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* Initial pgindent and pgperltidy run for v13.Tom Lane2020-05-14
| | | | | | | | | | | Includes some manual cleanup of places that pgindent messed up, most of which weren't per project style anyway. Notably, it seems some people didn't absorb the style rules of commit c9d297751, because there were a bunch of new occurrences of function calls with a newline just after the left paren, all with faulty expectations about how the rest of the call would get indented.
* Remove excess parens in ereport() callsAlvaro Herrera2020-01-30
| | | | | | | Cosmetic cleanup, not worth backpatching. Discussion: https://postgr.es/m/20200129200401.GA6303@alvherre.pgsql Reviewed-by: Tom Lane, Michael Paquier
* Update copyrights for 2020Bruce Momjian2020-01-01
| | | | Backpatch-through: update all files in master, backpatch legal files through 9.4
* Fix use of term "verifier"Peter Eisentraut2019-10-12
| | | | | | | | | | | Within the context of SCRAM, "verifier" has a specific meaning in the protocol, per RFCs. The existing code used "verifier" differently, to mean whatever is or would be stored in pg_auth.rolpassword. Fix this by using the term "secret" for this, following RFC 5803. Reviewed-by: Michael Paquier <michael@paquier.xyz> Discussion: https://www.postgresql.org/message-id/flat/be397b06-6e4b-ba71-c7fb-54cae84a7e18%402ndquadrant.com
* Clean up some SCRAM attribute processingPeter Eisentraut2019-08-20
| | | | | | | | | Correct the comment for read_any_attr(). Give a clearer error message when parsing at the end of the string, when the client-final-message does not contain a "p" attribute (for some reason). Reviewed-by: Michael Paquier <michael@paquier.xyz> Discussion: https://www.postgresql.org/message-id/flat/2fb8a15b-de35-682d-a77b-edcc9c52fa12%402ndquadrant.com
* Introduce safer encoding and decoding routines for base64.cMichael Paquier2019-07-04
| | | | | | | | | | | | | | | | | | | This is a follow-up refactoring after 09ec55b and b674211, which has proved that the encoding and decoding routines used by SCRAM have a poor interface when it comes to check after buffer overflows. This adds an extra argument in the shape of the length of the result buffer for each routine, which is used for overflow checks when encoding or decoding an input string. The original idea comes from Tom Lane. As a result of that, the encoding routine can now fail, so all its callers are adjusted to generate proper error messages in case of problems. On failure, the result buffer gets zeroed. Author: Michael Paquier Reviewed-by: Daniel Gustafsson Discussion: https://postgr.es/m/20190623132535.GB1628@paquier.xyz
* Fix buffer overflow when parsing SCRAM verifiers in backendMichael Paquier2019-06-17
| | | | | | | | | | | | | | | | | | | Any authenticated user can overflow a stack-based buffer by changing the user's own password to a purpose-crafted value. This often suffices to execute arbitrary code as the PostgreSQL operating system account. This fix is contributed by multiple folks, based on an initial analysis from Tom Lane. This issue has been introduced by 68e61ee, so it was possible to make use of it at authentication time. It became more easily to trigger after ccae190 which has made the SCRAM parsing more strict when changing a password, in the case where the client passes down a verifier already hashed using SCRAM. Back-patch to v10 where SCRAM has been introduced. Reported-by: Alexander Lakhin Author: Jonathan Katz, Heikki Linnakangas, Michael Paquier Security: CVE-2019-10164 Backpatch-through: 10
* Phase 2 pgindent run for v12.Tom Lane2019-05-22
| | | | | | | | | Switch to 2.1 version of pg_bsd_indent. This formats multiline function declarations "correctly", that is with additional lines of parameter declarations indented to match where the first line's left parenthesis is. Discussion: https://postgr.es/m/CAEepm=0P3FeTXRcU5B2W3jv3PgRVZ-kGUXLGfd42FFhUROO3ug@mail.gmail.com
* Fix detection of passwords hashed with MD5 or SCRAM-SHA-256Michael Paquier2019-04-23
| | | | | | | | | | | | | | | | | | | | | | This commit fixes a couple of issues related to the way password verifiers hashed with MD5 or SCRAM-SHA-256 are detected, leading to being able to store in catalogs passwords which do not follow the supported hash formats: - A MD5-hashed entry was checked based on if its header uses "md5" and if the string length matches what is expected. Unfortunately the code never checked if the hash only used hexadecimal characters, as reported by Tom Lane. - A SCRAM-hashed entry was checked based on only its header, which should be "SCRAM-SHA-256$", but it never checked for any fields afterwards, as reported by Jonathan Katz. Backpatch down to v10, which is where SCRAM has been introduced, and where password verifiers in plain format have been removed. Author: Jonathan Katz Reviewed-by: Tom Lane, Michael Paquier Discussion: https://postgr.es/m/016deb6b-1f0a-8e9f-1833-a8675b170aa9@postgresql.org Backpatch-through: 10
* Get rid of another unconstify through API changesPeter Eisentraut2019-02-14
| | | | | | | | This also makes the code in read_client_first_message() more similar to read_client_final_message(). Reported-by: Mark Dilger <hornschnorter@gmail.com> Discussion: https://www.postgresql.org/message-id/flat/53a28052-f9f3-1808-fed9-460fd43035ab%402ndquadrant.com
* Update copyright for 2019Bruce Momjian2019-01-02
| | | | Backpatch-through: certain files through 9.4
* Remove configure switch --disable-strong-randomMichael Paquier2019-01-01
| | | | | | | | | | | | | | | | This removes a portion of infrastructure introduced by fe0a0b5 to allow compilation of Postgres in environments where no strong random source is available, meaning that there is no linking to OpenSSL and no /dev/urandom (Windows having its own CryptoAPI). No systems shipped this century lack /dev/urandom, and the buildfarm is actually not testing this switch at all, so just remove it. This simplifies particularly some backend code which included a fallback implementation using shared memory, and removes a set of alternate regression output files from pgcrypto. Author: Michael Paquier Reviewed-by: Tom Lane Discussion: https://postgr.es/m/20181230063219.GG608@paquier.xyz
* Minor cleanup/future-proofing for pg_saslprep().Tom Lane2018-09-08
| | | | | | | | | | | | | | | | | Ensure that pg_saslprep() initializes its output argument to NULL in all failure paths, and then remove the redundant initialization that some (not all) of its callers did. This does not fix any live bug, but it reduces the odds of future bugs of omission. Also add a comment about why the existing failure-path coding is adequate. Back-patch so as to keep the function's API consistent across branches, again to forestall future bug introduction. Patch by me, reviewed by Michael Paquier Discussion: https://postgr.es/m/16558.1536407783@sss.pgh.pa.us
* Remove support for tls-unique channel binding.Heikki Linnakangas2018-08-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are some problems with the tls-unique channel binding type. It's not supported by all SSL libraries, and strictly speaking it's not defined for TLS 1.3 at all, even though at least in OpenSSL, the functions used for it still seem to work with TLS 1.3 connections. And since we had no mechanism to negotiate what channel binding type to use, there would be awkward interoperability issues if a server only supported some channel binding types. tls-server-end-point seems feasible to support with any SSL library, so let's just stick to that. This removes the scram_channel_binding libpq option altogether, since there is now only one supported channel binding type. This also removes all the channel binding tests from the SSL test suite. They were really just testing the scram_channel_binding option, which is now gone. Channel binding is used if both client and server support it, so it is used in the existing tests. It would be good to have some tests specifically for channel binding, to make sure it really is used, and the different combinations of a client and a server that support or doesn't support it. The current set of settings we have make it hard to write such tests, but I did test those things manually, by disabling HAVE_BE_TLS_GET_CERTIFICATE_HASH and/or HAVE_PGTLS_GET_PEER_CERTIFICATE_HASH. I also removed the SCRAM_CHANNEL_BINDING_TLS_END_POINT constant. This is a matter of taste, but IMO it's more readable to just use the "tls-server-end-point" string. Refactor the checks on whether the SSL library supports the functions needed for tls-server-end-point channel binding. Now the server won't advertise, and the client won't choose, the SCRAM-SHA-256-PLUS variant, if compiled with an OpenSSL version too old to support it. In the passing, add some sanity checks to check that the chosen SASL mechanism, SCRAM-SHA-256 or SCRAM-SHA-256-PLUS, matches whether the SCRAM exchange used channel binding or not. For example, if the client selects the non-channel-binding variant SCRAM-SHA-256, but in the SCRAM message uses channel binding anyway. It's harmless from a security point of view, I believe, and I'm not sure if there are some other conditions that would cause the connection to fail, but it seems better to be strict about these things and check explicitly. Discussion: https://www.postgresql.org/message-id/ec787074-2305-c6f4-86aa-6902f98485a4%40iki.fi
* Implement channel binding tls-server-end-point for SCRAMPeter Eisentraut2018-01-04
| | | | | | | | This adds a second standard channel binding type for SCRAM. It is mainly intended for third-party clients that cannot implement tls-unique, for example JDBC. Author: Michael Paquier <michael.paquier@gmail.com>
* Refactor channel binding code to fetch cbind_data only when necessaryPeter Eisentraut2018-01-04
| | | | | | | | | | | | | | | | | | | | As things stand now, channel binding data is fetched from OpenSSL and saved into the SCRAM exchange context for any SSL connection attempted for a SCRAM authentication, resulting in data fetched but not used if no channel binding is used or if a different channel binding type is used than what the data is here for. Refactor the code in such a way that binding data is fetched from the SSL stack only when a specific channel binding is used for both the frontend and the backend. In order to achieve that, save the libpq connection context directly in the SCRAM exchange state, and add a dependency to SSL in the low-level SCRAM routines. This makes the interface in charge of initializing the SCRAM context cleaner as all its data comes from either PGconn* (for frontend) or Port* (for the backend). Author: Michael Paquier <michael.paquier@gmail.com>
* Update copyright for 2018Bruce Momjian2018-01-02
| | | | Backpatch-through: certain files through 9.3
* Check channel binding flag at end of SCRAM exchangePeter Eisentraut2017-12-01
| | | | | | | We need to check whether the channel-binding flag encoded in the client-final-message is the same one sent in the client-first-message. Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
* Update typedefs.list and re-run pgindentRobert Haas2017-11-29
| | | | Discussion: http://postgr.es/m/CA+TgmoaA9=1RWKtBWpDaj+sF3Stgc8sHgf5z=KGtbjwPLQVDMA@mail.gmail.com
* Support channel binding 'tls-unique' in SCRAMPeter Eisentraut2017-11-18
| | | | | | | | | | | | | | | | | | This is the basic feature set using OpenSSL to support the feature. In order to allow the frontend and the backend to fetch the sent and expected TLS Finished messages, a PG-like API is added to be able to make the interface pluggable for other SSL implementations. This commit also adds a infrastructure to facilitate the addition of future channel binding types as well as libpq parameters to control the SASL mechanism names and channel binding names. Those will be added by upcoming commits. Some tests are added to the SSL test suite to test SCRAM authentication with channel binding. Author: Michael Paquier <michael@paquier.xyz> Reviewed-by: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
* Fix typoStephen Frost2017-11-13
| | | | | | | Determinisitcally -> Deterministically Author: Michael Paquier <michael.paquier@gmail.com> Discussion: https://postgr.es/m/CAB7nPqSauJ9gUMzj1aiXQVxqEkyko+WZ+wUac8_hB_M_bO6U_A@mail.gmail.com
* Tweak some SCRAM error messages and code commentsPeter Eisentraut2017-08-23
| | | | | | Clarify/correct some error messages, fix up some code comments that confused SASL and SCRAM, and other minor fixes. No changes in functionality.
* Phase 3 of pgindent updates.Tom Lane2017-06-21
| | | | | | | | | | | | | | | | | | | | | | | | | Don't move parenthesized lines to the left, even if that means they flow past the right margin. By default, BSD indent lines up statement continuation lines that are within parentheses so that they start just to the right of the preceding left parenthesis. However, traditionally, if that resulted in the continuation line extending to the right of the desired right margin, then indent would push it left just far enough to not overrun the margin, if it could do so without making the continuation line start to the left of the current statement indent. That makes for a weird mix of indentations unless one has been completely rigid about never violating the 80-column limit. This behavior has been pretty universally panned by Postgres developers. Hence, disable it with indent's new -lpl switch, so that parenthesized lines are always lined up with the preceding left paren. This patch is much less interesting than the first round of indent changes, but also bulkier, so I thought it best to separate the effects. Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
* Re-run pgindent.Tom Lane2017-06-13
| | | | | | | | This is just to have a clean base state for testing of Piotr Stefaniak's latest version of FreeBSD indent. I fixed up a couple of places where pgindent would have changed format not-nicely. perltidy not included. Discussion: https://postgr.es/m/VI1PR03MB119959F4B65F000CA7CD9F6BF2CC0@VI1PR03MB1199.eurprd03.prod.outlook.com
* Improve authentication error messages.Heikki Linnakangas2017-06-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Most of the improvements were in the new SCRAM code: * In SCRAM protocol violation messages, use errdetail to provide the details. * If pg_backend_random() fails, throw an ERROR rather than just LOG. We shouldn't continue authentication if we can't generate a random nonce. * Use ereport() rather than elog() for the "invalid SCRAM verifier" messages. They shouldn't happen, if everything works, but it's not inconceivable that someone would have invalid scram verifiers in pg_authid, e.g. if a broken client application was used to generate the verifier. But this change applied to old code: * Use ERROR rather than COMMERROR for protocol violation errors. There's no reason to not tell the client what they did wrong. The client might be confused already, so that it cannot read and display the error correctly, but let's at least try. In the "invalid password packet size" case, we used to actually continue with authentication anyway, but that is now a hard error. Patch by Michael Paquier and me. Thanks to Daniel Varrazzo for spotting the typo in one of the messages that spurred the discussion and these larger changes. Discussion: https://www.postgresql.org/message-id/CA%2Bmi_8aZYLhuyQi1Jo0hO19opNZ2OEATEOM5fKApH7P6zTOZGg%40mail.gmail.com
* Remove support for password_encryption='off' / 'plain'.Heikki Linnakangas2017-05-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Storing passwords in plaintext hasn't been a good idea for a very long time, if ever. Now seems like a good time to finally forbid it, since we're messing with this in PostgreSQL 10 anyway. Remove the CREATE/ALTER USER UNENCRYPTED PASSSWORD 'foo' syntax, since storing passwords unencrypted is no longer supported. ENCRYPTED PASSWORD 'foo' is still accepted, but ENCRYPTED is now just a noise-word, it does the same as just PASSWORD 'foo'. Likewise, remove the --unencrypted option from createuser, but accept --encrypted as a no-op for backward compatibility. AFAICS, --encrypted was a no-op even before this patch, because createuser encrypted the password before sending it to the server even if --encrypted was not specified. It added the ENCRYPTED keyword to the SQL command, but since the password was already in encrypted form, it didn't make any difference. The documentation was not clear on whether that was intended or not, but it's moot now. Also, while password_encryption='on' is still accepted as an alias for 'md5', it is now marked as hidden, so that it is not listed as an accepted value in error hints, for example. That's not directly related to removing 'plain', but it seems better this way. Reviewed by Michael Paquier Discussion: https://www.postgresql.org/message-id/16e9b768-fd78-0b12-cfc1-7b6b7f238fde@iki.fi
* Fix memory leaks if random salt generation fails.Heikki Linnakangas2017-05-07
| | | | | | | In the backend, this is just to silence coverity warnings, but in the frontend, it's a genuine leak, even if extremely rare. Spotted by Coverity, patch by Michael Paquier.
* Misc cleanup of SCRAM code.Heikki Linnakangas2017-05-05
| | | | | | | | | | * Remove is_scram_verifier() function. It was unused. * Fix sanitize_char() function, used in error messages on protocol violations, to print bytes >= 0x7F correctly. * Change spelling of scram_MockSalt() function to be more consistent with the surroundings. * Change a few more references to "server proof" to "server signature" that I missed in commit d981074c24.
* Don't use SCRAM-specific "e=invalid-proof" on invalid password.Heikki Linnakangas2017-05-05
| | | | | | | | | | | | | | | | | | | | | | | | | Instead, send the same FATAL message as with other password-based authentication mechanisms. This gives a more user-friendly message: psql: FATAL: password authentication failed for user "test" instead of: psql: error received from server in SASL exchange: invalid-proof Even before this patch, the server sent that FATAL message, after the SCRAM-specific "e=invalid-proof" message. But libpq would stop at the SCRAM error message, and not process the ErrorResponse that would come after that. We could've taught libpq to check for an ErrorResponse after failed authentication, but it's simpler to modify the server to send only the ErrorResponse. The SCRAM specification allows for aborting the authentication at any point, using an application-defined error mechanism, like PostgreSQL's ErrorResponse. Using the e=invalid-proof message is optional. Reported by Jeff Janes. Discussion: https://www.postgresql.org/message-id/CAMkU%3D1w3jQ53M1OeNfN8Cxd9O%2BA_9VONJivTbYoYRRdRsLT6vA@mail.gmail.com
* Add PQencryptPasswordConn function to libpq, use it in psql and createuser.Heikki Linnakangas2017-05-03
| | | | | | | | | | | | The new function supports creating SCRAM verifiers, in addition to md5 hashes. The algorithm is chosen based on password_encryption, by default. This fixes the issue reported by Jeff Janes, that there was previously no way to create a SCRAM verifier with "\password". Michael Paquier and me Discussion: https://www.postgresql.org/message-id/CAMkU%3D1wfBgFPbfAMYZQE78p%3DVhZX7nN86aWkp0QcCp%3D%2BKxZ%3Dbg%40mail.gmail.com
* Misc SCRAM code cleanups.Heikki Linnakangas2017-04-28
| | | | | | | | | | | | | | | | | | | | * Move computation of SaltedPassword to a separate function from scram_ClientOrServerKey(). This saves a lot of cycles in libpq, by computing SaltedPassword only once per authentication. (Computing SaltedPassword is expensive by design.) * Split scram_ClientOrServerKey() into two functions. Improves readability, by making the calling code less verbose. * Rename "server proof" to "server signature", to better match the nomenclature used in RFC 5802. * Rename SCRAM_SALT_LEN to SCRAM_DEFAULT_SALT_LEN, to make it more clear that the salt can be of any length, and the constant only specifies how long a salt we use when we generate a new verifier. Also rename SCRAM_ITERATIONS_DEFAULT to SCRAM_DEFAULT_ITERATIONS, for consistency. These things caught my eye while working on other upcoming changes.
* Change the on-disk format of SCRAM verifiers to conform to RFC 5803.Heikki Linnakangas2017-04-21
| | | | | | | | | | | | | | | | | | | It doesn't make any immediate difference to PostgreSQL, but might as well follow the standard, since one exists. (I looked at RFC 5803 earlier, but didn't fully understand it back then.) The new format uses Base64 instead of hex to encode StoredKey and ServerKey, which makes the verifiers slightly smaller. Using the same encoding for the salt and the keys also means that you only need one encoder/decoder instead of two. Although we have code in the backend to do both, we are talking about teaching libpq how to create SCRAM verifiers for PQencodePassword(), and libpq doesn't currently have any code for hex encoding. Bump catversion, because this renders any existing SCRAM verifiers in pg_authid invalid. Discussion: https://www.postgresql.org/message-id/351ba574-85ea-d9b8-9689-8c928dd0955d@iki.fi
* Rename "scram" to "scram-sha-256" in pg_hba.conf and password_encryption.Heikki Linnakangas2017-04-18
| | | | | | | | | | | | | | | | | Per discussion, plain "scram" is confusing because we actually implement SCRAM-SHA-256 rather than the original SCRAM that uses SHA-1 as the hash algorithm. If we add support for SCRAM-SHA-512 or some other mechanism in the SCRAM family in the future, that would become even more confusing. Most of the internal files and functions still use just "scram" as a shorthand for SCRMA-SHA-256, but I did change PASSWORD_TYPE_SCRAM to PASSWORD_TYPE_SCRAM_SHA_256, as that could potentially be used by 3rd party extensions that hook into the password-check hook. Michael Paquier did this in an earlier version of the SCRAM patch set already, but I didn't include that in the version that was committed. Discussion: https://www.postgresql.org/message-id/fde71ff1-5858-90c8-99a9-1c2427e7bafb@iki.fi
* Improve the SASL authentication protocol.Heikki Linnakangas2017-04-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This contains some protocol changes to SASL authentiation (which is new in v10): * For future-proofing, in the AuthenticationSASL message that begins SASL authentication, provide a list of SASL mechanisms that the server supports, for the client to choose from. Currently, it's always just SCRAM-SHA-256. * Add a separate authentication message type for the final server->client SASL message, which the client doesn't need to respond to. This makes it unambiguous whether the client is supposed to send a response or not. The SASL mechanism should know that anyway, but better to be explicit. Also, in the server, support clients that don't send an Initial Client response in the first SASLInitialResponse message. The server is supposed to first send an empty request in that case, to which the client will respond with the data that usually comes in the Initial Client Response. libpq uses the Initial Client Response field and doesn't need this, and I would assume any other sensible implementation to use Initial Client Response, too, but let's follow the SASL spec. Improve the documentation on SASL authentication in protocol. Add a section describing the SASL message flow, and some details on our SCRAM-SHA-256 implementation. Document the different kinds of PasswordMessages that the frontend sends in different phases of SASL authentication, as well as GSS/SSPI authentication as separate message formats. Even though they're all 'p' messages, and the exact format depends on the context, describing them as separate message formats makes the documentation more clear. Reviewed by Michael Paquier and Álvaro Hernández Tortosa. Discussion: https://www.postgresql.org/message-id/CAB7nPqS-aFg0iM3AQOJwKDv_0WkAedRjs1W2X8EixSz+sKBXCQ@mail.gmail.com
* Minor cleanup of backend SCRAM code.Heikki Linnakangas2017-04-13
| | | | | | | | | | | | | | | | | Free each SASL message after sending it. It's not a lot of wasted memory, and it's short-lived, but the authentication code in general tries to pfree() stuff, so let's follow the example. Adding the pfree() revealed a little bug in build_server_first_message(). It attempts to keeps a copy of the sent message, but it was missing a pstrdup(), so the pointer started to dangle, after adding the pfree() into CheckSCRAMAuth(). Reword comments and debug messages slightly, while we're at it. Reviewed by Michael Paquier. Discussion: https://www.postgresql.org/message-id/6490b975-5ee1-6280-ac1d-af975b19fb9a@iki.fi
* Use SASLprep to normalize passwords for SCRAM authentication.Heikki Linnakangas2017-04-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | An important step of SASLprep normalization, is to convert the string to Unicode normalization form NFKC. Unicode normalization requires a fairly large table of character decompositions, which is generated from data published by the Unicode consortium. The script to generate the table is put in src/common/unicode, as well test code for the normalization. A pre-generated version of the tables is included in src/include/common, so you don't need the code in src/common/unicode to build PostgreSQL, only if you wish to modify the normalization tables. The SASLprep implementation depends on the UTF-8 functions from src/backend/utils/mb/wchar.c. So to use it, you must also compile and link that. That doesn't change anything for the current users of these functions, the backend and libpq, as they both already link with wchar.o. It would be good to move those functions into a separate file in src/commmon, but I'll leave that for another day. No documentation changes included, because there is no details on the SCRAM mechanism in the docs anyway. An overview on that in the protocol specification would probably be good, even though SCRAM is documented in detail in RFC5802. I'll write that as a separate patch. An important thing to mention there is that we apply SASLprep even on invalid UTF-8 strings, to support other encodings. Patch by Michael Paquier and me. Discussion: https://www.postgresql.org/message-id/CAB7nPqSByyEmAVLtEf1KxTRh=PWNKiWKEKQR=e1yGehz=wbymQ@mail.gmail.com
* Remove bogus SCRAM_ITERATION_LEN constant.Heikki Linnakangas2017-04-06
| | | | | | It was not used for what the comment claimed, at all. It was actually used as the 'base' argument to strtol(), when reading the iteration count. We don't need a constant for base-10, so remove it.
* Allow SCRAM authentication, when pg_hba.conf says 'md5'.Heikki Linnakangas2017-03-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If a user has a SCRAM verifier in pg_authid.rolpassword, there's no reason we cannot attempt to perform SCRAM authentication instead of MD5. The worst that can happen is that the client doesn't support SCRAM, and the authentication will fail. But previously, it would fail for sure, because we would not even try. SCRAM is strictly more secure than MD5, so there's no harm in trying it. This allows for a more graceful transition from MD5 passwords to SCRAM, as user passwords can be changed to SCRAM verifiers incrementally, without changing pg_hba.conf. Refactor the code in auth.c to support that better. Notably, we now have to look up the user's pg_authid entry before sending the password challenge, also when performing MD5 authentication. Also simplify the concept of a "doomed" authentication. Previously, if a user had a password, but it had expired, we still performed SCRAM authentication (but always returned error at the end) using the salt and iteration count from the expired password. Now we construct a fake salt, like we do when the user doesn't have a password or doesn't exist at all. That simplifies get_role_password(), and we can don't need to distinguish the "user has expired password", and "user does not exist" cases in auth.c. On second thoughts, also rename uaSASL to uaSCRAM. It refers to the mechanism specified in pg_hba.conf, and while we use SASL for SCRAM authentication at the protocol level, the mechanism should be called SCRAM, not SASL. As a comparison, we have uaLDAP, even though it looks like the plain 'password' authentication at the protocol level. Discussion: https://www.postgresql.org/message-id/6425.1489506016@sss.pgh.pa.us Reviewed-by: Michael Paquier
* Allow plaintext 'password' authentication when user has a SCRAM verifier.Heikki Linnakangas2017-03-17
| | | | Oversight in the main SCRAM patch.
* Fix comments in SCRAM-SHA-256 patch.Heikki Linnakangas2017-03-07
| | | | Amit Kapila.
* Support SCRAM-SHA-256 authentication (RFC 5802 and 7677).Heikki Linnakangas2017-03-07
This introduces a new generic SASL authentication method, similar to the GSS and SSPI methods. The server first tells the client which SASL authentication mechanism to use, and then the mechanism-specific SASL messages are exchanged in AuthenticationSASLcontinue and PasswordMessage messages. Only SCRAM-SHA-256 is supported at the moment, but this allows adding more SASL mechanisms in the future, without changing the overall protocol. Support for channel binding, aka SCRAM-SHA-256-PLUS is left for later. The SASLPrep algorithm, for pre-processing the password, is not yet implemented. That could cause trouble, if you use a password with non-ASCII characters, and a client library that does implement SASLprep. That will hopefully be added later. Authorization identities, as specified in the SCRAM-SHA-256 specification, are ignored. SET SESSION AUTHORIZATION provides more or less the same functionality, anyway. If a user doesn't exist, perform a "mock" authentication, by constructing an authentic-looking challenge on the fly. The challenge is derived from a new system-wide random value, "mock authentication nonce", which is created at initdb, and stored in the control file. We go through these motions, in order to not give away the information on whether the user exists, to unauthenticated users. Bumps PG_CONTROL_VERSION, because of the new field in control file. Patch by Michael Paquier and Heikki Linnakangas, reviewed at different stages by Robert Haas, Stephen Frost, David Steele, Aleksander Alekseev, and many others. Discussion: https://www.postgresql.org/message-id/CAB7nPqRbR3GmFYdedCAhzukfKrgBLTLtMvENOmPrVWREsZkF8g%40mail.gmail.com Discussion: https://www.postgresql.org/message-id/CAB7nPqSMXU35g%3DW9X74HVeQp0uvgJxvYOuA4A-A3M%2B0wfEBv-w%40mail.gmail.com Discussion: https://www.postgresql.org/message-id/55192AFE.6080106@iki.fi