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| author | Mark Dickinson <mdickinson@enthought.com> | 2011-09-24 07:56:09 (GMT) |
|---|---|---|
| committer | Mark Dickinson <mdickinson@enthought.com> | 2011-09-24 07:56:09 (GMT) |
| commit | b2f6bc72a269a0c4ed389ad232b47e2a42b8dde0 (patch) | |
| tree | b1e691ab2afcc804385f38036708f598377a0051 | |
| parent | adde86d0e31ce486e72a9d1a2a7625e5e34d97e9 (diff) | |
| download | cpython-b2f6bc72a269a0c4ed389ad232b47e2a42b8dde0.zip cpython-b2f6bc72a269a0c4ed389ad232b47e2a42b8dde0.tar.gz cpython-b2f6bc72a269a0c4ed389ad232b47e2a42b8dde0.tar.bz2 | |
Issue #12973: Fix itertools bug caused by signed integer overflow. Thanks Stefan Krah.
| -rw-r--r-- | Misc/NEWS | 6 | ||||
| -rw-r--r-- | Modules/itertoolsmodule.c | 4 |
2 files changed, 6 insertions, 4 deletions
@@ -17,9 +17,9 @@ Core and Builtins - Issue #13021: Missing decref on an error path. Thanks to Suman Saha for finding the bug and providing a patch. -- Issue #12973: Fix overflow check that relied on undefined behaviour in - list_repeat. This bug caused test_list to fail with recent versions - of Clang. +- Issue #12973: Fix overflow checks that relied on undefined behaviour in + list_repeat (listobject.c) and islice_next (itertoolsmodule.c). These bugs + caused test failures with recent versions of Clang. - Issue #12802: the Windows error ERROR_DIRECTORY (numbered 267) is now mapped to POSIX errno ENOTDIR (previously EINVAL). diff --git a/Modules/itertoolsmodule.c b/Modules/itertoolsmodule.c index 71d5bb6..8b6fa85 100644 --- a/Modules/itertoolsmodule.c +++ b/Modules/itertoolsmodule.c @@ -1234,7 +1234,9 @@ islice_next(isliceobject *lz) return NULL; lz->cnt++; oldnext = lz->next; - lz->next += lz->step; + /* The (size_t) cast below avoids the danger of undefined + behaviour from signed integer overflow. */ + lz->next += (size_t)lz->step; if (lz->next < oldnext || (stop != -1 && lz->next > stop)) lz->next = stop; return item; |