The proposed OAUTHBEARER SASL mechanism will need to allow larger
messages in the exchange, since tokens are sent directly by the
client. Move this limit into the pg_be_sasl_mech struct so that
it can be changed per-mechanism.
Author: Jacob Champion <jacob.champion@enterprisedb.com>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://postgr.es/m/CAOYmi+nqX_5=Se0W0Ynrr55Fha3CMzwv_R9P3rkpHb=1kG7ZTQ@mail.gmail.com
PostgreSQL has for a long time mixed two BIO implementations, which can
lead to subtle bugs and inconsistencies. This cleans up our BIO by just
just setting up the methods we need. This patch does not introduce any
functionality changes.
The following methods are no longer defined due to not being needed:
- gets: Not used by libssl
- puts: Not used by libssl
- create: Sets up state not used by libpq
- destroy: Not used since libpq use BIO_NOCLOSE, if it was used it close
the socket from underneath libpq
- callback_ctrl: Not implemented by sockets
The following methods are defined for our BIO:
- read: Used for reading arbitrary length data from the BIO. No change
in functionality from the previous implementation.
- write: Used for writing arbitrary length data to the BIO. No change
in functionality from the previous implementation.
- ctrl: Used for processing ctrl messages in the BIO (similar to ioctl).
The only ctrl message which matters is BIO_CTRL_FLUSH used for
writing out buffered data (or signal EOF and that no more data
will be written). BIO_CTRL_FLUSH is mandatory to implement and
is implemented as a no-op since there is no intermediate buffer
to flush.
BIO_CTRL_EOF is the out-of-band method for signalling EOF to
read_ex based BIO's. Our BIO is not read_ex based but someone
could accidentally call BIO_CTRL_EOF on us so implement mainly
for completeness sake.
As the implementation is no longer related to BIO_s_socket or calling
SSL_set_fd, methods have been renamed to reference the PGconn and Port
types instead.
This also reverts back to using BIO_set_data, with our fallback, as a small
optimization as BIO_set_app_data require the ex_data mechanism in OpenSSL.
Author: David Benjamin <davidben@google.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://postgr.es/m/CAF8qwaCZ97AZWXtg_y359SpOHe+HdJ+p0poLCpJYSUxL-8Eo8A@mail.gmail.com
Commit 6aa44060a3 removed pg_authid's TOAST table because the only
varlena column is rolpassword, which cannot be de-TOASTed during
authentication because we haven't selected a database yet and
cannot read pg_class. Since that change, attempts to set password
hashes that require out-of-line storage will fail with a "row is
too big" error. This error message might be confusing to users.
This commit places a limit on the length of password hashes so that
attempts to set long password hashes will fail with a more
user-friendly error. The chosen limit of 512 bytes should be
sufficient to avoid "row is too big" errors independent of BLCKSZ,
but it should also be lenient enough for all reasonable use-cases
(or at least all the use-cases we could imagine).
Reviewed-by: Tom Lane, Jonathan Katz, Michael Paquier, Jacob Champion
Discussion: https://postgr.es/m/89e8649c-eb74-db25-7945-6d6b23992394%40gmail.com
The existing function PQprotocolVersion() does not include the minor
version of the protocol. In preparation for pending work that will
bump that number for the first time, add a new function to provide it
to clients that may care, using the (major * 10000 + minor)
convention already used by PQserverVersion().
Jacob Champion based on earlier work by Jelte Fennema-Nio
Discussion: http://postgr.es/m/CAOYmi+mM8+6Swt1k7XsLcichJv8xdhPnuNv7-02zJWsezuDL+g@mail.gmail.com
Commit f4b54e1ed9, which introduced macros for protocol characters,
missed updating a few places. It also did not introduce macros for
messages sent from parallel workers to their leader processes.
This commit adds a new section in protocol.h for those.
Author: Aleksander Alekseev
Discussion: https://postgr.es/m/CAJ7c6TNTd09AZq8tGaHS3LDyH_CCnpv0oOz2wN1dGe8zekxrdQ%40mail.gmail.com
Backpatch-through: 17
Make sure that function declarations use names that exactly match the
corresponding names from function definitions in a few places. These
inconsistencies were all introduced during Postgres 17 development.
pg_bsd_indent still has a couple of similar inconsistencies, which I
(pgeoghegan) have left untouched for now.
This commit was written with help from clang-tidy, by mechanically
applying the same rules as similar clean-up commits (the earliest such
commit was commit 035ce1fe).
libpq now always tries to send ALPN. With the traditional negotiated
SSL connections, the server accepts the ALPN, and refuses the
connection if it's not what we expect, but connecting without ALPN is
still OK. With the new direct SSL connections, ALPN is mandatory.
NOTE: This uses "TBD-pgsql" as the protocol ID. We must register a
proper one with IANA before the release!
Author: Greg Stark, Heikki Linnakangas
Reviewed-by: Matthias van de Meent, Jacob Champion
By skipping SSLRequest, you can eliminate one round-trip when
establishing a TLS connection. It is also more friendly to generic TLS
proxies that don't understand the PostgreSQL protocol.
This is disabled by default in libpq, because the direct TLS handshake
will fail with old server versions. It can be enabled with the
sslnegotation=direct option. It will still fall back to the negotiated
TLS handshake if the server rejects the direct attempt, either because
it is an older version or the server doesn't support TLS at all, but
the fallback can be disabled with the sslnegotiation=requiredirect
option.
Author: Greg Stark, Heikki Linnakangas
Reviewed-by: Matthias van de Meent, Jacob Champion
Apparently these markers cause the modules to not link correctly in some
platforms, at least per buildfarm member indri; moreover, this code is
only used in modules that don't have a translation. If we someday add
i18n support to contrib/ it might be worth revisiting this.
Commit 61461a300c introduced new functions to libpq for cancelling
queries. This commit introduces a helper function that backend-side
libraries and extensions can use to invoke those. This function takes a
timeout and can itself be interrupted while it is waiting for a cancel
request to be sent and processed, instead of being blocked.
This replaces the usage of the old functions in postgres_fdw and dblink.
Finally, it also adds some test coverage for the cancel support in
postgres_fdw.
Author: Jelte Fennema-Nio <postgres@jeltef.nl>
Discussion: https://postgr.es/m/CAGECzQT_VgOWWENUqvUV9xQmbaCyXjtRRAYO8W07oqashk_N+g@mail.gmail.com
This adds the X509 attributes notBefore and notAfter to sslinfo
as well as pg_stat_ssl to allow verifying and identifying the
validity period of the current client certificate. OpenSSL has
APIs for extracting notAfter and notBefore, but they are only
supported in recent versions so we have to calculate the dates
by hand in order to make this work for the older versions of
OpenSSL that we still support.
Original patch by Cary Huang with additional hacking by Jacob
and myself.
Author: Cary Huang <cary.huang@highgo.ca>
Co-author: Jacob Champion <jacob.champion@enterprisedb.com>
Co-author: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://postgr.es/m/182b8565486.10af1a86f158715.2387262617218380588@highgo.ca
In postmaster, use a more lightweight ClientSocket struct that
encapsulates just the socket itself and the remote endpoint's address
that you get from accept() call. ClientSocket is passed to the child
process, which initializes the bigger Port struct. This makes it more
clear what information postmaster initializes, and what is left to the
child process.
Rename the StreamServerPort and StreamConnection functions to make it
more clear what they do. Remove StreamClose, replacing it with plain
closesocket() calls.
Reviewed-by: Tristan Partin, Andres Freund
Discussion: https://www.postgresql.org/message-id/7a59b073-5b5b-151e-7ed3-8b01ff7ce9ef@iki.fi
We used to smuggle it to the child process in the Port struct, but it
seems better to pass it down as a separate argument. This paves the
way for the next commit, which moves the initialization of the Port
struct to the backend process, after forking.
Reviewed-by: Tristan Partin, Andres Freund
Discussion: https://www.postgresql.org/message-id/7a59b073-5b5b-151e-7ed3-8b01ff7ce9ef@iki.fi
Now that BackendId was just another index into the proc array, it was
redundant with the 0-based proc numbers used in other places. Replace
all usage of backend IDs with proc numbers.
The only place where the term "backend id" remains is in a few pgstat
functions that expose backend IDs at the SQL level. Those IDs are now
in fact 0-based ProcNumbers too, but the documentation still calls
them "backend ids". That term still seems appropriate to describe what
the numbers are, so I let it be.
One user-visible effect is that pg_temp_0 is now a valid temp schema
name, for backend with ProcNumber 0.
Reviewed-by: Andres Freund
Discussion: https://www.postgresql.org/message-id/8171f1aa-496f-46a6-afc3-c46fe7a9b407@iki.fi
This replaces dblink's blocking libpq calls, allowing cancellation and
allowing DROP DATABASE (of a database not involved in the query). Apart
from explicit dblink_cancel_query() calls, dblink still doesn't cancel
the remote side. The replacement for the blocking calls consists of
new, general-purpose query execution wrappers in the libpqsrv facility.
Out-of-tree extensions should adopt these. Use them in postgres_fdw,
replacing a local implementation from which the libpqsrv implementation
derives. This is a bug fix for dblink. Code inspection identified the
bug at least thirteen years ago, but user complaints have not appeared.
Hence, no back-patch for now.
Discussion: https://postgr.es/m/20231122012945.74@rfd.leadboat.com
Since C99, there can be a trailing comma after the last value in an
enum definition. A lot of new code has been introducing this style on
the fly. Some new patches are now taking an inconsistent approach to
this. Some add the last comma on the fly if they add a new last
value, some are trying to preserve the existing style in each place,
some are even dropping the last comma if there was one. We could
nudge this all in a consistent direction if we just add the trailing
commas everywhere once.
I omitted a few places where there was a fixed "last" value that will
always stay last. I also skipped the header files of libpq and ecpg,
in case people want to use those with older compilers. There were
also a small number of cases where the enum type wasn't used anywhere
(but the enum values were), which ended up confusing pgindent a bit,
so I left those alone.
Discussion: https://www.postgresql.org/message-id/flat/386f8c45-c8ac-4681-8add-e3b0852c1620%40eisentraut.org
Keep track of the used size of the array. That avoids looping through
the whole array in a few places. It doesn't matter from a performance
point of view since the array is small anyway, but this feels less
surprising and is a little less code. Now that we have an explicit
NumListenSockets variable that is statically initialized to 0, we
don't need the loop to initialize the array.
Allocate the array in PostmasterContext. The array isn't needed in
child processes, so this allows reusing that memory. We could easily
make the array resizable now, but we haven't heard any complaints
about the current 64 sockets limit.
Discussion: https://www.postgresql.org/message-id/7bb7ad65-a018-2419-742f-fa5fd877d338@iki.fi
This commit introduces descriptively-named macros for the
identifiers used in wire protocol messages. These new macros are
placed in a new header file so that they can be easily used by
third-party code.
Author: Dave Cramer
Reviewed-by: Alvaro Herrera, Tatsuo Ishii, Peter Smith, Robert Haas, Tom Lane, Peter Eisentraut, Michael Paquier
Discussion: https://postgr.es/m/CADK3HHKbBmK-PKf1bPNFoMC%2BoBt%2BpD9PH8h5nvmBQskEHm-Ehw%40mail.gmail.com
This adds the X509 attributes notBefore and notAfter to sslinfo
as well as pg_stat_ssl to allow verifying and identifying the
validity period of the current client certificate.
Author: Cary Huang <cary.huang@highgo.ca>
Discussion: https://postgr.es/m/182b8565486.10af1a86f158715.2387262617218380588@highgo.ca
Here are some notes about this change:
- As X509_get_signature_nid() should always exist (OpenSSL and
LibreSSL), hence HAVE_X509_GET_SIGNATURE_NID is now gone.
- OPENSSL_API_COMPAT is bumped to 0x10002000L.
- One comment related to 1.0.1e introduced by 74242c2 is removed.
Upstream OpenSSL still provides long-term support for 1.0.2 in a closed
fashion, so removing it is out of scope for a few years, at least.
Reviewed-by: Jacob Champion, Daniel Gustafsson
Discussion: https://postgr.es/m/ZG3JNursG69dz1lr@paquier.xyz
- Commit 3eb77eba5a, which moved the pending ops queue from md.c to
sync.c, introduced a duplicate, unused 'pendingOpsCxt'
variable. (I'm surprised none of the compilers or static analysis
tools have complained about that.)
- Commit c2fe139c20 moved the 'synchronize_seqscans' variable and
introduced an extern declaration in tableam.h, making the one in
guc_tables.c unnecessary.
- Commit 6f0cf87872 removed the 'pgstat_temp_directory' GUC, but
forgot to remove the corresponding global variable.
- Commit 1b4e729eaa removed the 'pg_krb_realm' GUC, and its global
variable, but forgot the declaration in auth.h.
Spotted all these by reading the code.
This reverts commit 3d03b24c3 (Revert Add support for Kerberos
credential delegation) which was committed on the grounds of concern
about portability, but on further review and discussion, it's clear that
we are better off explicitly requiring MIT Kerberos as that appears to
be the only GSSAPI library currently that's under proper maintenance
and ongoing development. The API used for storing credentials was added
to MIT Kerberos over a decade ago while for the other libraries which
appear to be mainly based on Heimdal, which exists explicitly to be a
re-implementation of MIT Kerberos, the API never made it to a released
version (even though it was added to the Heimdal git repo over 5 years
ago..).
This post-feature-freeze change was approved by the RMT.
Discussion: https://postgr.es/m/ZDDO6jaESKaBgej0%40tamriel.snowman.net
This reverts commit 3d4fa227bc.
Per discussion and buildfarm, this depends on APIs that seem to not
be available on at least one platform (NetBSD). Should be certainly
possible to rework to be optional on that platform if necessary but bit
late for that at this point.
Discussion: https://postgr.es/m/3286097.1680922218@sss.pgh.pa.us
Support GSSAPI/Kerberos credentials being delegated to the server by a
client. With this, a user authenticating to PostgreSQL using Kerberos
(GSSAPI) credentials can choose to delegate their credentials to the
PostgreSQL server (which can choose to accept them, or not), allowing
the server to then use those delegated credentials to connect to
another service, such as with postgres_fdw or dblink or theoretically
any other service which is able to be authenticated using Kerberos.
Both postgres_fdw and dblink are changed to allow non-superuser
password-less connections but only when GSSAPI credentials have been
delegated to the server by the client and GSSAPI is used to
authenticate to the remote system.
Authors: Stephen Frost, Peifeng Qiu
Reviewed-By: David Christensen
Discussion: https://postgr.es/m/CO1PR05MB8023CC2CB575E0FAAD7DF4F8A8E29@CO1PR05MB8023.namprd05.prod.outlook.com
This refactors libpq to copy addrinfos returned by getaddrinfo to
memory owned by libpq such that future improvements can alter for
example the order of entries.
As a nice side effect of this refactor the mechanism for iteration
over addresses in PQconnectPoll is now identical to its iteration
over hosts.
Author: Jelte Fennema <postgres@jeltef.nl>
Reviewed-by: Aleksander Alekseev <aleksander@timescale.com>
Reviewed-by: Michael Banck <mbanck@gmx.net>
Reviewed-by: Andrey Borodin <amborodin86@gmail.com>
Discussion: https://postgr.es/m/PR3PR83MB04768E2FF04818EEB2179949F7A69@PR3PR83MB0476.EURPRD83.prod.outlook.com
Replace the hardcoded value with a GUC such that the iteration
count can be raised in order to increase protection against
brute-force attacks. The hardcoded value for SCRAM iteration
count was defined to be 4096, which is taken from RFC 7677, so
set the default for the GUC to 4096 to match. In RFC 7677 the
recommendation is at least 15000 iterations but 4096 is listed
as a SHOULD requirement given that it's estimated to yield a
0.5s processing time on a mobile handset of the time of RFC
writing (late 2015).
Raising the iteration count of SCRAM will make stored passwords
more resilient to brute-force attacks at a higher computational
cost during connection establishment. Lowering the count will
reduce computational overhead during connections at the tradeoff
of reducing strength against brute-force attacks.
There are however platforms where even a modest iteration count
yields a too high computational overhead, with weaker password
encryption schemes chosen as a result. In these situations,
SCRAM with a very low iteration count still gives benefits over
weaker schemes like md5, so we allow the iteration count to be
set to one at the low end.
The new GUC is intentionally generically named such that it can
be made to support future SCRAM standards should they emerge.
At that point the value can be made into key:value pairs with
an undefined key as a default which will be backwards compatible
with this.
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Jonathan S. Katz <jkatz@postgresql.org>
Discussion: https://postgr.es/m/F72E7BC7-189F-4B17-BF47-9735EB72C364@yesql.se
Support for SCM credential authentication has been removed in the
backend in 9.1, and libpq has kept some code to handle it for
compatibility.
Commit be4585b, that did the cleanup of the backend code, has done
so because the code was not really portable originally. And, as there
are likely little chances that this is used these days, this removes the
remaining code from libpq. An error will now be raised by libpq if
attempting to connect to a server that returns AUTH_REQ_SCM_CREDS,
instead.
References to SCM credential authentication are removed from the
protocol documentation. This removes some meson and configure checks.
Author: Michael Paquier
Reviewed-by: Tom Lane
Discussion: https://postgr.es/m/ZBLH8a4otfqgd6Kn@paquier.xyz
The hook can be installed by a shared_preload library.
A similar mechanism could be used for radius paswords, for example, and
the type name auth_password_hook_typ has been shosen with that in mind.
John Naylor and Andrew Dunstan
Discussion: https://postgr.es/m/469b06ed-69de-ba59-c13a-91d2372e52a9@dunslane.net
The new connection parameter require_auth allows a libpq client to
define a list of comma-separated acceptable authentication types for use
with the server. There is no negotiation: if the server does not
present one of the allowed authentication requests, the connection
attempt done by the client fails.
The following keywords can be defined in the list:
- password, for AUTH_REQ_PASSWORD.
- md5, for AUTH_REQ_MD5.
- gss, for AUTH_REQ_GSS[_CONT].
- sspi, for AUTH_REQ_SSPI and AUTH_REQ_GSS_CONT.
- scram-sha-256, for AUTH_REQ_SASL[_CONT|_FIN].
- creds, for AUTH_REQ_SCM_CREDS (perhaps this should be removed entirely
now).
- none, to control unauthenticated connections.
All the methods that can be defined in the list can be negated, like
"!password", in which case the server must NOT use the listed
authentication type. The special method "none" allows/disallows the use
of unauthenticated connections (but it does not govern transport-level
authentication via TLS or GSSAPI).
Internally, the patch logic is tied to check_expected_areq(), that was
used for channel_binding, ensuring that an incoming request is
compatible with conn->require_auth. It also introduces a new flag,
conn->client_finished_auth, which is set by various authentication
routines when the client side of the handshake is finished. This
signals to check_expected_areq() that an AUTH_REQ_OK from the server is
expected, and allows the client to complain if the server bypasses
authentication entirely, with for example the reception of a too-early
AUTH_REQ_OK message.
Regression tests are added in authentication TAP tests for all the
keywords supported (except "creds", because it is around only for
compatibility reasons). A new TAP script has been added for SSPI, as
there was no script dedicated to it yet. It relies on SSPI being the
default authentication method on Windows, as set by pg_regress.
Author: Jacob Champion
Reviewed-by: Peter Eisentraut, David G. Johnston, Michael Paquier
Discussion: https://postgr.es/m/9e5a8ccddb8355ea9fa4b75a1e3a9edc88a70cd3.camel@vmware.com
OpenSSL 1.1.1 and newer versions have added support for RSA-PSS
certificates, which requires the use of a specific routine in OpenSSL to
determine which hash function to use when compiling it when using
channel binding in SCRAM-SHA-256. X509_get_signature_nid(), that is the
original routine the channel binding code has relied on, is not able to
determine which hash algorithm to use for such certificates. However,
X509_get_signature_info(), new to OpenSSL 1.1.1, is able to do it. This
commit switches the channel binding logic to rely on
X509_get_signature_info() over X509_get_signature_nid(), which would be
the choice when building with 1.1.1 or newer.
The error could have been triggered on the client or the server, hence
libpq and the backend need to have their related code paths patched.
Note that attempting to load an RSA-PSS certificate with OpenSSL 1.1.0
or older leads to a failure due to an unsupported algorithm.
The discovery of relying on X509_get_signature_info() comes from Jacob,
the tests have been written by Heikki (with few tweaks from me), while I
have bundled the whole together while adding the bits needed for MSVC
and meson.
This issue exists since channel binding exists, so backpatch all the way
down. Some tests are added in 15~, triggered if compiling with OpenSSL
1.1.1 or newer, where the certificate and key files can easily be
generated for RSA-PSS.
Reported-by: Gunnar "Nick" Bluth
Author: Jacob Champion, Heikki Linnakangas
Discussion: https://postgr.es/m/17760-b6c61e752ec07060@postgresql.org
Backpatch-through: 11
In the 90s we needed to deal with computers that still had the
pre-standard signal masking APIs. That hasn't been relevant for a very
long time on Unix systems, and c94ae9d8 got rid of a remaining
dependency in our Windows porting code. PG_SETMASK didn't expose
save/restore functionality, so we'd already started using sigprocmask()
directly in places, creating the visual distraction of having two ways
to spell it. It's not part of the API that extensions are expected to
be using (but if they are, the change will be trivial). It seems like a
good time to drop the old macro and just call the standard POSIX
function.
Reviewed-by: Nathan Bossart <nathandbossart@gmail.com>
Discussion: https://postgr.es/m/CA%2BhUKG%2BKfQgrhHP2DLTohX1WwubaCBHmTzGnAEDPZ-Gug-Xskg%40mail.gmail.com
Currently dblink and postgres_fdw don't process interrupts during connection
establishment. Besides preventing query cancellations etc, this can lead to
undetected deadlocks, as global barriers are not processed.
Libpqwalreceiver in contrast, processes interrupts during connection
establishment. The required code is not trivial, so duplicating it into
additional places does not seem like a good option.
These aforementioned undetected deadlocks are the reason for the spate of CI
test failures in the FreeBSD 'test_running' step.
For now the helper library is just a header, as it needs to be linked into
each extension using libpq, and it seems too small to be worth adding a
dedicated static library for.
The conversion to the helper are done in subsequent commits.
Reviewed-by: Thomas Munro <thomas.munro@gmail.com>
Discussion: https://postgr.es/m/20220925232237.p6uskba2dw6fnwj2@awork3.anarazel.de
While system_user was stored as an AuthToken in IdentLine, pg_user was
stored as a plain string. This commit changes the code as we start
storing pg_user as an AuthToken too.
This does not have any functional changes, as all the operations on
pg_user only use the string from the AuthToken. There is no regexp
compiled and no check based on its quoting, yet. This is in preparation
of more features that intend to extend its capabilities, like support
for regexps and group membership.
Author: Jelte Fennema
Discussion: https://postgr.es/m/CAGECzQRNow4MwkBjgPxywXdJU_K3a9+Pm78JB7De3yQwwkTDew@mail.gmail.com
The code that handles authentication for user maps was pretty confusing
with its choice of variable names. It involves two types of users: a
system user and a Postgres user (well, role), and these were not named
consistently throughout the code that processes the user maps loaded
from pg_ident.conf at authentication.
This commit changes the following things to improve the situation:
- Rename "pg_role" to "pg_user" and "token" to "system_user" in
IndetLine. These choices are more consistent with the pg_ident.conf
example in the docs, as well. "token" has been introduced recently in
fc579e1, and it is way worse than the choice before that, "ident_user".
- Switch the order of the fields in IdentLine to map with the order of
the items in the ident files, as of map name, system user and PG user.
- In check_ident_usermap(), rename "regexp_pgrole" to "expanded_pg_user"
when processing a regexp for the system user entry in a user map. This
variable does not store a regular expression at all: it would be either
a string or a substitution to \1 if the Postgres role is specified as
such.
Author: Jelte Fennema
Discussion: https://postgr.es/m/CAGECzQTkwELHUOAKhvdA+m3tWbUQySHHkExJV8GAZ1pwgbEgXg@mail.gmail.com
A comment in hba.h mentioned that AuthTokens are used when building the
IdentLines from pg_ident.conf, but since 8fea868 that has added support
of regexps for databases and roles in pg_hba.conf, it is also the case
of HBA files. This refreshes the comment to refer to both HBA and ident
files.
Issue spotted while going through a different patch.
Switch to a design similar to regular backends, instead of the previous
arrangement where signal handlers did non-trivial state management and
called fork(). The main changes are:
* The postmaster now has its own local latch to wait on. (For now, we
don't want other backends setting its latch directly, but that could
probably be made to work with more research on robustness.)
* The existing signal handlers are cut in two: a handle_pm_XXX() part
that just sets pending_pm_XXX flags and the latch, and a
process_pm_XXX() part that runs later when the latch is seen.
* Signal handlers are now installed with the regular pqsignal()
function rather than the special pqsignal_pm() function; historical
portability concerns about the effect of SA_RESTART on select() are no
longer relevant, and we don't need to block signals anymore.
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CA%2BhUKG%2BZ-HpOj1JsO9eWUP%2Bar7npSVinsC_npxSy%2BjdOMsx%3DGg%40mail.gmail.com
SCRAM_KEY_LEN was a variable used in the internal routines of SCRAM to
size a set of fixed-sized arrays used in the SHA and HMAC computations
during the SASL exchange or when building a SCRAM password. This had a
hard dependency on SHA-256, reducing the flexibility of SCRAM when it
comes to the addition of more hash methods. A second issue was that
SHA-256 is assumed as the cryptohash method to use all the time.
This commit renames SCRAM_KEY_LEN to a more generic SCRAM_KEY_MAX_LEN,
which is used as the size of the buffers used by the internal routines
of SCRAM. This is aimed at tracking centrally the maximum size
necessary for all the hash methods supported by SCRAM. A global
variable has the advantage of keeping the code in its simplest form,
reducing the need of more alloc/free logic for all the buffers used in
the hash calculations.
A second change is that the key length (SHA digest length) and hash
types are now tracked by the state data in the backend and the frontend,
the common portions being extended to handle these as arguments by the
internal routines of SCRAM. There are a few RFC proposals floating
around to extend the SCRAM protocol, including some to use stronger
cryptohash algorithms, so this lifts some of the existing restrictions
in the code.
The code in charge of parsing and building SCRAM secrets is extended to
rely on the key length and on the cryptohash type used for the exchange,
assuming currently that only SHA-256 is supported for the moment. Note
that the mock authentication simply enforces SHA-256.
Author: Michael Paquier
Reviewed-by: Peter Eisentraut, Jonathan Katz
Discussion: https://postgr.es/m/Y5k3Qiweo/1g9CG6@paquier.xyz
