reftable: ensure that obj_id_len is >= 2 on writing
When writing the same hash many times, we might decide to use a length-1 object ID prefix for the ObjectID => ref table, which is out of spec. Signed-off-by: Han-Wen Nienhuys <hanwen@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Han-Wen Nienhuys committed
Feb 21, 2022 at 18:46 UTC
b4007fcc6fe04deeeb3cdf7b018413f65c9de6e8
2 files changed
+40
-1
reftable/readwrite_test.c
+37
@@ -667,6 +667,42 @@ static void test_write_empty_table(void)
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strbuf_release(&buf);
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}
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+static void test_write_object_id_min_length(void)
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+{
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+ struct reftable_write_options opts = {
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+ .block_size = 75,
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+ };
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+ struct strbuf buf = STRBUF_INIT;
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+ struct reftable_writer *w =
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+ reftable_new_writer(&strbuf_add_void, &buf, &opts);
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+ uint8_t hash[GIT_SHA1_RAWSZ] = {42};
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+ struct reftable_ref_record ref = {
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+ .update_index = 1,
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+ .value_type = REFTABLE_REF_VAL1,
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+ .value.val1 = hash,
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+ };
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+ int err;
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+ int i;
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+
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+ reftable_writer_set_limits(w, 1, 1);
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+
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+ /* Write the same hash in many refs. If there is only 1 hash, the
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+ * disambiguating prefix is length 0 */
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+ for (i = 0; i < 256; i++) {
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+ char name[256];
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+ snprintf(name, sizeof(name), "ref%05d", i);
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+ ref.refname = name;
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+ err = reftable_writer_add_ref(w, &ref);
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+ EXPECT_ERR(err);
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+ }
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+
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+ err = reftable_writer_close(w);
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+ EXPECT_ERR(err);
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+ EXPECT(writer_stats(w)->object_id_len == 2);
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+ reftable_writer_free(w);
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+ strbuf_release(&buf);
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+}
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+
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static void test_write_empty_key(void)
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{
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struct reftable_write_options opts = { 0 };
@@ -772,5 +808,6 @@ int readwrite_test_main(int argc, const char *argv[])
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RUN_TEST(test_write_empty_key);
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RUN_TEST(test_write_empty_table);
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RUN_TEST(test_log_overflow);
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+ RUN_TEST(test_write_object_id_min_length);
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return 0;
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}
reftable/writer.c
+3
-1
@@ -515,7 +515,9 @@ static void object_record_free(void *void_arg, void *key)
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static int writer_dump_object_index(struct reftable_writer *w)
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{
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struct write_record_arg closure = { .w = w };
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- struct common_prefix_arg common = { NULL };
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+ struct common_prefix_arg common = {
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+ .max = 1, /* obj_id_len should be >= 2. */
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+ };
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if (w->obj_index_tree) {
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infix_walk(w->obj_index_tree, &update_common, &common);
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}