Messages in this thread | | | Date | Tue, 27 Apr 2021 16:58:06 +0200 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH 053/190] Revert "ecryptfs: replace BUG_ON with error handling code" |
| |
On Wed, Apr 21, 2021 at 11:13:29AM -0500, Tyler Hicks wrote: > On 2021-04-21 16:04:02, Al Viro wrote: > > 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. > > I agree that it was not a malicious change. There are other places > within the same function that return -EINVAL and the expectation is that > errors from this function should be handled safely. > > That said, I can find no real-world reports of this BUG_ON() ever being > a problem and I don't think that there's any actual need for this > change. So, I'm alright with it being reverted considering the > circumstances. > > Acked-by: Tyler Hicks <code@tyhicks.com>
Thanks for the review, I've update the commit log message and added your ack here.
greg k-h
| |