lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Thu, 25 Aug 2022 13:14:20 +0200 From: Juergen Gross <jgross@...e.com> To: Jan Beulich <jbeulich@...e.com> Cc: Stefano Stabellini <sstabellini@...nel.org>, Oleksandr Tyshchenko <oleksandr_tyshchenko@...m.com>, stable@...r.kernel.org, Rustam Subkhankulov <subkhankulov@...ras.ru>, xen-devel@...ts.xenproject.org, linux-kernel@...r.kernel.org Subject: Re: [PATCH v2] xen/privcmd: fix error exit of privcmd_ioctl_dm_op() On 25.08.22 12:22, Jan Beulich wrote: > On 25.08.2022 12:13, Juergen Gross wrote: >> On 25.08.22 11:50, Jan Beulich wrote: >>> On 25.08.2022 11:26, Juergen Gross wrote: >>>> --- a/drivers/xen/privcmd.c >>>> +++ b/drivers/xen/privcmd.c >>>> @@ -602,6 +602,10 @@ static int lock_pages( >>>> *pinned += page_count; >>>> nr_pages -= page_count; >>>> pages += page_count; >>>> + >>>> + /* Exact reason isn't known, EFAULT is one possibility. */ >>>> + if (page_count < requested) >>>> + return -EFAULT; >>>> } >>> >>> I don't really know the inner workings of pin_user_pages_fast() >>> nor what future plans there are with it. To be as independent of >>> its behavior as possible, how about bailing here only when >>> page_count actually is zero (i.e. no forward progress)? >> >> This would require to rework the loop in lock_pages() to be able to >> handle only a partial buffer. > > Oh, I see - I've misread the code as if the loop was capping each > iteration's count to the capacity of some internal buffer (as iirc > is being done elsewhere). So ... > >> This would add some complexity, but OTOH I'd get an exact error code >> back in case of failure. > > ... perhaps not worth it then, ... > >> I'll have a try and see how the result would look like. > > ... unless you think this might be relevant in certain cases. Not sure, but the resulting code is looking fine IMO. Juergen Download attachment "OpenPGP_0xB0DE9DD628BF132F.asc" of type "application/pgp-keys" (3099 bytes) Download attachment "OpenPGP_signature" of type "application/pgp-signature" (496 bytes)
Powered by blists - more mailing lists