[FilesUploadHandler] Add preliminary check for path traversal#10382
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[FilesUploadHandler] Add preliminary check for path traversal#10382
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The FilesUploadHandler uses `basename` on the client filename in order to ensure the user can not escape the configured path by uploading a filename containing ../../ (ie. web browsers will generally just provide the filename, but a malicious attacker can try and escape the path.) However, there is still a theoretical possibility that a caller to FilesUploadHandler does something such as insert the unsanitized value into the database, which can then be misused indirectly. This adds a preliminary check to ensure the filename provided does not look like a path so that an error is returned and the caller (hopefully) does not do anything with the value. The basename check is maintained.
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The FilesUploadHandler uses
basenameon the client filename in order to ensure the user can not escape the configured path by uploading a filename containing ../../ (web browsers will generally just provide the filename, but a malicious attacker can try and escape the path.)However, there is still a theoretical possibility that a caller to FilesUploadHandler does something such as insert the unsanitized value into the database, which can then be misused indirectly.
This adds a preliminary check to ensure the filename provided does not look like a path so that an error is returned and the caller (hopefully) does not do anything with the value if it has anything that looks like a path character. The basename check is maintained.