From c3818555611ab4c9c39dee90e9e56e69c2fcc1ed Mon Sep 17 00:00:00 2001 From: Sergey Fukanchik Date: Sun, 7 Sep 2025 12:06:03 +0300 Subject: [PATCH v2 1/2] Perform check for oversized WAL record before calculating record CRC --- src/backend/access/transam/xloginsert.c | 26 ++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) 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 -- 2.34.1