From 3af35f8d40bede09c4fe976050ff402dc346dbf2 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Thu, 3 Jan 2008 21:23:45 +0000 Subject: Make standard maintenance operations (including VACUUM, ANALYZE, REINDEX, and CLUSTER) execute as the table owner rather than the calling user, using the same privilege-switching mechanism already used for SECURITY DEFINER functions. The purpose of this change is to ensure that user-defined functions used in index definitions cannot acquire the privileges of a superuser account that is performing routine maintenance. While a function used in an index is supposed to be IMMUTABLE and thus not able to do anything very interesting, there are several easy ways around that restriction; and even if we could plug them all, there would remain a risk of reading sensitive information and broadcasting it through a covert channel such as CPU usage. To prevent bypassing this security measure, execution of SET SESSION AUTHORIZATION and SET ROLE is now forbidden within a SECURITY DEFINER context. Thanks to Itagaki Takahiro for reporting this vulnerability. Security: CVE-2007-6600 --- src/backend/commands/variable.c | 37 ++++++++++++++++++++++++++++++++++++- 1 file changed, 36 insertions(+), 1 deletion(-) (limited to 'src/backend/commands/variable.c') diff --git a/src/backend/commands/variable.c b/src/backend/commands/variable.c index c910f6376fd..730a3ac4289 100644 --- a/src/backend/commands/variable.c +++ b/src/backend/commands/variable.c @@ -9,7 +9,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/commands/variable.c,v 1.119 2006/10/04 00:29:52 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/commands/variable.c,v 1.119.2.1 2008/01/03 21:23:45 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -620,6 +620,22 @@ assign_session_authorization(const char *value, bool doit, GucSource source) /* not a saved ID, so look it up */ HeapTuple roleTup; + if (InSecurityDefinerContext()) + { + /* + * Disallow SET SESSION AUTHORIZATION inside a security definer + * context. We need to do this because when we exit the context, + * GUC won't be notified, leaving things out of sync. Note that + * this test is positioned so that restoring a previously saved + * setting isn't prevented. + */ + if (source >= PGC_S_INTERACTIVE) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("cannot set session authorization within security-definer function"))); + return NULL; + } + if (!IsTransactionState()) { /* @@ -727,6 +743,25 @@ assign_role(const char *value, bool doit, GucSource source) } } + if (roleid == InvalidOid && InSecurityDefinerContext()) + { + /* + * Disallow SET ROLE inside a security definer context. We need to do + * this because when we exit the context, GUC won't be notified, + * leaving things out of sync. Note that this test is arranged so + * that restoring a previously saved setting isn't prevented. + * + * XXX it would be nice to allow this case in future, with the + * behavior being that the SET ROLE's effects end when the security + * definer context is exited. + */ + if (source >= PGC_S_INTERACTIVE) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("cannot set role within security-definer function"))); + return NULL; + } + if (roleid == InvalidOid && strcmp(actual_rolename, "none") != 0) { -- cgit v1.2.3