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fix(security): normalize IPv6-mapped IPv4 addresses in SSRF checks

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::ffff:127.0.0.1 and ::ffff:169.254.169.254 are IPv6Address objects
that match neither the IPv4 blocklists (127.0.0.0/8, 169.254.0.0/16)
nor the IPv6 ones (::1/128), allowing SSRF bypass via DNS responses
that return IPv6-mapped IPv4 addresses.

Add _normalize_addr() to convert ipv4_mapped IPv6 addresses to their
IPv4 form before blocklist/allowlist matching.
This commit is contained in:
yorkhellen
2026-05-30 15:34:49 +08:00
committed by Xubin Ren
parent 1d4000560d
commit 13dec9d2c2
2 changed files with 66 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files
nanobot/security/network.py
+18 -2
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@@ -36,10 +36,26 @@ def configure_ssrf_whitelist(cidrs: list[str]) -> None:
_allowed_networks = nets
def _normalize_addr(
addr: ipaddress.IPv4Address | ipaddress.IPv6Address,
) -> ipaddress.IPv4Address | ipaddress.IPv6Address:
"""Normalize IPv6-mapped IPv4 addresses to their IPv4 form.
``::ffff:127.0.0.1`` is semantically identical to ``127.0.0.1`` but
Python's ipaddress treats it as an IPv6Address that matches neither
``127.0.0.0/8`` nor ``::1/128``. Converting it to IPv4 ensures
blocklist/allowlist checks work correctly.
"""
if isinstance(addr, ipaddress.IPv6Address) and addr.ipv4_mapped is not None:
return addr.ipv4_mapped
return addr
def _is_private(addr: ipaddress.IPv4Address | ipaddress.IPv6Address) -> bool:
if _allowed_networks and any(addr in net for net in _allowed_networks):
normalized = _normalize_addr(addr)
if _allowed_networks and any(normalized in net for net in _allowed_networks):
return False
return any(addr in net for net in _BLOCKED_NETWORKS)
return any(normalized in net for net in _BLOCKED_NETWORKS)
def validate_url_target(url: str, *, allow_loopback: bool = False) -> tuple[bool, str]: