Bug: ecdsa_is_valid_private_key() first returns "true" but later "false" for the same value

[joelonsql]

I've tested this on PostgreSQL 15.1 (Ubuntu 15.1-1.pgdg22.04+1) on aarch64-unknown-linux-gnu, compiled by gcc (Ubuntu 11.3.0-1ubuntu1~22.04) 11.3.0, 64-bit

Very strange problem:

joel@linux:~/pg-ecdsa$ make installcheck
echo "+++ regress install-check in  +++" && /usr/lib/postgresql/15/lib/pgxs/src/makefiles/../../src/test/regress/pg_regress --inputdir=./ --bindir='/usr/lib/postgresql/15/bin'    --dbname=contrib_regression pguecc_test_raw pguecc_test_public
+++ regress install-check in  +++
(using postmaster on Unix socket, default port)
============== dropping database "contrib_regression" ==============
SET
DROP DATABASE
============== creating database "contrib_regression" ==============
CREATE DATABASE
ALTER DATABASE
ALTER DATABASE
ALTER DATABASE
ALTER DATABASE
ALTER DATABASE
ALTER DATABASE
============== running regression test queries        ==============
test pguecc_test_raw              ... ok           13 ms
test pguecc_test_public           ... FAILED       14 ms

======================
 1 of 2 tests failed.
======================

The differences that caused some tests to fail can be viewed in the
file "/home/joel/pg-ecdsa/regression.diffs".  A copy of the test summary that you see
above is saved in the file "/home/joel/pg-ecdsa/regression.out".

make: *** [/usr/lib/postgresql/15/lib/pgxs/src/makefiles/pgxs.mk:433: installcheck] Error 1

joel@linux:~/pg-ecdsa$ cat /home/joel/pg-ecdsa/regression.diffs
diff -U3 /home/joel/pg-ecdsa/expected/pguecc_test_public.out /home/joel/pg-ecdsa/results/pguecc_test_public.out
--- /home/joel/pg-ecdsa/expected/pguecc_test_public.out	2022-12-01 13:06:54.798948391 +0000
+++ /home/joel/pg-ecdsa/results/pguecc_test_public.out	2022-12-01 13:14:16.060144414 +0000
@@ -77,7 +77,7 @@
 select ecdsa_is_valid_private_key('000000000000000000000000000000000000000000', 'secp160r1');
  ecdsa_is_valid_private_key
 ----------------------------
- f
+ t
 (1 row)


joel@linux:~/pg-ecdsa$ psql test
psql (15.1 (Ubuntu 15.1-1.pgdg22.04+1))
Type "help" for help.

test=# select ecdsa_is_valid_private_key('000000000000000000000000000000000000000000', 'secp160r1');
 ecdsa_is_valid_private_key
----------------------------
 f
(1 row)

test=# select ecdsa_is_valid_private_key('000000000000000000000000000000000000000000', 'secp160r1');
 ecdsa_is_valid_private_key
----------------------------
 t
(1 row)

test=# select ecdsa_is_valid_private_key('000000000000000000000000000000000000000000', 'secp160r1');
 ecdsa_is_valid_private_key
----------------------------
 t
(1 row)

test=# \q

[SvanteRichter]

@joelonsql Did you investigate this more? I'm trying to gauge how serious this bug is.