FazBrowse GitHub Viewer | Trending |
URL:
| Home
Tools: [Download Repo ZIP]   [Original HTTPS Page]

bpo-37947: Avoid double-decrement in symtable recursion counting by ncoghlan · Pull Request #15593 · python/cpython · GitHub

/ cpython Public

bpo-37947: Avoid double-decrement in symtable recursion counting #15593

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
ncoghlan merged 3 commits into from
Aug 29, 2019
Conversation 5 Commits 3 Checks 0 Files changed
Merged

bpo-37947: Avoid double-decrement in symtable recursion counting #15593

Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
eb863e1
bpo-37947: Avoid double-decrement in symtable recursion counting
ncoghlan Aug 29, 2019
b4a341e
Ensure the symtable recursion accounting balances
ncoghlan Aug 29, 2019
6e83dc2
Remove spurious line
ncoghlan Aug 29, 2019
File filter

Filter by extension

Filter by extension .c  (1) All 1 file type selected
Viewed files
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Unified
Split
Hide whitespace
Diff view
Unified
Split
Hide whitespace
18 changes: 14 additions & 4 deletions Python/symtable.c
Show comments
View file
Open in desktop
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode characters
Show hidden characters
Original file line number Diff line number Diff line change
Expand Up @@ -266,6 +266,7 @@ PySymtable_BuildObject(mod_ty mod, PyObject *filename, PyFutureFeatures *future)
int i;
PyThreadState *tstate;
int recursion_limit = Py_GetRecursionLimit();
int starting_recursion_depth;

if (st == NULL)
return NULL;
Expand All @@ -284,8 +285,9 @@ PySymtable_BuildObject(mod_ty mod, PyObject *filename, PyFutureFeatures *future)
return NULL;
}
/* Be careful here to prevent overflow. */
st->recursion_depth = (tstate->recursion_depth < INT_MAX / COMPILER_STACK_FRAME_SCALE) ?
starting_recursion_depth = (tstate->recursion_depth < INT_MAX / COMPILER_STACK_FRAME_SCALE) ?
tstate->recursion_depth * COMPILER_STACK_FRAME_SCALE : tstate->recursion_depth;
st->recursion_depth = starting_recursion_depth;
st->recursion_limit = (recursion_limit < INT_MAX / COMPILER_STACK_FRAME_SCALE) ?
recursion_limit * COMPILER_STACK_FRAME_SCALE : recursion_limit;

Expand Down Expand Up @@ -329,6 +331,14 @@ PySymtable_BuildObject(mod_ty mod, PyObject *filename, PyFutureFeatures *future)
PySymtable_Free(st);
return NULL;
}
/* Check that the recursion depth counting balanced correctly */
if (st->recursion_depth != starting_recursion_depth) {
PyErr_Format(PyExc_SystemError,
"symtable analysis recursion depth mismatch (before=%d, after=%d)",
starting_recursion_depth, st->recursion_depth);
PySymtable_Free(st);
return NULL;
}
/* Make the second symbol analysis pass */
if (symtable_analyze(st))
return st;
Expand Down Expand Up @@ -1501,16 +1511,16 @@ symtable_handle_namedexpr(struct symtable *st, expr_ty e)
PyErr_SyntaxLocationObject(st->st_filename,
e->lineno,
e->col_offset);
VISIT_QUIT(st, 0);
return 0;
}
if (st->st_cur->ste_comprehension) {
/* Inside a comprehension body, so find the right target scope */
if (!symtable_extend_namedexpr_scope(st, e->v.NamedExpr.target))
VISIT_QUIT(st, 0);
return 0;
}
VISIT(st, expr, e->v.NamedExpr.value);
VISIT(st, expr, e->v.NamedExpr.target);
VISIT_QUIT(st, 1);
return 1;
}

static int
Expand Down
Back | FazBrowse Home | New Git URL