If the user has certificates in $HOME/.postgresql/postgresql.crt
and $HOME/.postgresql/postgresql.key exist, they are provided
to the server. The certificate used to sign this cert must be
known to the server, in $DataDir/root.crt. If successful, the
cert's "common name" is logged.
Client certs are not used for authentication, but they could be
via the port->peer (X509 *), port->peer_dn (char *) or
port->peer_cn (char *) fields. Or any other function could be
used, e.g., many sites like the issuer + serial number hash.
Bear Giles
In order to reduce the risk of cryptanalysis during extended
sessions (or brief ones involving a substantial amount of data),
this patch renegotiates the session key after 64kib has been
transferred.
Bear Giles
are motivated by security concerns, it's not just bug fixes. The key
differences (from stock 7.2.1) are:
*) almost all code that directly uses the OpenSSL library is in two
new files,
src/interfaces/libpq/fe-ssl.c
src/backend/postmaster/be-ssl.c
in the long run, it would be nice to merge these two files.
*) the legacy code to read and write network data have been
encapsulated into read_SSL() and write_SSL(). These functions
should probably be renamed - they handle both SSL and non-SSL
cases.
the remaining code should eliminate the problems identified
earlier, albeit not very cleanly.
*) both front- and back-ends will send a SSL shutdown via the
new close_SSL() function. This is necessary for sessions to
work properly.
(Sessions are not yet fully supported, but by cleanly closing
the SSL connection instead of just sending a TCP FIN packet
other SSL tools will be much happier.)
*) The client certificate and key are now expected in a subdirectory
of the user's home directory. Specifically,
- the directory .postgresql must be owned by the user, and
allow no access by 'group' or 'other.'
- the file .postgresql/postgresql.crt must be a regular file
owned by the user.
- the file .postgresql/postgresql.key must be a regular file
owned by the user, and allow no access by 'group' or 'other'.
At the current time encrypted private keys are not supported.
There should also be a way to support multiple client certs/keys.
*) the front-end performs minimal validation of the back-end cert.
Self-signed certs are permitted, but the common name *must*
match the hostname used by the front-end. (The cert itself
should always use a fully qualified domain name (FDQN) in its
common name field.)
This means that
psql -h eris db
will fail, but
psql -h eris.example.com db
will succeed. At the current time this must be an exact match;
future patches may support any FQDN that resolves to the address
returned by getpeername(2).
Another common "problem" is expiring certs. For now, it may be
a good idea to use a very-long-lived self-signed cert.
As a compile-time option, the front-end can specify a file
containing valid root certificates, but it is not yet required.
*) the back-end performs minimal validation of the client cert.
It allows self-signed certs. It checks for expiration. It
supports a compile-time option specifying a file containing
valid root certificates.
*) both front- and back-ends default to TLSv1, not SSLv3/SSLv2.
*) both front- and back-ends support DSA keys. DSA keys are
moderately more expensive on startup, but many people consider
them preferable than RSA keys. (E.g., SSH2 prefers DSA keys.)
*) if /dev/urandom exists, both client and server will read 16k
of randomization data from it.
*) the server can read empheral DH parameters from the files
$DataDir/dh512.pem
$DataDir/dh1024.pem
$DataDir/dh2048.pem
$DataDir/dh4096.pem
if none are provided, the server will default to hardcoded
parameter files provided by the OpenSSL project.
Remaining tasks:
*) the select() clauses need to be revisited - the SSL abstraction
layer may need to absorb more of the current code to avoid rare
deadlock conditions. This also touches on a true solution to
the pg_eof() problem.
*) the SIGPIPE signal handler may need to be revisited.
*) support encrypted private keys.
*) sessions are not yet fully supported. (SSL sessions can span
multiple "connections," and allow the client and server to avoid
costly renegotiations.)
*) makecert - a script that creates back-end certs.
*) pgkeygen - a tool that creates front-end certs.
*) the whole protocol issue, SASL, etc.
*) certs are fully validated - valid root certs must be available.
This is a hassle, but it means that you *can* trust the identity
of the server.
*) the client library can handle hardcoded root certificates, to
avoid the need to copy these files.
*) host name of server cert must resolve to IP address, or be a
recognized alias. This is more liberal than the previous
iteration.
*) the number of bytes transferred is tracked, and the session
key is periodically renegotiated.
*) basic cert generation scripts (mkcert.sh, pgkeygen.sh). The
configuration files have reasonable defaults for each type
of use.
Bear Giles
A new pg_hba.conf column, USER
Allow specifiction of lists of users separated by commas
Allow group names specified by +
Allow include files containing lists of users specified by @
Allow lists of databases, and database files
Allow samegroup in database column to match group name matching dbname
Removal of secondary password files
Remove pg_passwd utility
Lots of code cleanup in user.c and hba.c
New data/global/pg_pwd format
New data/global/pg_group file
when to send what to which, prevent recursion by introducing new COMMERROR
elog level for client-communication problems, get rid of direct writes
to stderr in backend/libpq files, prevent non-error elogs from going to
client during the authentication cycle.
to use and significantly faster. This tweak saves 25% (!) of the runtime
of COPY IN in a test with 8000-character lines. I wouldn't normally
commit a performance improvement this late in the cycle, but 25% got
my attention...
postmaster children before client auth step. Postmaster now rereads
pg_pwd on receipt of SIGHUP, the same way that pg_hba.conf is handled.
No cycles need be expended to validate password cache validity during
connection startup.
> pam_strerror() should be used a few more times, rather than just saying
> "Error!". Also, the configure.in snippet seems wrong. You add
> -I$pam_prefix/include/security to $INCLUDES and then you #include
> <security/pam_appl.h>. This whole thing is probably unnecessary, since
> PAM is a system library on the systems where it exists, so the headers
> and libraries are found automatically, unlike OpenSSL and
> Kerberos.
See attached revised patch. (I'm sure the configure.in stuff can be done
right/better, I'm just not enough of a autoconf guru to know what to
change it to.)
Dominic J. Eidson
includes windows.h, which #defines ERROR to 0. PostgreSQL's logging functions
define ERROR to -1. This patch redefines ERROR to -1 to avoid current or
future breakage of the logging functions.
Gerhard H?ring
Allow pg_shadow to be MD5 encrypted.
Add ENCRYPTED/UNENCRYPTED option to CREATE/ALTER user.
Add password_encryption postgresql.conf option.
Update wire protocol version to 2.1.
system supports SO_PEERCRED requests for Unix sockets. This is an
amalgamation of patches submitted by Helge Bahmann and Oliver Elphick,
with some editorializing by yours truly.
number in the data structure so that we can give at least a minimally
useful idea of where the mistake is when we issue syntax error messages.
Move the ClientAuthentication() call to where it should have been in
the first place, so that postmaster memory releasing can happen in a
reasonable place also. Update obsolete comments, correct one real bug
(auth_argument was not picked up correctly).
a new postmaster child process. This should eliminate problems with
authentication blocking (e.g., ident, SSL init) and also reduce problems
with the accept queue filling up under heavy load.
The option to send elog output to a different file per backend (postgres -o)
has been disabled for now because the initialization would have to happen
in a different order and it's not clear we want to keep this anyway.
are now separate files "postgres.h" and "postgres_fe.h", which are meant
to be the primary include files for backend .c files and frontend .c files
respectively. By default, only include files meant for frontend use are
installed into the installation include directory. There is a new make
target 'make install-all-headers' that adds the whole content of the
src/include tree to the installed fileset, for use by people who want to
develop server-side code without keeping the complete source tree on hand.
Cleaned up a whole lot of crufty and inconsistent header inclusions.
to ensure that we have released buffer refcounts and so forth, rather than
putting ad-hoc operations before (some of the calls to) proc_exit. Add
commentary to discourage future hackers from repeating that mistake.
hosting product, on both shared and dedicated machines. We currently
offer Oracle and MySQL, and it would be a nice middle-ground.
However, as shipped, PostgreSQL lacks the following features we need
that MySQL has:
1. The ability to listen only on a particular IP address. Each
hosting customer has their own IP address, on which all of their
servers (http, ftp, real media, etc.) run.
2. The ability to place the Unix-domain socket in a mode 700 directory.
This allows us to automatically create an empty database, with an
empty DBA password, for new or upgrading customers without having
to interactively set a DBA password and communicate it to (or from)
the customer. This in turn cuts down our install and upgrade times.
3. The ability to connect to the Unix-domain socket from within a
change-rooted environment. We run CGI programs chrooted to the
user's home directory, which is another reason why we need to be
able to specify where the Unix-domain socket is, instead of /tmp.
4. The ability to, if run as root, open a pid file in /var/run as
root, and then setuid to the desired user. (mysqld -u can almost
do this; I had to patch it, too).
The patch below fixes problem 1-3. I plan to address #4, also, but
haven't done so yet. These diffs are big enough that they should give
the PG development team something to think about in the meantime :-)
Also, I'm about to leave for 2 weeks' vacation, so I thought I'd get
out what I have, which works (for the problems it tackles), now.
With these changes, we can set up and run PostgreSQL with scripts the
same way we can with apache or proftpd or mysql.
In summary, this patch makes the following enhancements:
1. Adds an environment variable PGUNIXSOCKET, analogous to MYSQL_UNIX_PORT,
and command line options -k --unix-socket to the relevant programs.
2. Adds a -h option to postmaster to set the hostname or IP address to
listen on instead of the default INADDR_ANY.
3. Extends some library interfaces to support the above.
4. Fixes a few memory leaks in PQconnectdb().
The default behavior is unchanged from stock 7.0.2; if you don't use
any of these new features, they don't change the operation.
David J. MacKenzie
