postgres

History

Tom Lane d053a879bb Fix timing-dependent failure in GSSAPI data transmission. When using GSSAPI encryption in non-blocking mode, libpq sometimes failed with "GSSAPI caller failed to retransmit all data needing to be retried". The cause is that pqPutMsgEnd rounds its transmit request down to an even multiple of 8K, and sometimes that can lead to not requesting a write of data that was requested to be written (but reported as not written) earlier. That can upset pg_GSS_write's logic for dealing with not-yet-written data, since it's possible the data in question had already been incorporated into an encrypted packet that we weren't able to send during the previous call. We could fix this with a one-or-two-line hack to disable pqPutMsgEnd's round-down behavior, but that seems like making the caller work around a behavior that pg_GSS_write shouldn't expose in this way. Instead, adjust pg_GSS_write to never report a partial write: it either reports a complete write, or reflects the failure of the lower-level pqsecure_raw_write call. The requirement still exists for the caller to present at least as much data as on the previous call, but with the caller-visible write start point not moving there is no temptation for it to present less. We lose some ability to reclaim buffer space early, but I doubt that that will make much difference in practice. This also gets rid of a rather dubious assumption that "any interesting failure condition (from pqsecure_raw_write) will recur on the next try". We've not seen failure reports traceable to that, but I've never trusted it particularly and am glad to remove it. Make the same adjustments to the equivalent backend routine be_gssapi_write(). It is probable that there's no bug on the backend side, since we don't have a notion of nonblock mode there; but we should keep the logic the same to ease future maintenance. Per bug #18210 from Lars Kanis. Back-patch to all supported branches. Discussion: https://postgr.es/m/18210-4c6d0b14627f2eb8@postgresql.org		2 years ago
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po	Translation updates	2 years ago
t	Pre-beta mechanical code beautification.	3 years ago
test	Remove distprep	2 years ago
.gitignore	…
Makefile	Remove distprep	2 years ago
README	…
exports.txt	libpq: Add support for Close on portals and statements	3 years ago
fe-auth-sasl.h	Update copyright for 2023	3 years ago
fe-auth-scram.c	Add trailing commas to enum definitions	2 years ago
fe-auth.c	Introduce macros for protocol characters.	2 years ago
fe-auth.h	Make SCRAM iteration count configurable	3 years ago
fe-connect.c	Introduce macros for protocol characters.	2 years ago
fe-exec.c	Call pqPipelineFlush from PQsendFlushRequest	2 years ago
fe-gssapi-common.c	Update copyright for 2023	3 years ago
fe-gssapi-common.h	Update copyright for 2023	3 years ago
fe-lobj.c	Pre-beta mechanical code beautification.	3 years ago
fe-misc.c	Pre-beta mechanical code beautification.	3 years ago
fe-print.c	Remove --disable-thread-safety and related code.	2 years ago
fe-protocol3.c	Introduce macros for protocol characters.	2 years ago
fe-secure-common.c	Pre-beta mechanical code beautification.	3 years ago
fe-secure-common.h	Update copyright for 2023	3 years ago
fe-secure-gssapi.c	Fix timing-dependent failure in GSSAPI data transmission.	2 years ago
fe-secure-openssl.c	Remove --disable-thread-safety and related code.	2 years ago
fe-secure.c	Remove --disable-thread-safety and related code.	2 years ago
fe-trace.c	Introduce macros for protocol characters.	2 years ago
legacy-pqsignal.c	Remove --disable-thread-safety and related code.	2 years ago
libpq-events.c	Update copyright for 2023	3 years ago
libpq-events.h	Update copyright for 2023	3 years ago
libpq-fe.h	libpq: Add support for Close on portals and statements	3 years ago
libpq-int.h	Fix timing-dependent failure in GSSAPI data transmission.	2 years ago
meson.build	Support connection load balancing in libpq	3 years ago
nls.mk	Rename port/thread.c to port/user.c.	3 years ago
pg_service.conf.sample	…
pqexpbuffer.c	Add some const qualifiers	2 years ago
pqexpbuffer.h	Update copyright for 2023	3 years ago
pthread-win32.c	Update copyright for 2023	3 years ago
win32.c	Update copyright for 2023	3 years ago
win32.h	…

README

src/interfaces/libpq/README

This directory contains the C version of Libpq, the POSTGRES frontend library.