From: Tom Lane Date: Thu, 23 Sep 2010 20:53:33 +0000 (-0400) Subject: Prevent show_session_authorization from crashing when session_authorization X-Git-Tag: REL8_3_12~12 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=7548ecb37380393fe6457fb405cdc86dd34a3390;p=postgresql Prevent show_session_authorization from crashing when session_authorization hasn't been set. The only known case where this can happen is when show_session_authorization is invoked in an autovacuum process, which is possible if an index function calls it, as for example in bug #5669 from Andrew Geery. We could perhaps try to return a sensible value, such as the name of the cluster-owning superuser; but that seems like much more trouble than the case is worth, and in any case it could create new possible failure modes. Simply returning an empty string seems like the most appropriate fix. Back-patch to all supported versions, even those before autovacuum, just in case there's another way to provoke this crash. --- diff --git a/src/backend/commands/variable.c b/src/backend/commands/variable.c index b16c1d38f6..b6bf4e1dc2 100644 --- a/src/backend/commands/variable.c +++ b/src/backend/commands/variable.c @@ -773,6 +773,10 @@ show_session_authorization(void) Oid savedoid; char *endptr; + /* If session_authorization hasn't been set in this process, return "" */ + if (value == NULL || value[0] == '\0') + return ""; + Assert(strspn(value, "x") == NAMEDATALEN && (value[NAMEDATALEN] == 'T' || value[NAMEDATALEN] == 'F'));