From 46817f30cee60bc5df8354ab326762e7c783fe2c 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 07dbab5d3e2..0b3e4f39455 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"); } } -- 2.23.0