| 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
| ||
|
Message-ID: <20230516094919.GA411@mutt>
Date: Tue, 16 May 2023 11:49:19 +0200
From: Anders Roxell <anders.roxell@...aro.org>
To: Lorenzo Stoakes <lstoakes@...il.com>
Cc: linux-mm@...ck.org, linux-kernel@...r.kernel.org,
Andrew Morton <akpm@...ux-foundation.org>,
Matthew Wilcox <willy@...radead.org>,
David Hildenbrand <david@...hat.com>,
linux-arm-kernel@...ts.infradead.org, kvm@...r.kernel.org,
linux-s390@...r.kernel.org, linux-fsdevel@...r.kernel.org,
linux-perf-users@...r.kernel.org,
linux-security-module@...r.kernel.org,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>,
Christian Borntraeger <borntraeger@...ux.ibm.com>,
Janosch Frank <frankja@...ux.ibm.com>,
Claudio Imbrenda <imbrenda@...ux.ibm.com>,
Heiko Carstens <hca@...ux.ibm.com>,
Vasily Gorbik <gor@...ux.ibm.com>,
Alexander Gordeev <agordeev@...ux.ibm.com>,
Sven Schnelle <svens@...ux.ibm.com>,
Eric Biederman <ebiederm@...ssion.com>,
Kees Cook <keescook@...omium.org>,
Alexander Viro <viro@...iv.linux.org.uk>,
Christian Brauner <brauner@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...nel.org>,
Namhyung Kim <namhyung@...nel.org>,
Ian Rogers <irogers@...gle.com>,
Adrian Hunter <adrian.hunter@...el.com>,
Kentaro Takeda <takedakn@...data.co.jp>,
Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>,
Paul Moore <paul@...l-moore.com>,
James Morris <jmorris@...ei.org>,
"Serge E . Hallyn" <serge@...lyn.com>,
Paolo Bonzini <pbonzini@...hat.com>,
Jens Axboe <axboe@...nel.dk>,
Pavel Begunkov <asml.silence@...il.com>,
Jason Gunthorpe <jgg@...pe.ca>,
John Hubbard <jhubbard@...dia.com>
Subject: Re: [PATCH v5 3/6] mm/gup: remove vmas parameter from
get_user_pages_remote()
On 2023-05-14 22:26, Lorenzo Stoakes wrote:
> The only instances of get_user_pages_remote() invocations which used the
> vmas parameter were for a single page which can instead simply look up the
> VMA directly. In particular:-
>
> - __update_ref_ctr() looked up the VMA but did nothing with it so we simply
> remove it.
>
> - __access_remote_vm() was already using vma_lookup() when the original
> lookup failed so by doing the lookup directly this also de-duplicates the
> code.
>
> We are able to perform these VMA operations as we already hold the
> mmap_lock in order to be able to call get_user_pages_remote().
>
> As part of this work we add get_user_page_vma_remote() which abstracts the
> VMA lookup, error handling and decrementing the page reference count should
> the VMA lookup fail.
>
> This forms part of a broader set of patches intended to eliminate the vmas
> parameter altogether.
>
> Reviewed-by: Catalin Marinas <catalin.marinas@....com> (for arm64)
> Acked-by: David Hildenbrand <david@...hat.com>
> Reviewed-by: Janosch Frank <frankja@...ux.ibm.com> (for s390)
> Signed-off-by: Lorenzo Stoakes <lstoakes@...il.com>
> ---
> arch/arm64/kernel/mte.c | 17 +++++++++--------
> arch/s390/kvm/interrupt.c | 2 +-
> fs/exec.c | 2 +-
> include/linux/mm.h | 34 +++++++++++++++++++++++++++++++---
> kernel/events/uprobes.c | 13 +++++--------
> mm/gup.c | 12 ++++--------
> mm/memory.c | 14 +++++++-------
> mm/rmap.c | 2 +-
> security/tomoyo/domain.c | 2 +-
> virt/kvm/async_pf.c | 3 +--
> 10 files changed, 61 insertions(+), 40 deletions(-)
>
[...]
> diff --git a/mm/memory.c b/mm/memory.c
> index 146bb94764f8..63632a5eafc1 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -5590,7 +5590,6 @@ EXPORT_SYMBOL_GPL(generic_access_phys);
> int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf,
> int len, unsigned int gup_flags)
> {
> - struct vm_area_struct *vma;
> void *old_buf = buf;
> int write = gup_flags & FOLL_WRITE;
>
> @@ -5599,13 +5598,15 @@ int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf,
>
> /* ignore errors, just check how much was successfully transferred */
> while (len) {
> - int bytes, ret, offset;
> + int bytes, offset;
> void *maddr;
> - struct page *page = NULL;
> + struct vm_area_struct *vma;
> + struct page *page = get_user_page_vma_remote(mm, addr,
> + gup_flags, &vma);
> +
> + if (IS_ERR_OR_NULL(page)) {
> + int ret = 0;
I see the warning below when building without CONFIG_HAVE_IOREMAP_PROT set.
make --silent --keep-going --jobs=32 \
O=/home/anders/.cache/tuxmake/builds/1244/build ARCH=arm \
CROSS_COMPILE=arm-linux-gnueabihf- /home/anders/src/kernel/next/mm/memory.c: In function '__access_remote_vm':
/home/anders/src/kernel/next/mm/memory.c:5608:29: warning: unused variable 'ret' [-Wunused-variable]
5608 | int ret = 0;
| ^~~
>
> - ret = get_user_pages_remote(mm, addr, 1,
> - gup_flags, &page, &vma, NULL);
> - if (ret <= 0) {
> #ifndef CONFIG_HAVE_IOREMAP_PROT
> break;
> #else
> @@ -5613,7 +5614,6 @@ int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf,
> * Check if this is a VM_IO | VM_PFNMAP VMA, which
> * we can access using slightly different code.
> */
> - vma = vma_lookup(mm, addr);
> if (!vma)
> break;
> if (vma->vm_ops && vma->vm_ops->access)
Cheers,
Anders
Powered by blists - more mailing lists