Merge branch 'uaccess.csum' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull uaccess/csum updates from Al Viro:
 "Regularize the sitation with uaccess checksum primitives:

   - fold csum_partial_... into csum_and_copy_..._user()

   - on x86 collapse several access_ok()/stac()/clac() into
     user_access_begin()/user_access_end()"

* 'uaccess.csum' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  default csum_and_copy_to_user(): don't bother with access_ok()
  take the dummy csum_and_copy_from_user() into net/checksum.h
  arm: switch to csum_and_copy_from_user()
  sh32: convert to csum_and_copy_from_user()
  m68k: convert to csum_and_copy_from_user()
  xtensa: switch to providing csum_and_copy_from_user()
  sparc: switch to providing csum_and_copy_from_user()
  parisc: turn csum_partial_copy_from_user() into csum_and_copy_from_user()
  alpha: turn csum_partial_copy_from_user() into csum_and_copy_from_user()
  ia64: turn csum_partial_copy_from_user() into csum_and_copy_from_user()
  ia64: csum_partial_copy_nocheck(): don't abuse csum_partial_copy_from_user()
  x86: switch 32bit csum_and_copy_to_user() to user_access_{begin,end}()
  x86: switch both 32bit and 64bit to providing csum_and_copy_from_user()
  x86_64: csum_..._copy_..._user(): switch to unsafe_..._user()
  get rid of csum_partial_copy_to_user()

5 files changed, 33 insertions, 57 deletions

diff --git a/arch/x86/include/asm/checksum.h b/arch/x86/include/asm/checksum.h
index d79d1e622dcf..0ada98d5d09f 100644
--- a/arch/x86/include/asm/checksum.h
+++ b/arch/x86/include/asm/checksum.h
@@ -1,4 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0 */
+#define  _HAVE_ARCH_COPY_AND_CSUM_FROM_USER 1
+#define HAVE_CSUM_COPY_USER
 #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..11624c8a9d8d 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;
 }
@@ -173,7 +176,6 @@ static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 /*
  *	Copy and checksum to user
  */
-#define HAVE_CSUM_COPY_USER
 static inline __wsum csum_and_copy_to_user(const void *src,
 					   void __user *dst,
 					   int len, __wsum sum,
@@ -182,11 +184,10 @@ static inline __wsum csum_and_copy_to_user(const void *src,
 	__wsum ret;
 
 	might_sleep();
-	if (access_ok(dst, len)) {
-		stac();
+	if (user_access_begin(dst, len)) {
 		ret = csum_partial_copy_generic(src, (__force void *)dst,
 						len, sum, NULL, err_ptr);
-		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 3ec6d3267cf9..0a289b87e872 100644
--- a/arch/x86/include/asm/checksum_64.h
+++ b/arch/x86/include/asm/checksum_64.h
@@ -129,27 +129,19 @@ 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
-
-
 /* Do not call this directly. Use the wrappers below */
 extern __visible __wsum csum_partial_copy_generic(const void *src, const void *dst,
 					int len, __wsum sum,
 					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_partial_copy_to_user(const void *src, void __user *dst,
+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);
 
-/* Old names. To be removed. */
-#define csum_and_copy_to_user csum_partial_copy_to_user
-#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 c66c8b00f236..ee63d7576fd2 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.
@@ -21,13 +21,13 @@
  * 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();
 	*errp = 0;
 
-	if (!likely(access_ok(src, len)))
+	if (!user_access_begin(src, len))
 		goto out_err;
 
 	/*
@@ -42,8 +42,7 @@ csum_partial_copy_from_user(const void __user *src, void *dst,
 		while (((unsigned long)src & 6) && len >= 2) {
 			__u16 val16;
 
-			if (__get_user(val16, (const __u16 __user *)src))
-				goto out_err;
+			unsafe_get_user(val16, (const __u16 __user *)src, out);
 
 			*(__u16 *)dst = val16;
 			isum = (__force __wsum)add32_with_carry(
@@ -53,25 +52,26 @@ csum_partial_copy_from_user(const void __user *src, void *dst,
 			len -= 2;
 		}
 	}
-	stac();
 	isum = csum_partial_copy_generic((__force const void *)src,
 				dst, len, isum, errp, NULL);
-	clac();
+	user_access_end();
 	if (unlikely(*errp))
 		goto out_err;
 
 	return isum;
 
+out:
+	user_access_end();
 out_err:
 	*errp = -EFAULT;
 	memset(dst, 0, len);
 
 	return isum;
 }
-EXPORT_SYMBOL(csum_partial_copy_from_user);
+EXPORT_SYMBOL(csum_and_copy_from_user);
 
 /**
- * csum_partial_copy_to_user - Copy and checksum to user space.
+ * csum_and_copy_to_user - Copy and checksum to user space.
  * @src: source address
  * @dst: destination address (user space)
  * @len: number of bytes to be copied.
@@ -82,14 +82,14 @@ EXPORT_SYMBOL(csum_partial_copy_from_user);
  * src and dst are best aligned to 64bits.
  */
 __wsum
-csum_partial_copy_to_user(const void *src, void __user *dst,
+csum_and_copy_to_user(const void *src, void __user *dst,
 			  int len, __wsum isum, int *errp)
 {
 	__wsum ret;
 
 	might_sleep();
 
-	if (unlikely(!access_ok(dst, len))) {
+	if (!user_access_begin(dst, len)) {
 		*errp = -EFAULT;
 		return 0;
 	}
@@ -100,9 +100,7 @@ csum_partial_copy_to_user(const void *src, void __user *dst,
 
 			isum = (__force __wsum)add32_with_carry(
 					(__force unsigned)isum, val16);
-			*errp = __put_user(val16, (__u16 __user *)dst);
-			if (*errp)
-				return isum;
+			unsafe_put_user(val16, (__u16 __user *)dst, out);
 			src += 2;
 			dst += 2;
 			len -= 2;
@@ -110,13 +108,16 @@ csum_partial_copy_to_user(const void *src, void __user *dst,
 	}
 
 	*errp = 0;
-	stac();
 	ret = csum_partial_copy_generic(src, (void __force *)dst,
 					len, isum, NULL, errp);
-	clac();
+	user_access_end();
 	return ret;
+out:
+	user_access_end();
+	*errp = -EFAULT;
+	return isum;
 }
-EXPORT_SYMBOL(csum_partial_copy_to_user);
+EXPORT_SYMBOL(csum_and_copy_to_user);
 
 /**
  * csum_partial_copy_nocheck - Copy and checksum.
diff --git a/arch/x86/um/asm/checksum.h b/arch/x86/um/asm/checksum.h
index 2a56cac64687..ff6bba2c8ab6 100644
--- a/arch/x86/um/asm/checksum.h
+++ b/arch/x86/um/asm/checksum.h
@@ -36,26 +36,6 @@ __wsum csum_partial_copy_nocheck(const void *src, void *dst,
 	return csum_partial(dst, len, sum);
 }
 
-/*
- * the same as csum_partial, but copies from src while it
- * checksums, and handles user-space pointer exceptions correctly, when needed.
- *
- * here even more important to align src and dst on a 32-bit (or even
- * better 64-bit) boundary
- */
-
-static __inline__
-__wsum csum_partial_copy_from_user(const void __user *src, void *dst,
-					 int len, __wsum sum, int *err_ptr)
-{
-	if (copy_from_user(dst, src, len)) {
-		*err_ptr = -EFAULT;
-		return (__force __wsum)-1;
-	}
-
-	return csum_partial(dst, len, sum);
-}
-
 /**
  * csum_fold - Fold and invert a 32bit checksum.
  * sum: 32bit unfolded sum