Are there any restrictions on access to browser extensions storage?











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I'm trying to understand security implications of using browser extensions storage. A few things are not clear to me when I read the WebExtensions storage documentation.



Documentation says among others that:




Values are scoped to the extension, not to a specific domain (i.e. the same set of key/value pairs are available to all scripts in the background context and content scripts).




also:




Each extension has its own storage area, which can be split into different types of storage.




also:




The storage area is not encrypted and shouldn't be used for storing confidential user information.




Considering the above I still have a few questions here:




  1. Is it possible for extension E to access data stored by extension A?

  2. Is it possible for an arbitrary webpage to access data stored by extension A?

  3. Is it possible for a webpage on which extension A is run to access data stored by this extension?


I read a few bits about localStorage (in)security but I'm not sure if and how those rules apply to



Thanks in advance for your help!










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    up vote
    0
    down vote

    favorite












    I'm trying to understand security implications of using browser extensions storage. A few things are not clear to me when I read the WebExtensions storage documentation.



    Documentation says among others that:




    Values are scoped to the extension, not to a specific domain (i.e. the same set of key/value pairs are available to all scripts in the background context and content scripts).




    also:




    Each extension has its own storage area, which can be split into different types of storage.




    also:




    The storage area is not encrypted and shouldn't be used for storing confidential user information.




    Considering the above I still have a few questions here:




    1. Is it possible for extension E to access data stored by extension A?

    2. Is it possible for an arbitrary webpage to access data stored by extension A?

    3. Is it possible for a webpage on which extension A is run to access data stored by this extension?


    I read a few bits about localStorage (in)security but I'm not sure if and how those rules apply to



    Thanks in advance for your help!










    share|improve this question
























      up vote
      0
      down vote

      favorite









      up vote
      0
      down vote

      favorite











      I'm trying to understand security implications of using browser extensions storage. A few things are not clear to me when I read the WebExtensions storage documentation.



      Documentation says among others that:




      Values are scoped to the extension, not to a specific domain (i.e. the same set of key/value pairs are available to all scripts in the background context and content scripts).




      also:




      Each extension has its own storage area, which can be split into different types of storage.




      also:




      The storage area is not encrypted and shouldn't be used for storing confidential user information.




      Considering the above I still have a few questions here:




      1. Is it possible for extension E to access data stored by extension A?

      2. Is it possible for an arbitrary webpage to access data stored by extension A?

      3. Is it possible for a webpage on which extension A is run to access data stored by this extension?


      I read a few bits about localStorage (in)security but I'm not sure if and how those rules apply to



      Thanks in advance for your help!










      share|improve this question













      I'm trying to understand security implications of using browser extensions storage. A few things are not clear to me when I read the WebExtensions storage documentation.



      Documentation says among others that:




      Values are scoped to the extension, not to a specific domain (i.e. the same set of key/value pairs are available to all scripts in the background context and content scripts).




      also:




      Each extension has its own storage area, which can be split into different types of storage.




      also:




      The storage area is not encrypted and shouldn't be used for storing confidential user information.




      Considering the above I still have a few questions here:




      1. Is it possible for extension E to access data stored by extension A?

      2. Is it possible for an arbitrary webpage to access data stored by extension A?

      3. Is it possible for a webpage on which extension A is run to access data stored by this extension?


      I read a few bits about localStorage (in)security but I'm not sure if and how those rules apply to



      Thanks in advance for your help!







      firefox-webextensions browser-extension webextension-storage






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      share|improve this question










      asked Nov 11 at 1:27









      maciejchmielarz

      687




      687
























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          Note: storage.local (e,g. browser.storage.local.get('item') or chrome.storage.local.get('item')) is a WebExtension API and limited to the extension. It should not be confused with Window.localStorage (e.g. localStorage.getItem('item')) which is a Web API and not secure and accessible.



          In case of storage.local:




          Is it possible for extension E to access data stored by extension A?




          No. Each extension has its own storage.local area and not accessible by other extensions.




          Is it possible for an arbitrary webpage to access data stored by
          extension A?




          No. As above access is limited to the extension only.




          Is it possible for a webpage on which extension A is run to access
          data stored by this extension?




          No. As above.






          share|improve this answer





















          • Thanks erosman for the answer and the clarifying note :) FTR I'm aware of the difference you mention and my problem was exactly that localStorage (Web API) security is extensively covered here and there but I had a really hard time to find similar details about storage (WebExtension API) security. Thanks for clarifying this for me.
            – maciejchmielarz
            Nov 11 at 20:21











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          active

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          up vote
          1
          down vote



          accepted










          Note: storage.local (e,g. browser.storage.local.get('item') or chrome.storage.local.get('item')) is a WebExtension API and limited to the extension. It should not be confused with Window.localStorage (e.g. localStorage.getItem('item')) which is a Web API and not secure and accessible.



          In case of storage.local:




          Is it possible for extension E to access data stored by extension A?




          No. Each extension has its own storage.local area and not accessible by other extensions.




          Is it possible for an arbitrary webpage to access data stored by
          extension A?




          No. As above access is limited to the extension only.




          Is it possible for a webpage on which extension A is run to access
          data stored by this extension?




          No. As above.






          share|improve this answer





















          • Thanks erosman for the answer and the clarifying note :) FTR I'm aware of the difference you mention and my problem was exactly that localStorage (Web API) security is extensively covered here and there but I had a really hard time to find similar details about storage (WebExtension API) security. Thanks for clarifying this for me.
            – maciejchmielarz
            Nov 11 at 20:21















          up vote
          1
          down vote



          accepted










          Note: storage.local (e,g. browser.storage.local.get('item') or chrome.storage.local.get('item')) is a WebExtension API and limited to the extension. It should not be confused with Window.localStorage (e.g. localStorage.getItem('item')) which is a Web API and not secure and accessible.



          In case of storage.local:




          Is it possible for extension E to access data stored by extension A?




          No. Each extension has its own storage.local area and not accessible by other extensions.




          Is it possible for an arbitrary webpage to access data stored by
          extension A?




          No. As above access is limited to the extension only.




          Is it possible for a webpage on which extension A is run to access
          data stored by this extension?




          No. As above.






          share|improve this answer





















          • Thanks erosman for the answer and the clarifying note :) FTR I'm aware of the difference you mention and my problem was exactly that localStorage (Web API) security is extensively covered here and there but I had a really hard time to find similar details about storage (WebExtension API) security. Thanks for clarifying this for me.
            – maciejchmielarz
            Nov 11 at 20:21













          up vote
          1
          down vote



          accepted







          up vote
          1
          down vote



          accepted






          Note: storage.local (e,g. browser.storage.local.get('item') or chrome.storage.local.get('item')) is a WebExtension API and limited to the extension. It should not be confused with Window.localStorage (e.g. localStorage.getItem('item')) which is a Web API and not secure and accessible.



          In case of storage.local:




          Is it possible for extension E to access data stored by extension A?




          No. Each extension has its own storage.local area and not accessible by other extensions.




          Is it possible for an arbitrary webpage to access data stored by
          extension A?




          No. As above access is limited to the extension only.




          Is it possible for a webpage on which extension A is run to access
          data stored by this extension?




          No. As above.






          share|improve this answer












          Note: storage.local (e,g. browser.storage.local.get('item') or chrome.storage.local.get('item')) is a WebExtension API and limited to the extension. It should not be confused with Window.localStorage (e.g. localStorage.getItem('item')) which is a Web API and not secure and accessible.



          In case of storage.local:




          Is it possible for extension E to access data stored by extension A?




          No. Each extension has its own storage.local area and not accessible by other extensions.




          Is it possible for an arbitrary webpage to access data stored by
          extension A?




          No. As above access is limited to the extension only.




          Is it possible for a webpage on which extension A is run to access
          data stored by this extension?




          No. As above.







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Nov 11 at 4:52









          erosman

          2,04431430




          2,04431430












          • Thanks erosman for the answer and the clarifying note :) FTR I'm aware of the difference you mention and my problem was exactly that localStorage (Web API) security is extensively covered here and there but I had a really hard time to find similar details about storage (WebExtension API) security. Thanks for clarifying this for me.
            – maciejchmielarz
            Nov 11 at 20:21


















          • Thanks erosman for the answer and the clarifying note :) FTR I'm aware of the difference you mention and my problem was exactly that localStorage (Web API) security is extensively covered here and there but I had a really hard time to find similar details about storage (WebExtension API) security. Thanks for clarifying this for me.
            – maciejchmielarz
            Nov 11 at 20:21
















          Thanks erosman for the answer and the clarifying note :) FTR I'm aware of the difference you mention and my problem was exactly that localStorage (Web API) security is extensively covered here and there but I had a really hard time to find similar details about storage (WebExtension API) security. Thanks for clarifying this for me.
          – maciejchmielarz
          Nov 11 at 20:21




          Thanks erosman for the answer and the clarifying note :) FTR I'm aware of the difference you mention and my problem was exactly that localStorage (Web API) security is extensively covered here and there but I had a really hard time to find similar details about storage (WebExtension API) security. Thanks for clarifying this for me.
          – maciejchmielarz
          Nov 11 at 20:21


















           

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