From 7e1098befe178e4b93657a4d49e6a354037beec4 Mon Sep 17 00:00:00 2001 From: Jan Sturm Date: Tue, 29 Oct 2024 19:26:19 +0100 Subject: [PATCH 1/2] py/objdeque: Fix buffer overflow in deque_subscr. In `deque_subscr()`, if `index_val` equals `self->alloc`, the index correction `index_val -= self->alloc` does not execute, leading to an out-of-bounds access in `self->items[index_val]`. The fix in this commit ensures that the index correction is applied whenever `index_val >= self->alloc`, preventing access beyond the allocated buffer size. Signed-off-by: Jan Sturm --- py/objdeque.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/py/objdeque.c b/py/objdeque.c index 2ad771284df53..22c380a05a926 100644 --- a/py/objdeque.c +++ b/py/objdeque.c @@ -208,7 +208,7 @@ static mp_obj_t deque_subscr(mp_obj_t self_in, mp_obj_t index, mp_obj_t value) { size_t offset = mp_get_index(self->base.type, deque_len(self), index, false); size_t index_val = self->i_get + offset; - if (index_val > self->alloc) { + if (index_val >= self->alloc) { index_val -= self->alloc; } From c88a9d60a17594bfd72d57b073eeb9150019b52c Mon Sep 17 00:00:00 2001 From: Damien George Date: Wed, 30 Oct 2024 15:07:58 +1100 Subject: [PATCH 2/2] tests/basics/deque2.py: Add tests for deque subscript-from-end. Signed-off-by: Damien George --- tests/basics/deque2.py | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/tests/basics/deque2.py b/tests/basics/deque2.py index 3552d5be37abe..ebc0872c7b4e0 100644 --- a/tests/basics/deque2.py +++ b/tests/basics/deque2.py @@ -31,6 +31,16 @@ d[3] = 5 print(d[3]) +# Access the last element via index, when the last element is at various locations +d = deque((), 2) +for i in range(4): + d.append(i) + print(i, d[-1]) + +# Write the last element then access all elements from the end +d[-1] = 4 +print(d[-2], d[-1]) + # Accessing indices out of bounds raises IndexError try: d[4] pFad - Phonifier reborn

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