43 lines
1.9 KiB
Diff
43 lines
1.9 KiB
Diff
From ac79778c91bd9a4a92111f7e06d4b12674571113 Mon Sep 17 00:00:00 2001
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From: Ben Darnell <ben@bendarnell.com>
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Date: Sat, 13 May 2023 20:58:52 -0400
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Subject: [PATCH] web: Fix an open redirect in StaticFileHandler
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Under some configurations the default_filename redirect could be exploited
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to redirect to an attacker-controlled site. This change refuses to redirect
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to URLs that could be misinterpreted.
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A test case for the specific vulnerable configuration will follow after the
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patch has been available.
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Upstream: https://github.com/tornadoweb/tornado/commit/32ad07c54e607839273b4e1819c347f5c8976b2f
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[Thomas: backported to fix CVE-2023-28370]
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Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
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---
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tornado/web.py | 9 +++++++++
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1 file changed, 9 insertions(+)
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diff --git a/tornado/web.py b/tornado/web.py
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index cd6a81b4..05b571eb 100644
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--- a/tornado/web.py
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+++ b/tornado/web.py
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@@ -2806,6 +2806,15 @@ class StaticFileHandler(RequestHandler):
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# but there is some prefix to the path that was already
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# trimmed by the routing
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if not self.request.path.endswith("/"):
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+ if self.request.path.startswith("//"):
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+ # A redirect with two initial slashes is a "protocol-relative" URL.
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+ # This means the next path segment is treated as a hostname instead
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+ # of a part of the path, making this effectively an open redirect.
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+ # Reject paths starting with two slashes to prevent this.
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+ # This is only reachable under certain configurations.
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+ raise HTTPError(
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+ 403, "cannot redirect path with two initial slashes"
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+ )
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self.redirect(self.request.path + "/", permanent=True)
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return None
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absolute_path = os.path.join(absolute_path, self.default_filename)
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--
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2.41.0
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