From 1795b6eca263db9a8a941f27c7ebae911954dcff Mon Sep 17 00:00:00 2001 From: Sergey Fukanchik Date: Sat, 6 Sep 2025 12:40:01 +0300 Subject: [PATCH] Perform check for oversized WAL record before calculating record CRC --- src/backend/access/transam/xloginsert.c | 26 +++++++++---------- .../regress/expected/oversized_wal_record.out | 5 ++++ src/test/regress/parallel_schedule | 2 +- src/test/regress/sql/oversized_wal_record.sql | 4 +++ 4 files changed, 23 insertions(+), 14 deletions(-) create mode 100644 src/test/regress/expected/oversized_wal_record.out create mode 100644 src/test/regress/sql/oversized_wal_record.sql diff --git a/src/backend/access/transam/xloginsert.c b/src/backend/access/transam/xloginsert.c index c7571429e8e..e8c55924c12 100644 --- a/src/backend/access/transam/xloginsert.c +++ b/src/backend/access/transam/xloginsert.c @@ -904,19 +904,6 @@ XLogRecordAssemble(RmgrId rmid, uint8 info, hdr_rdt.len = (scratch - hdr_scratch); total_len += hdr_rdt.len; - /* - * Calculate CRC of the data - * - * Note that the record header isn't added into the CRC initially since we - * don't know the prev-link yet. Thus, the CRC will represent the CRC of - * the whole record in the order: rdata, then backup blocks, then record - * header. - */ - INIT_CRC32C(rdata_crc); - COMP_CRC32C(rdata_crc, hdr_scratch + SizeOfXLogRecord, hdr_rdt.len - SizeOfXLogRecord); - for (rdt = hdr_rdt.next; rdt != NULL; rdt = rdt->next) - COMP_CRC32C(rdata_crc, rdt->data, rdt->len); - /* * Ensure that the XLogRecord is not too large. * @@ -930,6 +917,19 @@ XLogRecordAssemble(RmgrId rmid, uint8 info, errdetail_internal("WAL record would be %" PRIu64 " bytes (of maximum %u bytes); rmid %u flags %u.", total_len, XLogRecordMaxSize, rmid, info))); + /* + * Calculate CRC of the data + * + * Note that the record header isn't added into the CRC initially since we + * don't know the prev-link yet. Thus, the CRC will represent the CRC of + * the whole record in the order: rdata, then backup blocks, then record + * header. + */ + INIT_CRC32C(rdata_crc); + COMP_CRC32C(rdata_crc, hdr_scratch + SizeOfXLogRecord, hdr_rdt.len - SizeOfXLogRecord); + for (rdt = hdr_rdt.next; rdt != NULL; rdt = rdt->next) + COMP_CRC32C(rdata_crc, rdt->data, rdt->len); + /* * Fill in the fields in the record header. Prev-link is filled in later, * once we know where in the WAL the record will be inserted. The CRC does diff --git a/src/test/regress/expected/oversized_wal_record.out b/src/test/regress/expected/oversized_wal_record.out new file mode 100644 index 00000000000..c9da04b59ec --- /dev/null +++ b/src/test/regress/expected/oversized_wal_record.out @@ -0,0 +1,5 @@ +-- Try to create a WAL record which is larger than the limit. +-- That should raise an error. +select pg_logical_emit_message(false, 'a', repeat('00000000', (1020 * 1024 * 1024)/8+1), true); +ERROR: oversized WAL record +DETAIL: WAL record would be 1069547583 bytes (of maximum 1069547520 bytes); rmid 21 flags 0. diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule index fbffc67ae60..913e2583129 100644 --- a/src/test/regress/parallel_schedule +++ b/src/test/regress/parallel_schedule @@ -36,7 +36,7 @@ test: geometry horology tstypes regex type_sanity opr_sanity misc_sanity comment # execute two copy tests in parallel, to check that copy itself # is concurrent safe. # ---------- -test: copy copyselect copydml copyencoding insert insert_conflict +test: copy copyselect copydml copyencoding insert insert_conflict oversized_wal_record # ---------- # More groups of parallel tests diff --git a/src/test/regress/sql/oversized_wal_record.sql b/src/test/regress/sql/oversized_wal_record.sql new file mode 100644 index 00000000000..555b6035c0f --- /dev/null +++ b/src/test/regress/sql/oversized_wal_record.sql @@ -0,0 +1,4 @@ +-- Try to create a WAL record which is larger than the limit. +-- That should raise an error. + +select pg_logical_emit_message(false, 'a', repeat('00000000', (1020 * 1024 * 1024)/8+1), true); -- 2.34.1