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| author | Thomas Munro <tmunro@postgresql.org> | 2023-09-26 09:07:26 +1300 |
|---|---|---|
| committer | Thomas Munro <tmunro@postgresql.org> | 2023-09-26 10:54:02 +1300 |
| commit | 99d334a187ae5c283aca1c31b9fad0cea140a4b2 (patch) | |
| tree | 0aa0ebd1ce8bbc9358bb4dc302e12b6d90368822 /src/backend/access/transam/xlogreader.c | |
| parent | 9dc3c5472ed99a1046a4d7884270a35cfad29d1d (diff) | |
| download | postgresql-99d334a187ae5c283aca1c31b9fad0cea140a4b2.tar.gz postgresql-99d334a187ae5c283aca1c31b9fad0cea140a4b2.zip | |
Fix edge-case for xl_tot_len broken by bae868ca.
bae868ca removed a check that was still needed. If you had an
xl_tot_len at the end of a page that was too small for a record header,
but not big enough to span onto the next page, we'd immediately perform
the CRC check using a bogus large length. Because of arbitrary coding
differences between the CRC implementations on different platforms,
nothing very bad happened on common modern systems. On systems using
the _sb8.c fallback we could segfault.
Restore that check, add a new assertion and supply a test for that case.
Back-patch to 12, like bae868ca.
Tested-by: Tom Lane <tgl@sss.pgh.pa.us>
Tested-by: Alexander Lakhin <exclusion@gmail.com>
Discussion: https://postgr.es/m/CA%2BhUKGLCkTT7zYjzOxuLGahBdQ%3DMcF%3Dz5ZvrjSOnW4EDhVjT-g%40mail.gmail.com
Diffstat (limited to 'src/backend/access/transam/xlogreader.c')
| -rw-r--r-- | src/backend/access/transam/xlogreader.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 4b48abfa053..652c9a184e4 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -651,6 +651,15 @@ restart: } else { + /* There may be no next page if it's too small. */ + if (total_len < SizeOfXLogRecord) + { + report_invalid_record(state, + "invalid record length at %X/%X: wanted %u, got %u", + LSN_FORMAT_ARGS(RecPtr), + (uint32) SizeOfXLogRecord, total_len); + goto err; + } /* We'll validate the header once we have the next page. */ gotheader = false; } @@ -1188,6 +1197,8 @@ ValidXLogRecord(XLogReaderState *state, XLogRecord *record, XLogRecPtr recptr) { pg_crc32c crc; + Assert(record->xl_tot_len >= SizeOfXLogRecord); + /* Calculate the CRC */ INIT_CRC32C(crc); COMP_CRC32C(crc, ((char *) record) + SizeOfXLogRecord, record->xl_tot_len - SizeOfXLogRecord); |