From: Tom Lane Date: Thu, 3 Sep 2009 22:08:54 +0000 (+0000) Subject: Disallow RESET ROLE and RESET SESSION AUTHORIZATION inside security-definer X-Git-Tag: REL8_0_22~2 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7020c762c6effda79bad9d27877900aeb369219a;p=thirdparty%2Fpostgresql.git Disallow RESET ROLE and RESET SESSION AUTHORIZATION inside security-definer functions. This extends the previous patch that forbade SETting these variables inside security-definer functions. RESET is equally a security hole, since it would allow regaining privileges of the caller; furthermore it can trigger Assert failures and perhaps other internal errors, since the code is not expecting these variables to change in such contexts. The previous patch did not cover this case because assign hooks don't really have enough information, so move the responsibility for preventing this into guc.c. Problem discovered by Heikki Linnakangas. Security: no CVE assigned yet, extends CVE-2007-6600 --- diff --git a/src/backend/commands/variable.c b/src/backend/commands/variable.c index 2639a033f38..549725db705 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 1.105.4.4 2008/01/03 21:25:00 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/commands/variable.c,v 1.105.4.5 2009/09/03 22:08:54 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -656,22 +656,6 @@ assign_session_authorization(const char *value, bool doit, GucSource source) /* not a saved ID, so look it up */ HeapTuple userTup; - 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()) { /* diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 3309fbf4e7a..6b612fb5313 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -10,7 +10,7 @@ * Written by Peter Eisentraut . * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.252.4.5 2008/05/26 18:54:59 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.252.4.6 2009/09/03 22:08:54 tgl Exp $ * *-------------------------------------------------------------------- */ @@ -1682,7 +1682,7 @@ static struct config_string ConfigureNamesString[] = {"session_authorization", PGC_USERSET, UNGROUPED, gettext_noop("Sets the session user name."), NULL, - GUC_IS_NAME | GUC_REPORT | GUC_NO_SHOW_ALL | GUC_NO_RESET_ALL | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE + GUC_IS_NAME | GUC_REPORT | GUC_NO_SHOW_ALL | GUC_NO_RESET_ALL | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_NOT_WHILE_SEC_DEF }, &session_authorization_string, NULL, assign_session_authorization, show_session_authorization @@ -3374,6 +3374,32 @@ set_config_option(const char *name, const char *value, break; } + /* + * Disallow changing GUC_NOT_WHILE_SEC_DEF values if we are inside a + * security-definer function. We can reject this regardless of + * the context or source, mainly because sources that it might be + * reasonable to override for won't be seen while inside a function. + * + * Note: variables marked GUC_NOT_WHILE_SEC_DEF should probably be marked + * GUC_NO_RESET_ALL as well, because ResetAllOptions() doesn't check this. + * + * Note: this flag is currently used for "session_authorization". + * We need to prohibit this because when we exit the sec-def + * context, GUC won't be notified, leaving things out of sync. + * + * XXX it would be nice to allow these cases in future, with the behavior + * being that the SET's effects end when the security definer context is + * exited. + */ + if ((record->flags & GUC_NOT_WHILE_SEC_DEF) && InSecurityDefinerContext()) + { + ereport(elevel, + (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), + errmsg("cannot set parameter \"%s\" within security-definer function", + name))); + return false; + } + /* * Should we set reset/stacked values? (If so, the behavior is not * transactional.) diff --git a/src/include/utils/guc_tables.h b/src/include/utils/guc_tables.h index 4c26e10aaee..83bd78b32d4 100644 --- a/src/include/utils/guc_tables.h +++ b/src/include/utils/guc_tables.h @@ -7,7 +7,7 @@ * * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group * - * $PostgreSQL: pgsql/src/include/utils/guc_tables.h,v 1.19.4.1 2006/02/12 22:33:14 tgl Exp $ + * $PostgreSQL: pgsql/src/include/utils/guc_tables.h,v 1.19.4.2 2009/09/03 22:08:54 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -127,6 +127,8 @@ struct config_generic #define GUC_SUPERUSER_ONLY 0x0100 /* show only to superusers */ #define GUC_IS_NAME 0x0200 /* limit string to NAMEDATALEN-1 */ +#define GUC_NOT_WHILE_SEC_DEF 0x8000 /* can't change inside sec-def func */ + /* bit values in status field */ #define GUC_HAVE_TENTATIVE 0x0001 /* tentative value is defined */ #define GUC_HAVE_LOCAL 0x0002 /* a SET LOCAL has been executed */