Fix unlikely overflow bug in bms_next_member()
... and bms_prev_member().
Both of these functions won't work correctly when given a prevbit of
INT_MAX and would crash when operating on a Bitmapset that happened to
have a member with that value.
Here we fix that by using an unsigned int to calculate which member to
look for next.
I've also adjusted bms_prev_member() to check for < 0 rather than == -1
for starting the loop. This was done as it's safer and comes at zero
extra cost.
With our current use cases, it's likely impossible to have a Bitmapset
with an INT_MAX member, so no backpatch here. I only noticed this issue
when working on a bms function to bitshift a Bitmapset.
Author: David Rowley <dgrowleyml@gmail.com>
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://postgr.es/m/CAApHDvr1B2gbf6JF69QmueM2QNRvbQeeKLxDnF=w9f9--022uA@mail.gmail.com
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/e3e26d04bd52795083b3947151c5c71e989a01f8
Modified Files
--------------
src/backend/nodes/bitmapset.c | 34 ++++++++++++++++++++--------------
1 file changed, 20 insertions(+), 14 deletions(-)
