reftable: signal overflow
reflog entries have unbounded size. In theory, each log ('g') block in reftable can have an arbitrary size, so the format allows for arbitrarily sized reflog messages. However, in the implementation, we are not scaling the log blocks up with the message, and writing a large message fails. This triggers a failure for reftable in t7006-pager.sh. Until this is fixed more structurally, report an error from within the reftable library for easier debugging. Signed-off-by: Han-Wen Nienhuys <hanwen@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Han-Wen Nienhuys committed
Dec 23, 2021 at 19:29 UTC
0dd44584abf3fee0ba19b5edf856be2a79974228
4 files changed
+44
reftable/error.c
+2
@@ -32,6 +32,8 @@ const char *reftable_error_str(int err)
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return "wrote empty table";
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case REFTABLE_REFNAME_ERROR:
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return "invalid refname";
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+ case REFTABLE_ENTRY_TOO_BIG_ERROR:
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+ return "entry too large";
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case -1:
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return "general error";
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default:
reftable/readwrite_test.c
+35
@@ -155,6 +155,40 @@ static void test_log_buffer_size(void)
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strbuf_release(&buf);
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}
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+static void test_log_overflow(void)
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+{
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+ struct strbuf buf = STRBUF_INIT;
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+ char msg[256] = { 0 };
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+ struct reftable_write_options opts = {
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+ .block_size = ARRAY_SIZE(msg),
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+ };
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+ int err;
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+ struct reftable_log_record
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+ log = { .refname = "refs/heads/master",
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+ .update_index = 0xa,
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+ .value_type = REFTABLE_LOG_UPDATE,
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+ .value = { .update = {
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+ .name = "Han-Wen Nienhuys",
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+ .email = "hanwen@google.com",
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+ .tz_offset = 100,
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+ .time = 0x5e430672,
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+ .message = msg,
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+ } } };
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+ struct reftable_writer *w =
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+ reftable_new_writer(&strbuf_add_void, &buf, &opts);
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+
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+ uint8_t hash1[GIT_SHA1_RAWSZ] = {1}, hash2[GIT_SHA1_RAWSZ] = { 2 };
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+
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+ memset(msg, 'x', sizeof(msg) - 1);
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+ log.value.update.old_hash = hash1;
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+ log.value.update.new_hash = hash2;
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+ reftable_writer_set_limits(w, update_index, update_index);
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+ err = reftable_writer_add_log(w, &log);
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+ EXPECT(err == REFTABLE_ENTRY_TOO_BIG_ERROR);
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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_log_write_read(void)
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{
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int N = 2;
@@ -648,5 +682,6 @@ int readwrite_test_main(int argc, const char *argv[])
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RUN_TEST(test_table_refs_for_no_index);
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RUN_TEST(test_table_refs_for_obj_index);
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RUN_TEST(test_write_empty_table);
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+ RUN_TEST(test_log_overflow);
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return 0;
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}
reftable/reftable-error.h
+4
@@ -53,6 +53,10 @@ enum reftable_error {
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/* Invalid ref name. */
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REFTABLE_REFNAME_ERROR = -10,
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+
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+ /* Entry does not fit. This can happen when writing outsize reflog
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+ messages. */
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+ REFTABLE_ENTRY_TOO_BIG_ERROR = -11,
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};
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/* convert the numeric error code to a string. The string should not be
reftable/writer.c
+3
@@ -239,6 +239,9 @@ static int writer_add_record(struct reftable_writer *w,
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writer_reinit_block_writer(w, reftable_record_type(rec));
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err = block_writer_add(w->block_writer, rec);
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if (err < 0) {
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+ /* we are writing into memory, so an error can only mean it
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+ * doesn't fit. */
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+ err = REFTABLE_ENTRY_TOO_BIG_ERROR;
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goto done;
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}
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