[RFC][PATCH 03/14] x86: switch both 32bit and 64bit to providing csum_and_copy_from_user()

Al Viro
2020-03-27T23:31:21Z

... rather than messing with the wrapper. As a side effect,
32bit variant gets access_ok() into it and can be switched to
user_access_begin()/user_access_end()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
arch/x86/include/asm/checksum.h | 1 +
arch/x86/include/asm/checksum_32.h | 15 +++++++++------
arch/x86/include/asm/checksum_64.h | 5 +----
arch/x86/lib/csum-wrappers_64.c | 6 +++---
4 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/arch/x86/include/asm/checksum.h b/arch/x86/include/asm/checksum.h
index d79d1e622dcf..1ab9572ae4c2 100644
--- a/arch/x86/include/asm/checksum.h
+++ b/arch/x86/include/asm/checksum.h
@@ -1,4 +1,5 @@
/* SPDX-License-Identifier: GPL-2.0 */
+#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER 1
#ifdef CONFIG_X86_32
# include <asm/checksum_32.h>
#else
diff --git a/arch/x86/include/asm/checksum_32.h b/arch/x86/include/asm/checksum_32.h
index f57b94e02c57..2487b7fc2d24 100644
--- a/arch/x86/include/asm/checksum_32.h
+++ b/arch/x86/include/asm/checksum_32.h
@@ -44,18 +44,21 @@ static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst,
return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL);
}

-static inline __wsum csum_partial_copy_from_user(const void __user *src,
- void *dst,
- int len, __wsum sum,
- int *err_ptr)
+static inline __wsum csum_and_copy_from_user(const void __user *src,
+ void *dst, int len,
+ __wsum sum, int *err_ptr)
{
__wsum ret;

might_sleep();
- stac();
+ if (!user_access_begin(src, len)) {
+ if (len)
+ *err_ptr = -EFAULT;
+ return sum;
+ }
ret = csum_partial_copy_generic((__force void *)src, dst,
len, sum, err_ptr, NULL);
- clac();
+ user_access_end();

return ret;
}
diff --git a/arch/x86/include/asm/checksum_64.h b/arch/x86/include/asm/checksum_64.h
index ac9c06494827..2f8435542376 100644
--- a/arch/x86/include/asm/checksum_64.h
+++ b/arch/x86/include/asm/checksum_64.h
@@ -129,7 +129,6 @@ static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
*/
extern __wsum csum_partial(const void *buff, int len, __wsum sum);

-#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER 1
#define HAVE_CSUM_COPY_USER 1

@@ -139,15 +138,13 @@ extern __visible __wsum csum_partial_copy_generic(const void *src, const void *d
int *src_err_ptr, int *dst_err_ptr);

-extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
+extern __wsum csum_and_copy_from_user(const void __user *src, void *dst,
int len, __wsum isum, int *errp);
extern __wsum csum_and_copy_to_user(const void *src, void __user *dst,
int len, __wsum isum, int *errp);
extern __wsum csum_partial_copy_nocheck(const void *src, void *dst,
int len, __wsum sum);

-#define csum_and_copy_from_user csum_partial_copy_from_user
-
/**
* ip_compute_csum - Compute an 16bit IP checksum.
* @buff: buffer address.
diff --git a/arch/x86/lib/csum-wrappers_64.c b/arch/x86/lib/csum-wrappers_64.c
index 90d02c82bb7a..a12b8629206d 100644
--- a/arch/x86/lib/csum-wrappers_64.c
+++ b/arch/x86/lib/csum-wrappers_64.c
@@ -10,7 +10,7 @@
#include <asm/smap.h>

/**
- * csum_partial_copy_from_user - Copy and checksum from user space.
+ * csum_and_copy_from_user - Copy and checksum from user space.
* @src: source address (user space)
* @dst: destination address
* @len: number of bytes to be copied.
@@ -21,7 +21,7 @@
* src and dst are best aligned to 64bits.
*/
__wsum
-csum_partial_copy_from_user(const void __user *src, void *dst,
+csum_and_copy_from_user(const void __user *src, void *dst,
int len, __wsum isum, int *errp)
{
might_sleep();
@@ -68,7 +68,7 @@ csum_partial_copy_from_user(const void __user *src, void *dst,

return isum;
}
-EXPORT_SYMBOL(csum_partial_copy_from_user);
+EXPORT_SYMBOL(csum_and_copy_from_user);

/**
* csum_and_copy_to_user - Copy and checksum to user space.
--
2.11.0