Caddy's underscore header filter (GHSA-f59h-q822-g45g) only checked
for `_`. PHP folds `.` to `_` when registering $_SERVER keys the same
way CGI/FastCGI folds `-` to `_`, so a dotted alias (e.g. Remote.User)
survived the filter and collided with the legitimate hyphenated
header once it reached a PHP/FastCGI backend, bypassing forward_auth
copy_headers the same way the underscore alias did.
Extends the filter to drop `.` symmetrically, adds an
`expected_dot_headers` allowlist mirroring `expected_underscore_headers`,
and handles header names containing both separators (only an exact
allowlist entry is honored there, since a prefix glob's free-form
suffix can't be vetted for an embedded second separator).
Root cause identified by @iliaal in the FrankenPHP advisory
GHSA-49wc-4hcv-v58q.
* caddyhttp: restore allow_underscore_in_headers server option (#7808)
* caddyhttp: mark insecure_allow_underscore_in_headers as EXPERIMENTAL
* caddyhttp: replace underscore bool with expected_underscore_headers allowlist
* fix gofmt alignment in serveroptions.go
* caddyhttp: drop repeated allowlisted underscore headers
* caddyhttp: add tests for repeated-value drop and variant-drop logging
* feat: drop headers with underscore in their names
* feat: Caddyfile binding and tests for underscore-in-header drop
Add the `allow_underscore_in_headers` global server option, refine the
doc comment, and cover the filter end-to-end: server-level unit tests
(drop, opt-out, debug log, RFC-7230 space rejection), a fastcgi unit
test for the trimmed header name replacer, and forward_auth integration
tests for both the default-drop and opt-out paths.
* remove allow_underscore_in_headers option for now
* chore: upgrade .golangci.yml and workflow to v2
run `golangci-lint fmt`
Signed-off-by: Mohammed Al Sahaf <msaa1990@gmail.com>
* run `golangci-lint run --fix`
Signed-off-by: Mohammed Al Sahaf <msaa1990@gmail.com>
* more lint fixes
Signed-off-by: Mohammed Al Sahaf <msaa1990@gmail.com>
* bring back comments to .golangci.yml
Signed-off-by: Mohammed Al Sahaf <msaa1990@gmail.com>
* appease the linter some more
Signed-off-by: Mohammed Al Sahaf <msaa1990@gmail.com>
* oops
Signed-off-by: Mohammed Al Sahaf <msaa1990@gmail.com>
* use embedded structs
Signed-off-by: Mohammed Al Sahaf <msaa1990@gmail.com>
* use embedded structs where they were used before
Signed-off-by: Mohammed Al Sahaf <msaa1990@gmail.com>
* disable rule `-QF1006`
Signed-off-by: Mohammed Al Sahaf <msaa1990@gmail.com>
* missed a spot
Signed-off-by: Mohammed Al Sahaf <msaa1990@gmail.com>
---------
Signed-off-by: Mohammed Al Sahaf <msaa1990@gmail.com>
Kévin Dunglas
Bluegate Studio
Chris Seufert
joemicky
Mohammed Al Sahaf
Yifan Yang
Francis Lavoie
Nebez Briefkani
Dave Henderson