Hello Samuel,

On Sat, 29 May 2021 14:06:18 +0100 Samuel Henrique wrote:
>
> That's a great catch!
> I'm bumping the severity as this "makes the package in question
> unusable or mostly so".

thanks for getting back to me regarding this bug.

Since there is just an offset in the values used for key identification,
which stems from the `xor_count_256` respectively
`xor_count_128`-variable, the package is still kind of usable, if the
default threshold is raised -- either manually via `-t 50`or via a patch
during compile time. Nevertheless, this should be fixed in a proper way,
I think.

> I believe you accidentally pasted the same link twice when talking
> about two different functions.

Yes, this was a faux pas -- sorry for that! The second suspicious
function, which I mentioned in my previous message, seems to be
`key_core(...)` in `aes.h`. You can find it here [1]. The two referenced
functions basically perform the heavy lifting of aeskeyfind's compuations.

> Could you submit your tests so we can confirm any fix applied (if we
do so)?
> I would like to use your tests with git-bisect to make sure this
> regression wasn't caused by one of our patches.

I am very confident, that the Debian's patches applied during the
packaging are fine, since I checked the results of the unmodified
upstream source also, which I built by myself and got the same erroneous
results. Therefore it looks like to me, that the error stems from some
changes related to glibc 2.31-11 (or maybe even the kernel in Version
5.10.0.6).

The tests, that I created and which led to uncovering this issue can be
found here:

https://salsa.debian.org/jgru/aeskeyfind/-/commit/04c9a6038a047fa97e527cc05346416b98949c4c


You can get and run those tests with the following commands:
```
git clone g...@salsa.debian.org:jgru/aeskeyfind.git
git checkout add-autopkgtests
autopkgtest --debug -- schroot sid-amd64
```
If you remove line 62 of `debian/tests/helpers/ test_aes_extraction.sh`
[3] you can preserve the resulting dump for manual testing.
If you add `-t 50`to line 56 of `debian/tests/helpers/
test_aes_extraction.sh` [4]  the tests will succeed.

>
> It's possible that this bug also affects rsakeyfind, so I would
> appreciate it if you could run your test against that package as well
> (I assume it must be easy since they are so similar).
>

I performed similar tests regarding rsakeyfind and have to say, that
this software is not affected at all. Please refer to my merge request
containing the autopkgtests for rsakeyfind at [5].

If you have any ideas on how to debug this issue in a targeted manner,
please get back to me.

Thanks for tackling this problem!

Best regards,
   Jan
---
[1]
https://salsa.debian.org/pkg-security-team/aeskeyfind/-/blob/debian/master/aes.h#L12
[2]
https://citpsite.s3.amazonaws.com/memory-content/src/aeskeyfind-1.0.tar.gz
[3]
https://salsa.debian.org/jgru/aeskeyfind/-/blob/add-autopkgtests/debian/tests/helpers/test_aes_extraction.sh#L62
[4]
https://salsa.debian.org/jgru/aeskeyfind/-/blob/add-autopkgtests/debian/tests/helpers/test_aes_extraction.sh#L56
[5]
https://salsa.debian.org/pkg-security-team/rsakeyfind/-/merge_requests/2?commit_id=e7d030704f56c84ff48893883af2c5cc46414c4b

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