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path: root/src/interfaces/libpq/fe-secure-gssapi.c
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* In libpq, always append new error messages to conn->errorMessage.Tom Lane2021-01-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously, we had an undisciplined mish-mash of printfPQExpBuffer and appendPQExpBuffer calls to report errors within libpq. This commit establishes a uniform rule that appendPQExpBuffer[Str] should be used. conn->errorMessage is reset only at the start of an application request, and then accumulates messages till we're done. We can remove no less than three different ad-hoc mechanisms that were used to get the effect of concatenation of error messages within a sequence of operations. Although this makes things quite a bit cleaner conceptually, the main reason to do it is to make the world safer for the multiple-target-host feature that was added awhile back. Previously, there were many cases in which an error occurring during an individual host connection attempt would wipe out the record of what had happened during previous attempts. (The reporting is still inadequate, in that it can be hard to tell which host got the failure, but that seems like a matter for a separate commit.) Currently, lo_import and lo_export contain exceptions to the "never use printfPQExpBuffer" rule. If we changed them, we'd risk reporting an incidental lo_close failure before the actual read or write failure, which would be confusing, not least because lo_close happened after the main failure. We could improve this by inventing an internal version of lo_close that doesn't reset the errorMessage; but we'd also need a version of PQfn() that does that, and it didn't quite seem worth the trouble for now. Discussion: https://postgr.es/m/BN6PR05MB3492948E4FD76C156E747E8BC9160@BN6PR05MB3492.namprd05.prod.outlook.com
* Update copyright for 2021Bruce Momjian2021-01-02
| | | | Backpatch-through: 9.5
* Fix bugs in libpq's GSSAPI encryption support.Tom Lane2020-12-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The critical issue fixed here is that if a GSSAPI-encrypted connection is successfully made, pqsecure_open_gss() cleared conn->allow_ssl_try, as an admittedly-hacky way of preventing us from then trying to tunnel SSL encryption over the already-encrypted connection. The problem with that is that if we abandon the GSSAPI connection because of a failure during authentication, we would not attempt SSL encryption in the next try with the same server. This can lead to unexpected connection failure, or silently getting a non-encrypted connection where an encrypted one is expected. Fortunately, we'd only manage to make a GSSAPI-encrypted connection if both client and server hold valid tickets in the same Kerberos infrastructure, which is a relatively uncommon environment. Nonetheless this is a very nasty bug with potential security consequences. To fix, don't reset the flag, instead adding a check for conn->gssenc being already true when deciding whether to try to initiate SSL. While here, fix some lesser issues in libpq's GSSAPI code: * Use the need_new_connection stanza when dropping an attempted GSSAPI connection, instead of partially duplicating that code. The consequences of this are pretty minor: AFAICS it could only lead to auth_req_received or password_needed remaining set when they shouldn't, which is not too harmful. * Fix pg_GSS_error() to not repeat the "mprefix" it's given multiple times, and to notice any failure return from gss_display_status(). * Avoid gratuitous dependency on NI_MAXHOST in pg_GSS_load_servicename(). Per report from Mikael Gustavsson. Back-patch to v12 where this code was introduced. Discussion: https://postgr.es/m/e5b0b6ed05764324a2f3fe7acfc766d5@smhi.se
* Replace calls of htonl()/ntohl() with pg_bswap.h for GSSAPI encryptionMichael Paquier2020-10-15
| | | | | | | | | The in-core equivalents can make use of built-in functions if the compiler supports this option, making optimizations possible. 0ba99c8 replaced all existing calls in the code base at this time, but b0b39f7 (GSSAPI encryption) has forgotten to do the switch. Discussion: https://postgr.es/m/20201014055303.GG3349@paquier.xyz
* Fix severe memory leaks in GSSAPI encryption support.Tom Lane2020-05-05
| | | | | | | | | | | | | | | | | Both the backend and libpq leaked buffers containing encrypted data to be transmitted, so that the process size would grow roughly as the total amount of data sent. There were also far-less-critical leaks of the same sort in GSSAPI session establishment. Oversight in commit b0b39f72b, which I failed to notice while reviewing the code in 2c0cdc818. Per complaint from pmc@citylink. Back-patch to v12 where this code was introduced. Discussion: https://postgr.es/m/20200504115649.GA77072@gate.oper.dinoex.org
* Extensive code review for GSSAPI encryption mechanism.Tom Lane2020-01-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix assorted bugs in handling of non-blocking I/O when using GSSAPI encryption. The encryption layer could return the wrong status information to its caller, resulting in effectively dropping some data (or possibly in aborting a not-broken connection), or in a "livelock" situation where data remains to be sent but the upper layers think transmission is done and just go to sleep. There were multiple small thinkos contributing to that, as well as one big one (failure to think through what to do when a send fails after having already transmitted data). Note that these errors could cause failures whether the client application asked for non-blocking I/O or not, since both libpq and the backend always run things in non-block mode at this level. Also get rid of use of static variables for GSSAPI inside libpq; that's entirely not okay given that multiple connections could be open at once inside a single client process. Also adjust a bunch of random small discrepancies between the frontend and backend versions of the send/receive functions -- except for error handling, they should be identical, and now they are. Also extend the Kerberos TAP tests to exercise cases where nontrivial amounts of data need to be pushed through encryption. Before, those tests didn't provide any useful coverage at all for the cases of interest here. (They still might not, depending on timing, but at least there's a chance.) Per complaint from pmc@citylink and subsequent investigation. Back-patch to v12 where this code was introduced. Discussion: https://postgr.es/m/20200109181822.GA74698@gate.oper.dinoex.org
* Update copyrights for 2020Bruce Momjian2020-01-01
| | | | Backpatch-through: update all files in master, backpatch legal files through 9.4
* Make the order of the header file includes consistent in non-backend modules.Amit Kapila2019-10-25
| | | | | | | | | | | | Similar to commit 7e735035f2, this commit makes the order of header file inclusion consistent for non-backend modules. In passing, fix the case where we were using angle brackets (<>) for the local module includes instead of quotes (""). Author: Vignesh C Reviewed-by: Amit Kapila Discussion: https://postgr.es/m/CALDaNm2Sznv8RR6Ex-iJO6xAdsxgWhCoETkaYX=+9DW3q0QCfA@mail.gmail.com
* GSSAPI error message improvementsPeter Eisentraut2019-09-19
| | | | | | | | | | Make the error messages around GSSAPI encryption a bit clearer. Tweak some messages to avoid plural problems. Also make a code change for clarity. Using "conf" for "confidential" is quite confusing. Using "conf_state" is perhaps not much better but that's what the GSSAPI documentation uses, so there is at least some hope of understanding it.
* Update copyright year.Thomas Munro2019-05-24
| | | | | Reviewed-by: Michael Paquier Discussion: https://postgr.es/m/CA%2BhUKGJFWXmtYo6Frd77RR8YXCHz7hJ2mRy5aHV%3D7fJOqDnBHA%40mail.gmail.com
* Fix assorted minor bogosity in GSSAPI transport error messages.Tom Lane2019-04-17
| | | | | | | | | | | I noted that some buildfarm members were complaining about %ld being used to format values that are (probably) declared size_t. Use %zu instead, and insert a cast just in case some versions of the GSSAPI API declare the length field differently. While at it, clean up gratuitous differences in wording of equivalent messages, show the complained-of length in all relevant messages not just some, include trailing newline where needed, adjust random deviations from project-standard code layout and message style, etc.
* Handle errors during GSSAPI startup betterStephen Frost2019-04-04
| | | | | | | | | | | | | | | | | | | | | There was some confusion over the format of the error message returned from the server during GSSAPI startup; specifically, it was expected that a length would be returned when, in reality, at this early stage in the startup sequence, no length is returned from the server as part of an error message. Correct the client-side code for dealing with error messages sent by the server during startup by simply reading what's available into our buffer, after we've discovered it's an error message, and then reporting back what was returned. In passing, also add in documentation of the environment variable PGGSSENCMODE which was missed previously, and adjust the code to look for the PGGSSENCMODE variable (the environment variable change was missed in the prior GSSMODE -> GSSENCMODE commit). Error-handling issue discovered by Peter Eisentraut, the rest were items discovered during testing of the error handling.
* GSSAPI encryption supportStephen Frost2019-04-03
On both the frontend and backend, prepare for GSSAPI encryption support by moving common code for error handling into a separate file. Fix a TODO for handling multiple status messages in the process. Eliminate the OIDs, which have not been needed for some time. Add frontend and backend encryption support functions. Keep the context initiation for authentication-only separate on both the frontend and backend in order to avoid concerns about changing the requested flags to include encryption support. In postmaster, pull GSSAPI authorization checking into a shared function. Also share the initiator name between the encryption and non-encryption codepaths. For HBA, add "hostgssenc" and "hostnogssenc" entries that behave similarly to their SSL counterparts. "hostgssenc" requires either "gss", "trust", or "reject" for its authentication. Similarly, add a "gssencmode" parameter to libpq. Supported values are "disable", "require", and "prefer". Notably, negotiation will only be attempted if credentials can be acquired. Move credential acquisition into its own function to support this behavior. Add a simple pg_stat_gssapi view similar to pg_stat_ssl, for monitoring if GSSAPI authentication was used, what principal was used, and if encryption is being used on the connection. Finally, add documentation for everything new, and update existing documentation on connection security. Thanks to Michael Paquier for the Windows fixes. Author: Robbie Harwood, with changes to the read/write functions by me. Reviewed in various forms and at different times by: Michael Paquier, Andres Freund, David Steele. Discussion: https://www.postgresql.org/message-id/flat/jlg1tgq1ktm.fsf@thriss.redhat.com