| 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: <20220203181141.2682997-3-scgl@linux.ibm.com>
Date: Thu, 3 Feb 2022 19:11:41 +0100
From: Janis Schoetterl-Glausch <scgl@...ux.ibm.com>
To: scgl@...ux.ibm.com
Cc: akpm@...ux-foundation.org, arnd@...db.de,
borntraeger@...ux.ibm.com, hca@...ux.ibm.com,
keescook@...omium.org, linux-kernel@...r.kernel.org,
viro@...iv.linux.org.uk
Subject: [RFC PATCH 2/2] s390/uaccess: Provide raw_copy_from/to_user_opaque
This enables KVM to perform key checked guest accesses by passing the
access key via the opaque argument of __copy_from/to_user_opaque.
Since the existing uaccess implementation on s390 makes use of move
instructions that support having an additional access key supplied,
we can implement raw_copy_from/to_user_opaque by enhancing the
existing implementation.
Signed-off-by: Janis Schoetterl-Glausch <scgl@...ux.ibm.com>
---
arch/s390/include/asm/uaccess.h | 27 ++++++++++++++--
arch/s390/lib/uaccess.c | 56 ++++++++++++++++++++-------------
2 files changed, 60 insertions(+), 23 deletions(-)
diff --git a/arch/s390/include/asm/uaccess.h b/arch/s390/include/asm/uaccess.h
index 02b467461163..1a324bc3ae0b 100644
--- a/arch/s390/include/asm/uaccess.h
+++ b/arch/s390/include/asm/uaccess.h
@@ -33,11 +33,34 @@ static inline int __range_ok(unsigned long addr, unsigned long size)
#define access_ok(addr, size) __access_ok(addr, size)
+#define uaccess_opaque uaccess_opaque
+struct uaccess_opaque {
+ u8 key;
+};
+
unsigned long __must_check
-raw_copy_from_user(void *to, const void __user *from, unsigned long n);
+raw_copy_from_user_opaque(void *to, const void __user *from, unsigned long n,
+ struct uaccess_opaque opaque);
unsigned long __must_check
-raw_copy_to_user(void __user *to, const void *from, unsigned long n);
+raw_copy_to_user_opaque(void __user *to, const void *from, unsigned long n,
+ struct uaccess_opaque opaque);
+
+static __always_inline unsigned long __must_check
+raw_copy_from_user(void *to, const void __user *from, unsigned long n)
+{
+ struct uaccess_opaque opaque = { .key = 0};
+
+ return raw_copy_from_user_opaque(to, from, n, opaque);
+}
+
+static __always_inline unsigned long __must_check
+raw_copy_to_user(void __user *to, const void *from, unsigned long n)
+{
+ struct uaccess_opaque opaque = { .key = 0};
+
+ return raw_copy_to_user_opaque(to, from, n, opaque);
+}
#ifndef CONFIG_KASAN
#define INLINE_COPY_FROM_USER
diff --git a/arch/s390/lib/uaccess.c b/arch/s390/lib/uaccess.c
index d3a700385875..6446634c3b75 100644
--- a/arch/s390/lib/uaccess.c
+++ b/arch/s390/lib/uaccess.c
@@ -59,11 +59,13 @@ static inline int copy_with_mvcos(void)
#endif
static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr,
- unsigned long size)
+ unsigned long size, u8 key)
{
unsigned long tmp1, tmp2;
union oac spec = {
+ .oac2.key = key,
.oac2.as = PSW_BITS_AS_SECONDARY,
+ .oac2.k = 1,
.oac2.a = 1,
};
@@ -94,19 +96,19 @@ static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr
}
static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr,
- unsigned long size)
+ unsigned long size, u8 key)
{
unsigned long tmp1, tmp2;
tmp1 = -256UL;
asm volatile(
" sacf 0\n"
- "0: mvcp 0(%0,%2),0(%1),%3\n"
+ "0: mvcp 0(%0,%2),0(%1),%[key]\n"
"7: jz 5f\n"
"1: algr %0,%3\n"
" la %1,256(%1)\n"
" la %2,256(%2)\n"
- "2: mvcp 0(%0,%2),0(%1),%3\n"
+ "2: mvcp 0(%0,%2),0(%1),%[key]\n"
"8: jnz 1b\n"
" j 5f\n"
"3: la %4,255(%1)\n" /* %4 = ptr + 255 */
@@ -115,7 +117,7 @@ static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr,
" slgr %4,%1\n"
" clgr %0,%4\n" /* copy crosses next page boundary? */
" jnh 6f\n"
- "4: mvcp 0(%4,%2),0(%1),%3\n"
+ "4: mvcp 0(%4,%2),0(%1),%[key]\n"
"9: slgr %0,%4\n"
" j 6f\n"
"5: slgr %0,%0\n"
@@ -123,24 +125,31 @@ static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr,
EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
- : : "cc", "memory");
+ : [key] "d" (key << 4)
+ : "cc", "memory");
return size;
}
-unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n)
+unsigned long raw_copy_from_user_opaque(void *to, const void __user *from,
+ unsigned long n,
+ struct uaccess_opaque opaque)
{
+ u8 key = opaque.key;
+
if (copy_with_mvcos())
- return copy_from_user_mvcos(to, from, n);
- return copy_from_user_mvcp(to, from, n);
+ return copy_from_user_mvcos(to, from, n, key);
+ return copy_from_user_mvcp(to, from, n, key);
}
-EXPORT_SYMBOL(raw_copy_from_user);
+EXPORT_SYMBOL(raw_copy_from_user_opaque);
-static inline unsigned long copy_to_user_mvcos(void __user *ptr, const void *x,
- unsigned long size)
+inline unsigned long copy_to_user_mvcos(void __user *ptr, const void *x,
+ unsigned long size, u8 key)
{
unsigned long tmp1, tmp2;
union oac spec = {
+ .oac1.key = key,
.oac1.as = PSW_BITS_AS_SECONDARY,
+ .oac1.k = 1,
.oac1.a = 1,
};
@@ -171,19 +180,19 @@ static inline unsigned long copy_to_user_mvcos(void __user *ptr, const void *x,
}
static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x,
- unsigned long size)
+ unsigned long size, u8 key)
{
unsigned long tmp1, tmp2;
tmp1 = -256UL;
asm volatile(
" sacf 0\n"
- "0: mvcs 0(%0,%1),0(%2),%3\n"
+ "0: mvcs 0(%0,%1),0(%2),%[key]\n"
"7: jz 5f\n"
"1: algr %0,%3\n"
" la %1,256(%1)\n"
" la %2,256(%2)\n"
- "2: mvcs 0(%0,%1),0(%2),%3\n"
+ "2: mvcs 0(%0,%1),0(%2),%[key]\n"
"8: jnz 1b\n"
" j 5f\n"
"3: la %4,255(%1)\n" /* %4 = ptr + 255 */
@@ -192,7 +201,7 @@ static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x,
" slgr %4,%1\n"
" clgr %0,%4\n" /* copy crosses next page boundary? */
" jnh 6f\n"
- "4: mvcs 0(%4,%1),0(%2),%3\n"
+ "4: mvcs 0(%4,%1),0(%2),%[key]\n"
"9: slgr %0,%4\n"
" j 6f\n"
"5: slgr %0,%0\n"
@@ -200,17 +209,22 @@ static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x,
EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
- : : "cc", "memory");
+ : [key] "d" (key << 4)
+ : "cc", "memory");
return size;
}
-unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n)
+unsigned long raw_copy_to_user_opaque(void __user *to, const void *from,
+ unsigned long n,
+ struct uaccess_opaque opaque)
{
+ u8 key = opaque.key;
+
if (copy_with_mvcos())
- return copy_to_user_mvcos(to, from, n);
- return copy_to_user_mvcs(to, from, n);
+ return copy_to_user_mvcos(to, from, n, key);
+ return copy_to_user_mvcs(to, from, n, key);
}
-EXPORT_SYMBOL(raw_copy_to_user);
+EXPORT_SYMBOL(raw_copy_to_user_opaque);
static inline unsigned long clear_user_mvcos(void __user *to, unsigned long size)
{
--
2.32.0
Powered by blists - more mailing lists