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fix: handle exceptions during superuser switch #166

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fix: handle exceptions during superuser switch #166

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a0117ac
fix: handle exceptions during SU switch
soedirgo Nov 19, 2025
fa34c31
chore: remove redundant line
soedirgo Nov 19, 2025
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52 changes: 34 additions & 18 deletions src/supautils.c
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Original file line number Diff line number Diff line change
Expand Up @@ -227,7 +227,8 @@ static void supautils_hook(PROCESS_UTILITY_PARAMS) {
// Allow setting bypassrls & replication.
switch_to_superuser(supautils_superuser, &already_switched_to_superuser);

run_process_utility_hook(prev_hook);
run_process_utility_hook_with_cleanup(
prev_hook, already_switched_to_superuser, switch_to_original_role);

if (!already_switched_to_superuser) {
switch_to_original_role();
Expand Down Expand Up @@ -278,7 +279,8 @@ static void supautils_hook(PROCESS_UTILITY_PARAMS) {
bool already_switched_to_superuser = false;
switch_to_superuser(supautils_superuser, &already_switched_to_superuser);

run_process_utility_hook(prev_hook);
run_process_utility_hook_with_cleanup(
prev_hook, already_switched_to_superuser, switch_to_original_role);

if (!already_switched_to_superuser) {
switch_to_original_role();
Expand Down Expand Up @@ -367,7 +369,8 @@ static void supautils_hook(PROCESS_UTILITY_PARAMS) {
switch_to_superuser(supautils_superuser,
&already_switched_to_superuser);

run_process_utility_hook(prev_hook);
run_process_utility_hook_with_cleanup(
prev_hook, already_switched_to_superuser, switch_to_original_role);

if (!already_switched_to_superuser) {
switch_to_original_role();
Expand Down Expand Up @@ -482,11 +485,11 @@ static void supautils_hook(PROCESS_UTILITY_PARAMS) {
override_create_ext_statement(stmt, total_epos, epos);

if (is_extension_privileged(stmt->extname, privileged_extensions)) {
run_process_utility_hook(prev_hook);
run_process_utility_hook_with_cleanup(
prev_hook, already_switched_to_superuser, switch_to_original_role);
} else {
if (!already_switched_to_superuser) {
switch_to_original_role();
already_switched_to_superuser = false;
}

run_process_utility_hook(prev_hook);
Expand Down Expand Up @@ -519,7 +522,8 @@ static void supautils_hook(PROCESS_UTILITY_PARAMS) {

switch_to_superuser(supautils_superuser, &already_switched_to_superuser);

run_process_utility_hook(prev_hook);
run_process_utility_hook_with_cleanup(
prev_hook, already_switched_to_superuser, switch_to_original_role);

if (!already_switched_to_superuser) {
switch_to_original_role();
Expand All @@ -545,7 +549,8 @@ static void supautils_hook(PROCESS_UTILITY_PARAMS) {

switch_to_superuser(supautils_superuser, &already_switched_to_superuser);

run_process_utility_hook(prev_hook);
run_process_utility_hook_with_cleanup(
prev_hook, already_switched_to_superuser, switch_to_original_role);

if (!already_switched_to_superuser) {
switch_to_original_role();
Expand Down Expand Up @@ -580,7 +585,8 @@ static void supautils_hook(PROCESS_UTILITY_PARAMS) {

switch_to_superuser(supautils_superuser, &already_switched_to_superuser);

run_process_utility_hook(prev_hook);
run_process_utility_hook_with_cleanup(
prev_hook, already_switched_to_superuser, switch_to_original_role);

CreateFdwStmt *stmt = (CreateFdwStmt *)utility_stmt;

Expand Down Expand Up @@ -610,7 +616,8 @@ static void supautils_hook(PROCESS_UTILITY_PARAMS) {

switch_to_superuser(supautils_superuser, &already_switched_to_superuser);

run_process_utility_hook(prev_hook);
run_process_utility_hook_with_cleanup(
prev_hook, already_switched_to_superuser, switch_to_original_role);

CreatePublicationStmt *stmt = (CreatePublicationStmt *)utility_stmt;

Expand Down Expand Up @@ -639,7 +646,8 @@ static void supautils_hook(PROCESS_UTILITY_PARAMS) {

switch_to_superuser(supautils_superuser, &already_switched_to_superuser);

run_process_utility_hook(prev_hook);
run_process_utility_hook_with_cleanup(
prev_hook, already_switched_to_superuser, switch_to_original_role);

if (!already_switched_to_superuser) {
switch_to_original_role();
Expand All @@ -663,7 +671,8 @@ static void supautils_hook(PROCESS_UTILITY_PARAMS) {

switch_to_superuser(supautils_superuser, &already_switched_to_superuser);

run_process_utility_hook(prev_hook);
run_process_utility_hook_with_cleanup(
prev_hook, already_switched_to_superuser, switch_to_original_role);

if (!already_switched_to_superuser) {
switch_to_original_role();
Expand All @@ -690,7 +699,8 @@ static void supautils_hook(PROCESS_UTILITY_PARAMS) {

switch_to_superuser(supautils_superuser, &already_switched_to_superuser);

run_process_utility_hook(prev_hook);
run_process_utility_hook_with_cleanup(
prev_hook, already_switched_to_superuser, switch_to_original_role);

if (!already_switched_to_superuser) {
switch_to_original_role();
Expand Down Expand Up @@ -719,7 +729,8 @@ static void supautils_hook(PROCESS_UTILITY_PARAMS) {
switch_to_superuser(supautils_superuser,
&already_switched_to_superuser);

run_process_utility_hook(prev_hook);
run_process_utility_hook_with_cleanup(
prev_hook, already_switched_to_superuser, switch_to_original_role);

if (!already_switched_to_superuser) {
switch_to_original_role();
Expand Down Expand Up @@ -752,7 +763,8 @@ static void supautils_hook(PROCESS_UTILITY_PARAMS) {

switch_to_superuser(supautils_superuser, &already_switched_to_superuser);

run_process_utility_hook(prev_hook);
run_process_utility_hook_with_cleanup(
prev_hook, already_switched_to_superuser, switch_to_original_role);

if (!already_switched_to_superuser) {
switch_to_original_role();
Expand Down Expand Up @@ -782,7 +794,8 @@ static void supautils_hook(PROCESS_UTILITY_PARAMS) {

switch_to_superuser(supautils_superuser, &already_switched_to_superuser);

run_process_utility_hook(prev_hook);
run_process_utility_hook_with_cleanup(
prev_hook, already_switched_to_superuser, switch_to_original_role);

if (!already_switched_to_superuser) {
switch_to_original_role();
Expand Down Expand Up @@ -815,7 +828,8 @@ static void supautils_hook(PROCESS_UTILITY_PARAMS) {
bool already_switched_to_superuser = false;
switch_to_superuser(supautils_superuser, &already_switched_to_superuser);

run_process_utility_hook(prev_hook);
run_process_utility_hook_with_cleanup(
prev_hook, already_switched_to_superuser, switch_to_original_role);

if (!already_switched_to_superuser) {
switch_to_original_role();
Expand Down Expand Up @@ -852,7 +866,8 @@ static void supautils_hook(PROCESS_UTILITY_PARAMS) {
bool already_switched_to_superuser = false;
switch_to_superuser(supautils_superuser, &already_switched_to_superuser);

run_process_utility_hook(prev_hook);
run_process_utility_hook_with_cleanup(
prev_hook, already_switched_to_superuser, switch_to_original_role);

if (!already_switched_to_superuser) {
switch_to_original_role();
Expand Down Expand Up @@ -904,7 +919,8 @@ static void supautils_hook(PROCESS_UTILITY_PARAMS) {

switch_to_superuser(supautils_superuser, &already_switched_to_superuser);

run_process_utility_hook(prev_hook);
run_process_utility_hook_with_cleanup(
prev_hook, already_switched_to_superuser, switch_to_original_role);

if (!current_user_is_super)
// Change event trigger owner to the current role (which is a privileged
Expand Down
14 changes: 14 additions & 0 deletions src/utils.h
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Original file line number Diff line number Diff line change
Expand Up @@ -72,6 +72,20 @@
standard_ProcessUtility(PROCESS_UTILITY_ARGS); \
}

#define run_process_utility_hook_with_cleanup(process_utility_hook, \
already_switched_to_superuser, \
switch_to_original_role) \
PG_TRY(); \
{ run_process_utility_hook(prev_hook); } \
PG_CATCH(); \
{ \
if (!already_switched_to_superuser) { \
switch_to_original_role(); \
} \
PG_RE_THROW(); \
} \
PG_END_TRY();

// helper for testing a guc config
#if TEST
# define SUPAUTILS_GUC_CONTEXT_SIGHUP PGC_USERSET
Expand Down
16 changes: 16 additions & 0 deletions test/expected/privileged_role.out
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Original file line number Diff line number Diff line change
Expand Up @@ -246,3 +246,19 @@ drop cascades to function deny_drop_triggers.f()
set role privileged_role;
\echo

-- regression: is_switched_to_superuser is restored when an exception is thrown
create publication p;
do $$
begin
alter publication p add table missing_table;
exception
when undefined_table then
null;
end $$;
-- if is_switched_to_superuser is not restored, role switching won't happen here
-- and publication creation would fail
create publication pp for all tables;
drop publication p;
drop publication pp;
\echo

17 changes: 17 additions & 0 deletions test/sql/privileged_role.sql
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Original file line number Diff line number Diff line change
Expand Up @@ -189,3 +189,20 @@ set role postgres;
drop schema deny_drop_triggers cascade;
set role privileged_role;
\echo

-- regression: is_switched_to_superuser is restored when an exception is thrown
create publication p;
do $$
begin
alter publication p add table missing_table;
exception
when undefined_table then
null;
end $$;
-- if is_switched_to_superuser is not restored, role switching won't happen here
-- and publication creation would fail
create publication pp for all tables;

drop publication p;
drop publication pp;
\echo
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