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Adobe Acrobat Reader fails to open a pdf file on a user mode file system

New Here ,
Jun 24, 2019

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Hi everybody,

In our product (lucidlink.com) we have a virtual file system in Windows which is underpinned by the CBFS Connect driver (https://www.callbacktechnologies.com/cbfsconnect/)

This virtual file system is accessible through a junction (reparse point).

We have also implemented Windows/NTFS permissions on the virtual file system.

However we've hit a problem with Adobe Reader (which fails to open pdf files hosted on our virtual filesystem with an error "Access Denied".

The problem manifests only when Adobe Reader operates in its most secure mode (Protected Mode + AppContainer) which is enabled by default.

We have noticed that other sandboxed (AppContainer) applications like Edge, Chrome and various Windows Store apps can successfully open pdf files from our virtual file sytem.

I've monitored CreateFile calls (with ProcMon) made by the Adobe Reader processes (one with Medium Integrity and the other with AppContainer Integrity).

I cannot find a difference between the native filesystem (through a reparse point) and the user mode file system.

In both cases the CreateFile call from the AppContainer fails with ACCESS_DENIED and the one from Medium Integrity process succeeds.

Yet, Adobe Reader succeeds only when reading from a native file system and fails when reading from a user mode fs.

Is Adobe Reader (in AppContainer mode) compatible with user mode file systems?

Is there some drive/filesystem capability that we should implement in order to let Adobe Reader successfully open files?

Thanks,

Svilen Stoilov

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Adobe Acrobat Reader fails to open a pdf file on a user mode file system

New Here ,
Jun 24, 2019

Copy link to clipboard

Copied

Hi everybody,

In our product (lucidlink.com) we have a virtual file system in Windows which is underpinned by the CBFS Connect driver (https://www.callbacktechnologies.com/cbfsconnect/)

This virtual file system is accessible through a junction (reparse point).

We have also implemented Windows/NTFS permissions on the virtual file system.

However we've hit a problem with Adobe Reader (which fails to open pdf files hosted on our virtual filesystem with an error "Access Denied".

The problem manifests only when Adobe Reader operates in its most secure mode (Protected Mode + AppContainer) which is enabled by default.

We have noticed that other sandboxed (AppContainer) applications like Edge, Chrome and various Windows Store apps can successfully open pdf files from our virtual file sytem.

I've monitored CreateFile calls (with ProcMon) made by the Adobe Reader processes (one with Medium Integrity and the other with AppContainer Integrity).

I cannot find a difference between the native filesystem (through a reparse point) and the user mode file system.

In both cases the CreateFile call from the AppContainer fails with ACCESS_DENIED and the one from Medium Integrity process succeeds.

Yet, Adobe Reader succeeds only when reading from a native file system and fails when reading from a user mode fs.

Is Adobe Reader (in AppContainer mode) compatible with user mode file systems?

Is there some drive/filesystem capability that we should implement in order to let Adobe Reader successfully open files?

Thanks,

Svilen Stoilov

Views

251

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Jun 24, 2019 0

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