fix: whitelist safe characters in trailing-slash rewrite to prevent open redirect#2362
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fix: whitelist safe characters in trailing-slash rewrite to prevent open redirect#2362
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The [^\\\\] character class in the location regex didn't work in production due to nginx config backslash escaping differences across environments. Use a map directive with \x5c (PCRE hex escape for backslash byte 0x5C) which is completely unambiguous. The map sets $uri_has_backslash, and an if+return inside the trailing-slash location block returns 404 when a backslash is detected - preventing the redirect that would put \ in the Location header. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Previous approaches tried to detect/match the backslash character using \x5c hex escapes, [^\\\\] character classes, map directives, and if blocks - all worked in CI but failed in production. This takes the opposite approach: instead of blacklisting backslashes, whitelist the safe characters that should appear in documentation URLs. The trailing-slash location regex changes from ^(.+)/$ to ^(/[a-zA-Z0-9][a-zA-Z0-9_./-]*)/$ so it only matches URIs composed of letters, digits, dots, hyphens, underscores, and forward slashes. Uses only basic regex features (character ranges and literals) that work identically across all PCRE/POSIX ERE versions with zero escaping ambiguity. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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Not needed - the \x5c location approach works, previous test failures were due to CloudFront cache. |
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Summary
^(.+)/$to^(/[a-zA-Z0-9][a-zA-Z0-9_./-]*)/$Fixes apify/apify-core#26551
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