NEW 258443
Blob can't be read from opaque origined Workers 
https://bugs.webkit.org/show_bug.cgi?id=258443
Summary Blob can't be read from opaque origined Workers
Kaiido
Reported 2023-06-23 00:43:18 PDT
Test-case: https://codepen.io/_-0-_/pen/qBQqbLy Trying to read a Blob object with whatever method (`.arrayBuffer()` et al., `FileReader`, `new Response(blob).arrayBuffer()` etc.) from an opaque origin Web Worker throws an error: > [Error] Not allowed to load local resource: blob:null/70ccdfb9-8d83-4234-aec5-c45cb251b792 > [Error] Cannot load blob:null/70ccdfb9-8d83-4234-aec5-c45cb251b792 due to access control checks. > [Error] Failed to load resource: Not allowed to request resource (70ccdfb9-8d83-4234-aec5-c45cb251b792, line 0) > [Error] Unhandled Promise Rejection: NotReadableError: The I/O read operation failed. (anonymous function) (data:text/javascript,%0A…%0A:3) The issue seems to be that the fetch request made to access the blob's data goes through cross-origin checks, however the Blob should be by essence same origin, since it's supposed to be "in memory". This happens for Workers created from a data: URL, as well as for the ones created from a blob: URL in a file:// document. The weird thing is that it seems to work fine for opaque origin iframes (sandboxed or data: URL).
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Radar WebKit Bug Importer
Comment 1 2023-06-30 00:44:16 PDT
<rdar://problem/111555365>
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