ssrf.py
python
sha256:d035733f21ccff27735fddebfbbe0ed24565a32a22db8de5885402262671ecd2
chore: bump version to 0.2.0rc15 for musehub#113 fix release
Sonnet 4.6
patch
15 days ago
| 1 | """SSRF (Server-Side Request Forgery) protection for outbound HTTP requests. |
| 2 | |
| 3 | Any feature that makes outbound HTTP requests (webhooks, MCP callbacks, avatar |
| 4 | fetch) must validate the target URL through this module before sending. |
| 5 | |
| 6 | What is blocked: |
| 7 | * Non-HTTPS schemes (http://, file://, ftp://, etc.) |
| 8 | * Loopback: 127.0.0.0/8, ::1 |
| 9 | * RFC-1918 private ranges: 10.x, 172.16–31.x, 192.168.x |
| 10 | * Link-local: 169.254.0.0/16 (AWS metadata at 169.254.169.254), fe80::/10 |
| 11 | * Unique-local IPv6: fc00::/7 |
| 12 | * Shared address space: 100.64.0.0/10 (carrier-grade NAT, RFC-6598) |
| 13 | * Reserved / unspecified: 0.0.0.0/8, 240.0.0.0/4, ::/128 |
| 14 | |
| 15 | Two-layer defence: |
| 16 | 1. ``check_url_safe(url)`` — fast sync check (scheme + bare IP literal). |
| 17 | Called from Pydantic field validators at request-parse time. No DNS |
| 18 | resolution; suitable for the async event loop. |
| 19 | 2. ``validate_outbound_url(url)`` — full async check (scheme + IP literal + |
| 20 | DNS resolution via asyncio.to_thread). Called by webhook delivery before |
| 21 | each HTTP POST attempt. Blocks SSRF via DNS rebinding. |
| 22 | """ |
| 23 | |
| 24 | import asyncio |
| 25 | import ipaddress |
| 26 | import socket |
| 27 | from urllib.parse import urlparse |
| 28 | |
| 29 | # ── Blocked IP ranges ───────────────────────────────────────────────────────── |
| 30 | |
| 31 | _BLOCKED_NETWORKS: list[ipaddress.IPv4Network | ipaddress.IPv6Network] = [ |
| 32 | ipaddress.ip_network("127.0.0.0/8"), # Loopback IPv4 |
| 33 | ipaddress.ip_network("::1/128"), # Loopback IPv6 |
| 34 | ipaddress.ip_network("10.0.0.0/8"), # RFC-1918 class A |
| 35 | ipaddress.ip_network("172.16.0.0/12"), # RFC-1918 class B |
| 36 | ipaddress.ip_network("192.168.0.0/16"), # RFC-1918 class C |
| 37 | ipaddress.ip_network("169.254.0.0/16"), # Link-local IPv4 (AWS metadata) |
| 38 | ipaddress.ip_network("fe80::/10"), # Link-local IPv6 |
| 39 | ipaddress.ip_network("fc00::/7"), # Unique-local IPv6 |
| 40 | ipaddress.ip_network("100.64.0.0/10"), # Shared address space (RFC-6598) |
| 41 | ipaddress.ip_network("0.0.0.0/8"), # Unspecified IPv4 |
| 42 | ipaddress.ip_network("240.0.0.0/4"), # Reserved IPv4 |
| 43 | ipaddress.ip_network("::/128"), # Unspecified IPv6 |
| 44 | ] |
| 45 | |
| 46 | def _is_blocked_ip(addr: str) -> bool: |
| 47 | """Return True when *addr* falls within a blocked network range.""" |
| 48 | try: |
| 49 | ip = ipaddress.ip_address(addr) |
| 50 | except ValueError: |
| 51 | return True # unparseable address — block it |
| 52 | return any(ip in net for net in _BLOCKED_NETWORKS) |
| 53 | |
| 54 | # ── Sync check (scheme + bare IP literal) ───────────────────────────────────── |
| 55 | |
| 56 | def check_url_safe(url: str) -> str: |
| 57 | """Fast synchronous SSRF pre-check — no DNS resolution. |
| 58 | |
| 59 | Validates scheme (must be ``https``) and rejects bare IP literals that |
| 60 | fall in blocked ranges. Suitable for Pydantic field validators and other |
| 61 | synchronous call sites. |
| 62 | |
| 63 | Args: |
| 64 | url: The candidate outbound URL. |
| 65 | |
| 66 | Returns: |
| 67 | The original *url* string if safe. |
| 68 | |
| 69 | Raises: |
| 70 | ValueError: When the URL is malformed, uses a non-HTTPS scheme, or |
| 71 | contains a bare IP literal in a blocked range. |
| 72 | """ |
| 73 | try: |
| 74 | parsed = urlparse(url) |
| 75 | except Exception as exc: # pragma: no cover — urlparse is very forgiving |
| 76 | raise ValueError(f"Malformed URL: {exc}") from exc |
| 77 | |
| 78 | if parsed.scheme != "https": |
| 79 | raise ValueError( |
| 80 | f"Outbound URL must use https:// — got {parsed.scheme!r}. " |
| 81 | "Non-HTTPS schemes are blocked to prevent credential leakage and SSRF." |
| 82 | ) |
| 83 | |
| 84 | hostname = parsed.hostname |
| 85 | if not hostname: |
| 86 | raise ValueError("URL has no hostname.") |
| 87 | |
| 88 | # If the hostname is a literal IP address, check it immediately. |
| 89 | # DNS-based hostnames are deferred to the async validate_outbound_url check. |
| 90 | try: |
| 91 | ipaddress.ip_address(hostname) |
| 92 | # It parsed — it is a bare IP literal. |
| 93 | if _is_blocked_ip(hostname): |
| 94 | raise ValueError( |
| 95 | f"Outbound URL targets a private/reserved IP address ({hostname}). " |
| 96 | "Requests to RFC-1918, loopback, and link-local addresses are blocked." |
| 97 | ) |
| 98 | except ValueError as exc: |
| 99 | if "private/reserved" in str(exc) or "blocked" in str(exc): |
| 100 | raise |
| 101 | # Not an IP literal — hostname will be resolved at delivery time. |
| 102 | |
| 103 | return url |
| 104 | |
| 105 | # ── Async check (scheme + IP literal + DNS resolution) ──────────────────────── |
| 106 | |
| 107 | async def validate_outbound_url(url: str) -> str: |
| 108 | """Full async SSRF check including DNS resolution. |
| 109 | |
| 110 | Resolves the hostname and verifies that none of the resulting IP addresses |
| 111 | fall in a blocked range. Use this immediately before making an outbound |
| 112 | HTTP request to guard against DNS rebinding attacks. |
| 113 | |
| 114 | Args: |
| 115 | url: The candidate outbound URL. |
| 116 | |
| 117 | Returns: |
| 118 | The original *url* string if safe. |
| 119 | |
| 120 | Raises: |
| 121 | ValueError: When the URL fails any SSRF check. |
| 122 | """ |
| 123 | # Perform scheme + bare IP check first (cheap, no I/O). |
| 124 | check_url_safe(url) |
| 125 | |
| 126 | parsed = urlparse(url) |
| 127 | hostname = parsed.hostname or "" |
| 128 | |
| 129 | # If it's already a bare IP literal, it passed the sync check above. |
| 130 | # No DNS needed. |
| 131 | try: |
| 132 | ipaddress.ip_address(hostname) |
| 133 | return url # bare IP — already validated |
| 134 | except ValueError: |
| 135 | pass # not an IP literal — proceed to DNS resolution |
| 136 | |
| 137 | # Resolve via getaddrinfo in a thread so the event loop is not blocked. |
| 138 | try: |
| 139 | infos: list[tuple[int, int, int, str, tuple[str, int]]] = await asyncio.to_thread(socket.getaddrinfo, hostname, None) |
| 140 | except socket.gaierror as exc: |
| 141 | raise ValueError( |
| 142 | f"Outbound URL hostname cannot be resolved: {hostname!r} — {exc}" |
| 143 | ) from exc |
| 144 | |
| 145 | for _family, _type, _proto, _canonname, sockaddr in infos: |
| 146 | ip_str = sockaddr[0] |
| 147 | if _is_blocked_ip(ip_str): |
| 148 | raise ValueError( |
| 149 | f"Outbound URL {hostname!r} resolves to a private/reserved address " |
| 150 | f"({ip_str}). RFC-1918 / loopback / link-local targets are blocked." |
| 151 | ) |
| 152 | |
| 153 | return url |
File History
11 commits
sha256:d035733f21ccff27735fddebfbbe0ed24565a32a22db8de5885402262671ecd2
chore: bump version to 0.2.0rc15 for musehub#113 fix release
Sonnet 4.6
patch
15 days ago
sha256:0032d6cfa33bc3c8367436ad768e7dd0e339b4332153160247da8266cb5fa352
Merge branch 'task/version-tags-phase3-server' into dev
Human
17 days ago
sha256:4669620efda9ff41c55bdefd1f7bfe1c239d468428744c84ead9957e5a003a53
merge: rescue snapshot-recovery hardening (c00aa21d) into d…
Opus 4.8
minor
⚠
30 days ago
sha256:a59da49c4611b970fc4b6ae48678ce4943261c213a07ddbd73ce9201df869b4a
fix: remove false-positive proposal_comments index drop fro…
Sonnet 4.6
patch
34 days ago
sha256:0a240d6dbff234f07d98a28a4a9a68db702f3f9ff9260196f24219bdb1c0b6f3
feat: render markdown mists as HTML with heading anchor links
Sonnet 4.6
patch
35 days ago
sha256:24a7d47486ebc4ebd1832830580e177ec6f877b48dced8c000e198cdec4ce9d6
Merge 'task/bump-version-rc12' into 'dev' — proposal: Bump …
Human
36 days ago
sha256:b9ff931d147e0114a1f17060f415b89ed551c170a91ff226c70437aa5c85f9ee
Merge 'task/bump-version-rc12' into 'dev' — proposal: Bump …
Human
36 days ago
sha256:d1122d21e73471879b460037b22c0b50fded7c423444a176f248428f75dac39c
Merge 'task/fix-issue-pagination-cursor' into 'dev' — propo…
Human
36 days ago
sha256:01e18975e73d2b3cd5b6db7929c895bef9aa6e0d4391dc5b2adfc548b41318dd
Merge 'feat/adding-debug-logs-to-staging' into 'dev' — prop…
Human
36 days ago
sha256:6b1949fc2797ca4c1936a637a4cbfec828ef56cf52398a2e74ca3c4f494e728f
fix: use wire_bytes not mpack_bytes_raw in compute_object_b…
Sonnet 4.6
patch
48 days ago
sha256:b99f2455dc346966d040133f5203297e6e3ef5803a93728a2c30568d0a0f7583
rename: delta_add → delta_upsert across wire format, models…
Sonnet 4.6
patch
51 days ago