lkml.org 
[lkml]   [2021]   [Apr]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 053/190] Revert "ecryptfs: replace BUG_ON with error handling code"
    On Wed, Apr 21, 2021 at 02:58:48PM +0200, Greg Kroah-Hartman wrote:
    > This reverts commit 2c2a7552dd6465e8fde6bc9cccf8d66ed1c1eb72.
    >
    > Commits from @umn.edu addresses have been found to be submitted in "bad
    > faith" to try to test the kernel community's ability to review "known
    > malicious" changes. The result of these submissions can be found in a
    > paper published at the 42nd IEEE Symposium on Security and Privacy
    > entitled, "Open Source Insecurity: Stealthily Introducing
    > Vulnerabilities via Hypocrite Commits" written by Qiushi Wu (University
    > of Minnesota) and Kangjie Lu (University of Minnesota).
    >
    > Because of this, all submissions from this group must be reverted from
    > the kernel tree and will need to be re-reviewed again to determine if
    > they actually are a valid fix. Until that work is complete, remove this
    > change to ensure that no problems are being introduced into the
    > codebase.

    FWIW, commit message on the original (
    ecryptfs: replace BUG_ON with error handling code

    In crypt_scatterlist, if the crypt_stat argument is not set up
    correctly, the kernel crashes. Instead, by returning an error code
    upstream, the error is handled safely.

    The issue is detected via a static analysis tool written by us.

    Fixes: 237fead619984 (ecryptfs: fs/Makefile and fs/Kconfig)
    Signed-off-by: Aditya Pakki <pakki001@umn.edu>
    Signed-off-by: Tyler Hicks <code@tyhicks.com>
    )
    really stinks. First, the analysis: condition being tested is
    (!crypt_stat || !crypt_stat->tfm
    || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
    and their patch replaces BUG_ON() with return of -EINVAL. So the
    only thing their tool had detected the presence of BUG_ON().
    Was it grep, by any chance?

    IOW, the commit message is "we'd found BUG_ON(); let's replace it
    with returning some error value and hope everything works. Whaddya
    mean, how do we know? Our tool [git grep BUG_ON, that is] says
    it's there and look, it *is* there, so if it's ever reached there'll
    be trouble. What, assertion that returning an error will be handled
    safely? 'Cuz we saiz so, that's why"


    It *is* functionally harmless, AFAICS, but only because the condition
    is really impossible. However,
    * it refers to vague (s)tool they'd produced, nevermind that
    all they really do is "find BUG_ON(), replace with returning an error".
    * unlike BUG_ON(), the replacement does *NOT* document the
    fact that condition should be impossible.
    IMO either should be sufficient for rejecting the patch.

    \
     
     \ /
      Last update: 2021-04-21 18:04    [W:3.184 / U:0.236 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site