[PATCH v2 02/11] multi-pack-index: verify bad header

[Derrick Stolee via GitGitGadget]

From: Derrick Stolee <dsto...@microsoft.com>

When verifying if a multi-pack-index file is valid, we want the
command to fail to signal an invalid file. Previously, we wrote
an error to stderr and continued as if we had no multi-pack-index.
Now, die() instead of error().

Add tests that check corrupted headers in a few ways:

* Bad signature
* Bad file version
* Bad hash version
* Truncated hash count
* Extended hash count

Signed-off-by: Derrick Stolee <dsto...@microsoft.com>
---
 midx.c                      | 18 +++++----------
 t/t5319-multi-pack-index.sh | 46 ++++++++++++++++++++++++++++++++++++-
 2 files changed, 51 insertions(+), 13 deletions(-)

diff --git a/midx.c b/midx.c
index b253bed517..ec78254bb6 100644
--- a/midx.c
+++ b/midx.c
@@ -76,24 +76,18 @@ struct multi_pack_index *load_multi_pack_index(const char 
*object_dir, int local
        m->local = local;
 
        m->signature = get_be32(m->data);
-       if (m->signature != MIDX_SIGNATURE) {
-               error(_("multi-pack-index signature 0x%08x does not match 
signature 0x%08x"),
+       if (m->signature != MIDX_SIGNATURE)
+               die(_("multi-pack-index signature 0x%08x does not match 
signature 0x%08x"),
                      m->signature, MIDX_SIGNATURE);
-               goto cleanup_fail;
-       }
 
        m->version = m->data[MIDX_BYTE_FILE_VERSION];
-       if (m->version != MIDX_VERSION) {
-               error(_("multi-pack-index version %d not recognized"),
+       if (m->version != MIDX_VERSION)
+               die(_("multi-pack-index version %d not recognized"),
                      m->version);
-               goto cleanup_fail;
-       }
 
        hash_version = m->data[MIDX_BYTE_HASH_VERSION];
-       if (hash_version != MIDX_HASH_VERSION) {
-               error(_("hash version %u does not match"), hash_version);
-               goto cleanup_fail;
-       }
+       if (hash_version != MIDX_HASH_VERSION)
+               die(_("hash version %u does not match"), hash_version);
        m->hash_len = MIDX_HASH_LEN;
 
        m->num_chunks = m->data[MIDX_BYTE_NUM_CHUNKS];
diff --git a/t/t5319-multi-pack-index.sh b/t/t5319-multi-pack-index.sh
index 1c4e0e6d31..e04b5f43a2 100755
--- a/t/t5319-multi-pack-index.sh
+++ b/t/t5319-multi-pack-index.sh
@@ -154,6 +154,51 @@ test_expect_success 'verify multi-pack-index success' '
        git multi-pack-index verify --object-dir=$objdir
 '
 
+# usage: corrupt_midx_and_verify <pos> <data> <objdir> <string>
+corrupt_midx_and_verify() {
+       POS=$1 &&
+       DATA="${2:-\0}" &&
+       OBJDIR=$3 &&
+       GREPSTR="$4" &&
+       FILE=$OBJDIR/pack/multi-pack-index &&
+       chmod a+w $FILE &&
+       test_when_finished mv midx-backup $FILE &&
+       cp $FILE midx-backup &&
+       printf "$DATA" | dd of="$FILE" bs=1 seek="$POS" conv=notrunc &&
+       test_must_fail git multi-pack-index verify --object-dir=$OBJDIR 
2>test_err &&
+       grep -v "^+" test_err >err &&
+       test_i18ngrep "$GREPSTR" err
+}
+
+test_expect_success 'verify bad signature' '
+       corrupt_midx_and_verify 0 "\00" $objdir \
+               "multi-pack-index signature"
+'
+
+MIDX_BYTE_VERSION=4
+MIDX_BYTE_OID_VERSION=5
+MIDX_BYTE_CHUNK_COUNT=6
+
+test_expect_success 'verify bad version' '
+       corrupt_midx_and_verify $MIDX_BYTE_VERSION "\00" $objdir \
+               "multi-pack-index version"
+'
+
+test_expect_success 'verify bad OID version' '
+       corrupt_midx_and_verify $MIDX_BYTE_OID_VERSION "\02" $objdir \
+               "hash version"
+'
+
+test_expect_success 'verify truncated chunk count' '
+       corrupt_midx_and_verify $MIDX_BYTE_CHUNK_COUNT "\01" $objdir \
+               "missing required"
+'
+
+test_expect_success 'verify extended chunk count' '
+       corrupt_midx_and_verify $MIDX_BYTE_CHUNK_COUNT "\07" $objdir \
+               "terminating multi-pack-index chunk id appears earlier than 
expected"
+'
+
 test_expect_success 'repack removes multi-pack-index' '
        test_path_is_file $objdir/pack/multi-pack-index &&
        git repack -adf &&
@@ -191,7 +236,6 @@ test_expect_success 'multi-pack-index in an alternate' '
 
 compare_results_with_midx "with alternate (remote midx)"
 
-
 # usage: corrupt_data <file> <pos> [<data>]
 corrupt_data () {
        file=$1
-- 
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