fix(#123): add RFC6598 CGN check to Python SSRF validation in action.yml
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Python's ipaddress module does NOT classify 100.64.0.0/10 (RFC6598
carrier-grade NAT) as private/loopback/link_local/multicast/reserved.
This means a SERVER_URL resolving to a CGN address would bypass the
Python SSRF check and reach curl with ACTION_TOKEN.

Add an explicit network membership check for 100.64.0.0/10 to both
Python validation blocks in action.yml:
  - _ssrf_check.py (VCS URL pre-flight check)
  - _ssrf_check_install.py (binary download URL check)

The Go-level IsBlockedIP already covers this range correctly (ipcheck.go);
this fix closes the gap in the action.yml Python layer.

Also update comments to mention RFC6598 explicitly.
This commit is contained in:
Rodin
2026-05-14 13:41:17 +00:00
parent 934c6728ee
commit c349986187
+8 -5
View File
@@ -10,8 +10,8 @@
# github.server_url. Tokens are never sent to user-supplied URLs.
# - On Gitea (VCS_TYPE=gitea), inputs.vcs-url is validated (https scheme,
# no whitespace/newlines, and DNS resolution to a public IP) before use.
# Python3 resolves the hostname and rejects RFC1918, loopback, link-local,
# and other reserved addresses to prevent SSRF attacks.
# Python3 resolves the hostname and rejects RFC1918, RFC6598 (carrier-grade
# NAT), loopback, link-local, and other reserved addresses to prevent SSRF attacks.
# The installed review-bot binary additionally uses a safe HTTP transport
# (DialContext-level IP check) for all Gitea API calls at runtime.
# The binary also exposes a `validate-url` subcommand for use in any future
@@ -193,7 +193,8 @@ runs:
fi
# Additional IP-level SSRF defense: resolve the hostname and reject
# requests to RFC1918, loopback, link-local, and other reserved addresses.
# requests to RFC1918, RFC6598 (carrier-grade NAT), loopback, link-local,
# and other reserved addresses.
# python3 is required on ubuntu-* runners (see requirements comment above).
# Use printf to write the script to a temp file so the python lines are valid
# YAML (each indented line becomes a printf argument — no unindented code).
@@ -212,7 +213,8 @@ runs:
'for _,_,_,_,(a,*_) in rs:' \
' ip=ipaddress.ip_address(a)' \
' if isinstance(ip,ipaddress.IPv6Address) and ip.ipv4_mapped: ip=ip.ipv4_mapped' \
' if ip.is_private or ip.is_loopback or ip.is_link_local or ip.is_multicast or ip.is_reserved:' \
' cgn=ipaddress.ip_network("100.64.0.0/10")' \
' if ip.is_private or ip.is_loopback or ip.is_link_local or ip.is_multicast or ip.is_reserved or ip in cgn:' \
' print(f"blocked: {a}",file=sys.stderr); sys.exit(1)' \
> /tmp/_ssrf_check.py
CHECK_URL="${SERVER_URL}" python3 /tmp/_ssrf_check.py || {
@@ -359,7 +361,8 @@ runs:
'for _,_,_,_,(a,*_) in rs:' \
' ip=ipaddress.ip_address(a)' \
' if isinstance(ip,ipaddress.IPv6Address) and ip.ipv4_mapped: ip=ip.ipv4_mapped' \
' if ip.is_private or ip.is_loopback or ip.is_link_local or ip.is_multicast or ip.is_reserved:' \
' cgn=ipaddress.ip_network("100.64.0.0/10")' \
' if ip.is_private or ip.is_loopback or ip.is_link_local or ip.is_multicast or ip.is_reserved or ip in cgn:' \
' print(f"blocked: {a}",file=sys.stderr); sys.exit(1)' \
> /tmp/_ssrf_check_install.py
CHECK_URL="${SERVER_URL}" python3 /tmp/_ssrf_check_install.py || {