[Core] Add nesting-depth limit to If::validate_and_infer_types (CWE-674)

[axinging]

Details:

The constant-condition branch of If::validate_and_infer_types (if.cpp:109-113) calls validate_and_infer_type_body, which at multi_subgraph_base.cpp:164 invokes
body->validate_nodes_and_infer_types() with no depth counter or recursion limit. If the body contains another constant-condition If, the same path is re-entered, producing one native C++ stack frame per nesting level. A sufficiently deep chain overflows the call stack and crashes the process (SIGSEGV / EXCEPTION_STACK_OVERFLOW).

This path is distinct from the non-constant branch (:124-128): a model whose If ops all carry constant conditions never enters that branch, yet still recurses unboundedly here. The IR frontend (pugixml) imposes no XML nesting cap, making this fully exploitable via a crafted IR model.

Fix: introduce a shared ValidationDepthGuard RAII class (validation_depth_guard.hpp) with a per-op-type static thread_local counter and OV_VALIDATION_DEPTH_GUARD macro. In If::validate_and_infer_types, a single line guards both the constant and non-constant paths against nesting deeper than kMaxValidationDepth = 64.

// validation_depth_guard.hpp — reusable by Loop and other subgraph ops
OV_VALIDATION_DEPTH_GUARD(this, "If");

Tests added:

• type_prop.if_nested_constant_condition_exceeds_max_depth_throws (ov_core_unit_tests) — directly validates the depth guard throws NodeValidationFailure at depth 1024.
• IRFrontendTestsIf.nested_if_at_max_depth_loads (ov_ir_frontend_tests) — depth=64 equals kMaxIfValidationDepth and must load successfully.
• IRFrontendTestsIf.nested_if_depth_limit_is_rejected (ov_ir_frontend_tests) — end-to-end: depth-1024 nested If IR is rejected via core.read_model().

Tickets:

• CVS-192797

AI Assistance:

• AI assistance used: yes
• Bug root cause was found by AI.