Hi,
I was able to reproduce what you are seeing. I turned on debug statements
and discovered a few things that stand out. When a file is accessed through
apache the file is opened properly through ecryptfs, which includes reading
the header of the file. Once the file is open I see no sign of eCryptfs
being used to read the file. I'm going to have to dive into the apache code
to see how it reads files. It would seem that they do something out of the
ordinary that causes non-ecryptfs functions to be used for reading the file.
You can turn on debug messages with:
modprobe ecryptfs ecryptfs_verbosity=1
Trevor
On 9/8/07, Stefan Farestam <[EMAIL PROTECTED]> wrote:
>
> Hi again,
>
> I've investigated a bit more thoroughly into this problem, but I am still
> observing the same strange behavior. This time around I used strace on the
> apache server process and verified that apache did indeed only access the
> unencrypted file ($HOME/b/testfile.txt in the example below).
>
> Here is the exact procedure that I have followed:
>
> * reboot
>
> * stop any running instances of apache:
> % apache2ctl stop
>
> * delete and recreate the directories $HOME/a and $HOME/b
> % rm -rf $HOME/{a,b}
> % mkdir $HOME/{a,b}
>
> * mount the encrypted directory as root (plaintext passthrough
> disabled):
> % mount -t ecryptfs $HOME/{a,b} -o cipher=aes,ecryptfs_key_bytes=32
>
> * mtab entry becomes:
> % fgrep $HOME/a /etc/mtab
> /home/test/a /home/test/b ecryptfs
> rw,ecryptfs_sig=4733efbff603498e,ecryptfs_cipher=aes,ecryptfs_key_bytes=32 0
> 0
>
> * create testfile
> % cat << EOF > $HOME/b/testfile.txt
> 123456789-123456789-123456789-123456789-123456789-
> 123456789-123456789-123456789-123456789-123456789-
> 123456789-123456789-123456789-123456789-123456789-
> 123456789-123456789-123456789-123456789-123456789-
> 123456789-123456789-123456789-123456789-123456789-
> 123456789-123456789-123456789-123456789-123456789-
> EOF
>
> * start apache
> % apache2ctl start
>
> * retrieve file with wget
> % wget http://localhost/home/b/testfile.txt
>
> * check what we have:
> % od -c testfile.txt
> --- start
> 0000000 \0 \0 \0 \0 \0 \0 001 2 360 022 \b + 314 223 277 336
> 0000020 002 \0 \0 002 \0 \0 \0 \0 001 214 - 004 \t 003 001
> 0000040 \0 021 " 3 D U f w ` 336 361 ! s 326 262 220
> 0000060 272 356 h $ 5 : % w 364 d 231 \t 030 200 330 351
> 0000100 t 210 273 324 217 e 366 331 373 355 025 b \b _ C O
> 0000120 N S O L E \0 \0 \0 \0 G 3 357 277 366 003 I
> 0000140 216 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0
> 0000160 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0
> *
> 0000460 \0 \0
> 0000462
> --- end
>
> As I have previously noted the behavior appears only when the file is
> longer than 255 bytes.
>
> Variants of the above that I have tried (with the same result):
>
> * Used algorithms "aes" and "blowfish"
>
> * Varied blocksize from 32 to 16
>
> * Used Ubuntu kernel vmlinuz-2.6.20-16-generic with the
> ecryptfs module supplied with that kernel distribution
>
> * Used custom compiled kernel vmlinuz-2.6.21.7 with kernel supplied
> ecryptfs module
>
> * Used custom compiled kernel vmlinuz-2.6.22.6 with kernel supplied
> ecryptfs module
>
> * Used custom compiled kernel vmlinuz-2.6.23-rc5 with kernel supplied
> ecryptfs module
>
> I would be happy to run any other tests that someone suggests.
>
> --
> Stefan Farestam
> Mobile: +46 70 649 6838
>
>
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