Files
versitygw/iamapi
Tung Lam e63998fb31 fix: log the client IP from a trusted proxy header
Behind a reverse proxy the request log and the S3, admin, website and WebUI
access logs record the proxy's address instead of the client's. Add a
client-ip-header option that takes the logged address from X-Forwarded-For or
X-Real-Ip. It is off by default, so an existing deployment logs exactly what it
logged before.

The header is only honoured when the connecting peer is listed in the new
trusted-proxies list of IPs and CIDRs. Without that, the value is whatever the
client sent: nginx's standard
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for appends to a
client-supplied header, leaving the client's own address leftmost.
X-Forwarded-For is walked right to left, skipping the listed proxies, so the
first unlisted address is the client and a forged leftmost entry is never
reached; the two-proxy case from #2243 works once both proxies are listed.
Every header line is walked (a proxy may add its own line instead of
appending), ip:port entries are accepted, and a request from an unlisted peer
keeps the socket address. Setting the header with an empty trusted-proxies list
fails startup rather than silently trusting every peer.

X-Real-Ip reads the last header line, so a proxy that adds a line rather than
replacing the client's is the one that speaks. An address carrying an IPv6 zone
is rejected: the zone is free text that the space-delimited access log would
write verbatim, shifting every field after RemoteIP. When every hop in
X-Forwarded-For is a trusted proxy, the leftmost hop is logged, as nginx's
real_ip_recursive does, since the socket peer is then the nearest proxy. The
trusted-proxies list accepts the entry "unix" to trust the peer of a listener
bound to a unix socket path, which fasthttp reports as 0.0.0.0.

The resolver, middleware, log tag and parsers live in internal/clientip, shared
by s3api, iamapi, website and webui; s3api/utils re-exports them for the S3
callers, so the standalone IAM service no longer pulls in the S3 side. On this
branch go list -deps ./iamapi drops from 375 to 299 packages, against 298 on
main.

ctx.IP() is unchanged and still returns the socket peer address, because it
feeds aws:SourceIp in IAM policy conditions and SourceIP in policy evaluation;
only the address written to the logs and S3 event records comes from the
header.

Fixes #2243.
2026-10-16 00:51:53 +00:00
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