Re: [PATCH v4 2/3] commit-graph: fix buffer read-overflow
- From
SZEDER Gábor <szeder.dev@gmail.com>
- Date
- Jan 12, 2019, 10:57 UTC
- Message-ID
- <20190112105757.GE840@szeder.dev>
- In-Reply-To
- <80b5662f30cb87210385a6bd26e037ce39e46b6d.1544729841.git.steadmon@google.com>
On Thu, Dec 13, 2018 at 11:43:57AM -0800, Josh Steadmon wrote:
Show 21 quoted lines
> diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
> index 5fe21db99f..a1b5a75882 100755
> --- a/t/t5318-commit-graph.sh
> +++ b/t/t5318-commit-graph.sh
> @@ -366,21 +366,26 @@ GRAPH_OCTOPUS_DATA_OFFSET=$(($GRAPH_COMMIT_DATA_OFFSET + \
> GRAPH_BYTE_OCTOPUS=$(($GRAPH_OCTOPUS_DATA_OFFSET + 4))
> GRAPH_BYTE_FOOTER=$(($GRAPH_OCTOPUS_DATA_OFFSET + 4 * $NUM_OCTOPUS_EDGES))
>
> -# usage: corrupt_graph_and_verify <position> <data> <string>
> +# usage: corrupt_graph_and_verify <position> <data> <string> [<zero_pos>]
> # Manipulates the commit-graph file at the position
> -# by inserting the data, then runs 'git commit-graph verify'
> +# by inserting the data, optionally zeroing the file
> +# starting at <zero_pos>, then runs 'git commit-graph verify'
> # and places the output in the file 'err'. Test 'err' for
> # the given string.
> corrupt_graph_and_verify() {
> pos=$1
> data="${2:-\0}"
> grepstr=$3
> + orig_size=$(wc -c < $objdir/info/commit-graph) &&A minor nit: this test script is unusually prudent about which directory/repository each test is executed in, as the first thing each test does is to 'cd' into the right directory. (I think this is a Good Thing, and other test scripts should follow suit if they use a repo other than $TRASH_DIRECTORY.) Though it doesn't cause any immediate issues (the previous test happens to use the same repository), the above line violates this, as it accesses the '.git/.../commit-graph' file ...
> + zero_pos=${4:-${orig_size}} &&
> cd "$TRASH_DIRECTORY/full" &&... before this line could ensure that it's in the right repository.
Show 26 quoted lines
> test_when_finished mv commit-graph-backup $objdir/info/commit-graph && > cp $objdir/info/commit-graph commit-graph-backup && > printf "$data" | dd of="$objdir/info/commit-graph" bs=1 seek="$pos" conv=notrunc && > + dd of="$objdir/info/commit-graph" bs=1 seek="$zero_pos" count=0 && > + dd if=/dev/zero of="$objdir/info/commit-graph" bs=1 seek="$zero_pos" count=$(($orig_size - $zero_pos)) && > test_must_fail git commit-graph verify 2>test_err && > - grep -v "^+" test_err >err > + grep -v "^+" test_err >err && > test_i18ngrep "$grepstr" err > } > > @@ -484,6 +489,11 @@ test_expect_success 'detect invalid checksum hash' ' > "incorrect checksum" > ' > > +test_expect_success 'detect incorrect chunk count' ' > + corrupt_graph_and_verify $GRAPH_BYTE_CHUNK_COUNT "\377" \ > + "chunk lookup table entry missing" $GRAPH_CHUNK_LOOKUP_OFFSET > +' > + > test_expect_success 'git fsck (checks commit-graph)' ' > cd "$TRASH_DIRECTORY/full" && > git fsck && > -- > 2.20.0.rc2.10.g21101b961a >