| Date | Wed, 21 Apr 2021 12:49:14 -0700 | From | Kees Cook <> | Subject | Re: [PATCH 113/190] Revert "x86/hpet: Prevent potential NULL pointer dereference" |
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On Wed, Apr 21, 2021 at 02:59:48PM +0200, Greg Kroah-Hartman wrote: > This reverts commit 2e84f116afca3719c9d0a1a78b47b48f75fd5724. > > 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. > > Cc: Aditya Pakki <pakki001@umn.edu> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: kjlu@umn.edu > Cc: Borislav Petkov <bp@alien8.de> > Cc: "H. Peter Anvin" <hpa@zytor.com> > Cc: Kees Cook <keescook@chromium.org> > Cc: Joe Perches <joe@perches.com> > Cc: Nicolai Stange <nstange@suse.de> > Cc: Roland Dreier <roland@purestorage.com> > Cc: https > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > --- > arch/x86/kernel/hpet.c | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c > index 08651a4e6aa0..0515a97bf6f5 100644 > --- a/arch/x86/kernel/hpet.c > +++ b/arch/x86/kernel/hpet.c > @@ -930,8 +930,6 @@ int __init hpet_enable(void) > return 0; > > hpet_set_mapping(); > - if (!hpet_virt_address) > - return 0; > > /* Validate that the config register is working */ > if (!hpet_cfg_working())
FWIW, this patch looks harmless. It is checking for a failure in hpet_set_mapping(), and avoids the following code from performing 0-offset reads. hpet_set_mapping() is likely to never fail in real-world situations. *shrug*
I think it would make more sense for the check to live in hpet_cfg_working(), though.
-- Kees Cook
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