MDEV-35665 Potential Buffer Overrun in Gtid_log_event::write() #3717
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Two-Phase ALTER added a sa_seq_no field, but `Gtid_log_event::write()`'s size calculation doesn't have an addend in its name. This patch resizes the buffer to match `write()`'s code.
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Description
Two-Phase ALTER added a
sa_seq_nofield, butGtid_log_event::write()’s size calculation doesn’t have an addend in its name.This means
sa_seq_nocan overrunGtid_log_event::write()’s buffer.This patch resizes the buffer to match
write()'s code.Gtid_log_eventis variable-sized, but it’s possible that an instance flags all its fields for writing.Release Notes
Fixed internal buffer overrun when writing a GTID event with all flags active.
How can this PR be tested?
TODO: We need a test that writes a
Gtid_log_eventwith every field flagged active, not only so Valgrind (or a manualDBUG_ASSERT) can catch buffer overruns, but also to validate future new fields that they don’t impact any existing fields.Basing the PR against the correct MariaDB version
[ ] This is a new feature or a refactoring, and the PR is based against themainbranch.PR quality check