pgsql: Fix potential integer overflow in bringetbitmap()

Fix potential integer overflow in bringetbitmap()

This function expects an "int64" as result and stores the number of
pages to add to the index scan bitmap as an "int", multiplying its final
result by 10. For a relation large enough, this can theoretically
overflow if counting more than (INT32_MAX / 10) pages, knowing that the
number of pages is upper-bounded by MaxBlockNumber.

To avoid the overflow, this commit redefines "totalpages", used to
calculate the result, to be an "int64" rather than an "int".

Reported-by: Evgeniy Gorbanyov
Author: James Hunter
Discussion: https://www.postgresql.org/message-id/07704817-6fa0-460c-b1cf-cd18f7647041@basealt.ru
Backpatch-through: 13

Branch
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REL_13_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/332023e2d032743ce487b47f6d5f43111ca3fc0c

Modified Files
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src/backend/access/brin/brin.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)