From: Christian Borntraeger <borntraeger@linux.ibm.com>
To: Heiko Carstens <hca@linux.ibm.com>
Cc: Janis Schoetterl-Glausch <scgl@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Sven Schnelle <svens@linux.ibm.com>,
Nico Boehr <nrb@linux.ibm.com>,
Alexander Gordeev <agordeev@linux.ibm.com>,
linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH v1 01/10] s390/uaccess: Add storage key checked access to user memory
Date: Fri, 21 Jan 2022 08:32:25 +0100 [thread overview]
Message-ID: <b6896b1a-d529-1504-091c-d41287c01dc8@linux.ibm.com> (raw)
In-Reply-To: <YemnprCIEjjGFeTn@osiris>
Am 20.01.22 um 19:19 schrieb Heiko Carstens:
> On Thu, Jan 20, 2022 at 01:56:40PM +0100, Heiko Carstens wrote:
>>> 2. Implementation changes
>>> 2.1 Modify common code
>>
>> In general such changes are done in way that common code is or _may_ be
>> modified to fulfill our needs. Common code header file explicitely states
>> that architectures should get rid of private instances of
>> copy_{to,from}_user() and __copy_{to,from}_user{,_inatomic}().
>>
>> So we should not add anything like that to arch code again, since nobody
>> would expect that.
>
> Or to be more specific: I think the most simple solution would be to
> try to get the new *key variants into include/linux/uaccess.h, and add
> the raw variants in architecture code, similar to the rest of the
> uaccess functions.
> There is some (sort of) prior art with copy_mc_to_kernel() even,
> though that can only partially be compared.
So in essence adding something like this and then providing raw_copy_from/to_user_key?
(whitespace damaged, just pasted in)
diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index ac0394087f7d..3b6e78ee211c 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -201,6 +201,59 @@ copy_to_user(void __user *to, const void *from, unsigned long n)
return n;
}
+
+#if defined(__s390x__) && defined(CONFIG_KVM)
+/*
+ * Variants that pass along an access key. Uses by KVM on s390x to implement
+ * key checks for guests that use storage keys Must be kept in sync with the
+ * non-key variants from above. The only difference is the _key suffix when
+ * calling raw_copy_from/to_user_key.
+ */
+static inline __must_check unsigned long
+_copy_from_user_key(void *to, const void __user *from, unsigned long n, u8 key)
+{
+ unsigned long res = n;
+ might_fault();
+ if (!should_fail_usercopy() && likely(access_ok(from, n))) {
+ instrument_copy_from_user(to, from, n);
+ res = raw_copy_from_user_key(to, from, n, key);
+ }
+ if (unlikely(res))
+ memset(to + (n - res), 0, res);
+ return res;
+}
+
+static inline __must_check unsigned long
+_copy_to_user_key(void __user *to, const void *from, unsigned long n, u8 key)
+{
+ might_fault();
+ if (should_fail_usercopy())
+ return n;
+ if (access_ok(to, n)) {
+ instrument_copy_to_user(to, from, n);
+ n = raw_copy_to_user_key(to, from, n, key);
+ }
+ return n;
+}
+
+static __always_inline unsigned long __must_check
+copy_from_user_key(void *to, const void __user *from, unsigned long n, u8 key)
+{
+ if (likely(check_copy_size(to, n, false)))
+ n = _copy_from_user_key(to, from, n, key);
+ return n;
+}
+
+static __always_inline unsigned long __must_check
+copy_to_user_key(void __user *to, const void *from, unsigned long n, u8 key)
+{
+ if (likely(check_copy_size(from, n, true)))
+ n = _copy_to_user_key(to, from, n);
+ return n;
+}
+#endif
+
+
#ifndef copy_mc_to_kernel
/*
* Without arch opt-in this generic copy_mc_to_kernel() will not handle
next prev parent reply other threads:[~2022-01-21 7:32 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-18 9:52 [RFC PATCH v1 00/10] KVM: s390: Do storage key checking Janis Schoetterl-Glausch
2022-01-18 9:52 ` [RFC PATCH v1 01/10] s390/uaccess: Add storage key checked access to user memory Janis Schoetterl-Glausch
2022-01-18 13:18 ` Janosch Frank
2022-01-18 15:37 ` Sven Schnelle
2022-01-18 15:52 ` Janis Schoetterl-Glausch
2022-01-19 9:48 ` Heiko Carstens
2022-01-19 11:02 ` Janis Schoetterl-Glausch
2022-01-19 13:20 ` Heiko Carstens
2022-01-20 8:34 ` Janis Schoetterl-Glausch
2022-01-20 12:56 ` Heiko Carstens
2022-01-20 18:19 ` Heiko Carstens
2022-01-21 7:32 ` Christian Borntraeger [this message]
2022-01-21 11:04 ` Heiko Carstens
2022-01-21 13:46 ` Janis Schoetterl-Glausch
2022-01-21 14:26 ` Heiko Carstens
2022-01-24 10:38 ` [RFC PATCH] uaccess: Add mechanism for " Janis Schoetterl-Glausch
2022-01-24 17:41 ` Heiko Carstens
2022-01-25 12:35 ` Janis Schoetterl-Glausch
2022-01-25 13:23 ` Heiko Carstens
2022-01-18 9:52 ` [RFC PATCH v1 02/10] KVM: s390: Honor storage keys when accessing guest memory Janis Schoetterl-Glausch
2022-01-18 14:38 ` Janosch Frank
2022-01-20 10:27 ` Christian Borntraeger
2022-01-20 10:30 ` Janis Schoetterl-Glausch
2022-01-19 19:27 ` Christian Borntraeger
2022-01-20 8:11 ` Janis Schoetterl-Glausch
2022-01-20 8:50 ` Christian Borntraeger
2022-01-20 8:58 ` Janis Schoetterl-Glausch
2022-01-20 9:06 ` Christian Borntraeger
2022-01-18 9:52 ` [RFC PATCH v1 03/10] KVM: s390: handle_tprot: Honor storage keys Janis Schoetterl-Glausch
2022-01-18 9:52 ` [RFC PATCH v1 04/10] KVM: s390: selftests: Test TEST PROTECTION emulation Janis Schoetterl-Glausch
2022-01-20 15:40 ` Janosch Frank
2022-01-21 11:03 ` Janis Schoetterl-Glausch
2022-01-21 12:28 ` Claudio Imbrenda
2022-01-21 13:50 ` Janis Schoetterl-Glausch
2022-01-18 9:52 ` [RFC PATCH v1 05/10] KVM: s390: Add optional storage key checking to MEMOP IOCTL Janis Schoetterl-Glausch
2022-01-18 11:51 ` Christian Borntraeger
2022-01-18 9:52 ` [RFC PATCH v1 06/10] KVM: s390: Add vm IOCTL for key checked guest absolute memory access Janis Schoetterl-Glausch
2022-01-19 11:52 ` Thomas Huth
2022-01-19 12:46 ` Christian Borntraeger
2022-01-19 12:53 ` Thomas Huth
2022-01-19 13:17 ` Janis Schoetterl-Glausch
2022-01-20 10:38 ` Thomas Huth
2022-01-20 11:20 ` Christian Borntraeger
2022-01-20 12:23 ` Janis Schoetterl-Glausch
2022-01-25 12:00 ` Thomas Huth
2022-01-27 16:29 ` Janis Schoetterl-Glausch
2022-01-27 17:34 ` Claudio Imbrenda
2022-01-18 9:52 ` [RFC PATCH v1 07/10] KVM: s390: Rename existing vcpu memop functions Janis Schoetterl-Glausch
2022-01-18 9:52 ` [RFC PATCH v1 08/10] KVM: s390: selftests: Test memops with storage keys Janis Schoetterl-Glausch
2022-01-18 9:52 ` [RFC PATCH v1 09/10] KVM: s390: Add capability for storage key extension of MEM_OP IOCTL Janis Schoetterl-Glausch
2022-01-18 15:12 ` Christian Borntraeger
2022-01-18 9:52 ` [RFC PATCH v1 10/10] KVM: s390: selftests: Make use of capability in MEM_OP test Janis Schoetterl-Glausch
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=b6896b1a-d529-1504-091c-d41287c01dc8@linux.ibm.com \
--to=borntraeger@linux.ibm.com \
--cc=agordeev@linux.ibm.com \
--cc=gor@linux.ibm.com \
--cc=hca@linux.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-s390@vger.kernel.org \
--cc=nrb@linux.ibm.com \
--cc=scgl@linux.ibm.com \
--cc=svens@linux.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).