pgsql: Follow-up fixes for SHA-2 patch (commit 749a9e20c).

Follow-up fixes for SHA-2 patch (commit 749a9e20c).

This changes the check for valid characters in the salt string to
only allow plain ASCII letters and digits. The previous coding was
locale-dependent which doesn't really seem like a great idea here;
moreover it could not work correctly in multibyte encodings.

This fixes a careless pointer-use-after-pfree, too.

Reported-by: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Reported-by: Andres Freund <andres(at)anarazel(dot)de>
Author: Bernd Helmle <mailings(at)oopsware(dot)de>
Discussion: https://postgr.es/m/6fab35422df6b6b9727fdcc243c5fa1c667dd3b5.camel@oopsware.de

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/969ab9d4f5d141ac25db092a0e5cd004d3d60a60

Modified Files
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contrib/pgcrypto/crypt-sha.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)