build(deps): bump s3s from 0.12.0-rc.4 to 0.12.0-rc.5 in the s3s group (#1046)

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docs/security/dos-prevention-body-limits.md

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+# DoS Prevention: Request/Response Body Size Limits
+
+## Executive Summary
+
+This document describes the implementation of request and response body size limits in RustFS to prevent Denial of Service (DoS) attacks through unbounded memory allocation. The previous use of `usize::MAX` with `store_all_limited()` posed a critical security risk allowing attackers to exhaust server memory.
+
+## Security Risk Assessment
+
+### Vulnerability: Unbounded Memory Allocation
+
+**Severity**: High  
+**Impact**: Server memory exhaustion, service unavailability  
+**Likelihood**: High (easily exploitable)
+
+**Previous Code** (vulnerable):
+```rust
+let body = input.store_all_limited(usize::MAX).await?;
+```
+
+On a 64-bit system, `usize::MAX` is approximately 18 exabytes, effectively unlimited.
+
+## Implemented Limits
+
+| Limit | Size | Use Cases |
+|-------|------|-----------|
+| `MAX_ADMIN_REQUEST_BODY_SIZE` | 1 MB | User management, policies, tier/KMS/event configs |
+| `MAX_IAM_IMPORT_SIZE` | 10 MB | IAM import/export (ZIP archives) |
+| `MAX_BUCKET_METADATA_IMPORT_SIZE` | 100 MB | Bucket metadata import |
+| `MAX_HEAL_REQUEST_SIZE` | 1 MB | Healing operations |
+| `MAX_S3_RESPONSE_SIZE` | 10 MB | S3 client responses from remote services |
+
+## Rationale
+
+- AWS IAM policy limit: 6KB-10KB
+- Typical payloads: < 100KB
+- 1MB-100MB limits provide generous headroom while preventing DoS
+- Based on real-world usage analysis and industry standards
+
+## Files Modified
+
+- 22 files updated across admin handlers and S3 client modules
+- 2 new files: `rustfs/src/admin/constants.rs`, `crates/ecstore/src/client/body_limits.rs`