Issue #21787 has been updated by nobu (Nobuyoshi Nakada). Subject changed from `IO::Buffer` buffer overf to `IO::Buffer` Integer Overflow in Range Validation Leads to Out-of-Bounds Memory Access Backport changed from 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN to 3.2: REQUIRED, 3.3: REQUIRED, 3.4: REQUIRED From: https://hackerone.com/reports/3437743 The `IO::Buffer` implementation in Ruby contains a critical integer overflow vulnerability in its range validation logic. The `io_buffer_validate_range` function assumes that `offset+length` never wraps around, allowing an attacker to bypass bounds checking with a carefully chosen large offset value. When the sum overflows, it appears to be within bounds while the actual destination pointer underflows. Subsequent operations (write/read copies) use this wrapped offset without further validation, enabling out-of-bounds memory access directly from Ruby code. https://hackerone.com/reports/3437743#activity-38521790
We decided to fix this as a regular bug since `IO::Buffer` is experimental.
---------------------------------------- Bug #21787: `IO::Buffer` Integer Overflow in Range Validation Leads to Out-of-Bounds Memory Access https://bugs.ruby-lang.org/issues/21787#change-115764 * Author: nobu (Nobuyoshi Nakada) * Status: Open * Backport: 3.2: REQUIRED, 3.3: REQUIRED, 3.4: REQUIRED ---------------------------------------- -- https://bugs.ruby-lang.org/