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MDEV-28762: recursive call of some json functions without stack control

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This commit is a fixup for MDEV-28762

Analysis: Some recursive json functions dont check for stack control
Fix: Add check_stack_overrun(). The last argument is NULL because it is not
used
This commit is contained in:
Rucha Deodhar 2022-06-22 14:37:52 +05:30
parent 222e800e24
commit e94902c062
1 changed files with 32 additions and 8 deletions
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36
sql/json_table.cc
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@ -29,6 +29,22 @@
#define HA_ERR_JSON_TABLE (HA_ERR_LAST+1) #define HA_ERR_JSON_TABLE (HA_ERR_LAST+1)
/*
Allocating memory and *also* using it (reading and
writing from it) because some build instructions cause
compiler to optimize out stack_used_up. Since alloca()
here depends on stack_used_up, it doesnt get executed
correctly and causes json_debug_nonembedded to fail
( --error ER_STACK_OVERRUN_NEED_MORE does not occur).
*/
#define ALLOCATE_MEM_ON_STACK(A) do \
{ \
uchar *array= (uchar*)alloca(A); \
array[0]= 1; \
array[0]++; \
array[0] ? array[0]++ : array[0]--; \
} while(0)
class table_function_handlerton class table_function_handlerton
{ {
public: public:
@ -102,10 +118,13 @@ int get_disallowed_table_deps_for_list(MEM_ROOT *mem_root,
NESTED_JOIN *nested_join; NESTED_JOIN *nested_join;
List_iterator<TABLE_LIST> li(*join_list); List_iterator<TABLE_LIST> li(*join_list);
long arbitrary_var;
long stack_used_up= (available_stack_size(current_thd->thread_stack, &arbitrary_var));
DBUG_EXECUTE_IF("json_check_min_stack_requirement", DBUG_EXECUTE_IF("json_check_min_stack_requirement",
{alloca(my_thread_stack_size-(STACK_MIN_SIZE));}); {ALLOCATE_MEM_ON_STACK(my_thread_stack_size-stack_used_up-STACK_MIN_SIZE);});
if (check_stack_overrun(current_thd, STACK_MIN_SIZE, NULL)) if (check_stack_overrun(current_thd, STACK_MIN_SIZE , NULL))
return 1; return 1;
while ((table= li++)) while ((table= li++))
{ {
if ((nested_join= table->nested_join)) if ((nested_join= table->nested_join))
@ -1310,10 +1329,13 @@ static void add_extra_deps(List<TABLE_LIST> *join_list, table_map deps)
TABLE_LIST *table; TABLE_LIST *table;
List_iterator<TABLE_LIST> li(*join_list); List_iterator<TABLE_LIST> li(*join_list);
long arbitrary_var;
long stack_used_up= (available_stack_size(current_thd->thread_stack, &arbitrary_var));
DBUG_EXECUTE_IF("json_check_min_stack_requirement", DBUG_EXECUTE_IF("json_check_min_stack_requirement",
{alloca(my_thread_stack_size-(STACK_MIN_SIZE));}); {ALLOCATE_MEM_ON_STACK(my_thread_stack_size-stack_used_up-STACK_MIN_SIZE);});
if (check_stack_overrun(current_thd, STACK_MIN_SIZE, NULL)) if (check_stack_overrun(current_thd, STACK_MIN_SIZE , NULL))
return; return;
while ((table= li++)) while ((table= li++))
{ {
table->dep_tables |= deps; table->dep_tables |= deps;
@ -1402,9 +1424,11 @@ table_map add_table_function_dependencies(List<TABLE_LIST> *join_list,
table_map res= 0; table_map res= 0;
List_iterator<TABLE_LIST> li(*join_list); List_iterator<TABLE_LIST> li(*join_list);
long arbitrary_var;
long stack_used_up= (available_stack_size(current_thd->thread_stack, &arbitrary_var));
DBUG_EXECUTE_IF("json_check_min_stack_requirement", DBUG_EXECUTE_IF("json_check_min_stack_requirement",
{alloca(my_thread_stack_size-(STACK_MIN_SIZE));}); {ALLOCATE_MEM_ON_STACK(my_thread_stack_size-stack_used_up-STACK_MIN_SIZE);});
if ((res= check_stack_overrun(current_thd, STACK_MIN_SIZE, NULL))) if ((res=check_stack_overrun(current_thd, STACK_MIN_SIZE , NULL)))
return res; return res;
// Recursively compute extra dependencies // Recursively compute extra dependencies