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bpo-41060: Avoid SEGFAULT when calling GET_INVALID_TARGET in the grammar (GH-21020) 

`GET_INVALID_TARGET` might unexpectedly return `NULL`, which if not
caught will cause a SEGFAULT. Therefore, this commit introduces a new
inline function `RAISE_SYNTAX_ERROR_INVALID_TARGET` that always
checks for `GET_INVALID_TARGET` returning NULL and can be used in
the grammar, replacing the long C ternary operation used till now.
This commit is contained in:
Lysandros Nikolaou 2020-06-21 05:18:01 +03:00 committed by GitHub
parent 3ccb96c978
commit 6c4e0bd974
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 38 additions and 26 deletions
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23
Grammar/python.gram
View File

@ -653,9 +653,7 @@ invalid_assignment:
| a=expression ':' expression ['=' annotated_rhs] {
RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "illegal target for annotation") }
| (star_targets '=')* a=star_expressions '=' {
RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
GET_INVALID_TARGET(a),
"cannot assign to %s", _PyPegen_get_expr_name(GET_INVALID_TARGET(a))) }
RAISE_SYNTAX_ERROR_INVALID_TARGET(STAR_TARGETS, a) }
| (star_targets '=')* a=yield_expr '=' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "assignment to yield expression not possible") }
| a=star_expressions augassign (yield_expr | star_expressions) {
RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
@ -665,12 +663,7 @@ invalid_assignment:
)}
invalid_del_stmt:
| 'del' a=star_expressions {
GET_INVALID_DEL_TARGET(a) != NULL ?
RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
GET_INVALID_DEL_TARGET(a),
"cannot delete %s", _PyPegen_get_expr_name(GET_INVALID_DEL_TARGET(a))
) :
RAISE_SYNTAX_ERROR("invalid syntax") }
RAISE_SYNTAX_ERROR_INVALID_TARGET(DEL_TARGETS, a) }
invalid_block:
| NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block") }
invalid_comprehension:
@ -695,19 +688,11 @@ invalid_double_type_comments:
RAISE_SYNTAX_ERROR("Cannot have two type comments on def") }
invalid_with_item:
| expression 'as' a=expression {
RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
GET_INVALID_TARGET(a),
"cannot assign to %s", _PyPegen_get_expr_name(GET_INVALID_TARGET(a))
) }
RAISE_SYNTAX_ERROR_INVALID_TARGET(STAR_TARGETS, a) }
invalid_for_target:
| ASYNC? 'for' a=star_expressions {
GET_INVALID_FOR_TARGET(a) != NULL ?
RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
GET_INVALID_FOR_TARGET(a),
"cannot assign to %s", _PyPegen_get_expr_name(GET_INVALID_FOR_TARGET(a))
) :
RAISE_SYNTAX_ERROR("invalid syntax") }
RAISE_SYNTAX_ERROR_INVALID_TARGET(FOR_TARGETS, a) }
invalid_group:
| '(' a=starred_expression ')' {

8
Lib/test/test_syntax.py
View File

@ -199,6 +199,10 @@ SyntaxError: cannot assign to operator
Traceback (most recent call last):
SyntaxError: invalid syntax
>>> for a, b
Traceback (most recent call last):
SyntaxError: invalid syntax
>>> with a as b(): pass
Traceback (most recent call last):
SyntaxError: cannot assign to function call
@ -223,6 +227,10 @@ SyntaxError: cannot assign to function call
Traceback (most recent call last):
SyntaxError: cannot assign to function call
>>> with a as b
Traceback (most recent call last):
SyntaxError: invalid syntax
>>> p = p =
Traceback (most recent call last):
SyntaxError: invalid syntax

8
Parser/parser.c
View File

@ -14818,7 +14818,7 @@ invalid_assignment_rule(Parser *p)
)
{
D(fprintf(stderr, "%*c+ invalid_assignment[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "((star_targets '='))* star_expressions '='"));
_res = RAISE_SYNTAX_ERROR_KNOWN_LOCATION ( GET_INVALID_TARGET ( a ) , "cannot assign to %s" , _PyPegen_get_expr_name ( GET_INVALID_TARGET ( a ) ) );
_res = RAISE_SYNTAX_ERROR_INVALID_TARGET ( STAR_TARGETS , a );
if (_res == NULL && PyErr_Occurred()) {
p->error_indicator = 1;
D(p->level--);
@ -14922,7 +14922,7 @@ invalid_del_stmt_rule(Parser *p)
)
{
D(fprintf(stderr, "%*c+ invalid_del_stmt[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "'del' star_expressions"));
_res = GET_INVALID_DEL_TARGET ( a ) != NULL ? RAISE_SYNTAX_ERROR_KNOWN_LOCATION ( GET_INVALID_DEL_TARGET ( a ) , "cannot delete %s" , _PyPegen_get_expr_name ( GET_INVALID_DEL_TARGET ( a ) ) ) : RAISE_SYNTAX_ERROR ( "invalid syntax" );
_res = RAISE_SYNTAX_ERROR_INVALID_TARGET ( DEL_TARGETS , a );
if (_res == NULL && PyErr_Occurred()) {
p->error_indicator = 1;
D(p->level--);
@ -15379,7 +15379,7 @@ invalid_with_item_rule(Parser *p)
)
{
D(fprintf(stderr, "%*c+ invalid_with_item[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "expression 'as' expression"));
_res = RAISE_SYNTAX_ERROR_KNOWN_LOCATION ( GET_INVALID_TARGET ( a ) , "cannot assign to %s" , _PyPegen_get_expr_name ( GET_INVALID_TARGET ( a ) ) );
_res = RAISE_SYNTAX_ERROR_INVALID_TARGET ( STAR_TARGETS , a );
if (_res == NULL && PyErr_Occurred()) {
p->error_indicator = 1;
D(p->level--);
@ -15427,7 +15427,7 @@ invalid_for_target_rule(Parser *p)
)
{
D(fprintf(stderr, "%*c+ invalid_for_target[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "ASYNC? 'for' star_expressions"));
_res = GET_INVALID_FOR_TARGET ( a ) != NULL ? RAISE_SYNTAX_ERROR_KNOWN_LOCATION ( GET_INVALID_FOR_TARGET ( a ) , "cannot assign to %s" , _PyPegen_get_expr_name ( GET_INVALID_FOR_TARGET ( a ) ) ) : RAISE_SYNTAX_ERROR ( "invalid syntax" );
_res = RAISE_SYNTAX_ERROR_INVALID_TARGET ( FOR_TARGETS , a );
if (_res == NULL && PyErr_Occurred()) {
p->error_indicator = 1;
D(p->level--);

25
Parser/pegen.h
View File

@ -269,9 +269,28 @@ typedef enum {
FOR_TARGETS
} TARGETS_TYPE;
expr_ty _PyPegen_get_invalid_target(expr_ty e, TARGETS_TYPE targets_type);
#define GET_INVALID_TARGET(e) (expr_ty)CHECK(_PyPegen_get_invalid_target(e, STAR_TARGETS))
#define GET_INVALID_DEL_TARGET(e) (expr_ty)CHECK_NULL_ALLOWED(_PyPegen_get_invalid_target(e, DEL_TARGETS))
#define GET_INVALID_FOR_TARGET(e) (expr_ty)CHECK_NULL_ALLOWED(_PyPegen_get_invalid_target(e, FOR_TARGETS))
#define RAISE_SYNTAX_ERROR_INVALID_TARGET(type, e) _RAISE_SYNTAX_ERROR_INVALID_TARGET(p, type, e)
Py_LOCAL_INLINE(void *)
_RAISE_SYNTAX_ERROR_INVALID_TARGET(Parser *p, TARGETS_TYPE type, void *e)
{
expr_ty invalid_target = CHECK_NULL_ALLOWED(_PyPegen_get_invalid_target(e, type));
if (invalid_target != NULL) {
const char *msg;
if (type == STAR_TARGETS || type == FOR_TARGETS) {
msg = "cannot assign to %s";
}
else {
msg = "cannot delete %s";
}
return RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
invalid_target,
msg,
_PyPegen_get_expr_name(invalid_target)
);
}
return RAISE_SYNTAX_ERROR("invalid syntax");
}
void *_PyPegen_arguments_parsing_error(Parser *, expr_ty);
void *_PyPegen_nonparen_genexp_in_call(Parser *p, expr_ty args);