postgresql/src/interfaces/libpq/fe-auth.h

Ignoring revisions in .git-blame-ignore-revs. Click here to bypass and see the normal blame view.

33 lines
981 B
C
Raw Normal View History

/*-------------------------------------------------------------------------
*
* fe-auth.h
*
* Definitions for network authentication routines
*
* Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
2010-09-20 22:08:53 +02:00
* src/interfaces/libpq/fe-auth.h
*
*-------------------------------------------------------------------------
*/
#ifndef FE_AUTH_H
#define FE_AUTH_H
#include "libpq-fe.h"
#include "libpq-int.h"
Support SCRAM-SHA-256 authentication (RFC 5802 and 7677). 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
2017-03-07 13:25:40 +01:00
/* Prototypes for functions in fe-auth.c */
extern int pg_fe_sendauth(AuthRequest areq, int payloadlen, PGconn *conn);
extern char *pg_fe_getusername(uid_t user_id, PQExpBuffer errorMessage);
Fix libpq's behavior when /etc/passwd isn't readable. Some users run their applications in chroot environments that lack an /etc/passwd file. This means that the current UID's user name and home directory are not obtainable. libpq used to be all right with that, so long as the database role name to use was specified explicitly. But commit a4c8f14364c27508233f8a31ac4b10a4c90235a9 broke such cases by causing any failure of pg_fe_getauthname() to be treated as a hard error. In any case it did little to advance its nominal goal of causing errors in pg_fe_getauthname() to be reported better. So revert that and instead put some real error-reporting code in place. This requires changes to the APIs of pg_fe_getauthname() and pqGetpwuid(), since the latter had departed from the POSIX-specified API of getpwuid_r() in a way that made it impossible to distinguish actual lookup errors from "no such user". To allow such failures to be reported, while not failing if the caller supplies a role name, add a second call of pg_fe_getauthname() in connectOptions2(). This is a tad ugly, and could perhaps be avoided with some refactoring of PQsetdbLogin(), but I'll leave that idea for later. (Note that the complained-of misbehavior only occurs in PQsetdbLogin, not when using the PQconnect functions, because in the latter we will never bother to call pg_fe_getauthname() if the user gives a role name.) In passing also clean up the Windows-side usage of GetUserName(): the recommended buffer size is 257 bytes, the passed buffer length should be the buffer size not buffer size less 1, and any error is reported by GetLastError() not errno. Per report from Christoph Berg. Back-patch to 9.4 where the chroot failure case was introduced. The generally poor reporting of errors here is of very long standing, of course, but given the lack of field complaints about it we won't risk changing these APIs further back (even though they're theoretically internal to libpq).
2015-01-11 18:35:44 +01:00
extern char *pg_fe_getauthname(PQExpBuffer errorMessage);
/* Mechanisms in fe-auth-scram.c */
extern const pg_fe_sasl_mech pg_scram_mech;
extern char *pg_fe_scram_build_secret(const char *password,
Make SCRAM iteration count configurable 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
2023-03-27 09:46:29 +02:00
int iterations,
const char **errstr);
Support SCRAM-SHA-256 authentication (RFC 5802 and 7677). 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
2017-03-07 13:25:40 +01:00
#endif /* FE_AUTH_H */