pgcrypto: Detect and report too-short crypt() salts.

Certain short salts crashed the backend or disclosed a few bytes of
backend memory.  For existing salt-induced error conditions, emit a
message saying as much.  Back-patch to 9.0 (all supported versions).

Josh Kupershmidt

Security: CVE-2015-5288

contrib/pgcrypto/sql/crypt-blowfish.sql

@@ -6,6 +6,15 @@ SELECT crypt('', '$2a$06$RQiOJ.3ELirrXwxIZY8q0O');
 
 SELECT crypt('foox', '$2a$06$RQiOJ.3ELirrXwxIZY8q0O');
 
+-- error, salt too short:
+SELECT crypt('foox', '$2a$');
+
+-- error, first digit of count in salt invalid
+SELECT crypt('foox', '$2a$40$RQiOJ.3ELirrXwxIZY8q0O');
+
+-- error, count in salt too small
+SELECT crypt('foox', '$2a$00$RQiOJ.3ELirrXwxIZY8q0O');
+
 CREATE TABLE ctest (data text, res text, salt text);
 INSERT INTO ctest VALUES ('password', '', '');
 

contrib/pgcrypto/sql/crypt-des.sql

@@ -6,6 +6,10 @@ SELECT crypt('', 'NB');
 
 SELECT crypt('foox', 'NB');
 
+-- We are supposed to pass in a 2-character salt.
+-- error since salt is too short:
+SELECT crypt('password', 'a');
+
 CREATE TABLE ctest (data text, res text, salt text);
 INSERT INTO ctest VALUES ('password', '', '');
 

contrib/pgcrypto/sql/crypt-xdes.sql

@@ -6,6 +6,22 @@ SELECT crypt('', '_J9..j2zz');
 
 SELECT crypt('foox', '_J9..j2zz');
 
+-- check XDES handling of keys longer than 8 chars
+SELECT crypt('longlongpassword', '_J9..j2zz');
+
+-- error, salt too short
+SELECT crypt('foox', '_J9..BWH');
+
+-- error, count specified in the second argument is 0
+SELECT crypt('password', '_........');
+
+-- error, count will wind up still being 0 due to invalid encoding
+-- of the count: only chars ``./0-9A-Za-z' are valid
+SELECT crypt('password', '_..!!!!!!');
+
+-- count should be non-zero here, will work
+SELECT crypt('password', '_/!!!!!!!');
+
 CREATE TABLE ctest (data text, res text, salt text);
 INSERT INTO ctest VALUES ('password', '', '');