From 846fcc85167c417873865099d70068ed85f758a8 Mon Sep 17 00:00:00 2001 From: Robert Haas Date: Sun, 29 Oct 2017 12:58:40 +0530 Subject: [PATCH] Fix problems with the "role" GUC and parallel query. Without this fix, dropping a role can sometimes result in parallel query failures in sessions that have used "SET ROLE" to assume the dropped role, even if that setting isn't active any more. Report by Pavan Deolasee. Patch by Amit Kapila, reviewed by me. Discussion: http://postgr.es/m/CABOikdOomRcZsLsLK+Z+qENM1zxyaWnAvFh3MJZzZnnKiF+REg@mail.gmail.com --- src/backend/access/transam/parallel.c | 11 ++++++++ src/backend/utils/misc/guc.c | 25 +++++++------------ src/include/utils/guc.h | 1 + src/test/regress/expected/select_parallel.out | 16 ++++++++++++ src/test/regress/sql/select_parallel.sql | 11 ++++++++ 5 files changed, 48 insertions(+), 16 deletions(-) diff --git a/src/backend/access/transam/parallel.c b/src/backend/access/transam/parallel.c index d683050733..1f542ed8d8 100644 --- a/src/backend/access/transam/parallel.c +++ b/src/backend/access/transam/parallel.c @@ -75,9 +75,11 @@ typedef struct FixedParallelState Oid database_id; Oid authenticated_user_id; Oid current_user_id; + Oid outer_user_id; Oid temp_namespace_id; Oid temp_toast_namespace_id; int sec_context; + bool is_superuser; PGPROC *parallel_master_pgproc; pid_t parallel_master_pid; BackendId parallel_master_backend_id; @@ -296,6 +298,8 @@ InitializeParallelDSM(ParallelContext *pcxt) shm_toc_allocate(pcxt->toc, sizeof(FixedParallelState)); fps->database_id = MyDatabaseId; fps->authenticated_user_id = GetAuthenticatedUserId(); + fps->outer_user_id = GetCurrentRoleId(); + fps->is_superuser = session_auth_is_superuser; GetUserIdAndSecContext(&fps->current_user_id, &fps->sec_context); GetTempNamespaceState(&fps->temp_namespace_id, &fps->temp_toast_namespace_id); @@ -1115,6 +1119,13 @@ ParallelWorkerMain(Datum main_arg) */ InvalidateSystemCaches(); + /* + * Restore current role id. Skip verifying whether session user is + * allowed to become this role and blindly restore the leader's state for + * current role. + */ + SetCurrentRoleId(fps->outer_user_id, fps->is_superuser); + /* Restore user ID and security context. */ SetUserIdAndSecContext(fps->current_user_id, fps->sec_context); diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index ae22185fbd..65372d7cc5 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -446,6 +446,7 @@ char *event_source; bool row_security; bool check_function_bodies = true; bool default_with_oids = false; +bool session_auth_is_superuser; int log_min_error_statement = ERROR; int log_min_messages = WARNING; @@ -492,7 +493,6 @@ int huge_pages; * and is kept in sync by assign_hooks. */ static char *syslog_ident_str; -static bool session_auth_is_superuser; static double phony_random_seed; static char *client_encoding_string; static char *datestyle_string; @@ -8986,12 +8986,18 @@ read_nondefault_variables(void) * constants; a few, like server_encoding and lc_ctype, are handled specially * outside the serialize/restore procedure. Therefore, SerializeGUCState() * never sends these, and RestoreGUCState() never changes them. + * + * Role is a special variable in the sense that its current value can be an + * invalid value and there are multiple ways by which that can happen (like + * after setting the role, someone drops it). So we handle it outside of + * serialize/restore machinery. */ static bool can_skip_gucvar(struct config_generic *gconf) { return gconf->context == PGC_POSTMASTER || - gconf->context == PGC_INTERNAL || gconf->source == PGC_S_DEFAULT; + gconf->context == PGC_INTERNAL || gconf->source == PGC_S_DEFAULT || + strcmp(gconf->name, "role") == 0; } /* @@ -9252,7 +9258,6 @@ SerializeGUCState(Size maxsize, char *start_address) Size actual_size; Size bytes_left; int i; - int i_role = -1; /* Reserve space for saving the actual size of the guc state */ Assert(maxsize > sizeof(actual_size)); @@ -9260,19 +9265,7 @@ SerializeGUCState(Size maxsize, char *start_address) bytes_left = maxsize - sizeof(actual_size); for (i = 0; i < num_guc_variables; i++) - { - /* - * It's pretty ugly, but we've got to force "role" to be initialized - * after "session_authorization"; otherwise, the latter will override - * the former. - */ - if (strcmp(guc_variables[i]->name, "role") == 0) - i_role = i; - else - serialize_variable(&curptr, &bytes_left, guc_variables[i]); - } - if (i_role >= 0) - serialize_variable(&curptr, &bytes_left, guc_variables[i_role]); + serialize_variable(&curptr, &bytes_left, guc_variables[i]); /* Store actual size without assuming alignment of start_address. */ actual_size = maxsize - bytes_left - sizeof(actual_size); diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h index 467125a09d..aa130cdb84 100644 --- a/src/include/utils/guc.h +++ b/src/include/utils/guc.h @@ -245,6 +245,7 @@ extern bool log_btree_build_stats; extern PGDLLIMPORT bool check_function_bodies; extern bool default_with_oids; +extern bool session_auth_is_superuser; extern int log_min_error_statement; extern int log_min_messages; diff --git a/src/test/regress/expected/select_parallel.out b/src/test/regress/expected/select_parallel.out index 3c63ad1de8..ac9ad0668d 100644 --- a/src/test/regress/expected/select_parallel.out +++ b/src/test/regress/expected/select_parallel.out @@ -508,6 +508,22 @@ SELECT make_record(x) FROM (SELECT generate_series(1, 5) x) ss ORDER BY x; ROLLBACK TO SAVEPOINT settings; DROP function make_record(n int); +-- test the sanity of parallel query after the active role is dropped. +drop role if exists regress_parallel_worker; +NOTICE: role "regress_parallel_worker" does not exist, skipping +create role regress_parallel_worker; +set role regress_parallel_worker; +reset session authorization; +drop role regress_parallel_worker; +set force_parallel_mode = 1; +select count(*) from tenk1; + count +------- + 10000 +(1 row) + +reset force_parallel_mode; +reset role; -- to increase the parallel query test coverage SAVEPOINT settings; SET LOCAL force_parallel_mode = 1; diff --git a/src/test/regress/sql/select_parallel.sql b/src/test/regress/sql/select_parallel.sql index 720495c811..495f0335dc 100644 --- a/src/test/regress/sql/select_parallel.sql +++ b/src/test/regress/sql/select_parallel.sql @@ -201,6 +201,17 @@ SELECT make_record(x) FROM (SELECT generate_series(1, 5) x) ss ORDER BY x; ROLLBACK TO SAVEPOINT settings; DROP function make_record(n int); +-- test the sanity of parallel query after the active role is dropped. +drop role if exists regress_parallel_worker; +create role regress_parallel_worker; +set role regress_parallel_worker; +reset session authorization; +drop role regress_parallel_worker; +set force_parallel_mode = 1; +select count(*) from tenk1; +reset force_parallel_mode; +reset role; + -- to increase the parallel query test coverage SAVEPOINT settings; SET LOCAL force_parallel_mode = 1; -- 2.40.0