[RFC][PATCHSET] uaccess: getting csum_and_copy_..._user() into saner shape

[RFC][PATCHSET] uaccess: getting csum_and_copy_..._user() into saner shape

[Al Viro]

        In that area uaccess primitives actually used by the rest of the kernel
are csum_and_copy_{to,from}_user().  Currently we have a strange mix;
        * some architectures supply csum_and_copy_from_user().  That's
indicated by defining _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
        * the rest end up using the wrapper from net/checksum.h instead;
that (fairly thin) wrapper expects to find csum_partial_copy_from_user().
Some among those have csum_partial_copy_from_user() that tries to be smart,
some end up picking a dumb one from lib/checksum.c, some have a literal
copy of that dumb version...
        * some architectures supply csum_and_copy_to_user().  Those define
HAVE_CSUM_COPY_USER.
        * the rest pick the dumb (inlined) implementation from net/checksum.h
        * to confuse the situation even more, there's a couple of architectures
that call their csum_and_copy_to_user() "csum_partial_copy_to_user" instead...
and have a macro defining csum_and_copy_to_user as csum_partial_copy_to_user.
        The rules for access_ok() location are also messy - in principle,
csum_partial_copy_from_user() expects to have access_ok() done in the wrapper,
but e.g. i386 one does that on its own.

        A saner approach would be to turn the csum_partial_copy_from_user()
instances into csum_and_copy_from_user() ones, getting rid of the wrapper
for those, then move the dumb one (also converted) into net/checksum.h.
The series below does that; it lives in
	git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git #next.uaccess-4
based at #next.uaccess-3.  Individual patches in followups; please review.
Not sure which tree would that best go through, TBH...

Diffstat:
 arch/alpha/include/asm/checksum.h    |  3 ++-
 arch/alpha/lib/csum_partial_copy.c   |  6 +++---
 arch/arm/include/asm/checksum.h      | 14 ++++++++++++++
 arch/c6x/lib/checksum.c              | 22 ----------------------
 arch/ia64/include/asm/checksum.h     | 10 ----------
 arch/ia64/lib/csum_partial_copy.c    | 32 ++------------------------------
 arch/m68k/include/asm/checksum.h     |  3 ++-
 arch/m68k/lib/checksum.c             |  4 ++--
 arch/nios2/include/asm/checksum.h    |  2 --
 arch/parisc/include/asm/checksum.h   |  7 -------
 arch/parisc/lib/checksum.c           | 20 --------------------
 arch/s390/include/asm/checksum.h     | 19 -------------------
 arch/sh/include/asm/checksum_32.h    |  9 +++++++--
 arch/sparc/include/asm/checksum.h    |  1 +
 arch/sparc/include/asm/checksum_32.h | 15 ++++++++++-----
 arch/sparc/include/asm/checksum_64.h |  2 +-
 arch/x86/include/asm/checksum.h      |  2 ++
 arch/x86/include/asm/checksum_32.h   | 21 +++++++++++----------
 arch/x86/include/asm/checksum_64.h   | 12 ++----------
 arch/x86/lib/csum-wrappers_64.c      | 35 ++++++++++++++++++-----------------
 arch/x86/um/asm/checksum.h           | 20 --------------------
 arch/xtensa/include/asm/checksum.h   | 11 +++++++----
 include/asm-generic/checksum.h       |  9 ---------
 include/net/checksum.h               |  8 ++------
 lib/checksum.c                       | 20 --------------------
 25 files changed, 86 insertions(+), 221 deletions(-)

Shortlog:
      get rid of csum_partial_copy_to_user()
      x86_64: csum_..._copy_..._user(): switch to unsafe_..._user()
      x86: switch both 32bit and 64bit to providing csum_and_copy_from_user()
      x86: switch 32bit csum_and_copy_to_user() to user_access_{begin,end}()
      ia64: csum_partial_copy_nocheck(): don't abuse csum_partial_copy_from_user()
      ia64: 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()
      parisc: turn csum_partial_copy_from_user() into csum_and_copy_from_user()
      sparc: switch to providing csum_and_copy_from_user()
      xtensa: switch to providing csum_and_copy_from_user()
      m68k: convert to csum_and_copy_from_user()
      sh32: convert to csum_and_copy_from_user()
      arm: switch to csum_and_copy_from_user()
      take the dummy csum_and_copy_from_user() into net/checksum.h

[RFC][PATCH 01/14] get rid of csum_partial_copy_to_user()

[Al Viro]

From: Al Viro <viro@zeniv.linux.org.uk>

For historical reasons some architectures call their csum_and_copy_to_user()
csum_partial_copy_to_user() instead (and supply a macro defining the
former as the latter).  That's the last remnants of old experiment that
went nowhere; time to bury them.  Rename those to csum_and_copy_to_user()
and get rid of the macros.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/sparc/include/asm/checksum_32.h | 7 +++----
 arch/x86/include/asm/checksum_64.h   | 4 +---
 arch/x86/lib/csum-wrappers_64.c      | 6 +++---
 3 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/arch/sparc/include/asm/checksum_32.h b/arch/sparc/include/asm/checksum_32.h
index 5fc98d80b03b..450ddfb444c8 100644
--- a/arch/sparc/include/asm/checksum_32.h
+++ b/arch/sparc/include/asm/checksum_32.h
@@ -83,8 +83,10 @@ csum_partial_copy_from_user(const void __user *src, void *dst, int len,
 	return (__force __wsum)ret;
 }
 
+#define HAVE_CSUM_COPY_USER
+
 static inline __wsum
-csum_partial_copy_to_user(const void *src, void __user *dst, int len,
+csum_and_copy_to_user(const void *src, void __user *dst, int len,
 			  __wsum sum, int *err)
 {
 	if (!access_ok(dst, len)) {
@@ -113,9 +115,6 @@ csum_partial_copy_to_user(const void *src, void __user *dst, int len,
 	}
 }
 
-#define HAVE_CSUM_COPY_USER
-#define csum_and_copy_to_user csum_partial_copy_to_user
-
 /* ihl is always 5 or greater, almost always is 5, and iph is word aligned
  * the majority of the time.
  */
diff --git a/arch/x86/include/asm/checksum_64.h b/arch/x86/include/asm/checksum_64.h
index 3ec6d3267cf9..ac9c06494827 100644
--- a/arch/x86/include/asm/checksum_64.h
+++ b/arch/x86/include/asm/checksum_64.h
@@ -141,13 +141,11 @@ extern __visible __wsum csum_partial_copy_generic(const void *src, const void *d
 
 extern __wsum csum_partial_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
 
 /**
diff --git a/arch/x86/lib/csum-wrappers_64.c b/arch/x86/lib/csum-wrappers_64.c
index c66c8b00f236..875c2f5968a0 100644
--- a/arch/x86/lib/csum-wrappers_64.c
+++ b/arch/x86/lib/csum-wrappers_64.c
@@ -71,7 +71,7 @@ csum_partial_copy_from_user(const void __user *src, void *dst,
 EXPORT_SYMBOL(csum_partial_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.
@@ -82,7 +82,7 @@ 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;
@@ -116,7 +116,7 @@ csum_partial_copy_to_user(const void *src, void __user *dst,
 	clac();
 	return ret;
 }
-EXPORT_SYMBOL(csum_partial_copy_to_user);
+EXPORT_SYMBOL(csum_and_copy_to_user);
 
 /**
  * csum_partial_copy_nocheck - Copy and checksum.
-- 
2.11.0

[RFC][PATCH 02/14] x86_64: csum_..._copy_..._user(): switch to unsafe_..._user()

[Al Viro]

From: Al Viro <viro@zeniv.linux.org.uk>

We already have stac/clac pair around the calls of csum_partial_copy_generic().
Stretch that area back, so that it covers the preceding loop (and convert
the loop body from __{get,put}_user() to unsafe_{get,put}_user()).
That brings the beginning of the areas to the earlier access_ok(),
which allows to convert them into user_access_{begin,end}() ones.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/x86/lib/csum-wrappers_64.c | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/arch/x86/lib/csum-wrappers_64.c b/arch/x86/lib/csum-wrappers_64.c
index 875c2f5968a0..90d02c82bb7a 100644
--- a/arch/x86/lib/csum-wrappers_64.c
+++ b/arch/x86/lib/csum-wrappers_64.c
@@ -27,7 +27,7 @@ csum_partial_copy_from_user(const void __user *src, void *dst,
 	might_sleep();
 	*errp = 0;
 
-	if (!likely(access_ok(src, len)))
+	if (!likely(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(
@@ -53,15 +52,16 @@ 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);
@@ -89,7 +89,7 @@ csum_and_copy_to_user(const void *src, void __user *dst,
 
 	might_sleep();
 
-	if (unlikely(!access_ok(dst, len))) {
+	if (unlikely(!user_access_begin(dst, len))) {
 		*errp = -EFAULT;
 		return 0;
 	}
@@ -100,9 +100,7 @@ csum_and_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;
@@ -110,11 +108,14 @@ csum_and_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_and_copy_to_user);
 
-- 
2.11.0

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

[Al Viro]

From: Al Viro <viro@zeniv.linux.org.uk>

... 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

[RFC][PATCH 04/14] x86: switch 32bit csum_and_copy_to_user() to user_access_{begin,end}()

[Al Viro]

From: Al Viro <viro@zeniv.linux.org.uk>

consolidate HAVE_CSUM_COPY_USER for 32bit and 64bit, while are at it

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/x86/include/asm/checksum.h    | 1 +
 arch/x86/include/asm/checksum_32.h | 6 ++----
 arch/x86/include/asm/checksum_64.h | 3 ---
 3 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/checksum.h b/arch/x86/include/asm/checksum.h
index 1ab9572ae4c2..0ada98d5d09f 100644
--- a/arch/x86/include/asm/checksum.h
+++ b/arch/x86/include/asm/checksum.h
@@ -1,5 +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 2487b7fc2d24..11624c8a9d8d 100644
--- a/arch/x86/include/asm/checksum_32.h
+++ b/arch/x86/include/asm/checksum_32.h
@@ -176,7 +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,
@@ -185,11 +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 2f8435542376..0a289b87e872 100644
--- a/arch/x86/include/asm/checksum_64.h
+++ b/arch/x86/include/asm/checksum_64.h
@@ -129,9 +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_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,
-- 
2.11.0

[RFC][PATCH 05/14] ia64: csum_partial_copy_nocheck(): don't abuse csum_partial_copy_from_user()

[Al Viro]

From: Al Viro <viro@zeniv.linux.org.uk>

Just inline the call and use memcpy() instead of __copy_from_user() and
note that the tail is precisely ia64 csum_partial().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/ia64/lib/csum_partial_copy.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/ia64/lib/csum_partial_copy.c b/arch/ia64/lib/csum_partial_copy.c
index bf9396b1ed32..9ab570d0f756 100644
--- a/arch/ia64/lib/csum_partial_copy.c
+++ b/arch/ia64/lib/csum_partial_copy.c
@@ -134,8 +134,8 @@ EXPORT_SYMBOL(csum_partial_copy_from_user);
 __wsum
 csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
 {
-	return csum_partial_copy_from_user((__force const void __user *)src,
-					   dst, len, sum, NULL);
+	memcpy(dst, src, len);
+	return csum_partial(dst, len, sum);
 }
 
 EXPORT_SYMBOL(csum_partial_copy_nocheck);
-- 
2.11.0

[RFC][PATCH 06/14] ia64: turn csum_partial_copy_from_user() into csum_and_copy_from_user()

[Al Viro]

From: Al Viro <viro@zeniv.linux.org.uk>

Just use copy_from_user() there, rather than relying upon the wrapper
to have done access_ok()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/ia64/include/asm/checksum.h  |  3 ++-
 arch/ia64/lib/csum_partial_copy.c | 18 ++++--------------
 2 files changed, 6 insertions(+), 15 deletions(-)

diff --git a/arch/ia64/include/asm/checksum.h b/arch/ia64/include/asm/checksum.h
index 0ed18bc3f6cf..279ea4dcee79 100644
--- a/arch/ia64/include/asm/checksum.h
+++ b/arch/ia64/include/asm/checksum.h
@@ -37,13 +37,14 @@ extern __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
  */
 extern __wsum csum_partial(const void *buff, int len, __wsum sum);
 
+#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
 /*
  * Same as csum_partial, but copies from src while it checksums.
  *
  * Here it is even more important to align src and dst on a 32-bit (or
  * even better 64-bit) boundary.
  */
-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 sum,
 						 int *errp);
 
diff --git a/arch/ia64/lib/csum_partial_copy.c b/arch/ia64/lib/csum_partial_copy.c
index 9ab570d0f756..ab59eb399900 100644
--- a/arch/ia64/lib/csum_partial_copy.c
+++ b/arch/ia64/lib/csum_partial_copy.c
@@ -103,33 +103,23 @@ unsigned long do_csum_c(const unsigned char * buff, int len, unsigned int psum)
  * This is very ugly but temporary. THIS NEEDS SERIOUS ENHANCEMENTS.
  * But it's very tricky to get right even in C.
  */
-extern unsigned long do_csum(const unsigned char *, long);
-
 __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 psum, int *errp)
 {
-	unsigned long result;
-
 	/* XXX Fixme
 	 * for now we separate the copy from checksum for obvious
 	 * alignment difficulties. Look at the Alpha code and you'll be
 	 * scared.
 	 */
 
-	if (__copy_from_user(dst, src, len) != 0 && errp)
+	if (copy_from_user(dst, src, len))
 		*errp = -EFAULT;
 
-	result = do_csum(dst, len);
-
-	/* add in old sum, and carry.. */
-	result += (__force u32)psum;
-	/* 32+c bits -> 32 bits */
-	result = (result & 0xffffffff) + (result >> 32);
-	return (__force __wsum)result;
+	return csum_partial(dst, len, psum);
 }
 
-EXPORT_SYMBOL(csum_partial_copy_from_user);
+EXPORT_SYMBOL(csum_and_copy_from_user);
 
 __wsum
 csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
-- 
2.11.0

[RFC][PATCH 07/14] alpha: turn csum_partial_copy_from_user() into csum_and_copy_from_user()

[Al Viro]

From: Al Viro <viro@zeniv.linux.org.uk>

It's already doing the right thing - it does access_ok() and the wrapper
in net/checksum.h is pointless here.  Just rename it and be done with that...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/alpha/include/asm/checksum.h  | 3 ++-
 arch/alpha/lib/csum_partial_copy.c | 6 +++---
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/alpha/include/asm/checksum.h b/arch/alpha/include/asm/checksum.h
index 473e6ccb65a3..0eac81624d01 100644
--- a/arch/alpha/include/asm/checksum.h
+++ b/arch/alpha/include/asm/checksum.h
@@ -41,7 +41,8 @@ extern __wsum csum_partial(const void *buff, int len, __wsum sum);
  * here even more important to align src and dst on a 32-bit (or even
  * better 64-bit) boundary
  */
-__wsum csum_partial_copy_from_user(const void __user *src, void *dst, int len, __wsum sum, int *errp);
+#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
+__wsum csum_and_copy_from_user(const void __user *src, void *dst, int len, __wsum sum, int *errp);
 
 __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum);
 
diff --git a/arch/alpha/lib/csum_partial_copy.c b/arch/alpha/lib/csum_partial_copy.c
index e53f96e8aa6d..af1dad74e933 100644
--- a/arch/alpha/lib/csum_partial_copy.c
+++ b/arch/alpha/lib/csum_partial_copy.c
@@ -325,7 +325,7 @@ csum_partial_cfu_unaligned(const unsigned long __user * src,
 }
 
 __wsum
-csum_partial_copy_from_user(const void __user *src, void *dst, int len,
+csum_and_copy_from_user(const void __user *src, void *dst, int len,
 			       __wsum sum, int *errp)
 {
 	unsigned long checksum = (__force u32) sum;
@@ -369,7 +369,7 @@ csum_partial_copy_from_user(const void __user *src, void *dst, int len,
 	}
 	return (__force __wsum)checksum;
 }
-EXPORT_SYMBOL(csum_partial_copy_from_user);
+EXPORT_SYMBOL(csum_and_copy_from_user);
 
 __wsum
 csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
@@ -377,7 +377,7 @@ csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
 	__wsum checksum;
 	mm_segment_t oldfs = get_fs();
 	set_fs(KERNEL_DS);
-	checksum = csum_partial_copy_from_user((__force const void __user *)src,
+	checksum = csum_and_copy_from_user((__force const void __user *)src,
 						dst, len, sum, NULL);
 	set_fs(oldfs);
 	return checksum;
-- 
2.11.0

[RFC][PATCH 08/14] parisc: turn csum_partial_copy_from_user() into csum_and_copy_from_user()

[Al Viro]

From: Al Viro <viro@zeniv.linux.org.uk>

Already has the right semantics.  Incidentally. failing copy_from_user()
zeroes the tail of destination - no need to repeat that manually

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/parisc/include/asm/checksum.h |  3 ++-
 arch/parisc/lib/checksum.c         | 12 +++---------
 2 files changed, 5 insertions(+), 10 deletions(-)

diff --git a/arch/parisc/include/asm/checksum.h b/arch/parisc/include/asm/checksum.h
index c1c22819a04d..7c69ce9634c7 100644
--- a/arch/parisc/include/asm/checksum.h
+++ b/arch/parisc/include/asm/checksum.h
@@ -26,11 +26,12 @@ extern __wsum csum_partial(const void *, int, __wsum);
  */
 extern __wsum csum_partial_copy_nocheck(const void *, void *, int, __wsum);
 
+#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
 /*
  * this is a new version of the above that records errors it finds in *errp,
  * but continues and zeros the rest of the buffer.
  */
-extern __wsum csum_partial_copy_from_user(const void __user *src,
+extern __wsum csum_and_copy_from_user(const void __user *src,
 		void *dst, int len, __wsum sum, int *errp);
 
 /*
diff --git a/arch/parisc/lib/checksum.c b/arch/parisc/lib/checksum.c
index 256322c7b648..4e47c2ff2bcd 100644
--- a/arch/parisc/lib/checksum.c
+++ b/arch/parisc/lib/checksum.c
@@ -128,18 +128,12 @@ EXPORT_SYMBOL(csum_partial_copy_nocheck);
  * Copy from userspace and compute checksum.  If we catch an exception
  * then zero the rest of the buffer.
  */
-__wsum csum_partial_copy_from_user(const void __user *src,
+__wsum csum_and_copy_from_user(const void __user *src,
 					void *dst, int len,
 					__wsum sum, int *err_ptr)
 {
-	int missing;
-
-	missing = copy_from_user(dst, src, len);
-	if (missing) {
-		memset(dst + len - missing, 0, missing);
+	if (copy_from_user(dst, src, len))
 		*err_ptr = -EFAULT;
-	}
-		
 	return csum_partial(dst, len, sum);
 }
-EXPORT_SYMBOL(csum_partial_copy_from_user);
+EXPORT_SYMBOL(csum_and_copy_from_user);
-- 
2.11.0

[RFC][PATCH 09/14] sparc: switch to providing csum_and_copy_from_user()

[Al Viro]

From: Al Viro <viro@zeniv.linux.org.uk>

sparc64 already is equivalent to that (trivial access_ok());
add it into sparc32 csum_partial_copy_from_user() and we can
rename both to csum_and_copy_fromUser() and be done with that.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/sparc/include/asm/checksum.h    | 1 +
 arch/sparc/include/asm/checksum_32.h | 8 +++++++-
 arch/sparc/include/asm/checksum_64.h | 2 +-
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/arch/sparc/include/asm/checksum.h b/arch/sparc/include/asm/checksum.h
index c3be56e2e768..a6256cb6fc5c 100644
--- a/arch/sparc/include/asm/checksum.h
+++ b/arch/sparc/include/asm/checksum.h
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 #ifndef ___ASM_SPARC_CHECKSUM_H
 #define ___ASM_SPARC_CHECKSUM_H
+#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
 #if defined(__sparc__) && defined(__arch64__)
 #include <asm/checksum_64.h>
 #else
diff --git a/arch/sparc/include/asm/checksum_32.h b/arch/sparc/include/asm/checksum_32.h
index 450ddfb444c8..479a0b812af5 100644
--- a/arch/sparc/include/asm/checksum_32.h
+++ b/arch/sparc/include/asm/checksum_32.h
@@ -60,7 +60,7 @@ csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
 }
 
 static inline __wsum
-csum_partial_copy_from_user(const void __user *src, void *dst, int len,
+csum_and_copy_from_user(const void __user *src, void *dst, int len,
 			    __wsum sum, int *err)
   {
 	register unsigned long ret asm("o0") = (unsigned long)src;
@@ -68,6 +68,12 @@ csum_partial_copy_from_user(const void __user *src, void *dst, int len,
 	register int l asm("g1") = len;
 	register __wsum s asm("g7") = sum;
 
+	if (unlikely(!access_ok(src, len))) {
+		if (len)
+			*err = -EFAULT;
+		return sum;
+	}
+
 	__asm__ __volatile__ (
 	".section __ex_table,#alloc\n\t"
 	".align 4\n\t"
diff --git a/arch/sparc/include/asm/checksum_64.h b/arch/sparc/include/asm/checksum_64.h
index e52450930e4e..0fa4433f5662 100644
--- a/arch/sparc/include/asm/checksum_64.h
+++ b/arch/sparc/include/asm/checksum_64.h
@@ -46,7 +46,7 @@ long __csum_partial_copy_from_user(const void __user *src,
 				   __wsum sum);
 
 static inline __wsum
-csum_partial_copy_from_user(const void __user *src,
+csum_and_copy_from_user(const void __user *src,
 			    void *dst, int len,
 			    __wsum sum, int *err)
 {
-- 
2.11.0

[RFC][PATCH 10/14] xtensa: switch to providing csum_and_copy_from_user()

[Al Viro]

From: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/xtensa/include/asm/checksum.h | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/arch/xtensa/include/asm/checksum.h b/arch/xtensa/include/asm/checksum.h
index 8b687176ad72..d8292cc9ebdf 100644
--- a/arch/xtensa/include/asm/checksum.h
+++ b/arch/xtensa/include/asm/checksum.h
@@ -44,8 +44,6 @@ asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst,
 /*
  *	Note: when you get a NULL pointer exception here this means someone
  *	passed in an incorrect kernel address to one of these functions.
- *
- *	If you use these functions directly please don't forget the access_ok().
  */
 static inline
 __wsum csum_partial_copy_nocheck(const void *src, void *dst,
@@ -54,12 +52,17 @@ __wsum csum_partial_copy_nocheck(const void *src, void *dst,
 	return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL);
 }
 
+#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
 static inline
-__wsum csum_partial_copy_from_user(const void __user *src, void *dst,
+__wsum csum_and_copy_from_user(const void __user *src, void *dst,
 				   int len, __wsum sum, int *err_ptr)
 {
-	return csum_partial_copy_generic((__force const void *)src, dst,
+	if (access_ok(dst, len))
+		return csum_partial_copy_generic((__force const void *)src, dst,
 					len, sum, err_ptr, NULL);
+	if (len)
+		*err_ptr = -EFAULT;
+	return sum;
 }
 
 /*
-- 
2.11.0

[RFC][PATCH 11/14] m68k: convert to csum_and_copy_from_user()

[Al Viro]

From: Al Viro <viro@zeniv.linux.org.uk>

trivial access_ok() there...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/m68k/include/asm/checksum.h | 3 ++-
 arch/m68k/lib/checksum.c         | 4 ++--
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/m68k/include/asm/checksum.h b/arch/m68k/include/asm/checksum.h
index f9b94e4b94f9..3f2c15d6f18c 100644
--- a/arch/m68k/include/asm/checksum.h
+++ b/arch/m68k/include/asm/checksum.h
@@ -30,7 +30,8 @@ __wsum csum_partial(const void *buff, int len, __wsum sum);
  * better 64-bit) boundary
  */
 
-extern __wsum csum_partial_copy_from_user(const void __user *src,
+#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
+extern __wsum csum_and_copy_from_user(const void __user *src,
 						void *dst,
 						int len, __wsum sum,
 						int *csum_err);
diff --git a/arch/m68k/lib/checksum.c b/arch/m68k/lib/checksum.c
index 5fa3d392e181..31797be9a3dc 100644
--- a/arch/m68k/lib/checksum.c
+++ b/arch/m68k/lib/checksum.c
@@ -129,7 +129,7 @@ EXPORT_SYMBOL(csum_partial);
  */
 
 __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 sum, int *csum_err)
 {
 	/*
@@ -316,7 +316,7 @@ csum_partial_copy_from_user(const void __user *src, void *dst,
 	return(sum);
 }
 
-EXPORT_SYMBOL(csum_partial_copy_from_user);
+EXPORT_SYMBOL(csum_and_copy_from_user);
 
 
 /*
-- 
2.11.0

[RFC][PATCH 12/14] sh32: convert to csum_and_copy_from_user()

[Al Viro]

From: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/sh/include/asm/checksum_32.h | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/sh/include/asm/checksum_32.h b/arch/sh/include/asm/checksum_32.h
index 36b84cfd3f67..91571a42e44e 100644
--- a/arch/sh/include/asm/checksum_32.h
+++ b/arch/sh/include/asm/checksum_32.h
@@ -48,12 +48,17 @@ __wsum csum_partial_copy_nocheck(const void *src, void *dst,
 	return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL);
 }
 
+#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
 static inline
-__wsum csum_partial_copy_from_user(const void __user *src, void *dst,
+__wsum csum_and_copy_from_user(const void __user *src, void *dst,
 				   int len, __wsum sum, int *err_ptr)
 {
-	return csum_partial_copy_generic((__force const void *)src, dst,
+	if (access_ok(src, len))
+		return csum_partial_copy_generic((__force const void *)src, dst,
 					len, sum, err_ptr, NULL);
+	if (len)
+		*err_ptr = -EFAULT;
+	return sum;
 }
 
 /*
-- 
2.11.0

[RFC][PATCH 13/14] arm: switch to csum_and_copy_from_user()

[Al Viro]

From: Al Viro <viro@zeniv.linux.org.uk>

Note that csum_partial_copy_from_user() is in assembler here,
so I'm leaving it alone and just providing the wrapper for
it.  When/if we go for switching arm to user_access_{begin,end}()
(doing domain switches in those), somebody well need to look
into that one.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/arm/include/asm/checksum.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/arch/arm/include/asm/checksum.h b/arch/arm/include/asm/checksum.h
index 20043e0ebb07..ed6073fee338 100644
--- a/arch/arm/include/asm/checksum.h
+++ b/arch/arm/include/asm/checksum.h
@@ -40,6 +40,20 @@ csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum);
 __wsum
 csum_partial_copy_from_user(const void __user *src, void *dst, int len, __wsum sum, int *err_ptr);
 
+#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
+static inline
+__wsum csum_and_copy_from_user (const void __user *src, void *dst,
+				      int len, __wsum sum, int *err_ptr)
+{
+	if (access_ok(src, len))
+		return csum_partial_copy_from_user(src, dst, len, sum, err_ptr);
+
+	if (len)
+		*err_ptr = -EFAULT;
+
+	return sum;
+}
+
 /*
  * 	Fold a partial checksum without adding pseudo headers
  */
-- 
2.11.0

[RFC][PATCH 14/14] take the dummy csum_and_copy_from_user() into net/checksum.h

[Al Viro]

From: Al Viro <viro@zeniv.linux.org.uk>

now that can be done conveniently - all non-trivial cases have
_HAVE_ARCH_COPY_AND_CSUM_FROM_USER defined, so the fallback in
net/checksum.h is used only for dummy (copy_from_user, then
csum_partial) implementation.  Allowing us to get rid of all
dummy instances, both of csum_and_copy_from_user() and
csum_partial_copy_from_user().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/c6x/lib/checksum.c            | 22 ----------------------
 arch/ia64/include/asm/checksum.h   | 11 -----------
 arch/ia64/lib/csum_partial_copy.c  | 18 ------------------
 arch/nios2/include/asm/checksum.h  |  2 --
 arch/parisc/include/asm/checksum.h |  8 --------
 arch/parisc/lib/checksum.c         | 14 --------------
 arch/s390/include/asm/checksum.h   | 19 -------------------
 arch/x86/um/asm/checksum.h         | 20 --------------------
 include/asm-generic/checksum.h     |  9 ---------
 include/net/checksum.h             |  8 ++------
 lib/checksum.c                     | 20 --------------------
 11 files changed, 2 insertions(+), 149 deletions(-)

diff --git a/arch/c6x/lib/checksum.c b/arch/c6x/lib/checksum.c
index 46940844c553..335ca4900808 100644
--- a/arch/c6x/lib/checksum.c
+++ b/arch/c6x/lib/checksum.c
@@ -4,28 +4,6 @@
 #include <linux/module.h>
 #include <net/checksum.h>
 
-#include <asm/byteorder.h>
-
-/*
- * copy from fs while checksumming, otherwise like csum_partial
- */
-__wsum
-csum_partial_copy_from_user(const void __user *src, void *dst, int len,
-			    __wsum sum, int *csum_err)
-{
-	int missing;
-
-	missing = __copy_from_user(dst, src, len);
-	if (missing) {
-		memset(dst + len - missing, 0, missing);
-		*csum_err = -EFAULT;
-	} else
-		*csum_err = 0;
-
-	return csum_partial(dst, len, sum);
-}
-EXPORT_SYMBOL(csum_partial_copy_from_user);
-
 /* These are from csum_64plus.S */
 EXPORT_SYMBOL(csum_partial);
 EXPORT_SYMBOL(csum_partial_copy);
diff --git a/arch/ia64/include/asm/checksum.h b/arch/ia64/include/asm/checksum.h
index 279ea4dcee79..2a1c64629cdc 100644
--- a/arch/ia64/include/asm/checksum.h
+++ b/arch/ia64/include/asm/checksum.h
@@ -37,17 +37,6 @@ extern __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
  */
 extern __wsum csum_partial(const void *buff, int len, __wsum sum);
 
-#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
-/*
- * Same as csum_partial, but copies from src while it checksums.
- *
- * Here it is even more important to align src and dst on a 32-bit (or
- * even better 64-bit) boundary.
- */
-extern __wsum csum_and_copy_from_user(const void __user *src, void *dst,
-						 int len, __wsum sum,
-						 int *errp);
-
 extern __wsum csum_partial_copy_nocheck(const void *src, void *dst,
 					       int len, __wsum sum);
 
diff --git a/arch/ia64/lib/csum_partial_copy.c b/arch/ia64/lib/csum_partial_copy.c
index ab59eb399900..5d147a33d648 100644
--- a/arch/ia64/lib/csum_partial_copy.c
+++ b/arch/ia64/lib/csum_partial_copy.c
@@ -104,24 +104,6 @@ unsigned long do_csum_c(const unsigned char * buff, int len, unsigned int psum)
  * But it's very tricky to get right even in C.
  */
 __wsum
-csum_and_copy_from_user(const void __user *src, void *dst,
-				int len, __wsum psum, int *errp)
-{
-	/* XXX Fixme
-	 * for now we separate the copy from checksum for obvious
-	 * alignment difficulties. Look at the Alpha code and you'll be
-	 * scared.
-	 */
-
-	if (copy_from_user(dst, src, len))
-		*errp = -EFAULT;
-
-	return csum_partial(dst, len, psum);
-}
-
-EXPORT_SYMBOL(csum_and_copy_from_user);
-
-__wsum
 csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
 {
 	memcpy(dst, src, len);
diff --git a/arch/nios2/include/asm/checksum.h b/arch/nios2/include/asm/checksum.h
index 703c5ee63421..ec39698d3bea 100644
--- a/arch/nios2/include/asm/checksum.h
+++ b/arch/nios2/include/asm/checksum.h
@@ -14,8 +14,6 @@
 extern __wsum csum_partial(const void *buff, int len, __wsum sum);
 extern __wsum csum_partial_copy(const void *src, void *dst, int len,
 				__wsum sum);
-extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
-					int len, __wsum sum, int *csum_err);
 #define csum_partial_copy_nocheck(src, dst, len, sum)	\
 	csum_partial_copy((src), (dst), (len), (sum))
 
diff --git a/arch/parisc/include/asm/checksum.h b/arch/parisc/include/asm/checksum.h
index 7c69ce9634c7..fe8c63b2d2c3 100644
--- a/arch/parisc/include/asm/checksum.h
+++ b/arch/parisc/include/asm/checksum.h
@@ -26,14 +26,6 @@ extern __wsum csum_partial(const void *, int, __wsum);
  */
 extern __wsum csum_partial_copy_nocheck(const void *, void *, int, __wsum);
 
-#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
-/*
- * this is a new version of the above that records errors it finds in *errp,
- * but continues and zeros the rest of the buffer.
- */
-extern __wsum csum_and_copy_from_user(const void __user *src,
-		void *dst, int len, __wsum sum, int *errp);
-
 /*
  *	Optimized for IP headers, which always checksum on 4 octet boundaries.
  *
diff --git a/arch/parisc/lib/checksum.c b/arch/parisc/lib/checksum.c
index 4e47c2ff2bcd..c6f161583549 100644
--- a/arch/parisc/lib/checksum.c
+++ b/arch/parisc/lib/checksum.c
@@ -123,17 +123,3 @@ __wsum csum_partial_copy_nocheck(const void *src, void *dst,
 	return sum;
 }
 EXPORT_SYMBOL(csum_partial_copy_nocheck);
-
-/*
- * Copy from userspace and compute checksum.  If we catch an exception
- * then zero the rest of the buffer.
- */
-__wsum csum_and_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 csum_partial(dst, len, sum);
-}
-EXPORT_SYMBOL(csum_and_copy_from_user);
diff --git a/arch/s390/include/asm/checksum.h b/arch/s390/include/asm/checksum.h
index 91e376b0d28c..6d01c96aeb5c 100644
--- a/arch/s390/include/asm/checksum.h
+++ b/arch/s390/include/asm/checksum.h
@@ -39,25 +39,6 @@ csum_partial(const void *buff, int len, __wsum sum)
 	return sum;
 }
 
-/*
- * the same as csum_partial_copy, but copies from user space.
- *
- * here even more important to align src and dst on a 32-bit (or even
- * better 64-bit) boundary
- *
- * Copy from userspace and compute checksum.
- */
-static inline __wsum
-csum_partial_copy_from_user(const void __user *src, void *dst,
-                                          int len, __wsum sum,
-                                          int *err_ptr)
-{
-	if (unlikely(copy_from_user(dst, src, len)))
-		*err_ptr = -EFAULT;
-	return csum_partial(dst, len, sum);
-}
-
-
 static inline __wsum
 csum_partial_copy_nocheck (const void *src, void *dst, int len, __wsum sum)
 {
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
diff --git a/include/asm-generic/checksum.h b/include/asm-generic/checksum.h
index 34785c0f57b0..5a80f8e54300 100644
--- a/include/asm-generic/checksum.h
+++ b/include/asm-generic/checksum.h
@@ -25,15 +25,6 @@ extern __wsum csum_partial(const void *buff, int len, __wsum sum);
  */
 extern __wsum csum_partial_copy(const void *src, void *dst, int len, __wsum sum);
 
-/*
- * the same as csum_partial_copy, but copies from user space.
- *
- * here even more important to align src and dst on a 32-bit (or even
- * better 64-bit) boundary
- */
-extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
-					int len, __wsum sum, int *csum_err);
-
 #ifndef csum_partial_copy_nocheck
 #define csum_partial_copy_nocheck(src, dst, len, sum)	\
 	csum_partial_copy((src), (dst), (len), (sum))
diff --git a/include/net/checksum.h b/include/net/checksum.h
index 97bf4885a962..5f9c73c0eeb9 100644
--- a/include/net/checksum.h
+++ b/include/net/checksum.h
@@ -26,13 +26,9 @@ static inline
 __wsum csum_and_copy_from_user (const void __user *src, void *dst,
 				      int len, __wsum sum, int *err_ptr)
 {
-	if (access_ok(src, len))
-		return csum_partial_copy_from_user(src, dst, len, sum, err_ptr);
-
-	if (len)
+	if (copy_from_user(dst, src, len))
 		*err_ptr = -EFAULT;
-
-	return sum;
+	return csum_partial(dst, len, sum);
 }
 #endif
 
diff --git a/lib/checksum.c b/lib/checksum.c
index de032ad96f4a..7ac65a0000ff 100644
--- a/lib/checksum.c
+++ b/lib/checksum.c
@@ -146,26 +146,6 @@ __sum16 ip_compute_csum(const void *buff, int len)
 EXPORT_SYMBOL(ip_compute_csum);
 
 /*
- * copy from fs while checksumming, otherwise like csum_partial
- */
-__wsum
-csum_partial_copy_from_user(const void __user *src, void *dst, int len,
-						__wsum sum, int *csum_err)
-{
-	int missing;
-
-	missing = __copy_from_user(dst, src, len);
-	if (missing) {
-		memset(dst + len - missing, 0, missing);
-		*csum_err = -EFAULT;
-	} else
-		*csum_err = 0;
-
-	return csum_partial(dst, len, sum);
-}
-EXPORT_SYMBOL(csum_partial_copy_from_user);
-
-/*
  * copy from ds while checksumming, otherwise like csum_partial
  */
 __wsum
-- 
2.11.0

Re: [RFC][PATCH 05/14] ia64: csum_partial_copy_nocheck(): don't abuse csum_partial_copy_from_user()

[Guenter Roeck]

On Fri, Mar 27, 2020 at 11:31:08PM +0000, Al Viro wrote:
> From: Al Viro <viro@zeniv.linux.org.uk>
> 
> Just inline the call and use memcpy() instead of __copy_from_user() and
> note that the tail is precisely ia64 csum_partial().
> 
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

This patch results in:

arch/ia64/lib/csum_partial_copy.c: In function 'csum_partial_copy_nocheck':
arch/ia64/lib/csum_partial_copy.c:110:9: error: implicit declaration of function 'csum_partial'

for ia64:{defconfig, allnoconfig, tinyconfig}.

Guenter

---
# bad: [d6f9469a03d832dcd17041ed67774ffb5f3e73b3] Merge tag 'erofs-for-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs
# good: [b23c4771ff62de8ca9b5e4a2d64491b2fb6f8f69] Merge tag 'docs-5.8' of git://git.lwn.net/linux
git bisect start 'HEAD' 'b23c4771ff62'
# good: [6cf991611bc72c077f0cc64e23987341ad7ef41e] Merge tag 'drm-intel-next-2020-05-15' of git://anongit.freedesktop.org/drm/drm-intel into drm-next
git bisect good 6cf991611bc72c077f0cc64e23987341ad7ef41e
# bad: [faa392181a0bd42c5478175cef601adeecdc91b6] Merge tag 'drm-next-2020-06-02' of git://anongit.freedesktop.org/drm/drm
git bisect bad faa392181a0bd42c5478175cef601adeecdc91b6
# bad: [c5d6c13843880ad0112f0513f3eb041b258be66e] Merge tag 'mmc-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc
git bisect bad c5d6c13843880ad0112f0513f3eb041b258be66e
# bad: [94709049fb8442fb2f7b91fbec3c2897a75e18df] Merge branch 'akpm' (patches from Andrew)
git bisect bad 94709049fb8442fb2f7b91fbec3c2897a75e18df
# good: [a29adb6209cead1f6c34a8d72481fb183bfc2d68] mm: rename vmap_page_range to map_kernel_range
git bisect good a29adb6209cead1f6c34a8d72481fb183bfc2d68
# bad: [56446efab9ce4961fe0fe6bbc5bc66374b08b9f3] Merge branch 'uaccess.__copy_from_user' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
git bisect bad 56446efab9ce4961fe0fe6bbc5bc66374b08b9f3
# good: [87c233b8158a20a9c9ab1da96cb5cb1734d9006e] vmci_host: get rid of pointless access_ok()
git bisect good 87c233b8158a20a9c9ab1da96cb5cb1734d9006e
# bad: [001c1a655f0a4e4ebe5d9beb47466dc5c6ab4871] default csum_and_copy_to_user(): don't bother with access_ok()
git bisect bad 001c1a655f0a4e4ebe5d9beb47466dc5c6ab4871
# bad: [808b49da54e640cba5c5c92dee658018a529226b] alpha: turn csum_partial_copy_from_user() into csum_and_copy_from_user()
git bisect bad 808b49da54e640cba5c5c92dee658018a529226b
# good: [0a5ea224b2fdf9dca9291ef7b5a12fd846a5dc34] x86: switch both 32bit and 64bit to providing csum_and_copy_from_user()
git bisect good 0a5ea224b2fdf9dca9291ef7b5a12fd846a5dc34
# bad: [cc03f19cfd45f44a75f0445c5be0073bbd3dda1c] ia64: csum_partial_copy_nocheck(): don't abuse csum_partial_copy_from_user()
git bisect bad cc03f19cfd45f44a75f0445c5be0073bbd3dda1c
# good: [c281a6c1ac6b0867e4341ea801030fa9a62157f9] x86: switch 32bit csum_and_copy_to_user() to user_access_{begin,end}()
git bisect good c281a6c1ac6b0867e4341ea801030fa9a62157f9
# first bad commit: [cc03f19cfd45f44a75f0445c5be0073bbd3dda1c] ia64: csum_partial_copy_nocheck(): don't abuse csum_partial_copy_from_user()

Re: [RFC][PATCH 05/14] ia64: csum_partial_copy_nocheck(): don't abuse csum_partial_copy_from_user()

[Al Viro]

On Wed, Jun 03, 2020 at 08:37:14AM -0700, Guenter Roeck wrote:
> On Fri, Mar 27, 2020 at 11:31:08PM +0000, Al Viro wrote:
> > From: Al Viro <viro@zeniv.linux.org.uk>
> > 
> > Just inline the call and use memcpy() instead of __copy_from_user() and
> > note that the tail is precisely ia64 csum_partial().
> > 
> > Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
> 
> This patch results in:
> 
> arch/ia64/lib/csum_partial_copy.c: In function 'csum_partial_copy_nocheck':
> arch/ia64/lib/csum_partial_copy.c:110:9: error: implicit declaration of function 'csum_partial'
> 
> for ia64:{defconfig, allnoconfig, tinyconfig}.

Argh...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
diff --git a/arch/ia64/lib/csum_partial_copy.c b/arch/ia64/lib/csum_partial_copy.c
index 5d147a33d648..6e82e0be8040 100644
--- a/arch/ia64/lib/csum_partial_copy.c
+++ b/arch/ia64/lib/csum_partial_copy.c
@@ -12,7 +12,7 @@
 #include <linux/types.h>
 #include <linux/string.h>
 
-#include <linux/uaccess.h>
+#include <net/checksum.h>
 
 /*
  * XXX Fixme: those 2 inlines are meant for debugging and will go away

Re: [RFC][PATCH 05/14] ia64: csum_partial_copy_nocheck(): don't abuse csum_partial_copy_from_user()

[Guenter Roeck]

On Wed, Jun 03, 2020 at 08:10:38PM +0100, Al Viro wrote:
> On Wed, Jun 03, 2020 at 08:37:14AM -0700, Guenter Roeck wrote:
> > On Fri, Mar 27, 2020 at 11:31:08PM +0000, Al Viro wrote:
> > > From: Al Viro <viro@zeniv.linux.org.uk>
> > > 
> > > Just inline the call and use memcpy() instead of __copy_from_user() and
> > > note that the tail is precisely ia64 csum_partial().
> > > 
> > > Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
> > 
> > This patch results in:
> > 
> > arch/ia64/lib/csum_partial_copy.c: In function 'csum_partial_copy_nocheck':
> > arch/ia64/lib/csum_partial_copy.c:110:9: error: implicit declaration of function 'csum_partial'
> > 
> > for ia64:{defconfig, allnoconfig, tinyconfig}.
> 
> Argh...
> 
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Yes, that does the trick.

Tested-by: Guenter Roeck <linux@roeck-us.net>

> ---
> diff --git a/arch/ia64/lib/csum_partial_copy.c b/arch/ia64/lib/csum_partial_copy.c
> index 5d147a33d648..6e82e0be8040 100644
> --- a/arch/ia64/lib/csum_partial_copy.c
> +++ b/arch/ia64/lib/csum_partial_copy.c
> @@ -12,7 +12,7 @@
>  #include <linux/types.h>
>  #include <linux/string.h>
>  
> -#include <linux/uaccess.h>
> +#include <net/checksum.h>
>  
>  /*
>   * XXX Fixme: those 2 inlines are meant for debugging and will go away