From f74f871b80a13ef72b19e3d829a109f8df0df792 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 | 14 +++++++++++ src/test/regress/sql/select_parallel.sql | 8 ++++++ 5 files changed, 43 insertions(+), 16 deletions(-) diff --git a/src/backend/access/transam/parallel.c b/src/backend/access/transam/parallel.c index 867ccf855d..637f0dd9a4 100644 --- a/src/backend/access/transam/parallel.c +++ b/src/backend/access/transam/parallel.c @@ -70,9 +70,11 @@ 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; @@ -310,6 +312,8 @@ 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); @@ -1126,6 +1130,13 @@ 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 4f1891f844..7b8e108982 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -424,6 +424,7 @@ bool default_with_oids = false; bool SQL_inheritance = true; bool Password_encryption = true; +bool session_auth_is_superuser; int log_min_error_statement = ERROR; int log_min_messages = WARNING; @@ -470,7 +471,6 @@ 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; @@ -8873,12 +8873,18 @@ 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; } /* @@ -9139,7 +9145,6 @@ 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)); @@ -9147,19 +9152,7 @@ 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 0bf9f21067..4e3e15906a 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 SQL_inheritance; +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 2286fafab3..164c4bd61c 100644 --- a/src/test/regress/expected/select_parallel.out +++ b/src/test/regress/expected/select_parallel.out @@ -99,7 +99,21 @@ explain (costs off) -> Index Only Scan using tenk1_unique1 on tenk1 (3 rows) +-- test the sanity of parallel query after the active role is dropped. set force_parallel_mode=1; +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; +select count(*) from tenk1; + count +------- + 10000 +(1 row) + +reset role; explain (costs off) select stringu1::int2 from tenk1 where unique1 = 1; QUERY PLAN diff --git a/src/test/regress/sql/select_parallel.sql b/src/test/regress/sql/select_parallel.sql index 38d3166742..e310c09681 100644 --- a/src/test/regress/sql/select_parallel.sql +++ b/src/test/regress/sql/select_parallel.sql @@ -39,7 +39,15 @@ explain (costs off) select sum(parallel_restricted(unique1)) from tenk1 group by(parallel_restricted(unique1)); +-- test the sanity of parallel query after the active role is dropped. set force_parallel_mode=1; +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; +select count(*) from tenk1; +reset role; explain (costs off) select stringu1::int2 from tenk1 where unique1 = 1; -- 2.40.0