From 3c36e74aa9c6b760d0fbc5c50419052d531ffdb7 Mon Sep 17 00:00:00 2001 From: Casey Bodley Date: Tue, 26 May 2020 15:03:03 -0400 Subject: [PATCH] rgw: sanitize newlines in s3 CORSConfiguration's ExposeHeader the values in the element are sent back to clients in a Access-Control-Expose-Headers response header. if the values are allowed to have newlines in them, they can be used to inject arbitrary response headers this issue only affects s3, which gets these values from an xml document in swift, they're given in the request header X-Container-Meta-Access-Control-Expose-Headers, so the value itself cannot contain newlines Signed-off-by: Casey Bodley Reported-by: Adam Mohammed --- src/rgw/rgw_cors.cc | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/src/rgw/rgw_cors.cc b/src/rgw/rgw_cors.cc index 422767f34eb22..94d08f7ae3b9c 100644 --- a/src/rgw/rgw_cors.cc +++ b/src/rgw/rgw_cors.cc @@ -144,11 +144,12 @@ bool RGWCORSRule::is_header_allowed(const char *h, size_t len) { void RGWCORSRule::format_exp_headers(string& s) { s = ""; - for(list::iterator it = exposable_hdrs.begin(); - it != exposable_hdrs.end(); ++it) { - if (s.length() > 0) - s.append(","); - s.append((*it)); + for (const auto& header : exposable_hdrs) { + if (s.length() > 0) + s.append(","); + // these values are sent to clients in a 'Access-Control-Expose-Headers' + // response header, so we escape '\n' to avoid header injection + boost::replace_all_copy(std::back_inserter(s), header, "\n", "\\n"); } } -- 2.39.5