -t tag --stdin </dev/null
'
test_expect_success 'hash-object complains about bogus type name' '
test_must_fail git hash-object -t bogus --stdin </dev/null
'
test_expect_success 'hash-object complains about truncated type name' '
test_must_fail git hash-object -t bl --stdin </dev/null
'
test_expect_success '--literally' '
t=1234567890 &&
echo example | git hash-object -t $t --literally --stdin
'
test_expect_success '--literally with extra-long type' '
t=12345678901234567890123456789012345678901234567890 &&
t="$t$t$t$t$t$t$t$t$t$t$t$t$t$t$t$t$t$t$t$t$t$t$t$t$t$t$t$t$t$t" &&
echo example | git hash-object -t $t --literally --stdin
'
test_done