Yeah I was trying something similar only but with a much simpler Caeser cipher function of my own written as below:

void encrypt(char *data, char *encrypted, size_t size)
{
    unsigned int i;
    for(i=0;i<(unsigned int)size;i++)
        encrypted[i] = data[i] + 3;
    printk(KERN_INFO "%s",encrypted);
    return;
}

So in the given code wherever u see the calls to wrapfs_encrypt, I have replaced with my simpler encryption function.

But I am not able to figure out why calling this function creates a problem, the printk() statement inside the function shows me the correctly encrypted contents but the file is still blank.

Thanks

Kunal Baweja

Undergraduate B.E. (Hons.) Computer Science
Birla Institute Of Technology & Science, Pilani
K.K. Birla Goa Campus
+91 9049655665

On Fri, Jan 30, 2015 at 4:03 PM, Saket Sinha <saket.sinha89@gmail.com> wrote:
HI,

Kindly refer the following link that implements a minimal encryption over wrapfs.
https://github.com/piekill/wrapfs

Go through the wrapfs_encrypt in wrapfs_readpage and wrapfs_decrypt in wrapfs_writepage.

Regards,
Saket Sinha

On Fri, Jan 30, 2015 at 3:56 PM, Kunal Baweja <bawejakunal15@gmail.com> wrote:
Hi,
I am currently working on implementing a simple encrypted file system using a stackable file system WrapFS. In order to do so, as I read in the WrapFS mailing list one needs to implement address space operations, which I have done and posted on my github at this link and it works fine. But now when I am trying to modify the data before being written in wrapfs_lower() function I get a blank output in files written out.
Please guide where am I going wrong in modifying the data to be written and what could be the best way to decrypt it ?

Thanks

Kunal Baweja

Undergraduate B.E. (Hons.) Computer Science
Birla Institute Of Technology & Science, Pilani
K.K. Birla Goa Campus

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